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Maximum Rear Camber, Stock?

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I had camber adjusted at the most reputable shop around. They got the front to -3.2°, which is good (Vorshlag plates, no hole cutting). But they said they could only get the rear to -1.7°. I‘m looking for -2.0° and as far as I can see, that should be doable. Numerous drivers and the spec sheet below have said -2.2 is max with stock adjustment on inner control arm. Did this shop not know what they’re doing? Or perhaps the GT350R springs and PP shocks are somehow preventing it from going higher? They also have toe at zero in the rear, if that matters.

Thoughts?

A02EF67C-FEEE-4246-BBF0-09724C9147BC.jpeg
 

JDee

Ancient Racer
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5 miles from Mosport
Cars vary, production tolerances and so forth. I can get -2.2 on the rear and haven't added anything to get it there. My alignment guy is very fastidious about what he does but even he can't defy physics. Realistically, it doesn't need more, it's a front heavy car and it wants to push, I find the rear rarely if ever is a problem and that's a good thing. I cut the hole on the front, not a big deal to do it and can get over -4 now with Vorshlag plates though I find -3.5 is sweet. My experience says it's worth doing, improved both lap times and outer tire wear.

I have to wonder about using a PP shock with a GT350R spring, the info I have says the GT350R spring is 200 lbs heavier than the PP spring. They're not meant for each other and I would think the spring is likely overwhelming the shock. I'm a big fan of well engineered integrated suspensions, such as the Ford Racing FR3 track suspension. That kit makes this car magic, even a 70 year old doofus like me looks like a hero out there. No way I would try to out-think the company that designed and built this car and has about 10,000 engineers.
 
Cars vary, production tolerances and so forth. I can get -2.2 on the rear and haven't added anything to get it there. My alignment guy is very fastidious about what he does but even he can't defy physics. Realistically, it doesn't need more, it's a front heavy car and it wants to push, I find the rear rarely if ever is a problem and that's a good thing. I cut the hole on the front, not a big deal to do it and can get over -4 now with Vorshlag plates though I find -3.5 is sweet. My experience says it's worth doing, improved both lap times and outer tire wear.

I have to wonder about using a PP shock with a GT350R spring, the info I have says the GT350R spring is 200 lbs heavier than the PP spring. They're not meant for each other and I would think the spring is likely overwhelming the shock. I'm a big fan of well engineered integrated suspensions, such as the Ford Racing FR3 track suspension. That kit makes this car magic, even a 70 year old doofus like me looks like a hero out there. No way I would try to out-think the company that designed and built this car and has about 10,000 engineers.
Thanks. It would be great if I can leave the rear at -1.7 and not have to go back to them. I’m wondering what the shop could have missed - some small step they skipped?

I might cut the hole wider and dial on more when I’m ready to move the rest of the car up in classing.

The shocks/struts are specifically M-18000-F. I had the same question for the speed shop. As a total noob, I went to him as recommended, him having set up a bunch of S550’s for track use, and having a terrific rep (FlimFlam Speed, Richmond, VA). He said it was a proven combination that he sells almost as a package (with Eibach EIB-35145320 sway bars and Vorshlag cc plates). But I’m STILL a noob and you might be right. The car feels great at speed, but I came from a crappy set-up, and I don’t have the experience to know if it could be better.
 
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Thanks. It would be great if I can leave the rear at -1.7 and not have to go back to them. I’m wondering what the shop could have missed - some small step they skipped?

I might cut the hole wider and dial on more when I’m ready to move the rest of the car up in classing.

The shocks/struts are specifically M-18000-F. I had the same question for the speed shop. As a total noob, I went to him as recommended, him having set up a bunch of S550’s for track use, and having a terrific rep (FlimFlam Speed, Richmond, VA). He said it was a proven combination that he sells almost as a package (with Eibach EIB-35145320 sway bars and Vorshlag cc plates). But I’m STILL a noob and you might be right. The car feels great at speed, but I came from a crappy set-up, and I don’t have the experience to know if it could be better.
A couple of things - the rear at standard ride height should be adjustable to about -2.5 degrees. Also, and this is important, get the rear toe adjusted to spec, and if you're tracking the car, I'd borrow the 0.30 degrees toe-in spec from the later GT350 setup charts. The car will wander all over the road with zero toe at the back.

As to why your shop couldn't get more than 1.7 degrees, it's a mystery. One thing I saw when I adjusted my GT350 rear setup last year was that the rubber in the suspension "absorbs" some of the changes, and only releases it after a test drive. For instance, I adjusted from 1.1 up to 1.6 in the shop and when I measured it again after a drive around the block, I had more like 1.9 degrees. Also, there's a big interaction with the toe setting - change the toe and you get new camber as a byproduct. Now, that all said, it doesn't explain why you're not getting more rear camber - there's about 0.8 degrees missing.
 
A couple of things - the rear at standard ride height should be adjustable to about -2.5 degrees. Also, and this is important, get the rear toe adjusted to spec, and if you're tracking the car, I'd borrow the 0.30 degrees toe-in spec from the later GT350 setup charts. The car will wander all over the road with zero toe at the back.

