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S550 Vorshlag 2015 Mustang GT Road Race Build #TRIGGER Build Thread Profile - S550 Mustangs


Go Big or Go Home
Supporting Vendor
Plano, TX
Quick update: Our sales exploded at the beginning of the pandemic and hasn't stopped, and the shop is overfull with customer cars. We also bought another CNC machine and moved an older/slower unit to my other shop during the Fall. This has tied up ALL of my free time to update project build thread.


Here's a tease of where we are on #Trigger here...


The wildly over-sized (for this little LS engine) dual 3.5" exhaust is completed, ceramic coated, and installed.


We haven't had time to make the rear "heat shields" and we might change this to be able to vent the hood, as we have a giant diff cooler going in there next.


Speaking of coolers - the largest engine oil cooler Derale makes is mounted in front of the giant Howe rolled radiator. And all of the oil and fuel systems are fully plumbed.


The calcs showing air flow / power / filter size pushed us to this giant K&N dry unit + 4.5" ID tubing. We adapted up from the 102mm throttle body (4.25") to this 4.5" size.


Making the cold air was relatively easy and it will be fed from the corner of the upper grill.


Making the cold air filter box was tricky but it bolts in cleanly and keeps hot air from getting to the filter.


We have most of the car wired and plumbed now, only lack about 40-50 hours of work to fire it up and get it on track. Customers' cars come first so we can only attack this in fits and spurts.

More soon!


Go Big or Go Home
Supporting Vendor
Plano, TX
Project Update for April 18th, 2022: Another long break between forum thread posts (Sept '21 to April '22) comes from more of the same reasons - overwhelming parts sales and a very busy shop. Some customer cars have wrapped up and left and a few more are about to go, so we're working on our LS550 project more often of late. If we didn't have 6 paying customer builds going on and a record shattering volume of orders, then this Mustang could have been built in about 4-6 months. But "everyone good is busy", and we have been so very busy.


Since my last post (September '21) we have completed the exhaust system (and ceramic coated that), built the cold air inlet and filter box, added a massive oil cooler, added the Radium surge tank, plumbed the oil system underhood, plumbed the fuel system underhood and to the back, plumbed the fuel system and vent in the trunk, added a massive differential oil cooler & plumbed that, added an electric fan to the radiator, remote mounted the coils and wired those, plumbed the radiator, mounted the strut reservoirs, added the pressure sensor and solenoid for the Accusump, modified the front grills, improved the upper radiator mount, added a second front tow hook, cut out the rear speaker deck, built a firewall for the trunk, installed a remoter latch release for the carbon trunk, installed an Optima battery and box into the trunk, then added a remote coolant reservoir, added a heater core under the dash and plumbed the heater hoses to all of that.


As usual there is a good bit of detail on each task below - but I am still going to cover the last 7 months of work below. We are very close to starting the engine and driving this car as I write this - by the next update we should have fired it up and hopefully be on track. Lots to cover so we better get started!


From August to September of '21 our engineer / fabricator Zach (below right) built this crazy exhaust system, and it is a thing of beauty. Stuffing two GIANT mufflers in the trunk and routing two 3.5" diameter tubes around all manner of things, having good ground clearance, and getting it to look good took a lot of math, patience, and talent.


I made the requirements for this very custom exhaust even more complicated by insisting that Zach route these massive mandrel bends to an improbably challenging exhaust outlet location - the rear bumper cover.


I also wanted the mufflers to be symmetrical and "look pretty" when you open the trunk. And I wanted V-band clamps at various points along the way to make maintenance easy while removing any exhaust leaks. Oh, and mount everything with high temp silicone bushings with 100% stainless steel brackets.


Many have wondered at my sanity for this system - why spend 50+ hours to hang a pair of mufflers and exhaust through the rear bumper cover? Well maybe the pictures below will explain what I have in mind for the future...


The future plans for this car include a large rear diffuser - maybe now you can see why I had Zach go to so much trouble? The LARGE mufflers are also done to cancel out NOISE while allowing enough exhaust flow for a 1200 hp engine. Tucking them up at an angle allows these massive things to fit while making room for the diffuser down the road.


Some pretty terrible atrocities had to be done to the rear trunk to pass the giant 3.5" diameter tubing through here, and there's a curved bend there as well. Lots of fiddling to get the tips angled the same, making mounts, etc.


Zach left us in September of '21 for a fabulous job at Rivian, so our engineer / CNC operator Myles (above left) did the final TIG welding on this. Again, lots of patience and skill was needed, as well as a temporary structure to keep the two pipes from twisting. This went in and out of the car several times to check fit while Myles fully seam welded the exhaust tubes - which is made up of a lot of mandrel stainless bends.


By November of '21 the exhaust system was fully ceramic coated and polished, but Myles had left us for a fantastic DoD job (he still stops by for consulting help from time to time). So Doug (our new fabricator / tech) and Brad installed the finished exhaust on the Mustang.


I have dozens more pictures of this exhaust, and it is by far the nicest, largest, and wildest one we have built in 17 years of building cars here. I really cannot wait to hear what it sounds like when we fire it up! I have the same muffler on my built LS powered '00 Silverado and it sounds really good, but with 500+ whp and screaming around track at 7000 rpm, it should sound pretty amazing. With 1200 hp at 8500 would be something unworldly...


This is a minor task but one we recommend - covering the lower front opening of the bellhousing with this Canton plate.


Of course the Canton part didn't fit and needed some cutting, but that could be due to our non-OEM oil pan we're using. Regardless, we wanted to keep this area covered up so dirt, water, and debris cannot get into the bellhousing.


Just a minor thing but it is often overlooked, and getting this aluminum cover plate is very low cost. I have included the part number (21-870) so that others can buy this.


We started on the fuel system already with the fuel rails, and we will tackle the trunk / fuel tank / surge tank lines in another task. For now we needed to run the big lines from the front to back.


For various reasons I prefer to do the long runs of fuel lines with aluminum hard lines. I like running them UNDER the car but ABOVE the bottom of the lowest parts of the car (frame rails) so they cannot get snagged and ripped away in an off track incident. It isn't the ONLY way to run fuel lines, it is just the safest way that we have adopted on many cars. The OEMs also tend to run hard lines for long fuel runs - either metal or plastic. Of course plastic has so many downsides...


This aluminum tubing is bought in a roll, then straightened, then bent to fit the long runs, and finally flared at the ends for the fittings. We always build these to terminate and transition to flexible lines at bulkhead panels at both ends. Above are the two bulkhead panels built for the rear (top left) and at the front engine bay (top right).


The rear bulkhead on our LS550 is placed at a convenient spot near the fuel tank/trunk area, above left. For this build we chose larger than normal hard line sizes: the feed line is a -10 or 5/8" diameter, and the return is a -8 or 1/2" line. Normally on a ~500 whp engine like we have in Phase 1 we'd use a -8 and -6 lines, so we're up TWO sizes. This is to build for a Phase 2 engine, and this fuel system could support about 1200 hp.


In the engine bay we have a bulkhead connect panel in the back left corner of the engine bay (above left), right under the brake booster. I missed getting that picture after Doug installed it from the inside, and it is really hard to see now (above right) because there's a lot going on back here. We have three fuel lines (the main feed, the return, and a regulated line to the fuel rail), the Aeromotive fuel pressure regulator, and giant -12 oil lines snake around all of this as well. As big as this engine bay is, I really had trouble laying out a "clean" placement of everything on this side. But for now, this will do.


At this point we had all of the major components mounted under the hood. The engine was in place, the Accusump, the remote oil filter, radiator and fuel filter. Now it was time to lay out the air inlet tubing and air filter to feed this little 6.3L LS engine.


With the help of Erik at HPR and some tuner friends we had determined early on to use a 102mm Drive By Wire throttle body (DBW). A smaller TB only chokes down the engine, and the 102mm unit I bought cost $95. This unit is easily tuned with the Holley Dominator EFI we have. 102mm = 4.015". The problem is the Outer Diameter of a 102mm throttle body is 4.25"...


