Vorshlag 2018 Mustang GT + S550 Development Thread

Discussion in 'Vorshlag Motorsports' started by Fair, Mar 9, 2018.

  1. Fair

    Fair Go Big or Go Home

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    continued from above

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    We used a front spring length long enough to keep the spring package "above the tire" while making sure they weren't too short that they had excessive slack at full droop. Out back we used the Whiteline spring and added our prototype "Version 1" S550 spherical rear upper shock mounts - which are admittedly a bit ugly, due to a plating choice I made that didn't work well.

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    How were these made? We took the cast aluminum OEM upper shock mounts (above left) and drilled out the crimped in upper washer, which acts like a "fuse" - this pops out when someone bottoms the suspension hard enough in a crash. But it also pops when people convert the S550 rear shocks to coilover springs, and we don't want that. Moving from a divorced spring to coilover spring moves the suspension loads through the shock, and the stock top mount cannot withstand that for very long. We CNC machined a spherical bearing holder section and welded it into the modified stock casting (above right). It works, it just doesn't look very good, so we're not going to sell "Version 1" and instead will make a fully CNC machined "Version 2" with an additional feature we think is warranted. I will show that and explain further in a future post.

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    Both the rear shock and the front strut are inverted, which puts the single adjuster knob on the bottom. This is actually easier to access this way on the rear, and up front you just turn the wheels to lock and you can get to them fairly easy. An inverted front strut housing is very strong and has little deflection under lateral loads. We installed the modular camber "slug" inserts with zero offset on the upper spindle mount, to gain maximum wheel room. As we will show below, there is still plenty of camber adjustment on the plates so you don't need to "kick the struts" to get camber in the mounting holes. That gobbles up much needed inboard wheel room, and changes the SAI geometry, so we avoid that trick at all costs.

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    Installation up front is fairly straight forward. The Whiteline strut is about 2" shorter than the stock piece and getting the front spring and strut out is relatively easy on that end. Above you can see the installed Max-G coilover and swaybar.

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    OEM rear spring removal is not that easy - it takes a few tricks. Removing the rear shock while supporting the lower arm, then lowering the control arm doesn't release tension on the spring enough to remove it. You have to unbolt and lower the rear subframe from the chassis to unload the long, massive rear spring that Ford uses in the divorced location.

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    Even with the rear spring and shock removed, the rear control arm does not pivot freely. At all. Two guys can hang on this control arm, because it has so much bushing bind in it. It is amazing that this works in stock form, but it somehow does...

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    You can see the inboard bushings (left side of pic above) and how out of axis they are. These are fighting each other badly during suspension travel. One of these lower control arm bushings is a sealed spherical from Ford, the other is a big nasty rubber bushing, with chunks removed to allow it to rotate in bind. Of course we will look at fixing this down the road.

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    Weight loss was a benefit with the aftermarket coilovers - as it usually is. Even with the beefier inverted 44.5mm shafts the pair of Whiteline front struts they were still 5.0 pounds lighter than the stock front struts, with springs and top hats installed.

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    The weight loss out back was even more substantial at 9.2 pounds on the pair of rear shocks/springs/top mounts. This is mostly due to the massive OEM "divorced" spring being replaced with a 60mm coilover spring. If you look closely at the "T-bar" lower mount, it is asymmetrical, to kick the lower part of the shock away from the rear axles. If you install this backwards it will be pretty apparent, as the spring will be close to the axle, but Whiteline thought of this little trick to gain more room.

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    The rear shock is inverted so that the spring can sit "inside the barrel" of the wheel and not restrict the inboard wheel room for wider wheels and tires. With our 19x11" wheel it wasn't even close - we could move inboard another 1/2 to 3/4" and never get near the shock top. Moving the spring out to the shock can sometimes have negative side effects, but on the IRS suspension here with the ample wheel room its a non-issue. The effective wheel rate is higher due to the change in motion ratio - the lever effect of moving the spring out closer to the tire compared to the stock inboard "divorced" spring. 60mm springs are not only lighter but come in a lot more rates and lengths for adjusting around different conditions, tracks, and tire setups.

    Whiteline Swaybars and End Links

    The factory front swaybars on this 2018 GT were 32.5mm and the rear was 22 mm (0.855"), and of course non-adjustable. Since the rates the Max-G coilovers came with still looked a tad soft for what we had in mind for our next track test we went ahead and ordered up a set of adjustable swaybars from Whiteline.

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    The Whiteline bits are 35mm front and 25mm rear, with 3 adjustment holes on each side. The BFK006 kit comes with the front and rear bars, body mount bushings, locking rings, and Whiteline shortened/adjustable endlinks for both ends.

