Vorshlag 2011 Mustang 5.0 GT - track/autocross/street Project

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Costas had driven this BMW at a NASA TT event in 2010 here at ECR and set the track record for TTD at 2:12.9, which is still intact, but did it at the time on some shredded 265/35/18 Yokohama A048s. Our goal this day was to see if we could beat that time on a better prepped version of the same car (it's now at the limit for TTD preparation for points). This Bimmer now has a fresh M54 motor, fresh 285/30/18 Hoosier R6s, but the race seats have been removed and an emissions legal exhaust has been added (3" high flow cat), so who knows? Amy and I planned on swapping sessions between both cars, but with only one video camera and one lap timer (the dreaded G-Tech RR) we would have to do some gear swapping.



The driver's meeting was at 7:30 and immediately after they wanted the Advanced group to go on track - which Amy and I were both signed up for. Amy managed to get several laps in the BMW, but I was still mounting the video camera, wiring up the new Sony remote to that (which worked great! Now I can turn the camera on/off, record, zoom, and even snap pictures from this small remote that can be clipped to the E-brake handle - all while strapped into the race seat). I got out for one lap before the checkered flag, so I didn't bother to record that session.



The ECR crew was running everyone in about 20 minute sessions, split between the Advanced, Intermediate and Beginners groups. A few weeks ago the pre-registered car count was pretty low, under 22 cars, so I started hustling up some attendance online, along with several others that were going. We saw some SCCA autocross regulars that heard about the event from my Facebook postings and e-mail bombardments, many of which had never done a track day before. After today they were now hooked! With about 30 entrants in the beginner class it was nice to see a lot of new folks trying out an HPDE track event for the first time. Fresh blood - This is what its all about! Now they know first hand how much they need camber plates and better suspension parts...



Lots and lots... and lots of Mustangs. I think the final car count was 48, which was excellent considering that this was only one day past the Summer Solstice (longest day of the year, and we saw 101°F temps!) and the first event put on by Five Star Ford. Excellent event, catered food, relaxed atmosphere, instructors, perfect SCCA corner workers, and the usual great ECR track crew.



Costas (black GT-1 Camaro) had the field covered with his hardware and talent, bringing the lightest, most powerful, tube-framed race car with the largest tires. If you got it, bring it! His videos showed a best lap of 1:51, which is mind-bogglingly-fast, and betters the NASA TTR record by a good 4 seconds. He'd be foolish not to bring this car to the October NASA event to potentially get his name in the record books again. His buddy Mike brought his Gold/Orange GT-1 Camaro for some fun laps, but it's not nearly as wild and wooly as the black one. He's still having a lot of fun tracking it each time I see him out there.



Brian Hanchey of AST/Moton USA brought out his new track toy, a 2005 GT with some go fast goodies and suspension. This was his first track event or any real outing in the car, so he and Moton-USA VP (and AI Camaro racer) Mike Patterson wanted to get some shake down laps in after it received a new motor and some other ex-World Challenge bits (big Brembos, engine stuff, Torson T2R). He arrived on some heavy 18x9.5" wheels and 255mm BFGoodrich 300 treadwear tires that came with the car, but I thought those skinny tires were holding the performance back a good bit. I had brought the 295/35/18 Nitto NT-05s on the D-Force 18x10s to show off and possibly sell, so we mounted them on his Mustang for one session. These were better enough to drop his best lap time by about 2.9 seconds - NT05s still are not my favorite track "street tires", but they are a damn sight better than 255 BFG Comp TAs! Once again we realized that tires matter.



He got a lot of good laps in, blowing out the old track cobwebs and getting some good data logged on the car and set-up. He had to deal with some needless overheating issues at the event, but after checking data today he saw that it had a theoretical 2:06 lap (with merged sectors from other laps; this sector analyzing is done all the time) - which isn't too shabby for 200 treadwear street tires! Throw on some big fat R compounds and it is knocking on the golden 2 minute barrier. We've turned a few wrenches on this car (made custom race seat slider brackets + some exhaust mods), but most of the drivetrain work was done by a GRAND AM race team. The motor and exhaust sound MEAN on this car and once this hotted-up motor is dyno-tuned and running on real tires, this unassuming black GT will be a track terror. Brian really convinced me to quit screwing around and BUY the damned Torsen T2R, which he raved about in this car.




Vorshlag BMW and Mustang - On Track Impressions

So the track day event ran super smoothly, but how about some lap times in our cars? Amy went out in the BMW for 3 sessions, where I timed her from pit wall during part of one session (I came in early - after the steering rack's "death shudder" started), but we were mostly out on track together at the same time - hence very few on-track pictures of any of our cars or others' in the Advance group. It wasn't until days later that I had the in-car videos rolling to know the lap times in the Mustang, but we never got times in the BMW.



