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Vorshlag 2018 Mustang GT + S550 Development Thread


Go Big or Go Home
Supporting Vendor
Plano, TX
Vorshlag Shop car / S550 Development Thread Introduction - October 23rd, 2014: This thread is where we talk about our testing, shop work, parts development, and racing with S550 Mustangs. We will use this thread to share weights, pictures, and tech of various S550 Mustang parts and cars we work on. I started this thread in 2014 when this chassis was just arriving, and in February 2018 our shop bought a 2018 Mustang GT, which we are now using for more hands-on testing. We will use this shop car for development instead of just relying on outside testers' cars, and I have re-written this intro to reflect the change in direction for this thread.


This forum thread was started in 2014 just on our little forum, but when I revived it in 2018 we cross-posted it to some other forums we sponsor (or that allow us to post there), after we bought our red 2018 GT. Getting this car after the '18 major sheet metal facelift and new Direct Injected 5.0L engine made it seem more relevant now, and I'm glad we waited. Automotive forums are declining, but we feel these are much better places to share data and a better long-term repository for tech than social media (where everything posted is wiped out in about 48 hours), so that's why we go to the effort. We will be updating this thread on the following forums:
We will try to answer every question in this thread on all forums we have cross-posted on, so feel free to ask or comment about anything you see. Please keep your comments to S550 related things that "we would know" (we are not a basic repair shop, body shop, EFI tuner, or stereo/bling shop - we specialize in suspension, wheels/tires, brakes, safety gear, aero, and chassis work). You can always call or email us at Vorshlag, too.

Autocrossing and tracking this car on the skinny stock 235mm all season tires was hilarious!

We did both a track test and autocross (above) in the first week of ownership, in bone stock form, and it was pretty terrible. The next week we upgrade the base model GT with 11" wide wheels/tires, aftermarket monotube adjustable coilovers, plus our front camber/caster plates and spherical Rear Shock Mounts.

That's more like how a Mustang should look...! 19x11" Forgestars and 305 Bridgestones

As always, any picture you see can be clicked for higher resolution versions. Videos are almost always linked to our YouTube channel, for best results there. As you might know we weigh everything - and that is what prompted the start of this thread in October 2018, when we started weighing these S550 cars.


Stay tuned as we add more S550 content to this thread, from work we have done over the last 4 years as well as new development we tackle using our shop 2018 GT and other testers' and customers' cars.


At long last an S550 Performance Pack 6-speed GT finally arrived in Dallas. Not the one we ordered, but a stocking order GT with similar performance equipment. This one has power leather seats (not the leather Recarcos) with Sat Nav, 12 speaker stereo, the bigger 15" 6-piston brakes, the 19x9/19x9.5" wheels, the works. All the goodies, probably the heaviest way to get an S550 other than convertible automatic GT (yuck!)


You have all seen the "magazine" weights thrown around, and like usual, the numbers are bunk. I swear these writers don't know how to work a set of scales. ;) We see this every time a new model comes out - either they weigh a car with a full tank of fuel, or two people inside, or lead weights in the trunk, or just parrot the marketing materials they were given. Can they just plain dyno and weigh a car for us gearheads, PLEASE??


Corey White of Five Star Ford of Plano gave me a heads up that their very first 2015 Mustang had arrived earlier today. It was the FIRST GT 5.0 Performance Package car he knows of in Dallas, as there was a production delay on these cars due to some changes to the placement of the catalysts.

This 2013 GT is caged and has all the W2W safety gear. With one seat it is almost 3300 even

After finishing up with a customer's delivery of his race-prepped 2013 GT (built for NASA ST3, see above on the scales) we loaded up our brand new wireless Intercomp digital scales and rushed over to Five Star Ford to get that pony weighed. Why? Because I'm always a skeptic about almost ALL data on cars, and only believe what I can measure on real scales, first hand.


Turns out this thing is about 100 pounds lighter than all of the numbers the magazines had been throwing around. 3718 pounds with low fuel - low fuel levels are easier to compare between cars and is often how we race these cars in Autocross or Time Trial (depending on fuel tank/pick-up). This weight is with the "Trunk Junk" (TM) removed, which includes the floor mats, trunk mat, and the emergency tire inflation kit (no optional spare tire).


Trunk junk came to 13 pounds, and there's likely another 15-20 pounds in the trunk mounted sub-woofer. It is removable but they asked me NOT to take it out, since this car is their very first 2015 and going right on the showroom today. After we weighed the car, Corey White (the salesman in the pics, and a real gear head) told me to hop in and we drove to their fuel pumps to put a splash of 93 in the tank. Then he hopped out and said, "You're driving!" How could I say no?


We went on about a 15 minute test drive, re-striping the streets of Plano in Pirelli rubber. ;) The car drives REALLY well, rides very similarly to a CTS-V... good compression damping, firm but supple ride on the choppy concrete roads, and hauls ass when you give it the Go pedal. Motor feels strong for a zero mile car with similar acceleration to the 2011-14 GT or Boss 302. The PP cars all have the 3.73 gears and Torsen axle. The sticker price is shown below.

As always you can click any picture for a larger rez version

The ergonomics are spot on. I've sat in a couple of these but driving it was amazing. 6'7" Corey fits in here well, and my 6'3" frame was swallowed up with ease as well. The shifter feels GREAT and the lever is right where my arm wanted it. The steering wheel has a big FAT rim and gauges that were easy to read. The seats were good, but the Recaros are better - that option worth the extra coin, if you never plan on installing real racing seats.


Loved the switch gear, and the materials + leathers were top notch. Pedal spacing was perfect for heel-toe downshifts. Just a quick street drive but I really liked it.

Left: 2014 Camaro Z/28 with A/C and 3/4 tank, sans trunk junk = 3835 lbs. Right: 2011 GT Brembo Premium 6-spd, sans trunk junk = 3563 lbs

Closing thoughts: this car will be a hot seller. We happened to weigh a 2014 Camaro Z/28 today (equipped with A/C, see above) and it was 3835 pounds with 3/4 tank of fuel. So the S550 is considerably lighter, which is good news. I was pretty upset after hearing the (bogus) 3850+ pound numbers being thrown all over the internet for the S550, and had essentially given up on these cars before they even arrived. That was probably a bit rash, and now I am back on the Pro-S550 bandwagon.

Since we introduced them in 2014, our S550 camber/caster plates have been a huge seller

Look for products for this chassis coming from Vorshlag soon - and don't worry, we're going to keep supporting the S197 Mustang even after our 2011 GT is sold (edit: it was sold in 2015). The dyno numbers for the S550 look promising, and the exhaust gains seem pretty big for simple work. The wheel/tire packages on these cars are SUPER heavy - we have a Forgestar CF5 18x10 that fits this car, plus 18x11" wheels in the works, and there's even more "extra weight" in the exhaust and wheels. We will try to get some weight out where we can...

Thanks for reading,
Looking forward to more updates. Is the weight difference between the 2015 and 2018 mainly because of the performance pack and audio items on the 2015?


Lord knows I'm a Voodoo Child
Exp. Type
Time Attack
Exp. Level
10-20 Years
Cookeville TN
Camaro SS 2 has curb weight listed at 3685 so they are pretty close. When my PP2 car comes I will get it on the scales as well. I have the Ford Performance x-pipe arriving on Tuesday, removing that center resonator should save 20 lbs, Apex wheels vs OEM should shed another 20 more and GiroDisc front rotors will be 10 more. And so it begins again........................................
Exp. Type
Exp. Level
Under 3 Years
Just weighed my Apex 18x11" wheel, 23.2 lbs vs published 31.5 for the PP2 wheels, that would be a 33.2 lbs savings. Very good. Terry what do the Forgestars weigh?

That's a good savings. My 19x11 BC Forged race spec wheels came in at 21.3 lbs. With the small diet I've put my car on I need to weigh it to see where it's at.