4.25" ID intake hoses are VERY rare, and what we ended up doing was up-sizing the entire cold air intake tract to 4.5" dia hoses, aluminum tubing and air filter, which is much more common size. As you can see (above right) we have a "transition" hose that goes from 4.25" to 4.5" right at the throttle body, then a 90 deg silicone bend that is 4.5" dia, and an air filter that is 4.5" ID as well.


Brad spent a little time getting this cold air built, and worked with me to get it laid out just so. Where the filter ended up is exactly where I wanted it. Jason and I spent a good bit of time chasing down the right parts - the bend, transition, tubing and air filter. This filter is an oil-less K&N that barely fits the area we have for it. The parts to build this came from 5 different places, and took many weeks to arrive - like everything during this supply chain mess. Now it was time to build the filter box.


Brad builds some beautiful brackets and sheet metal assemblies and he always starts with cardboard templates. This airbox was going to be tricky...


The template came together in a few stages, and had to be built around a number of items - like the remote oil cooler, and a protrusion in the engine bay. The inboard side wall (with the "U" in it) is built to keep hot air from the radiator exhaust. Then a layer of cardboard was fitted to the top to mate up to the inner surface of the carbon hood we are using on this car, which will be sealed with some weatherstrip rubber along the top edge.


Brad transferred the final templates to aluminum sheet, which he cut on the shear and band saw, making 3 main pieces. As he was cleaning the edges of the aluminum, some contaminated sandpaper (which had been used on steel) was used. This all was being done in January of '22.


This made the aluminum nearly impossible to weld, due to the steel contamination. Both Doug and Austin both tried to weld the seams here and it wasn't pretty, but they cleaned up the worst of it and the two aluminum pieces were saved.


Brad then made a series of small "L" brackets and was able to rivet the third and final piece to this airbox assembly, which fit perfectly to the corner of the engine bay, allowed the 4.5" tube to slip through, and lined up to the underside of the hood. There is a "U" shaped opening that will allow some warm engine bay air into the airbox, so we will monitor Intake Air Temp sensor in our first track test - and likely we'll make a block off panel for this upper opening, to completely seal off the filter from warm air.


By February of this year we had ordered some more bits and pieces to wrap up the Cold Air Inlet system. Brad started off by covering the airbox with DEI gold foil. And yes, this should normally only be on the "outside" of the air box, but some of this was done to cover up the contaminated welds on the box.


With the airbox completely wrapped in GOLD it was time for Doug to located, drill, and TIG weld the threaded bung for the IAT sensor.


After that was welded up the aluminum tube was also wrapped in DEI gold foil. Then Brad added the upper welting to the "U" and the thicker weatherstrip seal along the top edge, which seals the box to the underside of the hood.


Last up was the grill openings that "feed" the airbox cold air from outside, as well as the radiator and oil cooler. The factory 2018 GT upper and lower grills have a lot of areas blocked off. The OEMs do this to reduce drag and eek out a fraction of one more MPG, after wind tunnel time spent with engineers, thermal testing, etc. Since we're adding more power than the regular 5.0L would have, so we need to open up things...


We have used this trick in the past to "uncover" grill openings when it is a cast plastic part with these decorative hexagon shapes on the front. A 36 grit sandpaper disc is used to remove the inner layer of plastic and the hexagons remain - so it still looks factory, but allows much more airflow.


This was done on the front left corner that feeds the air filter box, as shown above. This mod added 5x as much surface area for air to get to our uniquely positioned filter inlet & airbox, and will have a small "ram air" effect at speed once we seal off the inner wall of the airbox.


Since we have a rolled radiator and a low mounted oil cooler, the upper grill isn't feeding much (and we might block it off on the back side. To feed the lower opening Brad also opened up the lower grill area as well, which was about half closed off as well. This should help with cooling airflow to these two low mounted heat exchangers.


Almost every track car we have ever built needed a supplemental oil cooler or oil cooler upgrade. Our 2018 Mustang GT (below left) made 485 whp with the Gen 3 Coyote and headers, and the Mishimoto oil cooler we modified and added made the oil temps cooler. This car recently came back to us from the new owner, who complained of high oil temps (possibly a differing driving style, shift points, geographic location, etc) and we just installed a larger, thicker, and more efficient Derale stacked plate oil cooler (below right) on that car.


continued below


Go Big or Go Home
Supporting Vendor
Plano, TX
continued from above

Our LS550 is going to make a little more power than that in Phase 1, so we're installing one of the largest Derale 10000 series "stacked plate" coolers - with room for one more right next to it for the future Phase 2 engine.


We actually bought this Derale cooler for my wife's LS swapped 86, but that has been stuck in our lobby for a while awaiting its turn in the shop for completion, so we "acquired" it from her parts shelf and got to work mounting it on the LS550. We also ordered up a Derale part number 50022 mounting rail kit for Derale stacked plate coolers (above right), which we have used on a few in-house track car builds.


Brad made some simple brackets to attach these Derale rails to the car's main frame horns at the top and to the lower subframe / radiator support at the bottom (see above right). Our goal was to keep the cooler mounted low to get the airflow from the lower grill, and place it close to but not touching the aluminum radiator - so air cannot bypass around the Derale oil cooler (it sits 3/4" away from the radiator).


The same day this cooler was mounted, Brad began plumbing the rest of the engine oil system - from the pan to the remote Improved Racing oil cooler with thermostatic bypass and on to the Derale oil cooler. Again, when the oil is below 185F it will bypass the oil cooler. When it warms above that, then oil will go from the filter to the cooler then return to the engine.


We ran all of the oil lines in -12 AN sized Fragola braided lines. We have seen shops use smaller lines on engines like this but then they also tend to chase low oil pressure problems. On the 2018 GT we used -10 lines because that is what the Mishi oil cooler kit utilized, but on a higher RPM race engine you pretty much always use -12 AN lines or larger (-16 AN is also common).


The lower brackets looked a little "springy" to me so in February of '22 I asked Doug go back and reinforce these parts. Now the cooler is less likely to bounce on the lower mounts.


This sized cooler has worked on similar power levels for us in the past, and as you can see above that adding another identical cooler right next to this one will be pretty easy and take little effort. That would effectively double the oil cooling, which would be perfect if we double the power.


My love of Derale cooling products is no secret - we keep using their heat exchangers on virtually every project in the shop over the last 2-3 years. We utilized this massive differential oil cooler with integral shroud and twin fans on a customer's 680 whp track car and it worked well, so we ordered another for my Mustang track project here.


We purchased this cooler / fan setup in late November of '21 but the installation task didn't happen until December of '21, when Doug jumped in and started cutting out the floor for the hot "exhaust" side for this, then tackled mounting it in February '22.


Jason and I debated ducting cool air to this from several spots on the fender, then building a ducted exhaust out the bottom. We moved it this way and that, but the frame rail, mufflers, shock towers or something else was always in the way. In the end we decided to keep it simple, then use the giant "muffler hole" in the trunk and to give us some "cooling" air for the diff cooler. The hot air coming out of the back of this cooler will then exhaust out the rectangular hole in the floor outboard of the frame rail, shown above right.


The mounting brackets were fairly simple - a bent piece of aluminum at the bottom and another aluminum bracket at the top. The unit was "clocked and cocked" in a way to make for the easiest exhaust flow path, and we might still make a duct on the exhaust side if we don't see the temperature drop across this cooler that we want.


In late February of this year the same noisy but effective gerotor oil pump we used on the 2018 Mustang GT was added to the trunk floor of this 2015 with the same isolator mounts. Then in March '22 Doug plumbed the diff cooler system going from the rear cover, to the cooler, then to the pump and back to the diff housing. There is also an elevated "filler neck" on the rear most corner of this cooler, which has a AN "Tee" and cap to fill at. A long funnel will be used to fill this system with a measured amount of fluid. The pump will act as sort of a check valve so that when the system is turned off it won't drain all the oil from the cooler back into the diff housing, which could over-fill that. This car will only be driven with the diff pump going.


In the last installment we had the large Howe dual pass radiator mounted on a steep rolled mount. We still need an electric fan to pull air through this unit between autocross or track runs, and at speeds below ~40 mph. Yes, you still need a fan on a race car - don't let someone tell you otherwise. I've seen the folks who preach the "race cars don't need fans" theory, but they have also melted down engines numerous times, just sitting still.