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    Installing these was relatively straight forward and when doing coilovers doesn't add a lot of work. We always test fit any aftermarket bar with the supplied bushings and sleeves, then shim them to fit so that they rotate with "pinkie finger effort". Once they are shimmed and fitted, the body mount bushings and sleeves are removed and drilled/tapped for grease zerks. This allows us to squirt in fresh grease every 6-12 months for a low stiction, noise-free rotation.

    continued below
     
  2. Fair

    Fair Go Big or Go Home

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    continued from above

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    The factory S550 swaybar bushings are not just stuck to the bars - they are BONDED to the bars! This adds massive bind in roll - for the life of my I cannot see why Ford did this. Watch the video below to see what we are talking about. Bizarre. Of course we want the swaybars to pivot freely in the body mounts, without much deflection under load (rubber) or bind when they rotate (roll). This way the swaybar adds a known amount of "anti-roll" and the adjustability gives you some quick track-side adjustment to control under- or over-steer.

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    This video shows the S550 swaybar bind and how we fix that

    The end links are adjustable in length and have sealed ball bearing ends - not open metal sphericals, that get full of dirt and start banging around in weeks. This is a great for both track-only and dual purpose setups - we love their end links so much we use them in all sorts of customized suspension kits we make, on both race and street cars.

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    Weight change was about a wash, with the hollow, larger aftermarket Whiteline bits within a tenth of a pound of the hollow but smaller stock bits. We set them all to full stiff to start with, knowing that the spring rate on these coilovers was not super stiff.

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    The swaybars were shimmed, drilled for zerks, mounted, and greased. The end links were adjusted and the car was set for ride heights and it was time for wheels and tires...

    Forgestar 19x11" F14s + 305/30R19 Bridgestone RE-71R Tires

    We have sold a lot of 18x11 and 19x11" wheels for the S550 chassis, and luckily we had some 19x11's on order months earlier. The lead times are really out there lately and having a few sets in line helped us get a set quickly for our shop car. We got them raw and had them painted locally to save time. We picked 19" diameter because of the multitude of tires available in 305/30R19.

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    The tire we decided to use for these was a Bridgestone RE-71R. There are virtually no 315mm tires in 19", but this "305mm" model runs a tick big.

    continued from above

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    We compared the 305/30R19 RE-71R to the 315/30R18 Rival-S above. The 18" Rival is a good bit shorter, but for the S550 the extra tire height from the 19" tire model actually helps gearing.

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    We took weights of the 19x11" wheels and at 26.7 pounds. The flow formed 19" Forgestars are not super light, but this is a normal weight for a 19x11" wheel priced under $500/corner. The 305mm RE-71R tires are heavier still at 32.1 pounds, but that's typical as well.

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    Three of these RE-71Rs are stacked up evenly with all four of the OEM tires, above. We are adding another whole tire's width of extra rubber, yall!

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    Once installed we checked the tire/wheel package for rub everywhere - not a problem. The wheels clear inboard and out, but it is of course a tight fit. They even clear at full lock, as shown above.

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    This video shows our 19x11" wheel tire clearance on an S550 chassis

    There isn't anything magic about fitting 11" wide wheels under these cars, but you can get into rubbing (inboard) or "poking" past the fenders if you get the offsets wrong.

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    We had a 2018 GT "PP2" stop in this week and took the pics above. Ford got the offsets a little on the "poke" side with the 19x10.5" front and 19x11" rear. I'm sure they had their reasoning - maybe to clear tire chains in the Great White North - but that's not how we do it. ;)

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    I was pretty dang happy when I saw this angle, above. That's how you fit 19x11" wheels square on an S550, folks. There is no giant spacer or long wheel studs needed. No, they cannot rotate front to back but neither can the stock PP1, PP2 or GT350 wheels. If you have a decent suspension setup you shouldn't need to rotate. I will show tire wear after our first track event in the next post, to show what I mean.

    Initial Ride Heights + Custom Track Alignment

    The car's alignment was first tested for max negative camber up front, which was -4.0 degrees at this initial ride height. This is pretty extreme and would only be appropriate for Hoosier A7s on a very aggressive track-only setup.

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    Instead we setup the car with -3.4° camber up front and -2.0° out back, which is about the extent we would run for dual purpose street/track use. We used a 1/4" of total toe in on the rear axle and zero toe up front (front toe out kills tires on the street). We left the caster setting in the "forward" (stock) position on our camber/caster plates and ended up with +7.2° caster up front, which is about perfect (we shoot for 6-7 degrees on most cars).

    continued below
     
  3. Fair

    Fair Go Big or Go Home

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    continued from above

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    Ride heights are a little on the low side, and after a few scrapes on the street, we have since raised the car a full inch from these numbers. This happened after our first NASA event, so I will show the new ride heights next time. We ran at these lower ride heights at the second track test, below.

    First Front Brake Pad Upgrade + Major Flaw in 14" S550 Brakes

    We need to talk about S197 and S550 brakes for a minute, because we found a fatal flaw in the 14" S550 brakes on our car. Not many people knew about this but several folks had seen the same thing, and just never knew why until we showed a few pictures. Bear with us a minute here, its worth it.

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    All of my previous experience on track in S550 Mustang GTs - both coaching and driving - has been in the Performance Pack optioned cars. These 15" diameter / 6 piston Brembo brakes are MASSIVE and fairly unflappable. I was amazed that I could not cook these brakes when I drove Aaron's 2015 GT at a brake intensive track (ECR) back in December 2014 - on stock pads and fluid!