As to why your shop couldn't get more than 1.7 degrees, it's a mystery. One thing I saw when I adjusted my GT350 rear setup last year was that the rubber in the suspension "absorbs" some of the changes, and only releases it after a test drive. For instance, I adjusted from 1.1 up to 1.6 in the shop and when I measured it again after a drive around the block, I had more like 1.9 degrees. Also, there's a big interaction with the toe setting - change the toe and you get new camber as a byproduct. Now, that all said, it doesn't explain why you're not getting more rear camber - there's about 0.8 degrees missing.
Man, thank you. My ride eight is about an inch lower then stock, but I thought lowering the car increased negative camber. Very interesting, what you said about rubber parts absorbing some of the change.

If the toe goes to .30, does that open up more negative camber?

I track the car, but my perception was that toe eats up tires, and while I don‘t do much street driving, I do regularly drive it on 200+ mile round trips to events - Putting on a total of about 2500 miles per year. Not sure if that would require a compromise with toe settings.

Any further thoughts on these things? I’m going to take it to Ford this time and see what they can do with the rear camber and toe. Again, I really appreciate the help. Want to get this right.
 
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JDee

Ancient Racer
1,797
2,001
Exp. Type
W2W Racing
Exp. Level
20+ Years
5 miles from Mosport
I doubt you'll get much help on this out of a Ford dealer. My experience is they pretty much go by the Ford book and that will get you nowhere. My suggestion is to try to find a good independent guy with state of the art equipment who knows how to work to tight tolerances, as in close is not good enough.
Luckily for me, in my little town I have a guy exactly like that, you may well have one in your town as well.
 

TMSBOSS

Spending my pension on car parts and track fees.
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Illinois
I doubt you'll get much help on this out of a Ford dealer.
There are exceptions. The tech who aligned my 350R before delivery at Woodhouse had experience setting up performance suspensions on Mustangs, Vipers and other cars. He knew his sh----tuff. Most, have no idea how to set up a car to perform. When you have to explain adjustable caster/camber plates to them.......just move along.
 
1,246
1,243
In the V6L
Man, thank you. My ride eight is about an inch lower then stock, but I thought lowering the car increased negative camber. Very interesting, what you said about rubber parts absorbing some of the change.

If the toe goes to .30, does that open up more negative camber?

I track the car, but my perception was that toe eats up tires, and while I don‘t do much street driving, I do regularly drive it on 200+ mile round trips to events - Putting on a total of about 2500 miles per year. Not sure if that would require a compromise with toe settings.

Any further thoughts on these things? I’m going to take it to Ford this time and see what they can do with the rear camber and toe. Again, I really appreciate the help. Want to get this right.
If you're running GT350R springs then your ride height is the same as a GT350R, which is the same as a GT350, so start from the GT350R setup. The easiest way to do this is to download a late production GT350 Owner's Supplement from Ford's website and use the GT350R settings. Here's 2019. The settings are the same as 2020 except the front toe is 0.1 degree of toe-out in 2020 instead of 0.1 degree of toe-in. I prefer in over out, or you could just average them and run zero toe at the front. As for the rear, 0.3 degrees toe-in is the setting regardless of use. It really settles the car down.


I had never looked at the Mustang Owner's Manual itself before - it's singularly unhelpful when it comes to suspension setup for the track.

Your suspension has more compliance - softer bushings with more movement - than the GT350 suspension, but it's a good place to start. Note that the R settings assume the carbon fiber wheels, which are exceptionally stiff. If you're running a lightweight alloy wheel, you'll probably need an extra degree or so of negative camber to compensate for the wheel bending under side-loads. The lighter the wheel, regardless of forged or not, the more it bends under load.

If you do end up with adjustable rear upper control arms to make camber alignment easier (it's remarkably difficult on the S550) get the SPC product. It's easy to adjust and maintenance-free, unlike the units made with spherical bearings and poly bushings which need routine servicing.
 
The local Ford service foreman apparently races a Mustang, so I might be in luck. But I’ll believe it when I see it. Hoping to speak with him before I bring the car in, but I’m going in anyway to get a pair of front axle nuts.
 
The settings are the same as 2020 except the front toe is 0.1 degree of toe-out in 2020 instead of 0.1 degree of toe-in. I prefer in over out, or you could just average them and run zero toe at the front. As for the rear, 0.3 degrees toe-in is the setting regardless of use. It really settles the car down.
So, to be clear, the spec sheet I posted above says .30 TOTAL rear toe-in, .15 each side. Are you saying .30 total...or per side? Vorshlag recommended .60 total toe-in in another post, but that is for a coil-over set up and I have no idea if that applies to also to my car. They claim that won’t wear the tires badly.

Thanks again.
 
1,246
1,243
In the V6L
So, to be clear, the spec sheet I posted above says .30 TOTAL rear toe-in, .15 each side. Are you saying .30 total...or per side? Vorshlag recommended .60 total toe-in in another post, but that is for a coil-over set up and I have no idea if that applies to also to my car. They claim that won’t wear the tires badly.

Thanks again.
0.30 total, which is 0.15 per side which provides zero thrust angle.
 
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