After mocking up the 16" dia Mishimoto slim line fan in the last update (above left) it was time in February of '22 to get the protective cardboard off the radiator for the first time and build some fan mounting brackets.


Brad started with some cardboard templates and transferred them to some .100" thick aluminum sheet, which he cut and bent to shape for the two main vertical brackets. This thickness is plenty strong and yet still easy to bend on our box brake. A somewhat simple bracket but it works and does what we need - attaches to the four mounting tabs of the fan assembly.


These vertical brackets mount at the bottom to a simple aluminum angle cross brace, which bolts to the lower radiator mounts on the subframe. At the top are two simple bent brackets that bolt into two factory installed rivnuts on the upper radiator support. The fan sits 1/2" behind the radiator - close enough to be effective in this suction side mounting while far enough away not to touch the fins or damage the radiator in any way.


I'm so glad we bought this OEM replacement upper radiator support, as it has made mounting things on the front end SO much easier - the radiator, the fan, the front strut reservoirs (we've since moved them), and the Aerocatch hood pins (see above) all mount to this, as well as the bumper cover! We would have added many many hours of work trying to save 3 pounds and building this structural part "bespoke".



So I never liked the look of the 8 individual coils mounted to the factory LS valve covers. While it is an elegant and simple solution, and makes for easy spark plug wire runs, it is ugly. I'm vain and for this build needed something flashier. Moving the coils away from the heat of the headers was another secondary reason for "remote mounting" the coils. I also had a pair of these showy "CHEVROLET" valve covers, which I had custom powder coated in red with exposed lettering, that I really didn't want to cover up.


I spent way too much time mulling over the ignition coil locations, looking at show car and race car remote coil solutions. In the end these simple ICT billet mounts were "the most right" answer. And the big strut tower cross brace we had on the car was quite a bit further away from header heat, and looked like a nice mounting structure. I honestly wanted the coils further back and/or hidden completely, but the engine bay was starting to get tighter as we added more bits and pieces.


Doug tackled this installation and it went quickly - we mocked up the locations with measurements and symmetry, then he removed the hollow aluminum Ford Racing cross brace from the car. Doug marked and drilled the holes for M6 rivnuts, which made for a clean mounting arrangement.


This coil location exposes the valve covers and somewhat hides the coils, while keeping them a bit further from the heat of the exhaust headers. The Holley Dominator wiring has since been plugged in for the coils and tucked out of the way, with custom spark plug wires being built later this week.


The front tube bumper for this Mustang was built some time back, and it had a single tow hook on the left front. We use these tow hooks to pull cars into and out of a trailer, and for track side extraction. When we make them welded to a rigid bumper like this, we can also anchor tie down straps for us in towing in a trailer. When you have a massive splitter or diffuser this is a REAL bonus.


The guys who built the tube bumper for this S550 have since left Vorshlag, and with them also went the knowledge of how to run our CNC plasma. In December, while I was learning how to use our plasma table (lots of YouTube videos and text messages with our two former engineers), the PC that runs the servos on the CNC took a complete dump. Long story, but this ended up being a major hassle to replace and reprogram this PC. I spent weeks getting this plasma table back up and running.


The LS550 project also spent 8 months in purgatory in late '20 and early '21 - sitting in my barn, awaiting room in the shop to open up. While stored out there the raw steel bumper beam had gotten a light coating of surface rust. The lone tow hook also needed a matching unit. Once I had the PC replaced and the plasma table cutting again, the matching 1/4" thick steel tow hook was one of the first parts I successfully cut with the new setup.


Doug took some measurements for placement and angle and tack welded the second tow hook on to match the original, but mirrored on the other side.


With that verified (the front bumper cover went on and off to check fit) the tow hook was seam welded onto the bumper, then it was removed, cleaned, scuffed and painted silver. Yes, we have some other things that will mount to this bumper later (front splitter mounts), but I was tired of seeing a rusty tube bumper in so many pics - at least now its not an eyesore.


It will be so much nicer when we haul this car in the trailer - hooking up the front tie-down straps takes SECONDS with this type of setup, and if we do need a tow from a wrecker on track they have multiple places to hook up to.


This is pretty basic - finding a good place to mount the front shock reservoirs - but again, was a bit more challenging trying to satisfy my OCD inside this ever crowded engine bay.


It is no secret that we took all of the last versions of the suspension from my 2018 Mustang (above left) off that car before it was sold - even the shock reservoir brackets. We tried and failed to re-use those when we swapped the MCS RR2 coilovers over to the LS550 (above right) and for the longest time the canisters were wrapped in foam sheet and zip tied to the upper "dog bone" fender structures (above right).

How and where you mount the canisters for remote reservoir dampers is important. You want them in an easily accessible spot - so you actually use the knobs (in this case, low speed compression). Dampers turn motion into heat, and remotes can get hot - so keeping them away from the heat of a radiator or a turbo is important. And WHERE you clamp on them matters - they are made to be clamped on the ends, at grooves machined into the outside of in the canisters, far away from the travel of the working and floating pistons inside (see above).


Our guys made up a pair of these reservoirs - just some flat aluminum sheet, passed through our set of rollers to match the same radius of these cans, with a "spacer" block of flat aluminum welded to the back side. This spacer allows for a pair of counter sunk bolts to be hidden flush under the reservoirs when mounted, and the offset from the back with the spacer allows hose clamps to pass between brackets and whatever they are bolted to.


Brad knows my OCD and visual symmetry needs well - and shares it - so when we discussed the mounting of the reservoirs he found a common body panel angle and matching locations on both sides of the engine bay to mount to. The angle of the front panel was marked in blue tape and the reservoirs mount right to the strut towers. Holes were drilled, rivnuts added, and the brackets mounted symmetrically.


The reservoirs are mounted at the same angle and hose clamps attach in the designated "safe zones" on each canister. To class it up the stainless hose clamps, the exposed portions are wrapped in heat shrink tubing and heated to fit - this keeps the "teeth" on the clamps from scratching the finish on the MCS canisters.


The upper radiator bracket was originally built a while back, and was done rather hastily. We had the radiator out in late February '22 to "cap" the original filler neck that was cut off, since we will be using a remote mounted coolant reservoir and cap, which will be mounted higher than the radiator. Doug got that hole welded up, and while the radiator was out, Brad got to work making a better upper mounting bracket.


Brad's bracket work once again classed it up a lot. I missed the cardboard template steps but caught a few pictures as he made this new, full width, dimple-died, aluminum upper bracket.


More .100" thick aluminum was cut to fit and holes drilled, then it was dimpled with the press and our set of dies. These "lightening holes" help remove weight as well as adding stiffness. And it looks cool, too. There's a rubber isolator added to keep the aluminum radiator from touching the bracket (see the black bit in the above right pic.)


Once it was all fitted and tested, it was removed and brush finished, like Brad does to most aluminum brackets. This finish allows the part to look good in raw aluminum or it can take a nice anodize plating or powder coated finish later. Really happy with the upper mount worked out.

continued below


Go Big or Go Home
Supporting Vendor
Plano, TX
continued from above

The radiator hoses we make have proven to be reliable over the years. We're just trying to connect the radiator to the engine with hoses that have some flexibility, the right sizes, and never leak. The hoses often need to compensate for size changes between the water pump and the radiator; 1-1/2", 1-5/8" and 1-3/4" are all common sizes.


We start at the ends, sourcing these from Pegasus, HPS, and others. Parts took weeks to all arrive, test fit (above left), then it was time to connect the ends with aluminum tubing - all while trying to leave as much access room and radiator exhaust airflow room as possible. Sure, we could have modified the radiator and water pump to use -20 AN ends and built AN braided hoses for all of this, but it adds 5x the fab time and cost - plus makes sourcing a replacement water pump at a remote race weekend impossible.


We tend to make the hose bends and the adaptation between diameters on these silicone hose end sections. We connect the hose ends & bends on this install with straight 1.5" OD aluminum tubing, as shown above. We add these raised beads on the tubing at the ends, to help secure the hoses, using our little bead roller. Sure, you can often hack together some OEM rubber hoses from a car parts store, but these silicone + aluminum assemblies look good, work well, and do not leak - when built correctly.