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    2015-18 Performance Pack 15" dia front rotors are heavy but effective

    These 15" front rotors from the Performance Pack S550 Mustang GTs have regular rotor venting with access for cooling air from the rear. These bigger rotors are much better at absorbing and shedding heat to begin with, but with some forced brake cooling can be made pretty amazing for track use. In 2015 the Performance Package (PP1, which mostly consists of this brake upgrade) was $2500, but in 2018 it went up to $4000 for the same thing - so we skipped it. These are the same 15" 6 piston brakes used on the new for 2018 PP2 ($6500) package as well.

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    These are the front (left) and rear (right) brakes that come on the 2015-up S550 base model GT and Ecoboost Mustangs

    Well that's not what comes on the Ecoboost or the "basic b!tch" base model GT we got, of course. For 2015-18 base model GTs, Ford picked some pretty looking 14" rotors and 4 piston calipers, but they are not labeled "Brembo". Somebody at Ford must have had a hand in designing these, and they done messed up. They look to be bigger calipers than the S197 cars. This one uses a completely different pad shape, different rotor, etc. The S550 rear rotors are very sizable so there's a small improvement out back.

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    The 2015-18 S550 Mustang front 14" rotor (above left) got heavier than the S197 14" front rotors (above right) by about 3 pounds. And usually more rotor weight means more heat capacity, since a brake systems' ability to absorb and shed heat is loosely related to rotor mass. But there is one key downgrade Ford made in the S550 14" rotors. Do you see it yet? It wasn't obvious to me until after I bought the car - and this revelation has shocked people that have seen the issue when pointed out, even people that work at Ford.

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    I've seen the interwebs all abuzz with talk about using the 14" 4-piston S550 brakes on earlier model cars. We would recommend against this. While they do look pretty, they are worthless for track drivers. I have first hand experience with the 14" brake system's failures on track, which I will explain using the picture below.

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    What the what!?! If you look at the back of the S550 14" front rotors above notice that the cooling vanes are on the outside! This means we cannot ever add brake cooling to these rotors. They are ass-backwards! The access to the inner portion of the rotor's cooling vanes are only accessible from the outside, and you can't exactly run ducting to the rotors from the wheel side.

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    With no physical way to force feed air through the back of the rotor face and through the vented rotor section, we cannot cool these down. Ever. They will eventually get so hot that they stop stopping. Which is exactly what we are seeing in use. We ran these brakes with the factory pads with the tiny 235mm base GT tires and they lasted 8 laps on a "brake easy" track, in our first track test # 1. EIGHT LAPS. After the 7th laps in that first test session they were no longer capable of stopping the car at even my mild .85 g stops. I almost went off track, so I came in. The (Motul RBF600) fluid never boiled, I never lost pedal, they just wouldn't stop anymore.

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    The S197 "upgraded" Brembo 4 piston fronts also had 14" rotors (above left). The 11.5" rear rotors (above right) used a floating single piston caliper brakes, and these rotors were easy to kill on track (but we can and do upgrade them cost effectively to 14" dia GT500 rotors). The fronts were still just as undersized for the weight and power of the S197 chassis GT as the S550 14" versions, but we could make the S197 rotors work with forced brake cooling from the rear. Vorshlag sells 3" and 4" diameter backing plates and inlet / hose kits to force cooling air from the hub side out through the cooling vanes of the rotor, to shed heat. We tested these for 4 years on our car and they can make the 14" Brembos work for most folks up to even the pointy end of the grid.

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    We looked at the pads soon after this first track event (forgot to shoot pics!) and noticed that the material was 85% gone... just a sliver of pad left, with 300 street miles, an autocross, and those fateful 8 laps at MSRC. Those handful of laps KILLED the pads completely. So we ordered new front pads for the NASA weekend (above) and installed them before Track Test # 2. Since we had a Powerbrake 380x34mm / 6 piston big brake kit already on order for our car, and figured a simple pad upgrade would be enough for this "one track weekend" and the following autocross, we just got G-LOC's R8 compound front pads. This is their 2nd step up from their 7 track pad compounds. Mild enough for autocross and some limited daily driver use. Would they be enough...??

    2018 MUSTANG - TRACK TEST # 2

    After installing the Whiteline coilovers & bars + new wheels & tires I signed up for the next available event at MSRC on the 1.7 CCW course, which happened to be a NASA Texas competition event.

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    Ignoring the street tire aspect, the car slotted nicely into TT3 class (based on power and weight) using some internet dyno charts from 2018 GTs I found and calculations for avg power (we still had not dyno'd this car yet). We declared a minimum weight of 3800 pounds (with driver and fuel) and a declared avg power of 399 whp (in reality we ran at 3950 pounds with driver and a full tank). We were well within the max limits of the class using these "bonus" modifiers for TT3:

    Power to Weight for TT3 = 10:1
    Comp weight 3750-3899 lbs = +0.5
    OEM Aero = +0.4
    Adjusted Power-to-weight max = 9.1:1

    3800 lbs / 9.1 = 417 whp avg max

    (real weight of 3950 lbs / 9.1 = theoretical 434 whp avg for TT3, for reference)

    Not to mention we were on 200 treadwear street tires! We had no prayer of winning the class, but we turned in our sheets and ran with TT3 anyway. I wanted to see how far off we would be from the rest of the class - which had 6 competitors (4 of which were on Hoosiers), everyone else was in gutted race cars, and 4 of those had full aero. We brought a letter opener to a gun fight - but this really was about testing for us.