I'm glad to see Vorshlag working with their own S550 chassis. Terry provided great info and customer service when I had questions about their camber plates that I had installed on my RideTech coilovers. I'm looking forward to what they do next.


Go Big or Go Home
Supporting Vendor
Plano, TX
Thread Update for September 12th, 2016: Long time no update here, but we have been busy with S550 development. In this update we will show two camber plate designs we made for this chassis, plus wheels/tires and MCS coilovers we developed in early 2015.


Aaron's 2015 GT PP was weighed in stock form, with the trunk junk removed, at 3678 lbs (1/4 tank)

Shortly after Aaron Sockwell got his 2015 Mustang GT PP (May 2015), we borrowed it and took a number of measurements. He worked at a shop across town that competed at the same Optima events as us, and he had the first S550 locally that would be competitively run in their autocross and time trial events.

Above: The factory "Performance Pack" wheels are 19x9" front and 19x9.5" rear, but they can fit more...

We measured for wheels, MCS coilover shocks, and more. To measure for wheels we started with the stock GT Performance Pack 1 parts he had - pulled them off and of course weighed the wheels and tires (above). We used some other wheels we had on hand to help determine what we thought could fit this S550.


As always we were going for MAXIMUM width under stock fenders without significant modifications. We found out after years of testing on our similar weight/power/sized S197 Mustang GT that the more tire width you can run, the better. How wide? "As wide as they make!" - but on this car, he didn't want to cut the fenders, at first. So 315mm width tires was our goal, front and rear. That tire width needs a 11" wide wheel, but many of our customers want a "rotatable" set so we use a 10" wide wheel, which fits front and rear (shown above at right). The S550 needs different offsets for both the 10" and 11" wide wheels than the S197 chassis, and it also uses a different lug stud size (M14) than the older model.


The Forgestar CF5 wheels above are what we ended up with, in 18x11" size. These fit the S550 under the stock fenders with a 315/30/18 tire (he started with Falkens and moved to BFG Rivals) as shown, with some added camber up front. Its a tricky setup, and there is VERY little room for error. Some wheel makers just "get it close enough" and tell you to run a spacer for this width on these cars, but we have it down to the millimeter. The front and rear offsets are VERY different to fit this car, but that is what it takes to fit it.


Our shop took apart the suspension then Shannon and Jason measured the stock shocks, mounting locations, and made a bunch of drawings for MCS out of Georgia. Those drawings were fired off to them and we put Aaron's car back together for the day.


A couple of weeks later the shocks and wheels arrived, so then it was time for a camber plate design. We had the car for 2 days and in that 48 hours we measured, designed, programmed, machined, assembled and installed these camber-caster plates. It was a short deadline but Jason stepped up and got it done.


The prototype camber plates were installed onto the prototype MCS TT2 struts, shown above. These were installed along with a rear spring and MCS shock onto our tester's Aaron's Mustang, then it was on track 48 hours later and racing in the Optima/USCA series. He has run these prototype plates for 2 seasons and the parts are still working perfectly on the 2nd owners' car.


These S550 camber plates were initially only available for "coilover spring" sizes, which the market wasn't ready for. It would take another tester to prompt us to make that version, the following year.


At the time in early 2015, MCS had the first "serious" monotube adjustable on the market, after working with Vorshlag to get this set on our tester's car. We didn't have a good rear spring solution at the time (we do now) but with the Eibach lowering spring in the stock location, and a stiffer 60mm spring up front, the car was fast.


Since then we have moved to a coilover-rear spring, but I will show that in a future post. For certain racing classes where you have to use the spring in the stock location we have a ride height adjuster in the works for this car.


We had the TT2 set dyno'd and the shock dyno charts for the front struts and rear shocks are shown below. The red curves are at the least rebound or compression valving. The green is about mid-way up and the blue is at full stiff. Of course rebound and compression are independently adjustable on these 2 way non-remote MCS dampers. MCS makes S550 shocks in single adjustable (TT1: low speed rebound), 2 way non-remote (TT2:, low speed rebound, low speed compression), 2 way with remotes (RR2), and 3 way with remotes (RR3:, low speed rebound, low speed compression, and high speed compression).


We tend to avoid the 3 way option unless a customer is building a race car -and- they are very familiar with 3 way dampers. You can tune yourself into a bad place with too many adjustments. The dyno above shows the MCS TT2 fronts struts with damping force curves that can accommodate a large range of of spring rates without re-valving. Both rebound and compression curves are digressive - which allows for both aggressive track use and, when turned down, good ride for street use.


The MCS TT2 rear shocks are similar in their dyno shapes, ranges of damper forces, and adjustability. We tend to recommend these TT2 doubles for folks who are more serious about competition in autocross or track environments, that understand adjustable dampers, and don't want to spend the extra money on remote reservoirs. Remotes move the compression stack + the floating piston and Nitrogen chamber into the reservoir. This allows for more total damper travel in the same length shock as well as more heat shedding area and more total fluid. We recommend MCS remotes for dedicated race cars and Pro level teams.


The dampers and spring rates we picked for Aaron's 2015 GT really helped control the roll/dive/squat/heave of the very soft factory S550 chassis setup. Aaron raced his S550 for two years on the Optima Ultimate Street Car Circuit, with wins in the GT class and invites to the OUSCI shootout after SEMA. He moved to another shock brand sometime in his second year of competition, as well as wider 335mm tires, 18x12" wheels, and flares. Then he added a supercharger. Aaron sold the car soon after that so we lost our local S550 tester.


Shortly after the prototype set was built we made a production version of our S550 camber plate, shown below. This was still only compatible with the common coilover spring sizes: 2.25", 60mm, or 2.5". We make perches to fit any of those. But the problem was - the car was so new, people weren't ready for coilovers. They wanted to keep the stock shocks...


Adding negative camber is one of the FIRST modifications racers do to their cars, and the S550 chassis needs it just like so many others. Brian Matteucci was an old friend from college and he bought a used 2015 GT PP 6-speed Mustang in 2016. We used his car to develop a new version of our S550 camber plate for use with the OEM style springs. Like a lot of you out there Brian didn't want coilovers - he had three other road race cars and the Mustang was only supposed to be a stop-gap car, a quick build. Brian just wanted to do a handful of changes to make the S550 autocross and track worthy, without spending a lot of money.

continued below


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


The 2015 GT above was the test mule for a new design of our S550 camber plate made to use the OEM style springs and stock shocks. He ended up running our 18x11" Forgestar wheel and a 315/30/18 BFGoodrich Rival-S tire. These cars need front camber to help fit that massive tire under the stock fenders, but it also needed the camber to keep from excessively wearing the tire's outer shoulder.


The S550 camber plate for use with OEM springs (shown below) was a bit trickier to design, and we tackled this in early 2016. The OEM top mount / upper spring perch (above) made for a very short stack-up height, so we had to design some new parts and use a new bearing to make our parts match the factory height. Again, we want to neither raise nor lower a car with our camber plate + perch assembly when the stock springs are used.


Similar to the S197 design, the S550 camber plate has variable camber adjustment that "slides" for another 2.5° of negative camber travel, as well as 2 fixed caster settings (stock and +1.0°). These plates also have more travel built into them than the stock strut tower will allow, but like the S197 design you can modify the tower opening for more usable range. We found that with OEM springs and stock ride heights you can still get to -2.5 to -2.8° camber on an S550 without touching the towers or going to coilovers - which is ideal for the weekend warrior, dual purpose track rat.


We rated factory springs from the Shelby GT350 (left) and GT350R (right) in the charts above. We rated these at 1/2" increments on our digital spring rater. Many spring makers take the springs to coil bind, back them off a hair, and divide this load by the travel they reached - which leads to artificially high spring rates. We see this on almost every lowering spring on the market when we rate them what we consider "the right way", to get actually useful information.