She and I both ran the BMW on track at the same time as Hanchey's Mustang, who was running a new AIM Solo GPS lap timer ($399, or $699 with optional wired OBD-II data option). That little timer unit is nice, and I want one. The OBD-II data stream was quite impressive. The Solo has a great mount, easy to read display, on-board battery, predictive lap timing, it already had ECR in its memory, etc. If you are on the fence about what lap timer to get - just go to Bimmerworld (or your favorite AIM dealer) and get an AIM Solo and be done with it.

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The BMW felt damn near perfect - brakes were awesome (just some HP+ pads on the stock rotors + good lines), handling was flat and grippy (AST 4200s + 285mm Hoosiers + Powerflex bushings throughout), and the power was surprisingly peppy and easy to put down (OS Giken diff FTW). This lower mileage M54 is a lot better than the original lump we raced with in DSP in 2009. Old blue was pretty darned quick and we both passed most of the cars in attendance while driving it. We can tell from looking at Hanchey's laps during the same session when he was running behind us that the BMW ran at least a 2:09 laps, and more likely 2:08s. This is little better than speculation, but I did manage to get a 2:10 lap timed on one of Amy's many laps. So it easily beat it's old TTD record, now that it is on big Hoosiers. Tires matter.



Here is Amy's best lap in the Mustang (2:03.2), with some footage of me in the BMW. Click for 720P video

Here's Amy making laps in the Mustang. If you watch her in-car video above you will see me in the BMW, briefly, coming back on track. Yea, I uhh.... had an "off" in the BMW, but nothing got hurt, other than my pride. You see, I was dicing it up on track with Hanchey's Mustang for a couple of hot laps, was screwing around and got the rear tires REALLY hot drifting through Turn 4-5 (on accident!), then took Turn 6 as fast as before... but the rear tires had zero grip. Back end stepped out a little, which I counter-steered, added a little throttle. Didn't help. I added full lock and full throttle. Nope, still coming around. Felt like it was in slow motion, the whole time I'm thinking "What the hell, I don't EVER go off of tracks sideways!". Went for a ride, going off on the inside of the exit of Turn 6. Weirdest off I've ever had. No harm other than some grass packed in the tire bead (since fixed), no foul - except Amy drove by right after I got back on track, so she totally busted me.


Left: Amy's "look of displeasure" is obvious! Right: My driving talent on full display. I was merely "exploring an alternative line"...

Amy said she had a blast driving both cars, but really liked tracking the Mustang better. It's just always going to be so much quicker on any sort of road course, with nearly double the horsepower. With the same drivers, and on similar tires (R6 vs V710), suspension (AST 4200 doubles vs Moton Club Sport doubles), and preparation level (both cars have cold air/tune/header/custom exhaust) the Mustang was a solid 10 seconds a lap faster than the BMW. It is hard to ignore that. I enjoyed the hell out of the BMW, right until I drove it off track like an asshat. Embarrassing, but I share it all here on this thread. Great stress test for these well used and abused D-Force 18x10s... not a scratch. This set is 5 years old and has been used on 3 cars, including our E36 Alpha car, my M3, and this 330. Zero defects.


In-car video of Terry in the Mustang for three hot laps, 2nd session of the day. Best lap of 1:58.2. Click for 720P video

OK, now that I've taken my licks, let's get to my good laps in the Mustang. This video above is from my first "full" session on the track that day (remember, I only got one "installation lap" in the first Advance session of the morning's session #1). The cooler temps we saw earlier in the day once again made for the best laps, but at least this time I put in a better drive early rather than late, unlike two weeks ago at the Optima event. Still, this was only my 3rd time tracking this car on R's, and the first time there weren't HUGE problems (cording/bloated front tires at MSR-H, diff fluid pouring on the rear tires at TWS). I still found some driving improvements in the later sessions, like using 2nd gear exiting corner 11, but the rising ambient and track heat negated any lap time improvements. Hanchey rode through with me in session #5 for two hot laps and he enjoyed it, but we only managed to run laps of 2:01.2 and 2:00.4 times.

The steering rack's death shudder reappeared this time, like at TWS, but unlike two weeks ago at this same track when I was running street tires. So the issue gets worse on sticky R compounds, as we've proven time and again. Driven hard enough for enough laps it would eventually go crazy and get into a violent shudder, plus sometimes trigger an engine fault as well, like it did in my video above after three hard laps. Shutting the engine off and back on would clear the engine fault/limp mode, but not the steering shudder. Only dipping below 45 mph would temporarily stop it, but it came back as soon as you crossed back above 45. When this happened badly enough (only to me, not Amy) I would just come in, shut it off, and pop the hood and let everything cool down and "reset". Even on normal laps it was still shaking pretty good - we've just gotten used to it. New replacement steering racks should be available from Ford and Ford Motorsport "soon" - after months of "it's still on back-order" (I have heard that Ford continues to find bad *brand new* electronic steering racks in the 2013 production lines, which is why there has been none to spare for Ford Motorsport or repairs. The word is they've fixed the QC issues at the Mexico plant that makes these units).