These also have just enough flexibility to allow the engine a little movement (from torque). We use these turbo style T-bolt clamps to secure each junction, which have smooth inner clamp surface - unlike worm gear hose clamps. I will talk about the "steam vent" port and plumbing we added in the highest hose (see above right) in a future post.


The trunk of this car has two GIANT mufflers, a differential cooler, battery, remote surge tank and more. The rear seat is never going back into this car, so we have a giant hole between the trunk and the cabin. So let's make that hole even bigger!


To make the trunk firewall the rear speaker deck became pointless - it had two massive holes in it, plus lots of little holes and raised bits. Brad and I discussed this in February and he marked the main upper "structural beam" at the upper leading edge. This ties the two shock towers together and we want to keep that structure for now. The perimeter was marked and he used lots of tools to cut out this piece.


This speaker deck amounted to only 2.5 pounds (above left), but there were some raised sections in the remaining portion (above right) that had to be cut & ground away so a flat sheet could go over this panel with tight gaps. The point here is to seal air, fumes, and potential fuel / fire from reaching the cabin, so tight gaps to the remaining structures the firewall bolts to are key.


Brad got all of the metal trimmed and flat, taped off the raw ends and primed them - no more rusty metal - then got to work on the two pieces that would be made from aluminum sheet for the firewall.


Hot bits in the trunk with big openings that need to be sealed off from the cabin, as seen above.


The main "vertical" matches the back seat angle and mounts to a flat section of vertical structure on both sides of the main opening. This sheet was relatively easy to shear and fit to the car. The upper deck replacement was trickier and Brad made a full sized cardboard template for that.


There are two other portions that will remain in place on the sides of the back seat opening (see above left). These are riveted in place. The main vertical panel is bolted in place with button head bolts into rivnuts. The upper panel has a bend along the top leading edge and that bolts to the cross structure and overlaps the vertical panel (see above right). There are bolts along the back edge of the upper panel as well. Don't worry, the Lexan rear window will be removed with bolts as well - so if we need to remove this firewall we can, just takes a bit of time.


Things were really speeding up on the project here - with a bulk of the work in this post done in February '22, when we had a gap in customer work while we waited on a bunch of parts. Instead of making the trunk mounting complicated I decided to go ahead and ask Brad to install the stock trunk release latch and striker. It has never been closed up until now...


As I mentioned in previous posts before, this is an Anderson Composites carbon trunk, and it is very light - but has all the features and mounting points of the OEM trunk. This allows all of the factory hinges, brackets, and latches to bolt right up. As you can see above it also fits very well - we just bolted it on, and it fit like this.


Then it was time to really look at the trunk release. There won't be "keys" or remote solenoids on the doors or trunks on this race car, so we kept it simple and used an extra Lifeline remote fire bottle pull handle cable as the trunk release (above right). This would attach to the "emergency release" handle on the latch, mandated to be inside all trunks - in case someone is trapped inside. Brad made a bracket to mount the cable pull to the inner sheet metal behind the passenger door and the handle is reachable from the passenger side window opening.


Simple, effective, easy to see - and we'll add a proper label to the "pull" and a decal outside that window pointing to "trunk release", too. First time we have closed the trunk on this car, which was a nice thing to check off the ever shrinking To Do List.


As I have stated before, we're re-using an OEM fuel tank in this build along with a remote surge tank. This mega-stripped salvage car came with nothing back here - no tank, zero fuel system plumbing, nothing. So we had to track down some OEM bits (tank + stock pump / float assembly + in-tank crossover hoses) and then build the rest.


We got a stock fuel pump and sump assembly from my buddy Paul at Tri State Autoparts, and then got to work modifying that. The stock pump will be used just as a lift pump, which should be more than adequate at pushing fuel from the stock tank to the Radium remote surge tank.


Paul left us the stock "pig tail" so we can wire up the stock pump easily. We've drilled into the top of this plastic housing for the "overflow" return from the surge tank at the top. Then the quick connect for the stock feed line from the stock pump has an adapter to a -8 AN end, as shown above right. That's how we get fuel out of the stock pump and excess goes back in.


The feed and "overflow" lines are both -8 AN braided Fragola hoses, which Doug built and attached to this side. These feed up through the back seat and unto the trunk. The top of this side of the fuel tank will get another cover to act as a "firewall" to the cabin - I'll show that next time.


The stock filler neck nipple (not shown) connects to the filler neck hose, which is the only stock plumbing hose left on the fuel system. Above left is the big 5/8" quick connect for the "vent" on the stock tank. This allows air to escape when the tank is being filled as well as to allow air back in when the fuel level goes down. We found this AN adapter from Motion Raceworks and it connects to a big -10 AN hose that goes to the vent stack, shown below.


Next up comes the fuel tank vent system, and all this was done so we can do away with the factory charcoal filter (which is long gone). We are trying to vent the tank for filling and use, as well as make a "rollover valve". We started with a valve cover breather with a 5/8" opening, then a 5/8" barbed fitting to -10 AN, and finally this Vibrant -10 AN/ORB one-way check valve. The check valve was opened up and the spring modified to have a lower spring pressure. This way if the car ever rolls over on its lid, it acts as the rollover valve. It still should have enough spring pressure to keep the fuel separated from atmosphere as a check valve. If there are excess fuel fumes in use we will address this then, but with the sealed trunk firewall, it may be a non-issue.


Doug made a bracket to hold for the lower check valve portion, then machined that fitting to work like a bulkhead fitting at the bracket. The check valve is mounted at the trunk floor level (as shown below), then a ~18" long hose goes up to another bracket at the top of the trunk, which mounts the breather. This is mounted higher than the external fuel filler neck on the fender, to keep fuel from ever coming up and out this vent.


Next up was the Radium Remote Surge Tank, which we spec'd out with two Walbro 450 LPH pumps. This is tad overkill for the Phase 1 engine, but the single pump setup was a bit short. This has room for up to 3 pumps, and we will add a third when we go to Phase 2. We ordered this one "bare" so we needed to add the pumps, fuel hose, and wiring.


These setups are modular and easy to work with. We ordered it made for the Walbro 450s and Doug made quick work of the assembly. The included screen at the bottom is made to hold these Walbros and he used submersible hose for the connections at the top. The included wiring was connected to the machined Radium top plate, which has wiring bulkhead connectors for all 3 pumps (6 posts) and another spot for a fuel level sensor.


We added this optional fuel level float sensor, which basically tells you that the surge tank is NOT full - which is usually a "OMFG GET TO THE PITS NOW" warning. We'll mount a big LED in the center stack to warn the driver when this ever happens.


The Radium sensor has the two pink wires that come out of the hole, which is sealed by the float assembly from the underside. As you can see the float only moves about 1/2" and it is near the top of the surge tank, letting you know you have drained the main fuel tank and are on the emergency reserve that is within the surge tank only.


With the pumps and sensor installed and wired inside the Radium surge tank it was re-mounted in the trunk and the fuel lines plumed to and from that to the main tank. Two of these line run under the back seat floor and into the trunk, as shown in the two pictures above. The other two lines go to the rear bulkhead under the car for the main -10 / -8 lines to and from the engine bay. Fuel system plumbing is now complete - wiring and relays will happen in the next installment.


I have a lot of experience with car batteries, which can be made very light - but it always comes at a cost. After 3 decades of this stuff I have settled on larger batteries of AGM / gel cell types. Of the Optima series I like their 75/25 group options, and on a race car we use the heavier Yellow Tops (thicker plates/can be discharged to zero) vs the lighter Red Tops (thinner plates/higher CCA).


Nobody makes a good battery mount for these, but we do - shown below. Our mount is a steel lower tray we CNC cut and bend, then an aluminum upper. We've used these in numerous race car builds. First step is to find a good place to mount it.


I looked all over the LS550 for a spot and had my eye on this this lateral cross beam in the forward section of the trunk floor. There was a thick layer of sound deadening material here but otherwise it was flat, so I asked Doug to use a heat gun and scrape that area clean.