Brian installed the GT350R springs, our prototype camber plates made for OEM style springs, and the 11" wide wheels and some stick 200 treadwear tires. He then immediately took this otherwise stock Mustang and beat 19 CAM-C cars at its first National level autocross event, then won the CAM ProSolo class a few weeks later. Negative camber helps even more on a road course.


This has been our best selling camber plate since it was introduced in late 2016. It seems to be the first mod S550 owners do if they autocross or track their cars.


Just like the 2015-up Mustang GT V8 and turbo 4 Ecoboost cars, the Shelby GT350 is a great car to use on track - and with more cooling, better brakes, and bigger tires and wheels from the factory they are that much further ahead. These Shelbys are still just as heavy as the GT, and likewise suffer from the same "lack of camber adjustments" problems. If you run these cars in bone stock trim on track be prepared to replace the front tires often...


In 2016 we started to get our hands on more and more of these GT350 Mustangs. We used the installation of a production set of Vorshlag S550 camber plates on the 2016 Shelby above to make this installation instruction gallery, which has been viewed hundreds of times since.


Take a look at that gallery to see step-by-step instructions and tips to help make the install of these OEM style camber plates trouble-free. This can be done at home with hand tools and a floor jack, but an impact tool is needed to tighten the strut top nut. See this video for more explanation about that.

continued below


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

One of our GT350 customer's had a right rear CV boot rip and let go, and it looked like a rash of them. They all show evidence of a tear in the boot possibly from the production line, so its likely not a design issue at all. Ford is fixing these all under warranty. We haven't seen this pop up again since late 2016.


I haven't posted many pictures of the GT350 cars we have worked on, but took the time in today to share some things. There are a number of improvements to the GT350/R that are well thought out, with a number of innovative solutions to little problems - some of which stem from the 5.2L 180° firing order crank. One thing that caught us as strange was the plastic oil pan, only found on the Shelby GT350/R models until the 2018 Mustang GT 5.0L got it as well (as a weight saving measure).


We talked to one of the lead engineers on the Shelby GT350 project and he said this and many other items were changed to deal with the added vibrations of this unusual crankshaft layout. There are primary and secondary harmonics that cause vibrations that make things want to rattle, loosen/unscrew (oil filters), and more. They were trying to tackle these "NVH" items up until the last minute before production started.


There are mass damper weights mounted all over the GT350 chassis. It is amazing how much effort they put into damping the vibrations of this unusual engine, but people love the way it sounds, and it is made to rev up to a higher RPM, which helps it eek out more power (526 hp) than the 2015-17 5.0L (435 hp) or the 2018 GT engine (460 hp). The higher powered Shelbys also get a stronger 6 speed manual, the Tremec 3160 (read more here).


Some Shelby owners had been asking us about the caliper mounting bolts, which are HUGE. They wondered if there was a way to add a stud in place of that instead, to keep from galling/stripping the thread in the caliper mounts on the spindle. I suspected that the closeness of the bolt head to the 19" stock wheel might prevent that, but it looks like somebody has figured out the trick.


Ford has been employing what we call the "scoop and flap" method of front brake cooling. This starts with a front scoop that dumps high pressure air via a vent (see above) into the wheel well area. This is something Porsche figured out in the 1980s and we see it on high performance cars all the time. It is nothing like ducted brake cooling, which is common for race cars - where they take high pressure air from an inlet and plumb it through flexible hose to the back of the rotor. But the scoop-and-flap is at least... something.


Normally there is a "flap" that is attached to a control arm that directs the air stream towards the hub and rotor. The regular Mustang GT has this but the GT350 does not. Yet the control arm has the mounting bosses for the flap. Did it get left off for a reason?


The front 15.5" diameter, 2-piece, pin drive aluminum/iron front brake rotors from the Shelby are quite large, and they weigh in at 30 pounds. This is lighter than the front 15" rotors from the GT's Performance Pack, shown below at 33.3 pounds. The Performance Pack was a $2500 option from 2015-2017 on the base model GT and included those front brakes with 6 piston calipers, and they are pretty dang good. The Shelby had to be BIGGER so they went 15.5 and 2-piece. ;)

2015-18 GT Performance Pack front rotors are a little smaller and a little heavier, but a lot cheaper to replace

While we worked on our first Shelby GT350 this week we took a number of other pictures with it in the air.


Here are a couple of rear "underskirt" shots, showing some scoops leading to rear mounted coolers. We also measured axle width to the wheel mounting surfaces, just because.


This red GT350R (weights shown above) was out at the track with us a few weeks ago, when I was getting a baseline lap in our stock 2013 FR-S. We were at Motorsport Ranch Cresson (MSR-C) running their 1.7 mile CCW course. Pics are here.


The owner, Josh, hasn't done track events in a few years and just sold his Miata before getting into the GT350R. He drove in 3 thirty minute track sessions that day, hot and humid, and the cooling system did great. He ran a best of 1:25.22 but there was probably some time left in braking, as you might notice in the video above. Not trying to show a Stig lap here, just a regular guy making some fun laps in bone stock form on the stock tires. In the screenshot below and in the first lap of his in-car video you can see him passing me in the FR-S like I dropped an anchor (I was wide open throttle there!)


Some reference times for the MSR-C 1.7 CCW course:
  • My quickest lap time in a street legal car here is a 1:17.25 from 2014 in our NASA TT3 classed 2011 Mustang GT on giant Hoosier A6 tires + aero.
  • TTC classed 1992 Corvette (gutted, prepped, but nearly stock in every way) was a 1:21.9 on 245 Hoosier R7s.
  • 1:27.6 the same day in our TTD classed BMW E46 330 (with cord showing on the 245 R7 tires).
  • Stock 2016 Focus RS to the best of a 1:27.40 on the stock 235mm Michelin PSS tires.
  • 2015 VW GTI to a best of 1:28.10 on 225mm MPSS tires (stock but with our camber plates and a tune).
  • Stock 2013 FR-S to a 1:31.90 on 320 treadwear 215mm tires.


So far I'm fairly impressed with both the GT350 and R models, and once the price gouging ends these should make for fairly good track cars. I am heading back to Cresson this Friday to run the Focus RS on a 275mm Bridgestone RE71R on custom 18x9.5" wheels, with coilovers and a big oil cooler. Will also drive some laps in a 2017 C7 Corvette Grand Sport that we are aligning and weighing today. If Josh is there in his GT350 and finds more time I will post up the laps here.



Go Big or Go Home
Supporting Vendor
Plano, TX
Project Update for March 6th, 2018: I should lead with this bit of news first: Vorshlag bought a brand new 2018 Mustang GT two weeks ago! We're finally coming back into the Mustang market in a big way with our new S550 shop test mule.


We bought this car because the 2018 GT model has an exciting list of changes and upgrades that made it attractive to jump back into a new Mustang. The all-new 460 hp direct injected Coyote V8, new MT82-D4 6-speed manual transmission with a twin disc clutch, and of course the all new front bodywork, lighting, and other cosmetic updates. There are a ton of products we have wanted to develop for this 2015-up Mustang chassis, which we can finally do now. :)


In 2010 we ordered a 2011 Mustang GT. We used this test mule for extensive S197 product development for 5 years. The changes in the 2011 model were significant for the 2005-2014 S197 chassis - all new bodywork (2010), new brake options (14" 4 piston Brembo package), new transmission (MT82), and an all new motor (Coyote 5.0L) in 2011 that gained 100 hp from the previous 4.6L V8. It was a perfect time to get an S197... and Vorshlag has been known for S197 parts ever since then.

This 2011 GT won a lot of races, set 16 track records, and helped Vorshlag develop a lot of parts

Sure, the S550 chassis debuted in model year 2015, and we have done a good bit of product development on these cars since the beginning, but it has been difficult to find and keep some local "testers" to work with for long term testing and prototyping.