The Mustang's brakes worked flawlessly this time out, so that was a big plus! During the two weeks since Optima we replaced the original vacuum check-valve at the brake booster, which wasn't expensive. We weren't sure if the power assist would work until we revved the piss out of it on track. Well, once on track it was obvious - that fixed it! No telling how long this valve has been bad or "going bad", and leaking down vacuum, but hopefully this is the end of our "brick-like brake pedal" after long acceleration runs on track and in autocrosses. Keep this in mind if you run into similar a lack of brake assist.

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Our change back to 450F/175R spring rates was huge on track, just like it improved the street ride. The bad front end push we saw at Optima went away; now the car could turn-in easily and accelerate better, so this spring rate set-up stays until we find some reason to try the stiffer rates again. We had some serious rear tire rub in the rear with the 315s on the 18x12s... first from the tire to the fender lip with too much rear wheel spacer, then from the tire rubbing inboard on the stock rear swaybar with less spacer (I pulled 7mm of spacer off after the 3rd track session). The permanent fix here is to run less spacer and remove the stock rear swaybar - by making our own rear swaybar of an all new arrangement. The stock bar routing (and all aftermarket bars follow this) will always limit inboard wheel/tire room on this chassis. More on this in a future post!

Overall, I was very pleased with the performance of the Mustang this weekend, especially compared to the dismal performance on street tires just two weeks ago. The brake booster repair, the spring rate change, and the move to wider Kumho tires transformed the car - to the tune of 5.7 seconds faster per lap. Running my 1:58.2 lap in a heavy street car like this is pretty darned quick, considering the NASA TTS track record is 1:58.4, American Iron record is 2:00, and the CMC record is 2:04.2 - and those are set in October, when it's not 100 degrees, in real race cars.

I'm going to go ahead and say this, because it was obvious to anyone that watched laps at this event: our mildly tweaked Mustang GT was faster than anything else in attendance, other than Costas' 2200 pound, tube-framed GT-1 monster. Faster than the 2013 GT500, faster than the many Boss 302's, faster than the gutted race cars on Hoosiers (there were a surprising number on Hoosiers or Continental slicks), supercharged Lotus 7 on slicks, and on and on. Even with a girl driving. I don't get to say that often, as there's usually a bunch of prepped race cars at some events that can always beat a real street car like this. Having the fastest Mustang at a Mustang event was pretty cool - because we're not a "Mustang shop" per se, and don't have a big power set-up on this car. It's just a bone stock 5.0 motor with two bolt-ons.


On Monday the wing was removed, the street tires went back on, and Amy drove it to work with the AC blowing - like she does every week

So hopefully that statement doesn't offend anyone that was there, but... damn the red car was moving! Felt good to run a sub-2 minute lap at ECR again after all these years running in relatively slow cars at ECR since 2008. Major adrenaline rush, big grin for days, pulse pounding good time! And all of you reading this know exactly what we've got on this car - it is not crazy, the opposite of exotic, and we hide nothing. These 2011+ Mustangs really can get you to work and back and still haul ass on track, with the right mix of parts. Anyone could go buy a 2011-2013 Mustang GT (spend $20-30K), copy the parts we've used, and go just as fast or faster. It's easy. Call us - operators are standing by! ha! It really just boils down to running big enough and sticky enough tires (people that say 315s are too big for road course use on a 3500 pound car are misinformed), the right wheels to make those fit, the proper suspension parts (which we're still improving), a little brake cooling + good pads, and a few motor bolt-ons and a tune.

One thing to mention: both cars were easy to drive fast. We've got the brakes working very well on both and this is a brake intensive track. The handling and damping on both is exceptional, and this is a bumpy/shock intensive track. True, Amy and I both have many laps at this track (I probably have 20-25 hours on track at ECR) so that helps, but neither of us is some driving savant (look no further than my BMW mega-off at this event for proof of that). Sure, my times are a little quicker than Amy in the higher powered Mustang, but I have a lot more seat time in this car and just ran this car it at this same track two weeks ago; she has never run the Mustang at ECR. Racing these cars was relatively easy, and if it weren't for the lingering steering shudder (that only seems to affect our car this badly) it would have been a completely stress free drive. I missed having a good race seat to keep me planted in place in the BMW, and I let the Hoosier's tendencies to overheat in 100°F conditions sneak up and bite me, but otherwise it was a breeze. I will also note that driving the Mustang on R compounds at a 1:58.2 pace was much easier than sliding around on street tires doing no better than 2:03.9! There was a complete absence of hooning in the Mustang this time around. Hooning is hard work...


What's Next?

We've cancelled all previously planned track and autocross outings for the month of July, for a few reasons. One, because it iss freagin' HOT in Texas from now until August; many of our local racing clubs stop having events from June-August. Today it was 108°F in Dallas and it will be in the triple digits all week. Those are miserable conditions to race in. We could see 30-60 days of over 100, easily. Amy and I got a touch of heat exhaustion at the Optima weekend, and got another round at this past weekend's ECR events, so we need time to recover. We spent last Sunday in pain, trying to get fluids and electrolytes back into our systems. Once you get heat exhaustion it is too easy to "re-get it", so we need a break.