The bottom of our battery tray has 6 holes pre-cut for hold-down bolts, which can sit above the top of the tray and fit inside the voids on the bottom of these spiral wound Optima designs (see above left). I asked Doug to add 4 more tabs for even more bolt holes - because the section where we can bolt down the steel tray is "blind". This area is a thick hollow section and we would need to add Rivnuts here to mount the battery.


Yes I know this is less than ideal, but it was the "least bad" spot to put the battery for easy access, weight bias, and where much of the rear wiring would be anyway. These are LARGE for rivnuts, they were installed with a pneumatic gun, and there are eight of them. This battery is not coming loose in any crash, and we have a bomb-proof rear bulkhead right in front of it. I have zero worries here. I will show the battery wiring in the next forum update.


Some of you saw in my last post where I talked about buying this narrow body 2006 C6 we bought last year. We bought this to hold me and my wife over until this LS550 and her LS 86 are both on track, to keep our track skills fresh and to not wither away behind a keyboard for the ~3 years it took us to get this LS550 almost ready. Some wondered if this C6 would be a distraction or replacement that kept us from working on our two race cars.


We had upgraded to these cheap flow formed 19x10" wheels (2 sets) and 275/35R19 Hankook RS-4s - which I bought for long term testing consistency, but as an "endurance" 200TW tire is gives up some speed. We chased a particularly nasty ABS issue on this car for a long time, but eventually just punted and swapped in BMW Mk60 ABS and that solved that. This ABS fix & 275mm tire upgrade helped this stock LS2 powered (360 whp) car go from 1:30.0 to 1:26.2 lap times at MSR on the 1.7. Then this 3100 pound C6 got MCS RR2s coilovers and it dropped nearly 4 more seconds into the 1:22 range on these same tires just a week ago.


Honestly, this big lap time drop on the C6 motivated me to get our LS550 finished - because this C6 is roughly the final weight we will be at in this S550 (see recent weight check, above left), but we should start phase 1 at nearly +180 whp and be on better 305mm RE-71Rs (I have a fresh set to test with) and then the 315mm Hoosiers.


I think this is a good place to stop, before this post gets too long. This round of updates caught us up with work done into March 2022, which is close to when I'm writing this. We have some more work completed during the period while I was writing this - the heater core is mounted, the coolant reservoir as well, and the Peterson vented oil catch can. Some small plumbing to wrap up on this round, too.


The carbon doors are already being fitted to be installed soon, to keep the total weight down for Phase 1. Just some final wiring to knock out, digital dash, and tuning. Then we'll be on track "sooner rather than later".

Thanks for reading!


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Plano, TX
Project Update for September 20th, 2022: The last update here was April '22 and I'm updating it again in September - only a five month gap - so we're getting caught up on many build threads. I used one of the boring "sea days" on board a cruise (Sept 17th) to write much of this update, and my internet connection was crap, but its better than staring at the ocean for 8 straight hours.

We haven't really attacked the LS550 build as much as I wold have hoped, but between customer builds we are getting more and more done - and all four remaining customer builds are wrapping up and leaving quickly! That means we will be able to pour more man hours into this car and get it fired up VERY soon. We're are down to wiring then First Fire followed by alignment and dyno tune.


The shop is still full of cars, and my former red 2018 GT even arrived for a T56 Magnum XL swap (among other work) earlier in 2022, and you can see that + our black LS550 + our narrow body C6 in the image above.


Looking back over the last 5 months now, we actually did knock out a decent chunk of work, with Brad and Doug tag teaming the punch list on this Mustang. And I'm not helping things, as I keep adding more features and details along the way (just like our customers do!) - but this car is going to be our main "shop race car" for a few years, so it has to perform well AND look good.


In this installment we cover the last steps of the cooling system, the oil vent catch can plumbing, the Lexan back window install, carbon doors and even the new paint applied to the front fenders and nose - so now the car is all black or raw carbon! We also cover the steering wheel quick disconnect with a horn, digital dash mock-ups, shifter modifications, and a detailed guide to installing a fire suppression system. Its a big 3-part installment so get to a real computer (ie: a larger monitor - every image is linked to a higher rez version!), grab a snack and/or drink, and lets get caught up on this build!



We covered the radiator mounts and main radiator hoses last time, but in this round we will show the last bits of the cooling system being installed - namely, the heater core, defroster plenum, coolant reservoir, then heater and steam vent hoses .


We race 12 months out of 12 here in Texas, and our winters can and do get below freezing. I have been to a number of January events where there was frost or fog on the windshield so we always like to add a defroster to all of our race cars. Having a working heater will also help in Optima events - which this car will do.


The first step to getting the heater core mounted was removing the dash, which needs the doors off to access the mounting bolts - shown above left. And this step led to the carbon doors going on, shown below!


The dash in this 2015 GT was only loosely installed, as it was a parts car quickly thrown together from leftovers before I bought it. Brad worked on fitting the dash better for the reinstall by adjusting these screw-in width adjusters, so it won't be flopping around. With the 22.5 pound OEM "HVAC" box out of the way, the new 7.4 pound motorsports heater core looks tiny sitting on the trans tunnel.


We have used this 7.4 pound heater core from Summit Racing on many race cars for the past decade. It has a heater core inside, two outlets which fit up to 3" hoses, and a variable speed fan on the back side. All self contained and easy to mount - but we never use the included "universal" mounting brackets.


Doug made up a simple aluminum sheet metal bracket which bolts to the tunnel (into rivnuts), placing the core far enough behind the dash's center stack portion, but still with enough room to access the heater hose nipples. I am a fanatic about firewall integrity and insist on bulkhead connectors for all plumbing and virtually all wiring pass-thrus for any firewall.


The heater hoses going to and from the heater core here were another place for these stainless bulkheads. These have nipples made for simple hose clamps and hoses, which are fine for low pressure cooling systems (16 psi) we tend to run. For a higher pressure fluid system we would be using AN fittings. The placement for these two were planned out along with the reservoir mounting spot and several other items in that area. I will show the final plumbing in the heater hose section below.


In this step I will show how we will turn our heater box into a defroster - without trying to hobble together something with the OEM defrost plenum, which would be pretty ugly. I had found a potential "plenum" on Amazon, which you will see below.


First up was measuring the defroster inlet on the factory dash, shown above. Then Doug made a block off plate for part of that, which will make sense in a later step. This is made from aluminum sheet stock and bolts to the underside of the plastic dash.


Above you can see the "plenum" that i found online - its a shop vac attachment that was $12. Much cheaper than making a complicated aluminum structure. This bolts to the opening that we left from the block off plate above and has a 3" OD hose inlet that will attach to one of the two 3" outlets from the heater core. Above right you can see the silicone heater hoses that go from the core to the bulkheads at the firewall.


The dash went back in and I missed the connection of the hoses to the defroster plenum and eyeball vent, but they are there. The second outlet from the heater box feeds a single heater vent - one of the three "eyeball" vents in the center of the dash. I can open that vent up if I need to warm my hands in grid, but mostly it will remain closed. When the heater fan is on that will blow the warm air to the base of the windshield, to keep it from fogging up on cold / wet days. The other 2 round vents on the dash will house some gauges, later on.


We use a remote coolant reservoir in these LS builds. This allows us to mount the reservoir and radiator cap high in the engine bay, which allows for a better "purge" of air pockets. The larger the tank the more coolant we can have on board also. We tie this into the cooling system in two ways - via the steam vent system as well as through one of the heater hoses. And we try to use an aluminum version whenever possible, as these don't age and crack like the OEM plastic style.


We have used this big Canton remote reservoir before, as well as the Canton 16 psi cap. We test fit a 1/2" NPT fitting for the bottom bung and it was a bit too shallow so Doug ran a 1/2"-14 NPT tap a little further into that bung to allow the elbow to sit a little deeper.


The Fragola lower 90 deg elbow went from the threaded 1/2" NPT to a 5/8" diameter hose barb. This is Teed into one of the 5/8" dia heater hoses going to the firewall bulkhead. Above right you can see the steam vent hose which went into the upper 1/8" NPT bung. That ties into our 4 port steam vent system AND the same port at the top of the upper radiator hose.


