The Mustang Forum for Track & Racing Enthusiasts

Taking your Mustang to an open track/HPDE event for the first time? Do you race competitively? This forum is for you! Log in to remove most ads.

  • Welcome to the Ford Mustang forum built for owners of the Mustang GT350, BOSS 302, GT500, and all other S550, S197, SN95, Fox Body and older Mustangs set up for open track days, road racing, and/or autocross. Join our forum, interact with others, share your build, and help us strengthen this community!

Best known practice to correct front geometry?

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

ArizonaBOSS

Because racecar.
Moderator
8,730
2,734
Arizona, USA
Yea, the steering rack. I´m still curious how the 13 and the ford racing rack compare. @ArizonaBOSS, do you have any insight on that?

All of them (including the Ford Performance rack) are the same mechanically. It's all in the programming. Unfortunately, we have been down this road and there is no way to reprogram the racks.
What I do know is I have an MY2012 BOSS 302 street car rack, built in June 2011, and do not have ANY issues with this. Also it seems that only MY2011 cars are affected by the steering shake. So you may very well be able to get away with a junkyard/used rack from a 12+ S197.
 
218
369
Exp. Type
Time Attack
Exp. Level
5-10 Years
CA
@rwleonard
In regards of the MM K-member I am skeptical about marketing speak. E.g. the watts links was so praised as the silver bullet for everything but all I really needed was a cheap v6 sway bar to fix my issues. Nothing wrong the the Watts, it´s a great piece in itself. The real question is, is the K-Member bang for the buck or is the money better invested in other places?

@Norm Peterson
My current tires would require -5° of camber due to the mcpherson struts. Yikes. I`m kind of locked in with my current wheels though.

@ArizonaBOSS I`m more curious about what the benefits between the racing and the stock 12-14 racks are. Or if the difference is neglect-able.
 
What exactly does the MM K-member do? I know it`s more adjustable, but its also a hefty item to get and a lot of work to get it mounted.

I`m at -3.7 front camber right now and it`s not enough. I guess I can max it out at -4 to -4.5

Yea, the steering rack. I´m still curious how the 13 and the ford racing rack compare. @ArizonaBOSS, do you have any insight on that?

Like some mentioned, geometry. The main thing is the slightly higher A arm pickup, raising roll center and helping the camber curve.

When you say your 3.7° camber is not enough, are you still seeing more outer tire wear? We're on opposite ends of the spectrum.
 

Norm Peterson

Corner Barstool Sitter
939
712
Exp. Type
HPDE
Exp. Level
5-10 Years
a few miles east of Philly
Best I could find, but too dark to see the lateral distortion down at the bottom clearly. The wheel itself looks like it's got plenty of negative camber, though.

hqdefault.jpg

I'm guessing that being locked into 11's is either a consequence of some competition rule directly or indirectly by your choice on how to use preparation/modification points?


Norm
 
218
369
Exp. Type
Time Attack
Exp. Level
5-10 Years
CA
Norm, gotcha. I know what you mean. It´s mostly that I already got my sets of wheels and have other problems to fix first. 18x12 is a pretty penny to dish out.
Here is a better image:
tires.jpg

I ran -3.5 on street tires for a year, which was a pretty good spot and I had pretty even wear on 295 RS4.
I ran some 275 RSRR for a bit and they kept wearing hard on the outside with -3.5°

This season though I`m running take off slicks and slicks just need a lot more camber. Everyone who runs slick straight up tells me to go to -5°. Track depended obviously.

Our front suspension is camber hungry! Fore reference 949 Racing was dialing in their tires of their GT350 based on pyrometer readings at WSIR. They went full -5° on street tires to give the car what it needed.
 

Grant 302

basic and well known psychic
Required camber settings vary wildly depending on tires and the rest of the suspension geometry and spring rates and driver skill/style. On top of that, course specific settings like at Streets really matter.

For myself, when I was on P springs and street tires, I couldn't get enough camber with plates and bolts at Streets. Just after switching to the CorteX/JRi and 305 slicks I had to dial back even a moderate ~2.7º to ~2.4º at Laguna Seca (I remember Ron/moto had to do about the same after our first session). Racked the plates back to max in for Streets on slicks. Back to low 2.xºs on street tires at Chuckwalla.