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    We also wanted to generate some lap time data for NASA about the modern 200 treadwear street tires, in the hopes of possibly starting a 200 treadwear TT class - at least in this region. We think there are a lot of untapped Time Trial racers who run in other series that limit tires to 200 TW (Optima, Goodguys, some GTA classes, some of the new SCCA TT classes) that could open up new potential NASA TT customers. These guys don't want to run head-to-head against NASA TT cars on monster Hoosiers with massive aero. These tires last a lot longer than Hoosier A7s, we know for a fact, so the cost-per-lap goes way down. Grip level is lower, too.

    continued below
     
  4. Fair

    Fair Go Big or Go Home

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    continued from above

    SATURDAY MARCH 10TH - RACE DAY 1

    Due to some last minute work needed to get the suspension installed (this was only one week after doing our baseline lap times in stock form) we were not able to get out to the track on Friday. This would have been helpful to get a good paddock spot and to tech the car for the first time. Every TT car needs a logbook and special tech inspection, which is good for the year.

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    We got to the track early (7:15) and quickly found a paddock spot and unloaded our BMW (there to just show it was for sale). Amy drove the Mustang out to the track (1.5 hour drive) with no issues. She quickly got into the tech line and waited. I ran to my TT meeting and came back, and the line had grown but hadn't moved. At this rate it might take hours to get the car teched. So we jumped outta line, went to G-Speed's shop on site and got the logbook.

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    Sadly NASA has removed the right to give out annual Tech stickers to even their certified logbook shops, so we had to get back in line anyway. We finally got the Annual Tech sticker but by this time I had missed the TT Warm Up session - which is used to only get lap times for gridding purposes.

    With no lap time I had to slip into the first open spot on grid for the non-timed cars who missed the warm up, which was 34th! We had 51 TT entries this weekend, so it was a bit crowded on the 1.7 mile course. We also had over 270 total entrants that weekend - a NASA Texas record as well as a record for any event at MSR Cresson. This meant people were parked everywhere, and the all groups had to grid on part of the 1.3 mile course.

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    51 cars in TT is insane - we have never had that many sign up before. Luckily we never had all 51 TT cars on track at once, but it sure felt like it! ;) In that first session I ran the Big Red Pig passed at least a dozen cars, maybe more. It was a total mess but it was another lesson learned - get your car teched before race day! Vorshlag is a certified NASA "HPDE" tech shop but not a "Logbook" shop. Not yet - we are scheduled to take the SFI exam soon.

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    Somehow my old TT3 lap record in our 2011 GT, "Big Red", from 2014 was still holding strong (1:17.310) all day, and a previous customer KenO was chasing it once again in his fully prepped E46 M3 (shown above). He was on a sticker set of A7s with the most power and aero he had ever run on the car. I suspected he would win the class and take the TT3 record away from us...

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    in-car video of our 2014 TT3 track record lap - which was still holding

    On this first day the TT3 record still eluded him, but Ken was faster than he'd ever been before. His is a dedicated TT3 build with no compromises, and I was lucky to be within 5 seconds of him on street tires. Amy was also co-driving the car all day in HPDE4 an I took some laps with her using the helmet radios from the right seat, and she dropped a bunch of time.

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    The handling was spot on all day, and the only adjustments I needed to make were to tire pressures. I was looking at scrub at the sidewall and adjusted hot pressures to 34psi front, 33 psi rear. #500psi There aren't any major bumps at this track but damn, this suspension was downright plush. The roll and dive weren't bad and it was super easy to drive. I did managed to fuel starve the engine in a long left hand sweeper at 1/2 tank of gas, which triggered a CEL on the dash. We kept the fuel tank full for each session after that. The CEL stayed lit all day and into the next - but it ran great (it went off in her drive home Sunday night).

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    I fought all day with traffic, slowly working my way up the grid to 8th fastest TT car at one point. Since we grid based on your fastest lap times, the later sessions helped removed slower traffic from in front of me the next time sessions. Strangely I ran almost the exact same lap times in session 3 and 4 -within .001 sec of each other - but was still only 3rd fastest out of 5 in TT3 class. To have already found EIGHT seconds on my first day of testing - in heavy traffic - was outstanding, but I knew there was more in the car.

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    The brakes were not good. At all. I had to baby the braking to keep from overheating the rotors and upgraded front pads. Once again I never lost the pedal, so the fluid was fine, it would just lose stopping power if I pushed the brakes as hard as I used to push the S197, so I had to brake earlier and less aggressively or it wouldn't last 2 hard stops in a row. There was ample time between my TT sessions and Amy's HPDE4 sessions to cool the rotors down, so it was not compounded from double driving the car. Weather was beautiful all day, sunny in the afternoon, so we packed up and headed to the hotel to clean up and rest after the last HPDE4 session. We foolishly left our sun shade partially extended on the trailer...

