[VR Baron]

Hi all,
Had to much time on my hands and looking at fine tuning the car. After everyone’s experience in autocross with this car, I started to think, given a choice, use as much rear camber as possible, or go for more toe in? This is for trying to have more rear grip exiting corners to help, if it does, the SS 1le’s famous rear step out caused by the EDiff. I have been using -2.5 front camber and 1.5 rear, rear toe is .13” total in, that’s like .26 degrees., for the past year. Tires are 305/30/19 re71s and hotchkiss front bar set soft.
So far the setup works pretty well and on a low grip surface. Track race I have no rear snap oversteer at all, Nannie’s of in sport I can get some , but it’s controllable with a bit of counter steer.

Edit: I think the choice from what I have now,is to go to max rear camber, say -1.8 or so, if it can be adjusted that much, and cut toe to 1/16” total in. That seems to be about best that can be done.

That’s my story, any input would be great

[HMFDUCK]

VR ,
Ive hooked up with other drivers in my area and across the States. One thats closer to you would be JDP Motorsports (Jordan). Hes a wealth of info and very approachable.
I run the 3.0 in the front camber an 2.0 in the rear. The rear I also put 1 degree Toe. The 1 * Toe really helps, because if you think about it the rear squats down under torque and the tires want to point outwards so to comp for that give it 1* Toe, then they will be straight and give you better traction. I found this to work really well on my 18 ZL1-1LE, Torque i have to really learn to manage. Also Play with Tire pressures but thats a given. Im stepping up this rear with a Track Only wheel tire combo. Apex 18x11 Falkin RT660 315/30/18 X 4. This will be a fun year, done with the Mustangs on the Podium. SCCA / CAMC car #59 .

[VR Baron]

Originally Posted by HMFDUCK

VR ,
Ive hooked up with other drivers in my area and across the States. One thats closer to you would be JDP Motorsports (Jordan). Hes a wealth of info and very approachable.
I run the 3.0 in the front camber an 2.0 in the rear. The rear I also put 1 degree Toe. The 1 * Toe really helps, because if you think about it the rear squats down under torque and the tires want to point outwards so to comp for that give it 1* Toe, then they will be straight and give you better traction. I found this to work really well on my 18 ZL1-1LE, Torque i have to really learn to manage. Also Play with Tire pressures but thats a given. Im stepping up this rear with a Track Only wheel tire combo. Apex 18x11 Falkin RT660 315/30/18 X 4. This will be a fun year, done with the Mustangs on the Podium. SCCA / CAMC car #59 .

Thanks,

That’s what I understand also as to toe. More toe in and the rear tires don’t follow the fronts in a turn as much and more stable and less oversteer prone on exit. That and a full tank of gas does help as well, this with Nannie’s off, track race there is no issue. In my case as I said it’s our EDiff lock up on slow corner exit to straights where the issue is. It’s a SLE thing..lol right now I am at max camber with stock parts, I can get more rear camber as I said, but will have to lose toe. 1degree, about 1/16” toe as you have and what GM says to use helps , more like I have seems to help more. Just wondering if a little more camber vs the more toe is a better choice just of corners, but maybe a wash.

Yeah Jordan at JDP I have known for years and a good friend . He had done a lot of work on my old fifth gen, and I just raced with him two weeks ago out here at nmca and didn’t think to ask him😞

[Mountain]

Originally Posted by VR Baron

Edit: I think the choice from what I have now,is to go to max rear camber, say -1.8 or so, if it can be adjusted that much, and cut toe to 1/16” total in. That seems to be about best that can be done.