Our first S550 tester's 2015 GT (left) next to our shop S197 Mustang test mule (right)

Our first S550 test car was Aaron's 2015 GT PP, shown above at left. This car was borrowed in the first months of the S550 introduction to develop the first coilovers from MCS and our first S550 camber plate - which went from concept to CNC machined parts in 48 hours. We also used Aaron's S550 to help us come up with 10", 11", and even 12" wide wheels, which we have had built for us by Forgestar for this chassis since 2014.


We built 18x11" F14s for Aaron initially that he raced with in Optima series on a 315 Rival-S, and for the first year and a half of competition he used our prototype wheels, MCS shocks and camber plates. We have provided many many sets of wheels for S550 customers since. We also worked with G-LOC to come up their various S550 brake pad versions, which were also used on Aaron's 2015 GT. Aaron has since sold this car, so we lost our local S550 development tester.


Our second S550 tester was Brian from Houston with his white 2015 GT PP above. We developed a brand new S550 camber plate revision that could work the OEM springs for both the GT and GT350 - it was a complicated engineering, but this version works VERY well for stock springs, and we have sold many hundreds of sets of these camber plates.

Aaron's 2015 GT PP in bone stock form, testing at ECR Dec 6, 2014

But beyond those first few handful of items for the S550 (MCS coilovers, Forgestar wheels, and two camber plate versions) we have been limited on what we could develop and sell for this chassis, due to a lack of local testers or an in-house test car for the last 2 years. People haven't been rushing to Vorshlag for other S550 parts we carry, because we aren't "known" for racing a S550. We are fixing that now.

Look at that front end rise! Me putting in Baseline Test Laps in in Aaron's 2015 GT at ECR, Dec 6, 2014

What did it was a ride along on track. I had only ever driven Aaron's 2015 GT in stock form at ECR back in 2014, but I rode in Brian's white car (now owned by his buddy, Matt) at a NASA event in October 2017 at MSR-Houston. After riding/coaching with Matt for a session I was pretty damned impressed with this S550 - it only had our camber plates, some 350R springs, a Torsion T2R, the 19x11" wheels we sourced, and some 305/30/18 Bridgestone RE71R tires. It was just flat out fast, put all the power down easily, gobbled up bumps and curbs like no Mustang I had ever driven, and woke me up to the reality of how good the S550 can be with a few tweaks.

We are a little late to the S550 party, but this 460 hp direct injected 2018 Mustang GT is now part of our test fleet!

I started looking closer at the 2018 GTs last Fall when new cosmetic changes were introduced, just before the drivetrain upgrades were announced. The new motor having more power, the stronger twin disc clutch, the stronger version of the Getrag 6-speed manual with all new gearing and synchros (MT82-D4), and some other changes. I waited until this Spring until I drove one... we quickly found one with help from our friend Corey White at Roush and his compadre Rich at Five Star Ford in Plano. We bought the bare bones 2018 Mustang GT two weeks ago (above) and they made me keep it a secret - which nearly killed me. This car will be our in-house development mule for new S550 parts as well as our primary autocross and time trial car for the next few years.

First autocross was run on bone stock suspension, brakes, wheels and tires. It was hilarious!

So if you enjoyed the build thread and S197 development we did on our 2011 Mustang GT, buckle up because this S550 is likely going to be faster than that car. We are going to try to keep it streetable for at least the first 2 years, so it doesn't get too scary for some of you guys! :D


There are many reasons why we didn't buy an S550 when it first came out in 2014, and why we did now in 2018. I will go into that briefly below.

"The one that got away" - the 2015 Mustang GT we almost bought

We did look at purchasing a 2015 GT in the Fall of 2014, shown above. The dealer even brought it by our shop to test drive, measure, and check out - it was perfect. Performance Pack (15" 6 piston brakes + bigger wheels/tires), leather Recaro seats, touch screen Nav, Race Red. Problem was the $43K price tag was a bit more than I could swallow at the time. We had just renovated and moved into a new shop space (which costs $$$), just got back from two weeks of the whole shop going to SEMA/Optima shootout in Vegas (which cost $$), just bought CNC machines ($$$$$!), and I was tapped out. Bad timing, but our dealer was happy to sell this car to someone else for more money - it was the "hot new car" with the perfect options and color. It was sold within 24 hours.

"The one that got away" - the 2015 Mustang GT we almost bought

I have second guessed this decision ever since - this was a perfect test car, right when the S550 was new and hot. Sure, we could have gone into more debt and made that purchase happen, and we would have surely developed a stronger S550 following by now. But moving CNC manufacturing in-house was a big necessity back then, and tooling up was a giant time and money suck. We needed to concentrate on this aspect to keep growing our business.

"The one that got away" - the 2015 Mustang GT we almost bought

3.5 years later its a whole different situation at Vorshlag. Our CNC operation is running smoothly and our reputation for having a backlog on suspension parts is long gone - because we did concentrate on the CNC aspects instead of buying another car. We are now way ahead on our inventory production, and have been developing new parts every month since. The business is growing and yet... I still wanted an S550 to test some new product ideas. So we waited until the big round of 2018 changes and got one.


We have both short term and long term development, testing, and racing goals for this new shop 2018 GT. Unlike the S197 chassis, the S550 Mustang is a "world car", meaning it will be exported to 140+ countries for both Left Hand and Right Hand drive. The Ecoboost made it popular in countries were fuel is $10+/gallon, which helps over there. This exported model is paying off in Europe (out selling 911s in Germany!) and for the 2016 model year the Ford Mustang was the Best Selling Sports Car Globally.

New coilover S550 inverted rear remote double adjustable monotube design from MCS was tested on our car

This world car status has pushed German, Dutch, and Swedish shock makers to take the S550 more seriously, so we want to test some of the new coilover options from Ohlins, Bilstein, Whiteline, and MCS - this car let's us do that. Last week with the car only days old we already tested a new inverted MCS RR2 version (inverted) on our 2018. Sure is handy having one of these around!

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Since here in America fuel is cheaper than bottled water, we got the big 5.0L V8! #Murca Our goals there are to get as close to 500 whp as possible without ever pulling a valve cover. We've seen road race and autocross Coyote 5.0 guys try to get there and spend a fortune in upgrades and repairs, but this Direct Injected Coyote has the right foundation to build on.


New heads, cams, block, bearings, oil pan, fuel injection and compression ratio (12:1) puts power up to 460 hp @ 7000 rpm and 420 lb-ft @ 4,600 RPM (up 25 hp and 20 ft-lbs from 2017 GT) and runs from 0-60 mph in under 4.0 seconds. This article has a stock 2018 GT running a 11.8 quarter mile with the new 10 speed automatic!

What may come as a shock is that we did not buy the $4000 Performance Pack 1 or the new $6500 Performance Pack 2, on purpose. Why? Well most of the parts in those PPs would be replaced in the long term, with our plan.

Powerbrake X-Line X6EL 380x34mm front brake kit for a Ferrari F430 Challenge - similar to what we have on order

Instead we will test the first production 380x34mm 6-piston Powerbrake kit for the S550 on our car. The image above is a similar setup made for a Ferarri F430 Challenge car, so the hats will be different - but otherwise this is what we should have on the car by April 2018. We want to make several other products for this chassis that we haven't seen the aftermarket make yet - this car will let us do that.

The two SCCA autocross classes we will test this car in are CAM-C and STP

To test these new S550 products there is no other better place than in competition. We are eyeing a number of racing classes and organizations to play with this car in. Jon is going to autocross it in CAM-C, Amy and I will autocross in SCCA's STP class, at least initially. It is always a challenge to build around SCCA autox classes so we will keep it fairly casual so that restrictions for one class don't limit products we can make that we know people will want. There's also the Optima series to look at, which has classing closer to CAM than STP. We will talk more about those class choices and potential restrictions in future posts.