Also, there are some lingering repairs we might finally be able to fix on the Mustang - like the stupid freagin' steering rack! Just heard that these are scheduled to be back in stock June 29th - so we've got one on pre-order (along with a T2R!). Upon inspection on Monday, it appears that the rear brake caliper piston dust seals are now fried, too, but the fronts still look fine. We'll get some new rear seals coming and swap those. Considering how many autocross and track hours of abuse this car has seen in... coming up on two years, this is a pretty good lifespan for dust seals.


Tire rub sucks! I am damned tired of this condition making the handling intermittent and weird. We are finally going to remedy this.

Lastly, we have a list of new parts to design, build and develop for the S197 Mustang. Going to too many races lately has delayed this considerably. The stock-style rear swaybar flat will not work with a 315mm tire under stock fenders, and it has to be replaced. I refuse to go to smaller rear tires just because Ford routes the swaybar in an inefficient manner. If we can keep the car off of a race track for a few weeks we can build the custom, splined-tubular steel rear swaybar set-up we've been meaning to make for the last year (we now have pieces coming to make this). This will allow the 315mm rear tire to finally fit inside the fenders under heavy lateral loading (it has 1" of clearance now to the bar, but under load the tire is still hitting the rear swaybar). I cannot remember an event yet where the rear tires haven't been rubbing on something - that has to stop. We're trying to make a very tunable rear bar that can work for both semi-serious track/street cars as well as dedicated track cars, so there are some modular bits to work out. We also really want to make a better Watts link than we've seen offered - something that is beyond the "Bolt on Billy" crowd. No bling, less weight, just a new design that has better lateral location and tunable roll center without the need to be 100% "bolt-on".

It might be a month before I update this thread again. We have a LOT going on at Vorshlag HQ, including three job openings, and four other major project cars that have been getting worked on in the past month - and another LS1 swap chassis we're adding to the already large array of BMW chassis we've tackled. The E36 LS1 swap kits are selling like mad, with three kits sold in the past three days - and people still don't know about half the sub-system kits we've added in the past quarter (which aren't even on the website yet), not to mention the ones we're about to release.

In any case, I better wrap this up. Once again, thanks for reading!

Cheers,

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Project Update for August 30, 2012: I haven't updated this thread in two months, but we have been busy as ever here at Vorshlag in that timeframe, and a lot of work was done to the Mustang. After the two weekends of race events in the Mustang in June (Optima @ ECR + Ford Dealer @ ECR event) we took a break from racing that car and concentrated on other projects we had going on at the shop. We thrashed around the clock for 4 weeks, tested, and then went to Colorado to support Brianne Corn's Pike's Peak Subaru STi at the 90th running of the PPIHC event. That month is a blur. We also started build projects on a 2013 Subaru BRZ, dove headfirst into a new 1999 Miata LS1 swap, made some strides in our BMW E46 LS1 project, and prepped and sold our $2011 GRM Challenge winning E30 V8. We took on another turn-key E36 M3 LS1 swap, bought another car or two, and have been refocusing our service shop on the things we are really good at.

In my last post I was saying that we might not update this Mustang thread for a while because we needed to develop some parts to allow the big rear tires to fit. No, not the monster 345/45/18 Hoosiers, just the relatively tame 315/35/18 Kumhos on our Forgestar 18x12" rear wheels. These wheels should fit within the confines of the stock rear fender contour and inboard wheel constraints (if lateral axle displacement can be kept in check), but the stock style rear swaybar mounting location is sticking right in the way (see lower left picture), and this is where we are seeing the rear tires rubbing time and again. Whoever thought this was a good routing was not a "car guy", who would immediately see this is the inner wheel width limit.



We have to add spacers to push the wheel outboard and then they can rub on the fender lips and/or cut into the tread. We've been fighting this all year. Why try so hard to make 315s fit inside the fenders of this car? Well because we have tried tires with these widths - 255, 265, 275, 285, 305, 315 and 345mm - and the car goes faster/is easier to drive/has more rear traction with each step up in tire width. We've determined the 345 tire was a bad call (too wide and too tall - yes, as many of you told us before I raced on them), but the 315 is still a great size to use both front and rear. I prefer the 315/35/18's tire height but Hoosier only makes a 315/30/18 in 18" diameter so that's what I went with for the Solo Nationals.


Mustang racing on 315mm Kumhos with 18x11 front, 18x12 rear wheels, rub free. 75 hp worth of graphics are missing?!