The two images above show the routing of the heater hoses from the LS7 water pump to the bulkheads at the firewall as well as the "T" that diverts some of that flow to fill the reservoir (and also to fill the cooling system from above, when the cap is off).


The upper radiator hose is the highest part of the cooling system and radiator below the reservoir, and we added a small port to that with a nipple that Tees into the 4 port steam vent outlet. This hose then runs from that junction at the radiator hose to the reservoir at the back right corner of the engine bay.

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continued from above


This should tie the highest part of the cooling system inside the engine (steam vent system) to the highest part of the radiator (the upper radiator hose port) to the highest part of the entire system (the remote reservoir), removing any steam pockets in the system.


Any car driven on a road course with an internal combustion engine should have an oil/air separator and catch can system. This prevents excessive crank case pressure from spewing oil out of the engine - either into a sealed EGR system or an open vented system, like on this car. I explain the difference between these two types of oil catch can systems in this recent post on our narrow body C6 - and it applies here.


Since this going to be more "Race car" than "Daily driver", we went with a vented oil catch can from Peterson oil systems. This has an internal filter to catch the liquid oil droplets and keep them from spewing out of the vent at the top of the can (again, see the post on the C6 section showing this). This Peterson can is our "go to" option for race cars that have a wet sump oiling system.


To feed the crankcase pressure to this air/oil separator we needed to run big vent lines from both valve covers. The cast aluminum, tall, red "CHEVROLET" valve covers both got holes drilled to have 1/2" NPT fittings threaded. the Fragola fittings were then shortened on the bottom side so that they do not come close to the rocker arms - that would be bad!


That leaves two big -12 AN fittings on the back of both valve covers, which Doug then plumbed to the two inlet ports on the Peterson can with AN12 Fragola hoses.


This works our for a clean, dual fed, crank case vent system with an oil / air separator inside the can. There is a drain port at the bottom of the can which has a petcock, that Doug then plumbed with a hose down inside the RF fender area. After every track event we can open this petcock and drain the captured oil to keep the can from filling up. Again - every road raced car should have some sort of oil / air separators with a catch can and drain.


Wait, what?! We already had an S550 ABS system installed on this car earlier! Alas, since we installed a salvage yard sourced S550 ABS unit, as well as a master cylinder and lines from Ford, we have learned of CAN challenges with S550 ABS swaps. Namely - that is has never been done, and involves a LOT more CAN signals from OEM computers we don't have in this car. That is more work than we are ready to tackle at the moment.


The S550 ABS unit has been removed, boxed up, and shelved - for now. Instead of tilting that windmill, we instead decided to go with an ABS unit we know well and have successfully swapped into other chassis - the S197 ABS unit from a 2011-14 Mustang GT. These exist in the tens of thousands in salvage yards, after countless Mustangs have unsuccessful avoided ditches, trees, curbs and crowds.


Now I personally have driven 100s of laps in S197 Mustangs with this late 2011-14 ABS, both on track as well as autocross. And we know that we can make this work without ANY of the stock CAN inputs, if we use the right Ford Racing ABS computer, which we do have on hand for this car. But using a factory manual & wiring diagrams, plus a donor car we have on site (2011 Mustang chassis), we want to test some theories on an S197 ABS swap without using the expensive and rare Ford Racing computer (it is out of production and getting very hard to source!)


Again, if I thought there was a way to make the S550 ABS unit work with this completely CAN-free car, we would. This will save us months of frustration - and help prove out some alternatives for other chassis we want to ABS swap. We've done a number of Mk60 ABS swaps and one S197 swap, so this is just another option. We reached out to our friend Paul at Tri-State Auto to source a 2011-14 ABS brick + mount + harness connector, and he delivered once again. The image above right shows the S197 ABS next to the S550 - similar in many ways but still very different.


Now to be on the safe side we went ahead and mounted the S197 ABS unit at the same angle as Ford did (see above left). This will be oriented the same way and tilted at the same 18 deg angle. The S550 ABS unit (above right) sits "straight up", without this tilt. We planned to place the S197 unit in the same basic spot as the S550 unit, but with the 18 deg tilt.


I labeled the two units with the outputs of both units on the "top, but the input ports are on different planes. Doug then mocked up the S197 ABS brick in the engine bay with the 18 deg tilt, and it looks accessible. Now it was time to make the bracket and then the lines.


Doug took the S197 ABS brick's mounting bracket (which was bent / damaged) and flattened it out, then made a template of that. This was then modified to fit the S550 chassis. It took two versions to get everything aligned correctly but the CNC plasma table made this go quickly.


The second version was bent up to fit the ABS brick and the S550 chassis mounting points, then the S197 isolators were added to the big holes cut to accept those. This allows the hydraulic unit to not vibrate as it cycles, which can throw off the actuation. We do this isolation mounting on every ABS swap.


We received the S197 unit from salvage with the correct hard line fittings (tube nuts) and the harness with a "tail" of wires we can re-use. That proved to be critical, as the S197 and S550 used different end fitting flare angles on the M10 and M12 ends. Why? Nobody knows! You can see our S197 adapter bracket bolted into the S550, above right.


Doug caught this tube nut fitting difference - it was all lining up perfectly, but now we had to cut each hard line in the car, swap in the S197 tube nut, then re-flare each end. A bit cumbersome with the hard lines still in the car, but Doug used this pneumatic flaring tool to get them all swapped.

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Even the two "flex" feed lines from the master cylinder to the ABS brick (which we purchased new for an S550) had to be cut for new S197 tube nuts (both were the larger M12 sizes) and re-flared. This wrapped up the plumbing for the brake system and the ABS brick mounting. Next time we will show the wiring for the speed sensors as well as the additional yaw sensor needed to (hopefully) make this work with the OEM ABS computer.


We want to test the OEM S197 ABS system on this car (to verify that it can work on ABS swapped cars), then we will have found a good, low cost ABS system we can swap onto any car without needing the rare and expensive Ford Racing ABS computer. After we get this tested we can then swap in the Ford Racing ABS computer and retest the brakes with that setup - to see how much better it stops, if any.


Back in 2020 we had "The Carboning" - which was when a huge shipment of carbon fiber arrived from Anderson Composites & Seibon (sister companies) for several of our cars - including this 2015 Mustang. We have already showed the carbon Anderson trunk going on, as well as their carbon "GT500" hood that was transferred over from my 2015 GT.


I had honestly planned on adding the carbon doors AFTER we had a full roll cage, but the weight was already creeping up and I threw caution to the wind and since the lightened steel doors had to come off for the dash removal during the heater core install, it was a good time to drop some pounds.


The door handles and hinges were removed from the steel doors, as well as the stock mirrors and inner release handles. Now we did not add the crash bars from the stock doors, as that involves a lot of surgery and ultimately we want the future roll cage to provide that side intrusion protection. We will likely add some down bars from the main 4-point roll bar as a stop gap solution to this.


There was a lot of grinding, fitting, sanding and fiddly work getting the mirror pockets in the doors to fit the stock side mirrors. These are hand made doors, so this is to be expected. Doug spent a couple of hours creeping up on the right sized pockets, then both mirrors bolted in and fit snug.


The doors went on without any fuss - amazingly they fit the stock hinges and opening without any sanding or grinding, unlike other brands of composite doors we have worked with in the past. These fit like OEM parts, which is likely why Ford has Anderson build some of their factory race car carbon parts.


We have added lots of parts since the last weight check (3060 lbs on 4/1/22) but the carbon doors helped offset some of that and more, with this 3045 lb check (4/21/22). This 3045 weight was with all of the safety gear, both seats, and all of the plumbing. We still lack some wiring work and of course fluids, so a 3100 pound initial race weight is likely.


Up until this point we still had the original steering wheel installed, but that was never going to see any track use. To get from the stock wheel to the Momo model 88 wheel with a steering wheel Quick Release AND a working horn, took a bit of work.