New wheels (19x11" Forgestar F14) and tires (305/30R19 Bridgestone RE-71R) are already here...

For road course testing we want to run with both NASA and SCCA Time Trial classes, and of course Optima series as well. At first we want to keep 200 treadwear tires in mind, since this "200" limit is becoming so common across many series. We will start by using the 305/30/19 Bridgestone RE71R shown above (first set is here) on a 19x11" wheel (Forgestars just arrived today). We have already completed the first autocross and track tests in this car, which we will cover in our next post. We have a busy schedule planned, so we will have periodic updates in this thread to show testing and racing results.


Let's get into some tech here. Weight means almost everything in autocross and still a whole helluva lot on a road course. Tire-to-Weight and Power-to-Weight are damn near everything in Motorsports competitions (we expound on this in great detail in this SCCA Time Trials rules discussions, here). I am going to say it right now - comparing published "curb weights" is worthless. The car makers weigh their cars differently, with different options and fuel loads. Some with passengers, some without. Car magazines mostly just re-post those numbers. WE WEIGH CARS, with accurate, digital scales, always the same way. We weigh parts, wheels, and fuel loads, too!

My 2013 Mustang GT was 3518 pounds stock, and 3493 lbs with 2" wider 18x10" wheels and 295s

As I have posted before, the S550 is a bit of a fatty. Sure, its lighter than the 2010-15 Camaro by 100-200 pounds, and it's on par with the 6th gen Camaro, but *heavier than similarly equipped outgoing S197 models (*by +127 lbs, with similar options, comparing our base 2013 GT and our base 2018 GT). The S197s were not exactly lightweight cars themselves.

Left: A 2017 GT350 at 3703 lbs with low fuel. Right: The first GT350R we weighed was 3649 lbs with 3/8th tank

Much of the S550's weight gain over the outgoing "Stick Axle" S197 chassis was the beautifully designed Independent Rear Suspension that this car got. Unlike the bastardized parts-bin T-bird IRS on the 99-04 SN99 Mustangs, this S550 stuff is IRS DONE RIGHT. This is a game changer, boys. It puts power down like no other Mustang that Ford has ever built. Like... Ever.

This is what makes the S550 worth the weight!

These damn S550s also ride so well I forget its a pony car on the street. It is indescribable - if you have never driven an S550, do yourself a favor and go test drive a new one. Be prepared to never want to drive a stick axle pony car again. Yes, it's THAT much better.


Market Comparison Tangent: It might seem insane to compare a 2013-2018 Scion FR-S/Subaru BRZ/Toyota GT to the 2015-18 Mustang GT, but it is a valid comparison on price, and some folks do cross-shop these cars (esp the Ecoboost Mustangs, which aren't that much lighter than the GTs, just a bit slower/cheaper). Look at the weight on our bone stock 2013 FR-S above - that is a solid ONE THOUSAND and ELEVEN pounds lighter compared to our stripper 2018 GT. Granted it has 200 hp vs 460 hp, but not much less tire (215mm vs 235mm in base trim). The road course baseline lap times compare remarkably close, too! /tangent

We have weighed dozens of S550s and they range from 3600-3800 lbs

Back to the S550 Mustangs - we have seen weights on 2015-up Mustang V8s as low as 3590 lbs (this base 2015 GT below left) to as high as 3800 pounds (the Shelby GT350 below right), depending on options and fuel load. We always remove anything from the trunk - like spare tires, jack, carpet mat, and easily removed emergency tire inflation kits - to get a fair, consistent "race weight" for a car. Because you'd remove this crap at an autocross or track event. We also try to weigh cars with as little fuel as possible, to equalize our numbers. It doesn't always work out that way, so we include a picture showing the fuel level gauge on our weight pics for consistency.


We had hoped our base model 2018 GT would sneak into the high 3500s stock, but there has been some bloat in this model as the years have passed. The base GT now has two power seats up front, the 2018 now has a dual mass flywheel and twin disc clutch which adds some weight, as does the new Direct Injected motor (high pressure pumps and doo-dads)


We found the lightest GT possible with our base model 6-speed 2018 Mustang GT, above. We saw a weight of 3645 lbs with low fuel (25 miles to empty) and the optional trunk-mounted spare tire and jack removed.

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The optional mini spare tire is actually really nice but we will likely sell this soon - its a $405 option and $650 from the dealership purchased separately. If someone wants that peace of mind it might be worth the 35.1 pounds it adds. Also, the stock wheels and tires are always heavy, as we saw in the identically equipped 2013 GT at the top. We will still lose weight with 3" wider aftermarket wheels and tires. And more with Sparco race seats. And more with the larger Powerbrake BBK, more with the ARH long tubes, more with the Magnaflow exhaust. Weighing this car at each step is a key part of the game plan. #WeighEverything


The base model GT comes with these itty-bitty wheels and tires - 18x8" 5-spokes with 235/50/18 all season 400 treadwear tires. These things are AWFUL, and almost dangerous on a car with this power level, but we found this car with the least number of options for a reason: COST and an UPGRADE PATH that made the optional OEM upgraded parts pointless.


One of the theories we want to test is how does a Base Mustang GT compare to the Performance Pack 1 and new Performance Pack 2 cars, both on track and with respect to cost. We also want to compare to the GT350/350R models. And let's compare to the 6th Gen Camaro SS 1LE. And not just in stock vs stock form - on our 2018 GT build we will show costs of parts after each level of modifications, and see how close in lap times we can get to the obviously faster Mustang models on cost.


The 2018 Performance Pack 1 option package includes the 15" dia ront 6 piston Brembo brakes, 19x9/9.5" wheels a 255mm Michelin tire - it was once a $2500 option but is now $4000. Later in March of 2018 we will start to see the new Performance Package 2 option debuting with:

Performance Pack Level 2 includes all of the features of Performance Pack Level 1 – unique chassis and antilock brake tuning, unique stability control and electric power-assisted steering, Brembo™ six-piston front brake calipers with larger rotors, a k-brace, larger radiator, silver-painted strut tower brace and a TORSEN® rear differential with 3.73 axle ratio.

It’s highlighted by a lower stance, a redesigned front splitter and rear spoiler, and 305/30/R19 Michelin Pilot Sport Cup 2 tires wrapped around split-fitment aluminum wheels – 19x10.5-inch front and 19x11-inch rear.

The tires, 1.5 inches wider than those found with Performance Pack Level 1, provide a firmer grip, and work with a retuned chassis to put the car more than a half-inch closer to the ground. The package is available exclusively with a manual transmission.

Custom tuned MagneRide® dampers and quicker steering calibration provide better response. Other improvements over Performance Pack Level 1 equipment include a 67 percent stiffer rear stabilizer bar, a 12 percent stiffer front stabilizer bar, 20 percent stiffer front springs and rear springs that are 13 percent stiffer, all of which contribute to a more stable ride around corners with less body roll.

The PP2 option is $6500 on the Mustang GT, and requires a number of other pricey options to be able to order it. It has almost everything track related from the Shelby GT350 without the problematic 5.2L engine. The 2018 Mustang Shelby GT350 (below) is also one we will compare our build to. It has all of the PP2 bits and 527 hp, plus that Shelby name.


You can see more 2018 Mustang pricing here. We didn't buy a PP1, PP2 or GT350/350R car on purpose - because they come with a lot of parts that we would toss out at the first opportunity. Sure, these versions are faster right out of the box, but they come at a big price bump. We optioned up a 2018 GT with Premium, Recaros, PP2 and it was $52K. The Shelby GT350 starts at $57, the 350R at $65K, and they can quickly go into the $75K range with options, before considerable dealer mark-ups.