We also needed some unique suspension parts other than just camber plates and shocks (that we cannot get) to sell for the S197 market - Vorshlag is a business, after all. There are hundreds of shops selling the same old Mustang doo-dads and bolt-on bits, so we wanted to look for something new, unique and different - either that we designed and built ourselves or someone new in the S197 market could come up with. To make room for the rear wheels we had purchased components to use in the design and fabrication of a splined/NASCAR style rear swaybar, to move it away from the rear tires + to give us a cool new product that would have lots of adjustment and probably be lighter, too. As the splined bar, mounts and other parts are arriving I saw this S197 Mustang rear suspension photo on the Whiteline Flatout Facebook page...


Whiteline S197 prototype Panhard and rear swaybar

Hmm, there are a lot of new parts in that pictures. Whiteline UCA + mount, LCA arms + relocation brackets, Panhard bar and reinforcement, a new rear swabar, and big fat end links. I was staring at this picture for a second, not sure of what it was that caught my eye...then BOOM! The light bulb goes off: I yelled "They've routed the rear swaybar backwards from the stock bar! That clears up tons of inboard wheel room!!" Instead of hanging from the chassis via two stand-offs and attaching to the axle way out by the wheel, the Whiteline swaybar bolts right to the axle housing and has end links that grab the chassis. This routing now removes potential tire rub at the swaybar!

Matt heard me shouting in my office and ran over to take a look and to double-check my logic. Vorshlag was already on Whiteline's mailing list from several talks we had at SEMA and PRI, and we were talking all year about doing the buy-in to become a stocking Whiteline dealer. They make bushings, control arms, reinforcement brackets, swaybars and end links for lots of cars, and are the go-to brand for Subarus and EVOs, which are two car models we sell heavily to. But when I saw that their new S197 parts were finally coming out I did more digging. Then I saw their brand new Watts Link, which was unique from all other designs made for this S197 chassis, and I got on the phone, fast. This was another solution that we had a need for...



Long story short, about two weeks ago we got our hands on the latest yet still pre-production S197 Whiteline Watts Link kit, their front and rear adjustable swaybars, and their rear upper control arm (UCA) and chassis bracket. We also picked up their new production S197 Panhard bar kit + reinforcement bracket, just for pictures and to keep in inventory. After that round of parts shipped they heard we were running this car at a Global Time Attack race at Texas Motor Speedway at the end of this month, so they sent us their rear lower control arms and relocation brackets to test for that race. These bits aren't SCCA ESP legal (well... we found a way to make them legal, but are not pursuing it just yet), so they are not going on before the SCCA Solo Nationals next week. At the GTA event this car will get the LCA bracket + arms, a lower rear ride height (finally!), and then we will have a 100% "Whiteline equipped" S197 (we will then shoot some on-track video at GTA which they can use in their SEMA booth). Look for that update late in September.


Left: The rear swaybar (shown above) is solid and 27.5 mm dia. and routes very differently than any other. Right: Whiteline Endlinks are beefy!

The Whiteline parts look incredible, with materials, bushings, finishes and design aspects I'm not really used to seeing in the "Mustang Market". Why is that? Well my theory is that I think there are actually only a couple of real innovators in the Mustang aftermarket world, and then everyone else copies these one or two companies' products, and pretty soon it all looks the same. Then many times production goes overseas and it becomes a "race to the bottom" on price. I have also seen many older aftermarket designs from previous generation Mustangs (Fox/SN95) get re-hashed for the newer Mustangs (S197), too. Whiteline came in to this new (for them) market with fresh ideas from their other car markets, introduced an all-new Watts Link layout and design, and completely new swaybar routing. They have innovated instead of copied or rehashed, and fixed issues for me that I don't even know they intended to (more rear wheel room!). Again, this is my theory and I mean no offense to companies in the existing Mustang market. If you are at one of those Mustang companies and are reading this, I was referring to you guys as the only "real" Mustang innovators, OK?

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The Whiteline Watts kit is a 100% bolt-on affair, but it is still lightweight. Instead of being a giant stepladder bolted to the car, it is a slick, simple, beefy Watts unit that attaches in all the right places and uses the right materials. Because it is made with their well developed poly bushings it is SILENT in use, and it fit around our custom dual 3" exhaust with plenty of clearance. Will this bolt-on design hold up to the lateral forces of 315mm R compound tires? I was a bit skeptical, but these parts made it through roughly a year of autocross events (12 events x 4 runs) in a single day on 315 Rs, so I've got some confidence in their stuff now.



The front swaybar was a pretty straight forward upgrade, and we went with this new "4 hole" adjustable solid 33.5mm diameter Whiteline bar over the old "3 hole" adjustable hollow 35.5mm Eibach swaybar (the stock 2011 front bar was also 35.5mm hollow non-adjustable, at 12.7 lbs). Sure, there was a bit of a weight hit with the WL front bar, but I'm sure they had a reason for going with the solid bar, so we went with it. It doesn't have a dip in the middle like the other two, looking at the picture below.