That’s my story, any input would be great

Yep

[VR Baron]

Originally Posted by Mountain

Yep

Now to decide if it’s a real benefit to add -.25 more rear camber and lose over .25 degrees of toe? Seems EDiff issue is just as you straighten out on to the straight. More toe maybe better for that vs a bit more camber. Such small amounts maybe hard to tell🤔

[Cjw]

Originally Posted by HMFDUCK

VR ,
Ive hooked up with other drivers in my area and across the States. One thats closer to you would be JDP Motorsports (Jordan). Hes a wealth of info and very approachable.
I run the 3.0 in the front camber an 2.0 in the rear. The rear I also put 1 degree Toe. The 1 * Toe really helps, because if you think about it the rear squats down under torque and the tires want to point outwards so to comp for that give it 1* Toe, then they will be straight and give you better traction. I found this to work really well on my 18 ZL1-1LE, Torque i have to really learn to manage. Also Play with Tire pressures but thats a given. Im stepping up this rear with a Track Only wheel tire combo. Apex 18x11 Falkin RT660 315/30/18 X 4. This will be a fun year, done with the Mustangs on the Podium. SCCA / CAMC car #59 .

You run an entire degree rear toe in? Not a tenth, but 1.0?

[VR Baron]

Originally Posted by Cjw

You run an entire degree rear toe in? Not a tenth, but 1.0?

That does seem like the decimal is missing. 1 degree is about a 1/2”.

[Scargoes]

VR Baron, I'd suggest getting the SPL or BMR rear toe links so you can keep the toe(or go more) and have more camber.

As far as the GM Spec, 0.1* total is about 1/32" toe in on each side for a SS 1LE(27" for ease). Pretty much nothing. A full degree is about 1/2" total toe in at 27", or a 1/4" toe in each side.

https://static1.squarespace.com/stat...sion+Chart.pdf

For what it's worth, I'm running -2* camber in the rear and 0.2" toe in on each side and still have problems putting power down on corner exit at the local autocross. AutoClub Speedway just isn't that high of traction.

[VR Baron]

Originally Posted by Scargoes

VR Baron, I'd suggest getting the SPL or BMR rear toe links so you can keep the toe(or go more) and have more camber.

As far as the GM Spec, 0.1* total is about 1/32" toe in on each side for a SS 1LE(27" for ease). Pretty much nothing. A full degree is about 1/2" total toe in at 27", or a 1/4" toe in each side.

https://static1.squarespace.com/stat...sion+Chart.pdf

For what it's worth, I'm running -2* camber in the rear and 0.2" toe in on each side and still have problems putting power down on corner exit at the local autocross. AutoClub Speedway just isn't that high of traction.

Thanks for the input, and looks like we are as good as it gets. Only maybe the EDiff tune would help in conjunction with everything else.
I thought about the tune and spl parts but really not putting anymore into the car at this time. Yep the gm toe spec is nothing really at all. Fifth gen cars we would use .25 total as go to spec, but for high speed straight stability. Never had to worry about the EDiff issue obviously.
You running at autoclub to ? Been doing that lousy surface for ten years, and yeah part of the problem for us getting the grip! With 305 sq the hotchkiss front bar seems to really help with weight transfer, and a full tank of gas does work as well. Only traction issue as I mentioned was Nannie’s off, the slight traction control in track race fixes the problem, but rather do Nannie’s off.
So seems I am at the best I can area.

[kropscamaro16]

all the camber! but auto x is different than road racing so its hard to say have you talked to sam strano?

[VR Baron]

Originally Posted by kropscamaro16

all the camber! but auto x is different than road racing so its hard to say have you talked to sam strano?

No need really. All camber you can get for autocross is good. I am at that now almost as I said. I may get maybe .1 to .2 more in front from doing alignments, and .25 rear but I won’t know how much rear I can get till I try, then toe is reduced. You know how our cars are �� for better use of tread it can use a bit more, but need to watch it for the street use to not get into the bad tire wear area. At 30/28 tire psi the wear is to just above the tire arrows and tire temps are good as to the spread across the tire tread. So it’s pretty good now in those respects.