This is the actual window sticker from our 2018 GT

We decided to "keep it simple" on this 2018 GT and found a car with almost no options. We found 3 cars locally that were V8 GTs, 6-speeds, and almost nothing else added. This Race Red car was what we bought. Sticker was $36,695 but it wasn't hard to get them to knock $4200 off ($2000 rebate and the rest was just normal "under-invoice" pricing). The final $32,500 price (before TT&L) saved us nearly $20K off the 2018 GT PP2 I had optioned up, and $25K-35+ off the Shelby GT350s. What can we do with $20-35K in upgrades? We shall see... :D


We talk to a lot of new Shelby GT350 owners every week that call us because they want to track their cars and need some front camber adjustment. We ask them what their previous car was, and many of them had never bought a Mustang before. In a lot of cases their former car was a 911 GT3. Ford is doing something right to steal that clientele. So we thought - "Can we do a more focused GT3-like Mustang?"

2018 Porsche 911 GT3 RS is a glorious car - if you have $187K to spend

The Shelby owners we talk to say they like the GT350 because it is so much cheaper than a $144K 2018 911 GT3 ($187K for the GT3 RS). They can afford to take their $57-75K Shelby to the track a lot more often, and these Fords have no "Porsche Tax" on repairs or upgrade parts. There are still plenty of buzz-word technical items on the GT350R that impress their Porsche friends (MagneRide, carbon wheels, rear wing, 180° crank V8 sounds exotic) and the lap times are strong, too.


Most every gear head knows the track-focused 911 GT3 RS model, which comes from the factory with racing style seats, a roll bar, adjustable coilover suspension, wider/stickier tires, better brakes, more power, better aero, and less weight than the regular 911 - basically it has everything that can make this car faster on track, and nothing else. We think Ford tried to do that on the GT350R, but it missed the mark a little bit. There is no camber adjustment up front (so they KILL front tires), doesn't lose any substantial weight, the Recaros are not exactly race worthy seats, no roll bar, and they are still too softly sprung.

Our 2011 GT had a 4-point roll bar, Schroth harnesses, race seats, and fire bottle

So our plan for our shop 2018 Mustang GT will be to make it into as much of a GT3 RS clone as we can, for 1/4 the cost. Is this comparison a bit pretentious? Possibly, but we're going to give it a go. Look for an interior on our 2018 similar to the level (above) we had on our 2011 GT, before that car "went off the deep end" and became more of a race car. We will add racing seats, 4 point roll bar, and proper 6 point harnesses for track use. Adjustable coilovers and Motorsport level brakes. Of course our signature "max-width wheels" and the widest 200 treadwear tires. Some aero tricks that we will rob from the Shelby GT350R (wing) and PP2 (front splitter) initially. It will stay street legal this whole time, too.

Whiteline's Max-G coilover kit will be one of the first shock options we test

Should be a fun few years playing with this car and we hope you enjoy the write-ups. We already autocrossed and tracked this car in stock form to get some baseline numbers and have something to compare to. This post has gone too long so I will write that up next week - and have some better track numbers at Test # 2 (with the first round of upgrade parts) to show also.

Thanks for reading!


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I'm overdue in answering some questions and replies. Keep 'em coming.

Looking forward to more updates. Is the weight difference between the 2015 and 2018 mainly because of the performance pack and audio items on the 2015?

We don't see a huge weight increase in the 2015-17 GT to the 2018 GT, when you compare the same packages. Performance Pack to PP1, Base GT to Base GT.... here's one example:


This 2015 GT 6-speed was the lightest S550 we've ever weighed on our scales at 3590 pounds. It was a base model/non-premium/non-PP stripper model like our's.


Why our 2018 GT - with the same fuel load and equipment - was 50 pounds heavier is still a bit of a mystery. We weighed both cars on the same scales, so it wasn't a measurement difference. Probably a small part of that 50# increase is due to additional high pressure pumps and equipment related to the Direct Injection system.

Camaro SS 2 has curb weight listed at 3685 so they are pretty close. When my PP2 car comes I will get it on the scales as well. I have the Ford Performance x-pipe arriving on Tuesday, removing that center resonator should save 20 lbs, Apex wheels vs OEM should shed another 20 more and GiroDisc front rotors will be 10 more. And so it begins again........................................

Please post up the PP2 weight if you can measure it with no fuel - would love to see it. If anyone local to Dallas area has a PP2 coming I will weigh it for free at our shop - just call us ahead of time and try to get it low on fuel. :)


I didn't want to clutter up my S550 thread with too much non-Mustang data but here's a 2016 Camaro SS we weighed - it was about 6 pounds lighter than our car, so nearly identical.

That's a good savings. My 19x11 BC Forged race spec wheels came in at 21.3 lbs. With the small diet I've put my car on I need to weigh it to see where it's at.

That's a nice savings, especially in 19x11". Is that their published weight or did you check it yourself? 18" wheels are a bit lighter than 19" versions...


This weight above (26.7 lbs) is a normal weight for a one piece flow formed 19x11" wheel - a similar offset 18x11" F14 is nearly 4 pounds lighter (below).


I will show a lot more weights in my next post... working on it now, its big.


We now have three track/autox events to cover + a huge round of mods.

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That's a nice savings, especially in 19x11". Is that their published weight or did you check it yourself? 18" wheels are a bit lighter than 19" versions...

This weight above (26.7 lbs) is a normal weight for a one piece flow formed 19x11" wheel - a similar offset 18x11" F14 is nearly 4 pounds lighter (below).



Yes, I weighed it myself. It's the RZ05 and it came in at 21.3 lbs actually. BC Forged offers a race spec version for some of their wheels at no additional charge. There are some additional reliefs that are cut out of the back and the center bore for the hub size is drilled all the way through which eliminates the center cap. The extra material that is needed for the center caps saves weight. Plus, it helps that it was 50mm offset as well. Of course you have to add in the weight up front for the spacer.
Nice updates so far. I wanted to add a couple of comments from my experience with my GT350 and from driving Porsche's.

The first thing is have any of your customers had issues with the GT350 rear diffs running hot? From my experience I was getting into the 280's and I question either the effectiveness of the NACA ducts or the size of the diff cooler mounted at the rear of the car. This was under 100 degree days and for reference the engine oil temp was 260, trans stayed very cool, and ECT in the 220 range. So the diff seems to run hot relative to the others. The other coolers work great and what a nice change from the Boss 302. Something to keep an eye on.

I installed the brake cooling deflectors made by someone else and liked how cleanly they mounted and looked. But after I mounted them another TMO member told me the airflow from the front duct does not match up with the deflector. Sure enough if you take a straight edge you can see the airflow doesn't even come close to being directed at the deflectors. Unless you develop your own deflector this is a waste of time and I question if it's needed. If it is needed you're probably better off installing a proper system like on the race cars. GT3 airflow for comparison.

991_porsche_gt3_brake ducts.jpg

For my birthday last September my wife sent me to the Porsche Experience in L.A. and I drove a new Cayman 718 S and GT3 RS. I've owned two air cooled 911's in the past and always known I'd own another 911 but I didn't think it would happen a couple of months after my visit. Anyway this was on a Saturday and the following Monday I had a track day in my GT350 at Thunderhill scheduled. Let me first say if you get a chance to go to one of the Porsche Experience centers don't miss it. Even a 718 S is fast and fun and both of my drives were like a track day. I had the same instructor for both sessions. I explained to the guy that I wanted to spend as much time on their track as possible and probably spent 45 min of the first 90 minutes in the Cayman on their 1.5 mile track and 60+ minutes in the GT3 RS. I drove the RS so long and hard that I had to take a break!