Removing Suspension Noises

I haven't really spoken up about this but the last few months of street driving in the Mustang have sucked. After extensive testing, removing parts one at a time and replacing them with stock, we have finally isolated the noises to two components: the Spohn panhard and UCA parts + the UPR chassis mount we had on the Mustang have been making a lot of noise, starting just a couple of months after they were installed. Every bump was a rattle or bang, and it was not at all what I would consider streetable. It didn't happen right away, which was the mystery - they started off dead silent. We have re-tightened the UCA mount 5 or 6 times, which would quiet things down for a day or two, only to return and worsen with each iteration. The "Del-Sphere" joints that were supposed to be quiet were the opposite of that, at least on our car. The holes in the chassis mount did not match the holes in the Del-Sphere joints or bolt size, either, but even making custom bushings to fix that mismatch won't help. It seems to be in the joints.



In early August I had asked Ryan to pull the Spohn UCA to see if the noises would subside. The stock UCA with rubber bushing and the factory upper mounting bracket went back on and 50% of the noises went away. We still had the Del-Sphere equipped Panhard rod on - only wanting to change one variable at the time. My wife's daily commute in the Mustang is driven on super smooth concrete roads, but it was still banging and clanking over the tiniest ripple or seam, just not as loudly as before. When the Whiteline Watts link kit arrived (the Watts was delayed a bit but we kept hounding them and got an early release part - the first one outside of their own test car!) the Mustang got into our shop for that install + their rear swaybar.



Viola! With the last of the Del-Sphere joints removed ALL of the rear suspension noises were now gone. She street drove it like this last week and was very happy. Then one day this week the stock UCA with rubber bushing and the stock chassis bracket came back off and the Whiteline rear adjustable UCA + bracket and front swaybar went on. Again, it was 100% silent over bumps and articulation, which is exactly what you want on a street driven car.

So how do these parts work? So far the only thing I can say is "perfectly". We've pounded street miles on them for a week and then used all of it on the car at an autocross test yesterday with 38 laps of abuse. The new Watts Link kit came with a beautiful cast aluminum rear diff cover, which was a unique part to Whiteline kit. The bracket that holds Watts link "football" bolts to this new rear cover (which also has holes plumbed for a differential cooler), and the football mount can be adjusted up/down with 2 settings for rear roll center adjustment. Some kits have more settings, but I liked the compact nature of their kit.

With the new routing of the Whiteline rear swaybar installed the 18x12" Forgestar wheels can finally tuck inboard another 1/2" on each side and now we have no more tire rubbing swaybar. Woot! The swaybar is a big win in my book, because it lets us run bigger wheels. And this big car needs all the rubber on the road it can get.

Next up - Testing!

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Project Update for August 31, 2012: Before someone asks why we went to a Watts, hopefully I can explain this. I'll back up a bit and talk about the Fox and SN95 Mustang suspensions, the stock S197 suspensions, and then the differences between a Panhard rod and Watts link. Then I will cover the dedicated test day we did in the Mustang yesterday, to get the brand new Whiteline Watts link and bars dialed in, and then our last minute preparations and trailer loading for the 2012 Solo Nationals next week.

Why is a Watts Better?

There are several ways to laterally locate a solid rear axle assembly relative to the chassis in a RWD car like the S197 Mustang. The earlier Fox and SN95 generation Mustangs with solid axles used an opposing 4 link rear suspension that had the upper two control arms canted in at a severe angle, which made their intersecting arcs of travel automatically bind. The upper arms sort of worked to locate the axle, at least with a 4 to 5" window of lateral displacement (with R compounds we would commonly see that much movement!). If you put poly bushings in all control arm locations it would instantly bind up the rear suspension and eventually rip the mounts out of the car. Entire companies existed for a time replacing this car's terrible rear suspension with 3 links, Torque arms, Watts links and Panhard rod solutions. The IRS that came in the 1999 model year Mustang Cobra was a Big Hot Mess adapted from an earlier MN12 chassis (Thunderbird/Lincoln MarkVIII), with new toe links. It never really worked all that well, added weight tot he car (like IRS often does), and had pretty bad axle hop during straight line acceleration. And yes, a solid axle rear suspension is actually lighter than most IRS systems, but just more unsprung weight.


Left: The Fox and SN95 solid axle Mustangs has this opposed 4 link. Right: 1999 Cobra introduced this parts-bin IRS

Things changed for the better on the 20056 Mustang "S197" chassis. The two most common laterally locating solutions for solid axles in use today are a Watts linkage and Panhard rod. Both of these do essentially the same thing, but in different ways and with different levels of complexity and costs. They provide a linkage which connects the axle to the frame and gives positive lateral locations, while still allowing fluid up-down movement of the axle. The locating device must be free to move in other directions so it does not interfere with the intended motions of the axle. When Ford began the S197 chassis design they used a Panhard rod and a 3-link, with 2 lower control arms and a single upper arm that are pointing directly fore-aft. Much improved, but not perfect. The rear suspension in the Crown Vic of the day was actually more advanced, as it had a 3-link and a Watts.