    SUNDAY - RACE DAY 2

    As perfect as the weather was Saturday it was 100% more awful on Sunday. We woke up to hear the wind howling and rushed from the hotel to the event site. Sure enough we were greeted to a trashed sun shade. Lots of E-Z-up tents were down and destroyed, everywhere. Wind was blowing hard all day, which made it COLD.

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    We managed to retract and secure our now ruined sun shade and then got the Mustang ready with plenty of time to make the "golden session" of the weekend - the coolest of the day, TT session 1 Sunday. Was worried the wind might slow us down but it didn't. I started in the 10th grid spot (really 7th, we had some no-shows) and quickly passed the car ahead of me when he spun off track in the first lap, shown below.

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    Our best lap Sunday in the 2018 GT - 10 seconds quicker than a week earlier

    That was good because I was held up badly on the first hot lap. Lap 2 was pretty good and my times fell a little, then lap 3 was perfect. Tires were up to temp, brakes were still working. Lateral grip on the RE-71R tires was 1.2g sustained with 1.34g spikes (see below). Braking was limited to about .90g stops, otherwise it would overheat the rotors/pads (it could spike to 1.0g stops but only about once every lap, for one good stop). I also had to compromise the last corner on my best lap because I had a 1:10 sec lap TTU car driving up my tailpipe into the last turn - scary fast! I got outta his way and braked a hair early, but that 1:21.733 lap was still 1.5 seconds better than Saturday, so I "banked the lap" and came in. Rear tires were already getting hot.

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    When I used 2nd gear in "Rattlesnake" it could easily spin the tires on corner exit. Even 3rd gear exits on "Little Bend" and "Boot Hill" had to be made at part throttle or risk sliding the rears. The Base GT has an old style clutch Limited Slip Diff, unlike the Torson style diff that comes in the PP1/PP2/GT350 models, so we plan on upgrading to a Torson-style LSD later this season.

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    I didn't run in any other sessions that day. I felt like it would be wasting consumables to try to catch P2 in TT3 class, and I might only find a tenth or two. Instead I worked with Amy (see above) coaching her for a couple of sessions, and she found more confidence and lap time. We packed up by lunch time and headed home for some hard labor at the house - we're building a shop behind our house and we needed to shovel 6 yards of crushed concrete to start making a road back there. It was back breaking work, so we bought a tractor the next week - we have many more tasks like this to tackle.

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    Some of the temp data I am getting via OBD-II isn't super accurate, but the dash does have a readout for some things. Cylinder head temps were at 220°F after my last session, oil temps were creeping up into the "yellow". This car does have a factory oil cooler (at the oil filter, aka: the oil heater) but we may do something more substantial this summer.

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    Sunday's final results were about the same: the #BigRedPig took 3rd out of 5 in TT3 class - and everyone got quicker. KenO finally beat my old TT3 record with a 1:17.1 lap, and the second place driver dropped into the 1:20.3 range, which I was never going to catch that day. Final thoughts - the stock seats suck, big time. I had to go to the chiropractor Monday to pop things back in place, ha! The crushed concrete shoveling that night didn't help, either. Great event overall, lots of good data learned. To end up 10th fastest out of 51 TT entries, in a car we drove there on street tires, was pretty remarkable.

    MOD BUDGET VS LAP TIMES

    We want to show where we are on lap times vs overall budget for this car, to compare against other NEW Mustang options. I am not trying to compare against an older car, or another new car model, but instead between the various OEM 2018 Mustang purchase options. I will show the MSRP or street price for models at our time of purchase + our mod costs to date. Sure, deals change and rebates come and go - these new purchase price numbers are relevant for Feb 2018.

    2018 Mustang GT PP1 w/ Premium + Recaros = $48,270
    2018 Mustang GT PP2 w/ Premium Plus + Recaros = $51,280
    2018 Shelby Mustang GT350 = $58,140
    2018 Shelby Mustang GT350R = $65,640

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    Our "basic b!tch" 2018 Mustang GT base model 6-speed = $32,500 (what we paid)
    + Whiteline MAX-G+ Coilover Kit for S550 Ford Mustang GT - TrackPro = $3,154
    + Whiteline Front & Rear Adj Swaybar Kit, S550 Mustang = $585
    + G-LOC Brake Pads, Front, Base GT 4-piston, R8 = $234
    + Forgestar 19x11" F14 wheels = $1720
    + Bridgestone RE-71R 305/30R18 tires = $1368
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    $39,531 in the budget, dropped ten seconds a lap from stock, and we cannot find a quicker lap time from any stock S550 at this track.

    Now we have spent less than that, since we make some of this stuff and we're a dealer for the rest. And we kept labor out of the tally because not everyone pays for wrenching. I'm not going to count fluids - those upgrades are a must, and would be done on all of these Mustang options for track use. That's like tracking fuel costs - its a consumable. The tire and brakes are consumables, but I'll factor those into the budget since these really are upgrades. When/if we change out one of the "mods" listed above we will show the subtraction of their costs and the addition of the new upgrade in place.