One of the interesting things was the instructor, who is an accomplished racer and was absolutely flying during his demo laps, kept telling me how great the brakes are in the RS. I ran Pagid RS29 pads in my 350 which are favorites of Porsche owners. For all I know the RS has Pagid RS29's on it. I was driving the RS hard, the instructor was constantly pushing me to go faster vs slowing down like a few of us were told at a Ron Fellows advanced class some TMO members and I attended. As I kept pushing the car harder and braking harder I kept thinking the brakes don't feel any better than the brakes on my 350 and possibly not as firm. These were the PCCB brakes as well. The calipers look very similar to the ones on the GT350.

Now there were some distinct advantages with the RS. IMO the steering is significantly better. I felt I could place the car anywhere on the track. The instructor would tell me to be over 2" more at corner entry and I felt complete confidence that I could, and did, place the car there at speed. The other is you notice the overall weight and the difference between the front and rear engine designs obviously. Two ways to go fast for sure. I had been on track in my GT350 and chased down several 991.1 GT3's and even a 991.1 GT3RS. After driving the RS I though I could be 5 seconds a lap faster in that car at Thunderhill than I could in my GT350.

I was expecting a let down at my track day on Monday but I wasn't. :D While the GT350/R is very close in performance to a regular GT3, and the vehicle dynamics are completely different, the GT350 still handles great, brakes well and has more power. While the braking in the GT3 RS didn't feel any better I was only braking from just over 100 MPH. I suspect it could be a lot better braking hard from much higher speeds. The GT3's better aero would also help. So the bottom line is I don't think the GT350 is that far off of a GT3 stock and with proper mods you'll have no problem chasing them down. You'll have similar results with your 2018 GT.

Screen Shot 2018-03-15 at 7.03.08 PM.pngScreen Shot 2018-03-15 at 7.03.00 PM.png
I need to bring my car in again with current mods and have it weighed to compare from when it started life at 3703 lbs above.

Apex wheels 19x11 (R hubs and 28mm front spacer)
Michelin 305 SC2 tire (they are several lbs lighter than PSS)
Watson Roll Bar
R-seat Delete
Resonator delete


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Project Update for April 3rd, 2018: Things are really busy around here and I started writing this two weeks ago, and every day that goes by more stuff is going into this 2018 Mustang.

Track Test #2 at a NASA race weekend - the lap times were a welcomed surprise!

I am going to cover what I can quickly and save the rest for next time. This time we will cover the first track test in stock form, the first autocross in stock form, a big round of upgrades, and then the 2nd track test with these suspension and a wheel/tire updates.


On my way to the baseline track test # 1 I found a coin-op car wash and had brought my car wash supplies with me to hand wash the car properly. I don't know why but the First Wash I do is always sort of a bonding moment for me with a new car. (re-reading this - I sound a bit mental)


Up and out of the house before dawn, I left to go to Motorsport Ranch Cresson (MSRC), our chosen road course test track for the past 4 years. I teased the picture below on Facebook - and this was before we had announced that we even bought a new car. Some sharp eyed people figured out what we bought within minutes. I suck at keeping secrets. :D


The track layout we use at MSRC is their 1.7 mile CCW course, shown in the daily map below. This facility also runs a 1.3 mile course, which can be combined with the 1.7 to form a 3.1 mile course, and even the 1.7 mile course "backwards" (CW), which I am not fond of. We stick with the 1.7 CCW because it is the primary configuration that NASA uses, and it has the most room for "oops"... there are 100-200 yards of runoff from any corner, so I can use my hack skillz and push 10/10ths and if I screw up and have an "off", nothing bad happens. :D


We went on a Friday morning where I met up with some friends for a member day. It had been raining hard for two weeks straight. It stopped raining the day before but the ground was saturated, so there was an unusual amount of drainage across the track in a few spots, as shown above. This meant we had to deal with some water on the track, but only in a few spots initially and it dried up (only damn in front of "Rattle Snake") by the time we went on track at 10:30 am.


I went out that morning with two of my homies: Jerry Cecco in his C6 Z06 and Aaron Sockwell in his C5 Z06. Both of these guys have been testers for Vorshlag in the past; Jerry in his Boss302 that tested our TrackPro suspension and his C6Z which has tested a variety of our C6 specific parts, like our brake cooling and our 18x12F/18x13R wheel setup. He was on 335F/345R Hoosier R7 tires. Aaron's C5Z is relatively new to him but already has rear flares, 18x11F/18x12R wheels, 315/335 BFR Rival-S tires, and some CAM legal aero.

MSR-C Track Test, March 2nd, 2018 - Gallery

My hope was to go on track at the same time as these two and compare the stock lap times of the 2018 GT to them - who have both run this track many times as well. I waited until they both got to the track and we went out at the same time. This would be my 3rd track test at MSRC 1.7 CCW for 2018 so I was still "fresh" on this track layout, but the first time to drive this Mustang on track.


The car was a week old, had 340 miles on the odometer, and still had the paper tags out back! Temps were 55°F and I had the tire pressures at 31-32 psi with some warmth in the tires from driving 85+ miles out here in the car. As you can see from the picture above right (which I took in a later session that the Corvette boys ran) the water on track was right in the braking zone for the first turn after the start/finish. So let's see the lap...

Click here for in-car video of Track Test # 1

If you click the image above you will see the youtube video of my best lap, which was anything but pretty. The stock tires are GARBAGE and it amazes me that Ford has upgraded the engine in this car SO MUCH yet still supplies the same base tires they put on a 2005 3V 4.6L Mustang. Laughably bad, borderline dangerous. Of course I ran with the traction control completely off and was not pushing the revs hard - because if the engine torqued up too much in a corner, it would just start spinning the rear tires.

The worst possible tire Ford could put on their 460 hp Mustang - 235mm 400 treadwear all seasons!

Though "Horseshoe" and "Boot Hill" the car wants to be in 3rd gear - the 6 speed gearing of the MT82-D4 is COMPLETELY different than the old MT82 - and it was all too easy to get the rear to step out under power. I was lucky if I could use half throttle through that series of 3 left turns. In normal cornering (turn in) the handling led to heavy understeer, and as you can see from the AiM Solo DL data logging (finally got a tach and throttle trace!) the lateral grip was between .90 (sustained) to 1.02g (peaks). In my best lap (hot lap 3) I was using all of the track surface, and maybe a little dirt, before the tires got so hot they fell off.

The brakes were atrocious. If I tried to stop with more than .85g it would overheat the pads in two stops (2 corners). After a total of 8 hot laps I lost brakes completely, even babying the pads with 8/10ths stops. Pedal got HARD and would no longer stop (we did have Motul RBF600 fluid in the car - I won't use stock brake fluid on track!) My best lap time of 1:31.412 stacks up pretty poorly to many other cars (see listing of lap times in the Track Test # 2 section), but most of this was due to the base model's sub-standard tires and undersized brakes. We expected the brakes to kinda suck when we bought the car, and had plans to add better pads to these and maybe brake cooling (which we later found to be impossible), before ditching the 14" 4 piston fronts for something more appropriate. The Performance Pack 15" 6 piston brakes are much better factory offerings than these.


After 8 hot laps brakes were DONE so I parked it. The Corvette boys went out again at 12:00 (member days here run 30 minute sessions that alternate between sports cars, open wheel, and motorcycles) but gave up after a handful of laps due to the water into Rattlesnake. This BADLY affected both Corvettes' ABS systems, but the 2018 GT took the wet braking in stride and still pulled the same .85g stopping through this water. It was so sketchy in the C5Z (Ice Mode) that Aaron parked it after trying just a few laps in both sessions. Ford ABS still rules supreme. :)


After grabbing some lunch with Aaron and Jerry at the BBQ joint next to the track, I headed back to work on this Friday, armed with the knowledge that this 460 hp Mustang GT was only 1/2 second quicker in stock form than our 200 hp FR-S at the same track, on equally crap tires and brake pads (1:31.90). The extra power didn't help when the Mustang has to carry an extra 1000 pounds around on only 20mm wider tires... the tire-to-weight ratio winner in this battle goes to the 2634 pound FR-S.