The S197 Mustang had an all-new rear suspension design for 2005, with a 3 link and a Panhard rod

A Panhard rod is commonly used by factories that still build solid axle RWD cars because it is simple and cheap. A Panhard rod normally runs across the entire width of the car, with one end pivoted on the axle housing and the other end is pivoted on the frame. Ideally the Panhard rod should be horizontal with the car at the resting ride height position. A Panhard rod does not provide true vertical motion at the end attached to the axle because it arcs about the end pivoted on the frame and there is a slight sideways motion of the axle through suspension travel - this is the big limitation. If the bar is long, if it is horizontal at normal ride height, and if the axle vertical motion is small, then the sideways motion is minimized and not too important, which is the case for most racing cars.

On a road car with soft suspension and a fairly large amount of wheel travel, a Panhard rod has downsides. The lateral axle movement allowed by the rod gives a rear-axle steering effect when the wheels rise and fall over larger bump travel. The bar can flex, the rubber pivot bushings can deflect, and when the static ride height is lowered the axle will displace laterally at rest (our car's axle was moved 3/4" to one side) - this is why all lowered cars need an adjustable length Panhard rod, to re-center the axle. Aftermarket Panhard rods usually replace the rubber pivot bushings with Polyurethane, Metal rod ends or some sort of plastic rod ends. Metal rod ends have lots of noise and accelerated wear, and as we have seen the Delrin sphericals seem to suffer the same fate: noise and wear.


Left: The black "football" shaped part pivots at the axle cover. Right: The chassis "tower" that the left side Watts link mounts to.

A lateral locating device without these problems is the Watts linkage, which is much more common to see on a race car with a solid axle RWD set-up. This design is more complex (2x as many arms and a complicated pivoting axle bracket called a "football") and takes up more space than a Panhard rod, so it is not always the best factory solution - more cost, more difficult to package. The geometry is inherently better, though, and it should be considered on any competition vehicle if at all possible. A Watts linkage consists of the two parallel lateral links plus a vertical link connecting them. If the horizontal links are parallel and equal length they will have the same amount of lateral motion as the ends attached to the vertical link. Because each lateral motion is in a different direction, this rotates the vertical link (football) through some angle, but the center of the vertical link is not affected. This center point travels in a true vertical path, and that is where the axle is attached - thus the axle goes strictly up and down, without the lateral displacement associated with the arc of a Panhard rod.

A Watts linkage can consist of tubing for the lateral links, using spherical rod ends for pivots or polyurethane bushings. On a true race car you use rod ends but for a quieter, street-worthy set-up polyurethane is much preferred. The vertical links should be designed to carry bending loads and the center football pivot is usually a rigid bearing on a post so it can rotate but not pivot laterally, often connected to the rear axle differential cover (many Watts kits come with a new cast aluminum diff cover that has rigid holes cast into it for a bracket to mount the football). The attachment between the Watts linkage and the axle is difficult and it must be designed strong enough to carry the side loads in cornering. I've seen some that clamp onto the cover bolts, but the styles that have an all-new rigid cover are preferred.

The improvement a proper Watts Link makes over the Panhard design is the rear roll center is fixed at the football, and does not move up and down with ride height changes due to braking, acceleration, and road undulation. This creates more consistent tire loading, more predictable handling, and especially improved transitional response. So in short, you definitely want a Watts Link system if you are competing in any form of motorsports that involves changing lateral loads, like autocrossing or road course racing. The more changes in direction (slaloms or esses), the more a Watts link is desired.

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August 30th Private Autocross Test Event

We had not autocrossed the Mustang since the late May "Spring Nationals" at Lincoln, so yesterday we did twelve autocrosses worth of runs at a private test event. With the 315/35/18 Kumho V710s still mounted on the Forgestar 18x11/12 wheels from the late June track day event, and located farther inboard by 1/2" from before, we loaded the Mustang onto the trailer and crammed in all of our gear. We brought more tools and equipment than we ever have, with a generator and air compressor, air tools, multiple floor jacks, extra springs, and all of our normal gear + our Farmtech timing system. We were loaded for war!



Like on our August 2nd Test in Brianne's Pikes Peak Subaru where I got to drive that beast around an improvised road course at 130+ mph, we rented the "Mineral Ring" once again. Getting this 62 acre paved site on a week day is a breeze if you know the right person to call, so we headed out yesterday with the Mustang and our gear. Its 2+ hours each way from our shop to this facility in Mineral Wells, TX, and it always ends up being a battle to miss traffic across Dallas and Ft. Worth along the route. We hit 8 am traffic leaving and 5 pm traffic coming back, but we got a lot accomplished in about 10 hours.



Once we arrived we set up the old "Hollis Test Course" that was painted on the site for the past 6 years or so. Laid out about 50 cones, set-up the timers, and unloaded the Mustang. Conditions for August in Texas were as perfect as they get: sunny and clear with 88°F tempts and a nice 10-15 mph breeze all day. It crept up to 98°F by 2 pm but it was still pretty comfortable, considering it wasn't 110°F with a dead calm.