    Remember I showed Josh's stock Shelby GT350R lap time on PSC2 tires earlier in this thread at a 1:25.22 lap (different driver, so its hard to compare). Sadly I do not have any first hand experience in a stock S550 at this track, yet. If I can finagle my way into a few laps in any of the above cars I will update the "lap time list" below (any volunteers??) For now here is our list of data logged videos showing lap times in cars I have driven personally at MSR-Cresson on this same 1.7 mile CCW configuration:
    • 1:31.90 in our stock 2013 Scion FR-S
    • 1:31.412 in our stock 2018 GT
    • 1:29.630 in our 2013 Scion FR-S with camber and front brake upgrade
    • 1:28.564 in our 2013 Scion FR-S with Whiteline Max-G coilovers & bars
    • 1:27.40 in Todd's stock 2016 Focus RS
    • 1:26.212 in Todd's Focus RS on coilovers and camber (which then ran a 1:23.658 on 275 Bridgestones later that day)
    • 1:25.10 in a Spec Iron Mustang on Toyo tires (with passenger)
    • 1:25.075 in our TTD prepped E46 330 (195 whp)
    • 1:22.63 in Jerry's stock 2012 C6 Z06
    • 1:22.56 in Joe's modded 2013 1LE Camaro on Hankook RS-3 tires
    • 1:21.90 in our TTC prepped 1992 Corvette (288 whp)
    • 1:21.89 in Joe's stock 2017 Corvette C7 Grand Sport
    • 1:21.733 in our 2018 GT on Whiteline Max-G coilovers & bars + 305mm RE-71Rs
    • 1:17.310 in our old TT3 Prepped 2011 Mustang GT on 335/345 Hoosier A7 (447 whp)
    As you can see the 2018 GT has both one of the slowest and one of the quickest lap times listed here. It improved a dramatic amount in only one week, and we have more plans to upgrade brakes and power very soon. Gonna be fun to see how far we can push this one!

    WHAT'S NEXT?

    Next time we will show our second autocross - with the new suspension and tires. Or will the SCCA or other outside forces conspire against us and thwart out second autocross test????

    [​IMG]

    We just ran an SCCA Club Trials event event at ECR last weekend (above), which was a very brake intensive track. Before this event we upgraded to the craziest G-LOG compound pads, both front and rear, to deal with this track. Will it work? Can the Mustang hang with the swarm of Corvettes and 50 time trial racers that attended? Tune in next time to find out!

    Thanks for reading,
     
    JeffV8, RaiderJatt02 and Nvrfinished like this.
  5. TrEvoRS

    TrEvoRS TMO Beginner

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    A lot of great information! Just curious, have you not addressed the bushing / roll-center related concerns yet, or are you just not mentioning those and focusing on the bigger stuff you are developing?
     
  6. stuntman

    stuntman TMO Advanced

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    It's interesting to hear your praise of GT3 & (especially) GT3RS as a good dual purpose car when they ride quite harsh on the street compared to GT350s. Really the GT350 only needs camber plates and it's pretty much good to go for extensive track use without overheating.

    It will be interesting to see how well the trans and diff holds up once you get some brakes under your 2018 and can actually put down some hard laps, especially in summer. That's one area where the GT350s and Camaros have a big advantage over the GT, and while weighing very similar to a GT with all those heavy coolers.
     
  7. Krispy

    Krispy TMO Intermediate

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    Any ideas to fix the fuel starvation issue aside from running atleast a half tank of fuel?
     
  8. bpracer

    bpracer Mark

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    The non-torsen diff is probably already toast. The PP offers a larger radiator over the base car, so between the lack of transmission/rear end coolers, the smaller radiator and the minimal engine oil cooler, I don't think the car will be happy in the Texas summers.

    I've run my GT350 down to "5 miles until empty" without an issue so not sure if this can be car specific or not.
     
    stuntman likes this.
  9. stuntman

    stuntman TMO Advanced

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    The base diff is crap, but it will still generate heat and probably cause a limp mode. It would be an interesting bet on which causes it first: water, trans, or diff temps. Anyone want to make a wager?
     
  10. Fair

    Fair Go Big or Go Home

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    There are definitely "bushing issues" we have run across, and I mentioned the worst offenders so far as being the rear lower control arms. We have some ideas on what to do there and we will continue to investigate other bushing issues as we tear into this car. But so far, there's no "catastrophic" issues so far - its pretty dang fast for what we've done.

    [​IMG]

    As "bad" as the rear bind we found is, this car still puts power down better and soaks up bumps on track more composed than our S197 ever did... so... ??

