Torque Steers?

[JrRifleCoach]

This problem has been haunting me (and others) for years; The vette rear end will drift right when you lift off the throttle. This is most noticeable when traveling downhill at 45-55+MPH. If you reapply throttle, the car will now drift to the left.

It must be remembered that the suspensions of these cars vary in condition. Mine is completely rebuilt with the best parts. Others are DD's or weekend cars with high component times.

The only one parallel I can draw on is the rear toe. One suggestion was that the rear spring may not have equal amount of pressure on each side.

Any of your thoughts are appreciated. Even the satrical. (I may regret that)

I'm almost ready to call Gordon......$$$$$

 

[Mad-Mic]

This problem has been haunting me (and others) for years; The vette rear end will drift right when you lift off the throttle. This is most noticeable when traveling downhill at 45-55+MPH. If you reapply throttle, the car will now drift to the left.

It must be remembered that the suspensions of these cars vary in condition. Mine is completely rebuilt with the best parts. Others are DD's or weekend cars with high component times.

The only one parallel I can draw on is the rear toe. One suggestion was that the rear spring may not have equal amount of pressure on each side.

Any of your thoughts are appreciated. Even the satrical. (I may regret that)

I'm almost ready to call Gordon......$$$$$

i'm not sure if i understand this. are you spinning the tires when you say drift? when i drift i'm dead sideways boiling the tires.

this might be silly but have you checked the tire pressures on all 4 corners lately?

 

[tlong]

Mine too. Been told it's the C-beam connection aft. Many have the little tail wiggle.
There were some plates available to correct it but it's not enough to worry about for me. Other fish to fry with my car.

 

[MBDiagMan]

Check to make sure that all linkage points are tight with no slack.

Good luck,

 

[Moonunit 451]

This problem has been haunting me (and others) for years; The vette rear end will drift right when you lift off the throttle. This is most noticeable when traveling downhill at 45-55+MPH. If you reapply throttle, the car will now drift to the left.

It must be remembered that the suspensions of these cars vary in condition. Mine is completely rebuilt with the best parts. Others are DD's or weekend cars with high component times.

The only one parallel I can draw on is the rear toe. One suggestion was that the rear spring may not have equal amount of pressure on each side.

Any of your thoughts are appreciated. Even the satrical. (I may regret that)

I'm almost ready to call Gordon......$$$$$

C-Beam plates Steve

 

[JrRifleCoach]

i'm not sure if i understand this. are you spinning the tires when you say drift? when i drift i'm dead sideways boiling the tires. this might be silly but have you checked the tire pressures on all 4 corners lately?

NO!!! :L Not drifting! The drift I refer to is when the car slowly drifts rather than being steered. At certain speeds above 65 this drift can amount to half a lane. But again, we're talking about negligable power settings, not WOT. This happens when the drive train is wound up and applying light cruise power and then when the drivetrain unwinds as you let off the gas.

Yes I have C-beam plates which did resolve the WOT, AZZ out to the right! otfl Like I indicated in the begining, I found almost every mod and quality parts to get this problem resolved only for it to return. Thats why I'm fishing for anyone elses experiences to built a plan of attack.

Now one guy at the CF had a rather interesting twist. He races gas powered Radio Controlled cars and experienced that different spring pressures can cause the RC to " torque steer" under power. I know that the rear spring is centered, but the adjustments are considerably different from side to side. So I'm thing of spinning the spring around and testing the theroy.

What say you!?

 

[Moonunit 451]

I've never experienced what you are referring to that I'm aware of. Could your alignment be messed up?

I'm guessing you are talking about spinning the spring like a helicoptert blade, not flipping it upside down

 

[SPANISHVETTS]

I've never experienced what you are referring to that I'm aware of. Could your alignment be messed up?

Thunder has no such bad habits either. I can load the chassis up with torque(over 450ftlbs) to the point that you expect the windshield or top to pop out and the beast still goes where I point it. How is your rear alignment. Thunder´s toe is 1/16¨in with .60º negitive camber and I am running 285s on the back.

Have you checked the shocks, etc.?

 

[Ted Krempa]

better have someone check that frame...sounds like it is 'diamonded'. Measure wheel center to wheel center on the side and then 'x' (LF to RR, etc)

 

[JrRifleCoach]

better have someone check that frame...sounds like it is 'diamonded'. Measure wheel center to wheel center on the side and then 'x' (LF to RR, etc)

Thats a good idea! Time to get the tapes and plumb bobs out.