We started with a quick alignment check, setting front camber to -3.6° and toe to +1/8" out. Ride heights were already set fairly high, as we cannot lower the car as much as we like without knocking the rear geometry all to crap (those $100 relocation brackets work wonders, if only Street Prepared would allow them). Tire pressures were set at 35 psi front, 32 psi rear and the Moton ClubSport 2-way shocks were set at the middle rebound and compression settings front and rear. The Whiteline swaybars were set in their middle settings front and rear as well. Blue tape was placed on sections where we thought the tires could rub, the video camera was installed, and the new AIM Solo timing display was set-up for this course. Then I started taking laps....



Some early and some late test laps in the Mustang - click for video

This is a course I have driven hundreds of times so it usually doesn't take long before I am familiar with the course layout and my times stabilize within a tenth. Then we can make adjustments and check times - I let the clocks by the guide and not my "impressions". The AIM Solo was within hundredths of the Farmtek timers so I could see my laps real time. I took 2 hot laps at a time going clockwise on a course with a single start-stop line. In the video above you can hear me keeping notes, but Jason kept a full log of adjustments and lap times throughout the 3 hours of test driving I did. Ryan was busy all day making set-up changes to the bars, shocks, alignment and tire pressures. Plus we had one unexpected delay - a flat tire.



A flat out at the Mineral Ring it shouldn't be much of a surprise, as we got a flat in Brianne's Subaru at the same site a month ago (which shut down our testing early that day), but this time we were prepared. Theoretically we are always learning from our past mistakes, right? So I had just gone out for a two lap blast but after the 2nd slalom cone I new something was "off". The car wouldn't turn right the the left front tire was howling under load - I waived off the lap quickly and got back to the trailer for a look. Yep, there was a pin hole in the left front and it was deflating fast. With a plug in the tire, the generator fired up and the compressor buzzing along, the tire was fixed, aired up, and I was back on course in about 3 minutes.

Over 3 hours of testing I made a total of 38 laps, and finished with blisters on my hands and a shoulder injury that was howling from some violent corrections I had to make using some of the wackier settings we tried, but we made it through the full sweep of component adjustments we wanted to attack. The new bars worked great and had more adjustments than many others out there with 4 holes per side. The rear tires were no longer rubbing and tucked inboard for a 1" narrower track than before. The Mustang was handling better than ever, especially in slaloms, where I could violently throw it back and forth. The pictures show that the lateral axle movement is much reduced from before (when we had a Panhard rod), and it was easier to drive. We had fixed some other long standing issue, too, but I forget what that was at the moment? It will come back to me.



After 3 hours in the car I was pretty hot, sweaty, sore and tired; so were Jason and Ryan, who did most of the heavy lifting with the test adjustments. My driving was starting to get sloppy by about lap 30, where I could only do 1 clean lap out of 2. The temps were climbing towards 100°F so we called it a day. After we loaded back up, grabbed a late lunch, we headed back to the shop in Plano and made it back by 5:45 pm. We have a lot of new cut vinyl graphics and decals to install today that Jason has been working on for the past few days. The graphic design is all Amy's doing, and not at all my thing. If you see the car and have any comments, direct them to her! We are mounting up a sticker set of 315/30/18 Hoosier A6 tires, and I hope this is the right tire choice. I know that 335's would rub the fenders almost as badly as the 345s did, so I am staying safe with the 315s all around. It will likely always pushed with a non-square set-up anyway (it sure did with 315/345s!).



So now its Friday and we have to leave for the 2012 SCCA Solo Nationals on Sunday night to make it the 12 hours north to Nebraska by mid-day Monday. Might sneak out to Cars&Coffee Dallas on Saturday morning, as the Pikes PEak car will be on display. Amy and I are going to this Women of Solo Luncheon that Vorshlag sponsored on Monday, celebrating 50 years of Women in Solo. Then she and I race Tuesday and Wednesday, drive back Thursday and are back to work on Friday.


This is how the Mustang currently sits, ready for a fresh set of graphics and tires over the next few hours....

SportsCar magazine picked Amy to win ESP-L, and I hope they are right. In the past when she had a halfway decent car she has pulled off Nationals wins (2 times), and almost pulled it off in a super-heavy EVO X with a transmission going berserk in STU-L in 2009 (losing by .07 sec). This is the best prepared car we've ever taken to the Solo Nats, so who knows? We still don't have proper rain tires, as they just were not in the budget. We will bring some STX wheels and full tread street tires along for a Hail Mary if it rains, but it is a big gamble - I will just hope that it doesn't rain, and know that if it does it is our fault for not spending the $$$ on Hoosier H2Wets. The ESP open class is packed with well prepped cars and lots of talent, so I will just put in my best effort and see how I do.

I will give a post-event update on this thread, of course. You can "like" our "Vorshlag" Facebook page for live updates from Lincoln, and of course SoloLive will have results for the 1200 competitors all week.