"Even after 31 years, the SCCA finds new and interesting ways to piss me off"

So the gluttony for punishment in stock form continues, plus I subjected myself to the typical shenanigans of the SCCA to boot! :D I was mistakenly looking forward to this autocross - the first I had done in years in a car I owned and had planned on prepping around an SCCA autocross class (STP). Yea, that was a short lived plan.


Amy and I drove out to Texas Motor Speedway to run this, the first autocross (of 9) for the year with Texas Region SCCA. Jon Beatty (our order manager here at Vorshlag) was to meet us there and run the car in CAM-C, while I was going to run in STP and Amy in the paxed Womens class. We have a lot of friends in this region and all 3 of us were looking forward to seeing our autocross buddies and running in this car - even knowing it would suck on the stock suspension, tires and brakes.

We got the car teched and headed over to the registration trailer to sign the waivers and see our worker assignments, then walk the course. That's where "the bus went right into the ditch"...


So this region is a stickler for checking your SCCA membership card and driver's license. Some insurance thing they say. My license had expired a few weeks earlier, but I didn't think about it - because I had updated my address and got a fresh one just a few months earlier. They saw the two week expiration and said I was not allowed to drive.


So I got to WATCH as Amy and Jon autocrossed our brand new car for the first and last time in stock form, on the day we debuted to the public that we owned it. I was less than thrilled with the people involved and thus began my spiral of disdain for all things SCCA, once again. :D


I did get to ride shotgun with both Amy and Jon on some of their runs, to experience the awful stock suspension and tires.

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Plano, TX
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CAM-C is a pretty hotly contested class in the Texas Region SCCA and they had 12 drivers that day. There were 7 seriously prepared cars on Bridgestone RE-71R or Rival-S tires that day, and a few more coming to the class in the coming weeks. So Jon had a pretty tough job to get any regional championship points with such a painfully stock setup.


The grip levels were junk but he was still able to work on corner placement (getting close to the cones), figuring out the gearing of the new motor/trans setup, and overall learning to manage understeer.


The tire pressures were the only thing we could work with so we adjusted them down slightly (29 psi rear) to try to mitigate the severe lack of grip. You can see the deformation and camber loss in the front suspension in the images posted here. The stock suspension is SO soft that it allows the 3650 pounds of Mustang to flop around like a dying fish.


Both Amy and Jon liked how predictable the 2018 GT was to drive, even on the tiny 235mm tires. Unlike the stick axle S197, the S550 is very easy to drive with no prior experience - no gotchas. It went where you pointed it, just not very quickly. The rear tires struggled to put the power down but Jon felt like it didn't have the grunt of 460 hp engine. That could be a torque management thing for new motors - we barely rolled 500 miles on the odometer on the drive to the site that morning.


Both Amy and Jon put in some hard driving, yet the car was holding them back. Jon managed a 51.108 sec 4th run while it was just starting to mist rain, and sat as high as 6th out of 12 at one point, but fell to 9th in CAM-C class at the end. Amy managed a slightly quicker 50.646 sec run on her 5th and final run (in another run group), within 2 tenths of the 2 drivers ahead of her, but the STP "PAX" is almost identical to CAM-C (bad), so she took 4th out of 5 in this PAX factored Women's class (a regional only class).

We took video from most of their runs and I have video posted Jon's best one above. On one of his runs and two of Amy's runs the AdvancTrac warning light came on, bonging away with warning chimes. Of course they run with the system completely turned off, but something about the sliding around triggered it to come on again. Nothing bad happened it just freaked them both out. The brakes felt awful but we later found out that the 8 laps on track had killed the stock pads - they were down to only a sliver of material left.

Lastly we will talk about overall PAX placement - our only indication from event-to-event on how well the car is improving since the courses are different each time. Out of 160 cars Amy took 88th and Jon took 96th, so we have a ways to go yet with this car. It did about as badly as we expected for stock suspension, tires, and brakes.


We have worked with Motion Control Suspension for half a dozen years and often they will make something for a new car based on measurements and/or drawings we send them. This time they wanted to test an inverted shock design for the rear of an S550 - so they shipped it to us for a test fit just a few days after we bought our 2018 GT. Nothing of note has changed on the rear shock/suspension from 2015-up on the S550 chassis.


We always try to start with a side-by-side shot against the stock damper. The MCS version looks properly shortened, assuming it was 50mm shorter or so. Which is ideal. The goal here is to shorten the shock enough to allow for a good balance between droop and bump travel - at a lower than stock ride height. The shock length is critical to getting this right... and why so many people have terrible experiences with lowering springs on stock length shocks and struts (all of the lowering gobbles up bump travel... one good bump and BAM, its bottomed out).


Above left is the stock S550 rear shock mount / shock / divorced spring. Above right shows a spherical upper with the MCS inverted remote double installed on my 2018 GT.


You can see the lower spring perch clearance and rebound adjuster knob at the bottom of the strut shaft, above left. Then we checked the shock for full bump travel measurement (above right).


These pictures show the shock at ride height (above left) and full droop (above right). This is the ride height we shoot for on S550s = 14.5" center of wheel to fender lip (1" lower than stock). From these measurements we can calculate total wheel travel (5.25", which is a lot) and pick the ideal ride heights based on bump vs rebound travel. Maybe not super interesting, but this is some of the work we get to do when working with shock manufacturers.


There were several suspension items we upgraded in our first round of mods to our 2018 Mustang GT. We're going to keep a running tally of the parts costs and in the case of parts that are removed or replaced, we will adjust the "Mod Budget" as well as lap times at our test track Motorsport Ranch Cresson.


This was a substantial change that happened over 24 hours at our shop, but its a typical round of upgrades that people tend to do all at once. Coilovers, camber plates, swaybars, wheels and tires. We'll break it down into 3 sections below to show what we did and why.

Whiteline Max-G Coilovers + Vorshlag Camber Plates

This is the first of several monotube adjustable coilover dampers we will likely test on our shop 2018 GT. The S550 chassis benefits due to its "world car" status and higher global sales volume in that many higher end shock makers cover this chassis vs the S197 before it. There are good coilover kits we sell made by Ohlins, Bilstein, MCS, and now Whiteline.


This "Max-G" kit is made by a high end Dutch shock maker and is private labeled for Whiteline with spring rates and damping set to their specs. We had such good luck with the "Max-G" Whiteline coilovers on our shop 2013 FR-S (#Agent86) that we decided to test a set for our S550. Whiteline was thrilled to have some good test data so they sent these and the swaybars to us as soon as they heard we ordered this car. The shock kit arrived as shown above, with front springs on the front that were coilover at the bottom but made to fit the OEM style upper perch and strut top mount on top.


We haven't seen many people try this S550 Max-G kit yet, so we got this set in and took a closer look. This kit is made to be a "suspension in a box" and is supposed to work with the OEM front strut top mounts and OEM rear shock mounts. Jason rated the included springs (click on the chart, above left) on our digital spring tester. While the rear's looked to be in the right ball park (avg rate of 535 #/in) the fronts were pretty soft (205 #/in). So instead of "burning an event" with a test of the included soft front spring, we just jumped in and did what we've done on many other "kits" that come with springs - we substituted our own spring and camber plate up front with something more aggressive, and used our spherical rear shock mount as well.

The Hyperco 60mm coilover spring we chose for the front was 400 #/in. When you run the numbers for the motion ratios out back (with a coilvoer spring instead of the stock "divorced" spring location) this gave us nearly an even split with about a 400 #/in front and rear wheel rate. Having sold and tested MCS dampers with many different spring rates on the S550 chassis, we felt this customized 400F/535R spring set would offer a very streetable ride yet should still substantially cut down on the "floppiness" of the stock suspension on track.

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