I wanted a smaller steering wheel on at this point in the build so we could size and place the digital dash unit. Of course if we are adding an aftermarket steering wheel, and not hoping to keep any airbag or wheel mounted buttons working, we want to add a Quick Release steering wheel hub (aka: "QR").


Normally we would reach into the Sparco/Lifeline catalog and pick one of their beautiful units - but I did want a working horn, and a thinner QR unit. Having driven recently with an NRG branded QR, I rolled the dice and bought the hub adapter and "thin" style QR from them. Unlike other import QR hubs, this brand has an SFI rated unit - so its better than most.


To make the horn button work we needed a clock spring, which was missing along with virtually all wiring on this salvage car. So we went to eBay and bought one for $34, $100 cheaper than the Ford supplied unit. Hey, its just for a horn.


The NRG branded QR hub had a 2 wire pass-thru, which Sparco/Lifeline charge a large up-charge to get. The listing they had for the adapter hub showed "2005-up", but I worried that the 2015-2023 Mustang S550 unit would be different. And it was. I will show below what it took to make their hub adapter fit the S550 with a working clock spring, so we could have a working horn.


Once we bought the clock spring we had to chase down the steering wheel sub-harness, to connect to the wiring of the clock spring once it was mounted. We found that on eBay and only needed one connector - to connect two wires into the clock spring.


This is where the "2005-up" adapter hub from NRG needed major modifications. First up, Doug had to mark and drill the two holes in the hub to align with the clock spring pins, otherwise the tunable clock sprung unit would never rotate. Next up a pocket had to be machined into the back side of the hub to clear the clock spring wiring connector...


You can see the connector on the clock spring, above left. This has to fit within the pocket on the back of the hub adapter. Doug also added a hole for the wiring connector that stays within the hub and sends the wires to the horn button on the Momo wheel.


Details of the steering wheel harness that normally connects to the stock steering wheel, which has a lot of pins for a lot of circuits. We only need two pins for the horn, and those are being connected, above right.


The automotive horn circuit is very simple... it is just a momentary button that closes the circuit, that then triggers a relay that runs the horn. And yes, we use horns on race cars - this has saved me from being backed into in grid TWICE. Thousands of dollars of bodywork damage avoided by a quick "HONK!". The two pass-through contacts for the horn circuit are seen on the open QR hub, above right. again, most QR hubs do NOT have wiring pass-thrus.

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We were a bit short on stainless M5 countersunk bolts, so we had a mix of black oxide and SS bolts when mounting the Momo model 88 wheel. I chose the 330 mm version over the larger 350 mm, as it fits my legs and still allows plenty of visibility to a digital dash when looking through it.


All of that work just to have a horn? Yep - hopefully NRG will see this and make a proper S550 hub adapter, so you don't have to drill and machine pockets into your hub if you go with this brand. But this NRG unit is very low cost for the quality of the actual "release" and connection of this unit, and it is also very thin. Moving the wheel away from your body is much more difficult than when using a spacer to move it closer to you. A thin QR setup is tough to find.


When we were attacking the steering wheel I noticed that the direct mounted shifter on our Tremec T56 Magnum XL was a little too close to the round opening on the S550 transmission tunnel (the "LS" version of this transmission just dropped $400 in price, BTW!) I asked Doug to open that up and prep it for a proper fire-proof shift boot. You can see below how much he cut away, and it now fits perfectly. No, the normal T56 F wouldn't fit this chassis - it places the shifter 5.5" further forward, which would be buried under the dash. And taking a direct shifted trans and adding a remote shifter to it is so backwards that it hurts my brain.


Now there is a bigger hole in the tunnel that needs to be covered up, and the rubber OEM shifter "gasket" wouldn't fit - but it isn't exactly a great fire-proof covering for a hole in the tunnel. We want something better in every race car - to prevent fluids, gasses, heat and fire from breaching the cabin from underneath the car.


I love this Joe's Racing fire-proof and heat repelling shift boot assembly. These are about $125 for the aluminum mounting base + the multi-layer shift boot shown above. This is easy to mount to a flat transmission tunnel like the S550 has, and Doug used 4 riv nuts and bolts to mount the base. The fire-proof shift boot snaps onto the base with 8 snaps.


Now was the time to clean up the center console plastics, which came with this car fortunately. This stuff was pretty gross but Doug cleaned all of this up with some Armor All and rags. This 8.3 pound unit was then placed into the chassis and we looked at the shifter location with the console in place.


Well that added some new restrictions to the shifter path up from the tunnel to the console opening. This led to THREE different shifter extensions which were cut on the CNC plasma table, then threaded and bolted to the shifter base in the transmission and the included shift handle from Tremec. These were each made and tested with the console and stock shift boot in place, then tweaked to fit my driving position.


I will admit that I like a taller shifter, with the knob as close to the steering wheel as possible. But the "S" shaped handle is necessary to allow the shifter to clear the console opening. If you have a gutted interior this won't be necessary, and possibly a T56 Magnum F transmission might fit this swap on a race car. Given enough time I would like to test fit that trans and possibly offer that + the matching driveshaft as an option. Once I drive the car on track we will see how all of this works.


With the Momo steering wheel in place we could finally mock-up some digital dash cut-outs we made to scale off of 4 of the main AiM dash options. And yes, it is no secret that we would rather choose one of this brands digital dash systems if at all possible, simply from how well their on-board PREDICTIVE TIMING systems work. That one feature makes this brand coveted above all others - the ubiquitous AiM lap timer feature.


Of their many sizes we have a handful we tend to use on most race cars - the MXG, the MXP and the MXS. There is also a new wide 10" display that comes with their PDM system shown below that we have been dying to try out on one of our builds. This wide screen is full color and has all sorts of LEDs and icons (or not, you can order it either way) and strangely this would fit well within the S550's dash.


Jason drew these four AiM dash outlines up in CAD and Austin cut them on the CNC plasma table, and these have now been used in a number of cars to size the right unit to fit the dash / driver / steering wheel.


As you can see below, the tall and narrow units did not fit as well as the low and wide - but we have tried to buy the 10" AiM "PDM" dash many times over the last 2.5 years, with zero luck. We keep trying to get one of these from AiM but we keep getting the "well these should be back in stock in 6-8 weeks", which is code for "we have no idea when these will be back in stock". Real lead times have been in the 3-6 month range for this unit every time we try to order. Since AiM is based out of Italy they got really hammered by Covid restrictions, then this new PDM system had some software development delays, this might not be a viable option for a while yet.


We're holding off as long as possible to try to get this 10" digital dash unit - but who knows if we ever will? We might have to punt and try another AiM dash or worse - try another digital dash. The Holley Dominator EFI only works with a handful of brands, and if we do a non-AiM display we would have to utilize an AiM SOLO lap timer separately, which is how we've been doing predictive lap timing in my own cars for 15+ years.


Thinking we would lose some weight by ditching the rear glass, I decided to go with a Lexan rear window a while ago. We got these from a UK company called Plastics4Performance, and they always produce great fitting Lexan that is pre-cut, curved to shape and pre-painted borders. Even with overseas shipping from the UK their parts cost less than domestic suppliers. We love using P4P whenever we can!


We had Titan Glass (a windshield company) back in the shop in June 2021 and had them pull the rear window, which they got out cleanly and in one piece. Modern glued in windshield and rear glass can be tricky to remove, and tempered side and rear glass literally explodes if you break it - so we let the pros handle removal and reinstallation most times.


Fast forward to Spring 2022 and it was time to get the Lexan installed. Doug mocked these up in the empty back window channel and they fit perfectly. They looked pretty close on the quarter windows as well, but I decided to hold off on installing these for now - seeing how little weight these actually remove.


As you can see the rear Lexan window is only 9 pounds lighter than the stock glass window. Hmm, not much weight loss, which is why I held off on the quarter windows. Remember: glass windows are VERY hard and scratch resistant, but Lexan is the opposite of that.


Doug cleaned out the stock weather strip material and (after the steps below) installed the 1" wide x 1/8" thick, adhesive backed weather strip material we purchased for this install.


Dozens of M4 rivnuts were installed along the perimeter to mount this window in place. We like to use these Tinnerman countersunk stainless steel washers to make the M4 countersunk bolts fit flush to the surface of this window. Drilling the Lexan is easy with a sharp drill bit, and we leave the outer (blue) film on until after all holes are drilled and counter sunk.

