Dirty Howie

Since I changed my alignment I am having problems with the rear end oversteering when applying power on turn exit.

At first I thought it was my used R6 but new MPSC did the same thing.

I went from stock alignment to -1.5 camber front and -1.25 rear. I have a little TOE IN. I get my before and after specs and post them if anyone wants to see.

My question is: If I reduce the rear camber back to Neg .75 to 1.0 will this help. I have been told by several track guys that I have lost some contact patch with increased negative camber.

Thanks for any advise. This has bee slowing me down as I have lost confidence it turns now


DH

Joy of 6

First you should not have toe in it should be neutral on a little out. Also you don't mention the toe setting for the rear, that will make a difference on corner exit. The camber sounds ok on the front and back. I am sure there will be an alignment expert out there to expand on this.

AU N EGL

rear is tow IN ( corrected )

what tire pressures are you running on what tires ?

How many heat cycles on the tires?

naschmitz

Rears should be toed in. With toe out in the rear, the loaded side will want to come around especially when you apply throttle.

I've heard from people with more experience than me that too much camber in the rear can also induce oversteer on corner exit.

mikahb

Your new camber settings don't sound too far off to me, and yes - you want some toe-in in the rear (probably between 1/16" and 1/8" total) and zero or slight toe-out in front.

It's true that going crazy with camber in the rear can decrease your contact patch to the point that you're inducing oversteer, but I don't think that 1.25 degrees is over the top by any means.

You might double-check your rear tie-rods to make sure they're not worn, a pretty common wear item there. Any other changes to the car - swaybars, etc. that are not stock? Also, like Tom said, what tire pressures?

Dirty Howie

I will take a pic of my alignment sheet and upload it.

The tire pressure was the same as before the alignment changes. And it is happening with used R6 and new MPSC.

Suspension is completely stock C6Z06


DH

exracer28

Might want to go back to the alignment shop and have them check thier work and verify the setting and ensure nothing moved.

LG Motorsports

Howie,

Especially with stock bushings, I would run 3/16 rear toe in. and 1/8 + toe out at the front.

Make sure that you do not have all your toe in on one side, and zero or out on the other.

You can check this with a simple laser level. (this is the tip of the day here)

with your car on the ground, lay the laser level against the rear tire, and shoot the laser beam to the front of the car aimed at a tape measure that is against the frame near the front upper suspension arm.

Then do the same on the other side, to the same point on the frame and your measurement should be within 1/8" on each side.
(remember that 1/8" measured over 100 inches to the front is equal to 1/100 th of 1/8", so it is small. If you get it that close over that distance, you will essentially be square.)

if it is not, then adjust until they are equal, then set your toe after that.

Always go back and check the laser measurement over, and ALWAYS make sure that the same side of the laser level is against the tire. Put a mark on the level to mark the "tire side".

That will help you set "Thrust" in a matter of moments.

We run as much as 1/4" toe in at the rear on a tight track.

If the car is still loose, then lower the rear ride height, and try that, or lower the tire pressure 1-2 pounds.

THen Drive the snot out of it.

Thanks

Lou Gigliotti


Home depot laser level:

fatbillybob

Lou,

Many people do these types of alignment adjustments with wheels off on jackstands so you can get good access and make good readings. When using jackstands how can you settle the suspension so you can get proper readings? Does stichion in the suspension effect toe readings like it will on camber readings?

SIK02SS

i'm keeping an eye on this thread because at fontana this weekend i was lighting the tires up in 2nd gear exiting a couple turns (including the hairpin)

stano

Howie, go see Darren@West End Alignment and tell him what it's doing. Then trust his judgment, he only aligns race cars. For $250 you get an alignment and corner balance.

Just do it

spazegun2213

I run a more aggressive setup with something like -2.5 1/8 out up front, and -1.5 1/8 toe in rear. I have no problem romping on the throttle on corner exit, then again I'm using V710's and its a race car.

Dare i say it, be easier on the throttle application? Looking at your settings i would drop the rear camber to -1 or -.75, but how is your corner entry, and mid corner grip? Does the car push at all? With that type of rear camber I think it would.. but i have no idea.

AU N EGL

did I miss the pressures you use?

LG Motorsports

I would never do it that way. It is hard enough to settle the suspension with the car on the ground but it can never be done consistently in the air.

Plus the jack stands will push the rubber bushings in an odd direction and you won't get an accurate or consistent set up.

Plus you don't race on jack stands either


Hope that helps.

LG

AU N EGL

I jack my car up then set it on concrete blocks.

Two blocks with two linoleum squares and grease between the squares on the blocks, tire on top of the squares.

8 blocks total

May not be perfect but best I can do. Then I get it checked at a shop, and they dont make any adjustments. Tell me I get it more accurate by hand then they could do with a Hunter.

LG Motorsports

In 1990 driving a Corvette in the new World Challenge series, i had sponsorship from Hunter. They would bring a full machine set up to the track and two local engineers to help with the alignment.

By the end of the season, we put a street car on the Hunter machine for demonstration, and we aligned the Race Car with our normal method.

Hunter took too long and if the operator was not really good, they could mess it up even worse.

So it is all about the operator and the time available.

LG

AU N EGL

Yup it took me all day. and I would spend 1/2 the time just looking at the wheels in relationship to the body and other wheels

mountainbiker2

DH

You may have more grip up front then before. That could make you think that you have less grip in the back. Change the toe to 3/16" or 1/4" toe in and put on a stock C6 sway bar. I can help you.

Steve

larryfs

too much camber in the rear.

gonzalezfj

I respectfully disagree. I run -2.7 degrees of camber up front and -1.7 degrees in the rear with excellent grip all around. Toe is 1/8" out in front and 3/16" toe-in on the rear. Everyone that has driven the car has commented on how well it handles. This includes the likes of Andy Pilgrim. Steve Landstra's car has similar alignment by Phoenix Performance and also sticks like glue.

Tires are Hoosier A6s with 28 PSI front and 26 PSI rear, COLD.

I bet DH has an alignment or tire pressure problem. Maybe the shop did not set something properly, or maybe one of the eccentrics moved, or there is play in one of the joints.

Frank Gonzalez