 

[vader86]

Could very well be the spring being loaded and unloading unevenly.

 

[JrRifleCoach]

Could very well be the spring being loaded and unloading unevenly.

I've tried to give this theroy some weight. The only way to prove/disprove it is installing a different spring. Flipping (or helicoptering) the spring may work as well.

 

[jmccloud]

Drift

Have you changed tires during the years of your 'drift' problem?
Some tires will display a different 'lead' (as in 'our leader') and will cause more drag or pull (if on the drive axle) depending on whether the car is slowing or speeding up. Some tires cause drag just like slight brake pressure or poor inflation. In the old days when brakes weren't on the centerline of the tire, 'lead' would cause significant pull on the steering if the bad tire were on the front.
We used to swap tires around to diagnose 'lead' but with the directional tires on a Corvette, you couldn't do that.
If you have a spare set of tires/wheels, or a friend with similar tire/wheel sizes, you might swap tires to maintain directionality.
"lead" sounds far-fetched but it's real and very difficult to diagnose.
Hope you solve it and let us know what it is,
East coast HP Master (SR).

 

[JrRifleCoach]

Thanks for the input JMCCloud.

At first I did suspect the tires. Those were 6-7 year old Michelins. Since then a new set of Kumhos were mounted on confirmed straight wheels. Even measured the offset.... At first the car felt straight, then about ten miles down the road the behavior returned.

Tomorrow we measure the frame for square. For sure!

 

[IH2LOSE]

Thanks for the input JMCCloud.

At first I did suspect the tires. Those were 6-7 year old Michelins. Since then a new set of Kumhos were mounted on confirmed straight wheels. Even measured the offset.... At first the car felt straight, then about ten miles down the road the behavior returned.

Tomorrow we measure the frame for square. For sure!

I have a 1962 vette I am running a tubeular chassis under with a C4 suspention in it.

I exspereance the same problem but it when its under Hard axcellaration.

It was suggested I look into the alighnment and thats what I plan to do as soon as I get a chance.

 

[jmccloud]

Drift

You've mentioned a couple of times that some of the 'fixes' were only temporary (including new tires). Is is possible that each temporary fix was accompanied by the car being on a lift? If so, what's moving to eliminate the drift (when lifting) then settling back in about 10 miles of running.?
This will be a good one to solve and put the solution 'in the bank'

 

[Achilles]

Never experienced this type of problem, but it sounds like its alignment related. Is it possible the control arm bushings are worn out? This would allow the wheel to move fore & aft, causing some alignment issues.

 

[Hrtbeat1]

Part of the problem is the geometry of the rear spring itself. During movement the spring will slightly change the toe of the rear wheels. I recently saw an show on Speed channel that was talking about this problem in reference to autocrossing. As the spring loads and the tires/wheels go upwards it causes the rear tires to toe in more, thus changing the driveability. The suggested change was to toe the rears out slightly.

It is a little harder to explain but with the video of the wheel travel it made more sense.

 

[G Winter]

Part of the problem is the geometry of the rear spring itself. During movement the spring will slightly change the toe of the rear wheels. I recently saw an show on Speed channel that was talking about this problem in reference to autocrossing. As the spring loads and the tires/wheels go upwards it causes the rear tires to toe in more, thus changing the driveability. The suggested change was to toe the rears out slightly.

It is a little harder to explain but with the video of the wheel travel it made more sense.

That makes sence to me the same would be true if it was on a lift for awhile and didn't settle in all the way for about 10 miles like JrRifleCoach mentioned. On my 90 I have noticed at about 100 under exceleration if I lift quickly it does that just a little.That could relate because under exceleration the rear would pull down just slightly and on deceleration it would come up. Just my thoughts on it.
Glenn

 

[JrRifleCoach]

That makes sence to me the same would be true if it was on a lift for awhile and didn't settle in all the way for about 10 miles like JrRifleCoach mentioned. On my 90 I have noticed at about 100 under exceleration if I lift quickly it does that just a little.That could relate because under exceleration the rear would pull down just slightly and on deceleration it would come up. Just my thoughts on it. Glenn

Wow! now we're getting somewhere. Didn't get the chance to plumb the chassis. Spent the afternoon driving around the area. Met with the POSSE for lunch and then to wine country with family.

Back to the topic. Glenn, do you happen to have the alignment settings for your Vette? For that matter would anyone else care to share their settings?

My rear toe is 1/16 IN on the LR and 1/8 IN on the RR. I know this off the top of my head, the rest I'll dig up and post later.