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The final Lexan install looks great, but again, all of this work only dropped 9 pounds. We still like these removable Lexan windows for the rear, as they can be unbolted without breaking the glass or needing special cutting tools, which we needed to attack the rear deck lightening and the trunk bulkhead install. Also, when a Lexan window breaks it doesn't shatter, so that's a plus for a race car.


I was going to add a full fire suppression system on this car later, to keep the "initial race weight" down (trying to win a bet with a buddy!), but I just don't like taking chances with fire - so a Lifeline Zero 2000 4.0 liter AFFF Fire Suppression System was added before the car ever turned a tire in anger. With as many plumbing and wiring changes made here, this is just smart insurance. The further from stock your race car gets the more likely you will need to use a fire system. We also added one of these to our old red 2018 GT for the next owner in early 2021 - and some of those images are shown below.


This is the exact same "aqueous foam" system going into our black 2015 GT, and on the red 2018 we mounted the bottle in the trunk, the nozzles in the cabin the same as our '15, and even the engine bay nozzles we well. But we are making some small changes from this point forward. After talking to a fellow racer at PRI in December of 2021 - who had suffered a horrific race car fire fire - we used some improvements based on what he saw. For one, we are changing how we will install the two fire pulls in all cars from here on out. I will pull this section out and make that its own forum post in our "Safety" section, too.


On the red 2018 GT above, which is still very much a street driven car and track car, we put the two fire system "pulls" in the same places we always used to - one below the headlight switch on the driver's left, and a secondary pull in the center console within reach of the driver. Let's call this "driver-centric placement".


That was a common way to place fire pulls for a fire system for a decade of more. But in Mark Patronis' Corvette crash and subsequent fire (his helmet above should tell you a lot), the right side of his car was buried in a tree - which was where his only externally accessible fire pull was located. The other pull was in the middle of the car - which was on fire - but he was knocked unconscious. So nobody could get to either fire system pulls, and precious seconds were lost before the fire truck could arrive.

As you will see below on our 2015 GT, we have started placing both pulls with an emphasis on "corner worker access", with a strapped in driver's easy access as a secondary concern. Hey, you can always grab the fire pull on your way out of the car. Hopefully we can all learn and progress over time to avoid these situations.


After Jason and I went all over the 2015 GT, and the very crowded trunk area, we found a place to mount the Lifeline 4 liter fire bottle, it came down to the back seat area. Instead of mounting this above the factory fuel tank covers, it looked like this could fit right behind the driver's seat and still allow access to the fuel tank cover. Doug made the domed aluminum sheet metal cover for this side of the saddle tank at the same time as he made this fire bottle bracket, which itself bolted to the rear "cross beam" normally under the back seat.


The next step in any fire system install is to locate the best places to mount the nozzles that discharge the fire suppressant. Aluminum sheet metal brackets are mounted and the nozzles are aimed at the common fire source locations - a pair of nozzles are aimed at the two fuel rails, where the fuel injectors live. These are also near the exhaust headers, a high source of heat. In the trunk we mounted a nozzle above the remote fuel surge tank, which houses the two fuel pumps and many fittings for the fuel system.


Inside the passenger cabin we have two nozzles. One points to the passenger's lap and the second points at the driver's lap. These areas are eventually covered in plastic trim, but with holes to allow the nozzles free aim.


With the nozzles all placed it was time to plumb them from the main tank. The system comes with plenty of aluminum tubing, T fittings, and is relatively easy to connect. These are cut with a tubing cutter then pressed into the quick connect fittings. To remove them, a tool is used to release the locking clamps internally.


From the bottle one line goes into the trunk to feed the nozzle there, then another goes forward to feed the cabin nozzles and engine bay nozzles. These were routed to fit underneath the center console, with notches in the plastics to fit these without crimping the lines.


With all of the nozzles plumbed, the final step is mounting the fire system PULL handles. We used to put one in the center console by the driver and another at the driver's side front window front corner - but after hearing about a crash where one side was buried in a tree, we have opted to put one on each side, reachable from the outside but also within reach of the driver (on the left side). You can see the first pull on the above right image, where one of the aluminum panels Doug built fits in place of the outermost air vents. A custom machined bung is attached to this flat panel to point the pull handle at an angle for easy access by a corner worker from the outside.


This type of placement of the two fire pulls allows a corner worker from either side of the car to reach and pull the fire suppression, even if the cabin is engulfed in flames or one side is buried into a barrier or another car. Now there are other safety measures you can take - like an automated (170F) release, which could help a driver who is unconscious to be safe before a corner worker can get there. I will cover this and more in that separate fire system install forum post.


I talked to our painter Shiloh about our multi-colored Mustang. Making this car with salvage yard parts and marketplace finds, it was 4 colors.


The driver's side of the Mustang had black, white, blue and carbon fiber panels. But the passenger side was all black, with the black primer RF fender. It looks a lot better and once we got rid of the steel doors and had carbon doors / hood / trunk, I decided to have Shiloh paint the front nose and front fenders a matching factory black. I took him these panels plus the stock trunk to match the paint to that.


I dropped these panels off in April and picked them up a few weeks later in May, and it was time to install them for a black and carbon car. I will admit that my original plans were to paint this entire car red but my painter and everyone here at Vorshlag talked me into an all black car, and we can just add graphics for some color.


Brad began reassembly of the front end by installing both front fenders, which had both been on the car so they fit up nicely. Next it was time to install the newly painted black nose.


The bumper cover plastics are flimsy but when the grills and lower lip are installed it all "firms up" and takes shape. This is a bit of a fiddly process and it takes 4 hands to get everything popped into place, but once assembled the nose went onto the car - held on at the top by the radiator support and on the sides by the fenders. The headlight assemblies went in last.


The ride heights on the MCS remote double struts were setup for the 3650 lb weight of the 2018 GT, but with 600 fewer pounds on this car the front ride height needed a big adjustment. Brad lowered the lower collars on the struts and got the front end to drop another inch, now with "normal" fender gaps up front.


I am not a huge fan of black paint jobs, but changing colors was going to be a LOT of work and a LOT of expense. I'm glad I let everyone convince me to go ahead and paint the fenders and nose - it was affordable and really looks a LOT better than the multi-colored mess from before.


The temporary 2006 Corvette light build we did "just to get some track time" has fallen right into a great class for SCCA Time Trial called Tuning 2, or T2. After adding some 2 year old 315mm Yokohama A052 "200TW" tires and then some headers + a cold air, its actually won 3 TT events in a row in T2 class. At two of those, it was the 2nd quickest car of the entire event. Nobody is more surprised about this than me! Getting in a lot of test events in this car helped me blow the cob webs out of my driving, but there is more to it than that.


Why does this matter for this LS550 build? Well the C6 weighs 3117 lbs (virtually the same as this LS550 should weigh in Phase 1) and makes 382 whp, and runs on very similar suspension (MCS RR2), tires (315mm 200TW), but much worse brakes (Z51 2 piston PBR + Mk60 ABS) - yet it has turned a 1:19.702 lap at MSR Cresson 1.7 CCW course, on street tires. That's quicker than we ever ran on 200TW tires on the red 2018 GT - and it did that with 100 whp less than the red car.

The S197 ABS and 380mm 6 piston Powerbrake setup we have for #Trigger are both much better, race weight should be similar or less, and the stroker LS6 should have +150 whp more than the C6's LS2. This all bodes well for my guesstimated performance of this 2015 GT from day one with fresh 305mm RE-71Rs I have on hand. We shall see soon enough!


We are closing in on the last items on the punch list before we attempt "first fire" for the 385" LS6 - when we fire up the engine for the first time. There is a big check list to go through for that milestone, and we will cover that next time.


Most of what lies ahead is wiring - both chassis wiring and Holley EFI wiring, as well as the main battery cable work (which is nearly done at the moment). We have to nail down a digital dash to use as well - but we have something on hand that might work. Tune in next time to see that and hopefully some video of this engine running.

Until next time!

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