People also manage their tire pressures differently. lower hot pressures often need more camber. And there's rim/tire size fitment differences as discussed earlier.

Anyway, I don't think anyone should be too hung up on what others are running for camber unless you are running the same, same, same. I don't see the 'need' for more camber in those two pics above, but I'm sure it needs more rounding the skidpad.
 
6,360
8,180
a tale of 2 pics....
your car on a relatively flat turn..
tires-jpg.jpg

a T2 car on a bank at Homestead/Miami

F6Z2WGJl.jpg

now the bottom car is limited to about 3 degrees of camber, I want to say that's a 275 tire on a 10 in wheel, but notice the similarity in how far the wheel is punching out of the bead area of the tire, not sure if your car is trying to understeer or not, but you might want to throw a couple of extra psi of air into that tire. Generally..and by that I mean very generally, front engine cars like about 1 to 5 psi more air in the front than the rear. I'm not worried (well, at least at this moment) of the red car losing the bead because of the design of that particular wheel, you, on the other hand, might need to keep an eye on that, especially if it's a painted wheel.
I've said this before, you guys aren't trying to reinvent the wheel, you're basically building a T2 r T3 suspension, so find one that works, and copy it.
 
218
369
Exp. Type
Time Attack
Exp. Level
5-10 Years
CA
My car rarely under steers in that turn. The goal is rather to rotate it.
It`s a fast straight with heavy uphill braking which leads into a slow 180° and slightly cambered turn. Its basically the crest before the track leads downhill again. I´m hitting ~1.2 - 1.3G in that pic. I usually hit 1.4 with a peak of 1.6.

I´ll try adding some more PSI. The tire is indeed very soft even after the first lap. Depending on the track I usually start at 25-27PSI and end up with 32-33. I do not know the actual temperatures of my tire surface though. I also don´t know what session or lap that picture was taken in.

S197 are kinda rare on the tracks over here. Only NASA has a hand full of them and I don´t run NASA right now. It`s tricky to find and copy a good example, that`s why I keep asking all these questions.
 

Grant 302

basic and well known psychic
I've said this before, you guys aren't trying to reinvent the wheel, you're basically building a T2 r T3 suspension, so find one that works, and copy it.

Agreed with Badger about this part. Not gonna have access to such cars out here. Even if they were here in SoCal, I'm not gonna expect somebody to share the specifics.
 
6,360
8,180
Understood and I appreciate that. People in the know are usually very tight-lipped about anything they or their team does. Even more so for winning teams.

Don't get me wrong, some stuff is proprietary, but the guys at Phoenix have handed people creepers and let them go under the car. I remember putting the car on the hauler and these guys were looking at it, they were amazed that there was nothing "trick" there..it's mostly in the details...
my biggest issue is I try to lead someone in a certain direction and they go off and ask everyone else for advice...Okay...you're on your own.
 
218
369
Exp. Type
Time Attack
Exp. Level
5-10 Years
CA
I always hold Robs advice in the highest regard and as my baseline. I had a lot of questions recently with a certain amount of overlap. I hope I did not create the perception of inquiring multiple times on the same topic. That certainly was not the intent.

My buddy and me have the fastest local s197. Which really doesn’t mean anything as no one tracks them and they are kinda rare here. But it also makes it incredibly hard to chase down info in person. You guys though have been really informative and probably helped us a lot more than you are aware :)
 
Last edited:
6,360
8,180
I always hold Robs advice in the highest regard and as my baseline. I had a lot of questions recently with a certain amount of overlap. I hope I did not create the perception of inquiring multiple times on the same topic. That certainly was not the intent.

My buddy and me have the fastest local s197. Which really doesn’t mean anything as no one tracks them and they are kinda rare here. But it also makes it incredibly hard to chase down info in person. You guys though have been really informative and probably helped us a lot more than you are aware :)

You're fine, you gotta go a lot longer ways than that to yank my chain.
 
If anybody knows how to properly set up an S197 race car it's Rob aka Blacksheep-1, the Aquilantes and Phoenix Racing . Numerous PWC and SCCA class wins including two back to back PWC championships says it all.
 
Last edited:

TMO Supporting Vendors

Top