And sadly it isn’t a basic grip, over/understeer issue. It’s all to negate the EDiff snap oversteer on slow exit to straights in autocross. And appears even at -2 camber and .2degrees tie in per side on our lousy no grip Fontana surface won’t help, so my question is answered ��

[Scargoes]

VR Baron- I have the alternate eLSD tune and still have these problems. Running 315/30-18s now (Nankang). I want to do NMCA events too but I never seem to be able to get a ticket, always sold out. I'm usually just at the SCCA events. I'm still on stock sway bars. I do have the DSC controller and play with it from time to time but I've been on the stock computer for the past year. In talks with Tom Berry and Guy Ankeny they both think more rear toe is necessary. Guy was telling me that on one Corvette he prepped they ran 3/4" total toe in on the rear. No saying we should do that, but I will be playing around with rear toe this year to see what works better.

[VR Baron]

Originally Posted by Scargoes

VR Baron- I have the alternate eLSD tune and still have these problems. Running 315/30-18s now (Nankang). I want to do NMCA events too but I never seem to be able to get a ticket, always sold out. I'm usually just at the SCCA events. I'm still on stock sway bars. I do have the DSC controller and play with it from time to time but I've been on the stock computer for the past year. In talks with Tom Berry and Guy Ankeny they both think more rear toe is necessary. Guy was telling me that on one Corvette he prepped they ran 3/4" total toe in on the rear. No saying we should do that, but I will be playing around with rear toe this year to see what works better.

All good to know, thanks! Nmca tickets are a pain. You have to go in and refresh the site continuously till it opens for sale then go like hell or it sells out in 10 seconds. Only 35 event tickets each time. Reason is 50 season passes sold out in January. I got one as always to avoid the hassle and stress..lol
What you have done to your car is sure confirming all I have done and others also. And with Fontana surface we are screwed basically. DaveC113 said same on EDiff tune with square tires and stock bars, still a bit loose on corner exits, but better. I am keeping car as is, not reducing toe. I think that seems to be more important then more rear camber from what people say, as it isn’t steady state grip , but grip at end of a corner to a straight that toe appears to be more important and helpful. And that’s the spot where our problem lies.if I get EDiff oversteer, it’s right after I transition to a straight and the car is already in a straight line. That said, and as I have stated, it’s only in sport mode and Nannie’s off, in track race no issue at all.and Nannie’s off oversteer it is easily corrected by a bit of counter steer. It doesn’t take much and all good, but annoying!

I bet if you get a hotchkiss front bar set to soft it may do the trick. That’s my setup vs getting the tune. Solid stable front end, better turn in and weight to the rear tires for more traction, that and a full tank of gas does help also. With sq tires the big bar gives about the same feel as a stock car with staggered tires as it adds understeer to compensate for the oversteer the sq tires add in. At Fontana soft bar is best, the middle bar setting you read people do doesn’t work with a shitty surface. At lake Elsinore and better grip mid bar is good from what a friend who wins in scca has said.

And Nannie’s off in sport feels a bit more slippery and easy to rotate a bit more then track race , more like you are racing on the surface then in the surface like track race does, do you get the same feel?

[Scargoes]

On hot days I'll run the suspension in track. But sometimes the course layout isn't great with how the surface was laid and the car will hop along the high spots. When that happens I'll put the suspension in sport setting. On cooler days I run the suspension in sport and on cold days I run in tour. I always run in track mode for the throttle curve and adjust the suspension as needed. I drive with the steering locked in either tour or sport. Exhaust is always locked in track mode.

I think toe is important. It's not just a high speed stability or tire wear thing. adding more rear toe in can help keep the rear of the car in check when applying power in the corner. When I added more toe in on the rear last time, it made a noticeable difference in how early I could get on the throttle. But I still had to be reserved. I want to be able to use a bit more throttle on corner exit without fighting oversteer. The DSC controller was good in that regard as I could reduce compression to get more traction but they were not real helpful with some of the settings. And their latest base file made for some slow transitions. Like seriously losing time in the slaloms. So either I need to go with bigger bars or rent some data acquisition equipment and measure the mA the GM uses in track mode so I can adjust the file to suit me more.

I got into NMCA once, my first time trying. Then never again. Maybe I'll just pop down there some time and bug Robert. As much as I like the SCCA events and my friends there, I want to drive against quicker people so I have motivation to go quicker. And the no work thing is nice too.