    True, but a lot of GT350 owners we talk to used to own a GT3 or GT3RS. They make these comparisons to us, and yes - all the GT350s seem to need are camber plates and a more aggressive alignment to haul ass on track. :)

    Honestly, I don't think everyone is going to see this issue. Look, we're putting spikes of 1.45g and sustained 1.28g lateral loads through this car, and with that kind of loading it will slosh the fuel out of the "dead" side of the saddle tank in LOOOONG left hand turns at our main test track (MSR-C). Neither the S197 or S550 like doing that, in any form (GT/Boss/GT350). And while most OEM saddle tanks have some sort of vacuum jet pump to keep the fuel pump pick-up side loaded with fuel, they don't really work all that well with an OEM saddle tank in any car I've ever tested here. Not any Ford, BMW, Corvette, nothing.

    [​IMG]

    The solution most folks will point to is "get a fuel cell" but that's not always the answer. We've seen slosh in those, too. What it takes is either an internal surge tank/accumulator (which is what we order for fuel cells) or an external tank.

    [​IMG] [​IMG]

    The fuel cell above was made for a BMW we're building for a customer, and it is shaped to match one half of the OEM saddle fuel tank, so it can mount in the same position. We built the enclosure and had the fuel cell built to fit that. It uses an internal accumulator section that has dual pumps that feed from and return to this trapped area. Horrendously expensive solution for a dual purpose track/street car!

    [​IMG]

    We fixed this once and for all in Jamie Beck's 2013 Mustang race car (ST3 now ST2) by modifying the stock tank to work with an external surge tank/pump. This Radium surge tank sits in the trunk and is fed by the stock in-tank pump, and then the surge tank has an internal pump that feeds the engine. The surge has an overflow return goes back to the stock tank if this is over-filled. This way we can keep this ~1 gallon tank full down to the last drop in the main tank.

    [​IMG]

    After a half dozen races it seems to be working perfectly, and he no longer has to keep a "half tank of ballast" fuel in the car. So we will do the same to our S550 when we have the time.

    [​IMG]

    On our S550 we still need to add larger brakes, longer wheel studs, some brake cooling, tow hooks, racing seats, roll bar, harnesses, and much more before we tackle a surge tank. Until then we'll just keep the tank full for every session. :D

    True, the clutch-style diff is "losing its battle with longevity" and the stock radiator looks TINY in his GT.

    [​IMG]

    We never keep the plastic end tank OEM radiators in any S197 Mustang, so we will begin the search for a proper aluminum radiator for this S550 in the coming weeks...

    [​IMG]

    Everyone betting on failure - no faith in Ford's engineering here? ;)

    [​IMG]

    These are all valid concerns and we are monitoring all of the temps we can. The 14" brakes that come on this car are what have held us back so far, and at our last event I couldn't make more than 1 hot lap at a time. So the fluid temps were less of an issue.

    [​IMG] [​IMG]

    The Getrag still worries me, and I was seeing some higher oil temps (into the "yellow") on longer stints at MSR-Cresson both times we have run there so far. So before our 3rd track weekend we swapped to 8 liters of 5W50 Motul synthetic in the engine and the trans got Motul DCTF. We noticed cooler oil temps at a warmer event at ECR, so that might buy us a little margin - but a proper oil cooler, radiator, trans cooler and diff cooler are in the works.

    [​IMG]

    Today we are upgrading to the 15" 6 piston brakes + brake cooling so we will see what is the next limitation. Tonight we load up to tow 9 hours to run this weekend at NOLA with the Optima series. I will show much more detail on these improvements in my next post. A Torsen style Wavetrac diff is also going in as soon as we figure out what gear ratio we want to use. Normally I'd use a 3.31 with a Getrag but ALL of the trans gear ratios changed in 2018 so we're still chasing the right ratio for this 26.2" tall tire.

    [​IMG]

    We will account for the costs of ALL of these upgrades and keep tally in our base GT budget and compare to the GT350 and PP1/PP2 cars as we go. We still haven't run against a GT PP1, PPP2, or GT350 that has similar or faster lap times, tho.

    More soon,
     
    VoodooBoss likes this.
  11. Tommy J

    Tommy J TMO Intermediate

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    The information you are providing really helps someone who is contemplating on getting a 18. Hope it really is worth the upgrade from a 17. Appreciate your info and VLogs.
     
  12. Mad302

    Mad302 TMO Race

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    I think what you're doing is great. However i feel for most people just adding the expense of PP1 or PP2 is the way most people would lean. Not all of us have the access to a shop with FAB skills and knowledge such as yours. Adding brakes, suspension, coolers and rear end parts you're building your version of PP2 car nothing wrong with that all but taking account of what labor hours are and part costs, a factory prepped PP2 car with a warranty would be a valid price tag.

    Again nothing wrong with what your doing. I find it really interesting that you and your team are building on a budget and proving what works and needs to be replaced for track use. What you've done in months would take us years. I would really like to see what you can do behind the wheel of PP1/PP2 car and see your thoughts on that and how compares to your current car.

    Keep up the great work
     
    Last edited: Apr 11, 2018
  13. Fair

    Fair Go Big or Go Home

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    Years? Nah, maybe two days worth of real work done so far. :) Most of our "time" has been spent designing new prototype parts - that we plan to sell in production form so they are easy for the bolt-on guys to add in as little time as possible. Things like our brake inlet ducting, brake backing plates, front and rear tow hook kits, spherical rear shock mounts, and of course our camber plates and wheel offsets which we worked on years ago.

    [​IMG]

    Sure, for many folks the "easy button" is to just "pony up" and buy a PP1, PP2, or GT350. After seeing how badly the 14" base brakes did I am re-thinking the decision to start with a base car. ;) But the price difference is still a staggering $15-30K less when you start with a base GT. Hey I'm not going to talk people out of spending $50-70K on a Mustang, I know this. But I will challenge some PP2 and GT350 cars to a "lap battle" if we can compare total money spent. ;)

    [​IMG]

    The PP1/PP2 brake upgrade install actually goes on very quickly, and the PP1 is a $4000 option in 2018, PP2 is $6500. This swap takes about an hour to do - its very easy. It uses the same bolts, even uses the same brake hoses. Unbolt old bits, swap to the new rotors/calipers, bolt it on, bleed the system. We added long wheel studs just because... but Ford Racing hubs for the front come with the ARP 3" studs.

    [​IMG]

    The brake cooling we added is a damned good idea for any GT PP1/PP2 owner that tracks their car hard enough to need track pads. Cooling makes the bearings, pads, and rotors last a lot longer.

    [​IMG]

    The camber plates, coilovers & swaybars are significantly better than the PP1, PP2, or GT350 shocks and springs, no offense to the lovers of MagRide bits. :) The spring rates that Ford uses are VERY soft and allow for a lot of dive, squat, roll and heave (our front rates are about 4x the stock rates). So any of those S550s that want to do serious track work would be better off with these upgraded parts - yet more PP1/PP2 parts that go in the bin. All of these suspension parts + the wheels and tires were installed in an afternoon - lots of Mustang folks are capable of installing these parts, then getting an alignment.

    [​IMG]

    The 19x11" wheels and RE-71R tires are much better than PP1 bits and on par with PP2 and GT350 parts, with a more reasonable replacement cost. The PP2 wheels don't fit worth a damn (mega poke) but they are decent looking wheels. The fronts should fit better with some camber but the rears never will fit right...

    [​IMG]
    PP2 17x11" rear wheels have about an inch of poke

    Of course the GT350 comes with coolers and a tick more power (barely), but at 2X the price. But the rear wheels, once again, have the "Wrong" offsets if you look at them objectively.

    [​IMG]
    The GT350R wheels have rear poke that is just as bad...

    Ford is not perfect, mostly because it is such a big company with so many layers of bureaucracy. I'm sure some engineer somewhere spoke up about this but was over-ruled by a bean counter - they already had that wheel designed and paid for! And we are not perfect, but we're small and nimble enough to make quick changes. When the first set of 11" wide wheels we ordered for an S550 wasn't a 100% perfect offset front and rear....

    [​IMG]
    19x11" wheels built to our specs with 305/30R19 sure seems to fit a lot better than PP2/GT350

    ... you can bet our second set was. :) Sure, I wish we had the slightly wider GT350 front fenders, but we got these 11" wide wheels to tuck nicely at both ends without that extra room. And there's another 3/4" of inboard wheel room out back.

    [​IMG]

    So yea, it might seem cocky but I think we did some things better than a PP2, GT350 and even the mighty 350R. And we've barely gotten started. We still have easy horsepower we can grab, seat/harness upgrades, and some mix of 350R/PP2 aero bits we will add - all of which will drop more lap time. Not to mention Hoosiers.

    "Its hard being this humble..." ;)

    Thanks,
     
    TMSBOSS and RES_22 like this.
  14. ArizonaBOSS

    ArizonaBOSS Because racecar. Moderator

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    This 2018 front fascia update is growing on me.......
     
  15. stuntman

    stuntman TMO Advanced

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    I wouldn't call limp mode a "failure". Unfortunately the PPs don't have coolers like the GT350 or Camaro SS. And the Camaro is lighter WITH coolers.

    It would be interesting to see your cost analysis WITH shop labor for putting on the brakes and Wavetrac and how all of that compares to the PP2 & GT350. Also considering the MSRP or readily available discounts rather than a rare, big discount on a "stripper" model base GT.

    The 4 piston brakes shouldn't really ever be tracked . The GTPPs are quite good. Combined with a Torsen, the GTPP still has a lot of value for those who don't want to deal with LSD installs, shops who screw up the lash, making the rear end clunk under Decel and throttle tip in. But wave and truetraks are better units than stock, as are most aftermarket options.

    Stiffer spring rates (even when done right with good dampers) will still sacrifice ride quality to levels that probably wouldn't pass what the PP2 & GT350 is able to. So there will always be less constraints when going to the aftermarket for suspension which makes it difficult to compare to an OEM car. Picking the cheapest, base car is always the route for the best bang/buck for a track car. Likewise an old Miata can be built to be even faster for less money than a base 2018 GT.
     
  16. bpracer

    bpracer Mark

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    Terry, I have two PP control arms sitting at my house if you want to throw them on.

    Sent from my SAMSUNG-SM-G900A using Tapatalk
     

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