[Tim Corcoran]

Under heavy acceleration with tires spinning in 2nd gear car goes to the left hard enough that I have to let off to maintain control.

67 LeMans
Tubular adjustable upper control arms pinion angle set to 2.5-3.0 degrees down
Boxed lower control arms with .75' sway bar
No Hop bars, 12 bolt posi 3.08's
All bushings are rubber and new
Measurements taken indicate housing is in proper position for and aft and even from side to side

Does anyone know why it is pulling to the left and is there a cure.

[steve25]

Sounds like the wheels are spinning at a different rate.

Is it a locked rear?

[johnta1]

With no way for suspension adjustments, probably can't?


Might try stiffening the right rear shock compression if you had adjustable shocks?

[Tim Corcoran]

Originally Posted by johnta1

With no way for suspension adjustments, probably can't?


Might try stiffening the right rear shock compression if you had adjustable shocks?

I do have adjustable upper control arms

[Tim Corcoran]

Originally Posted by steve25

Sounds like the wheels are spinning at a different rate.

Is it a locked rear?

Its a new Yukon posi unit in a 12 bolt

[Formulas]

Are your axle tubes welded to center section? If one let loose a car will want to swap lanes on you per my experience with a 1966 GTO

put jack stands under rear frame and floor jack center section looking at tubes for movement

[Tim Corcoran]

Originally Posted by Formulas

Are your axle tubes welded to center section? If one let loose a car will want to swap lanes on you per my experience with a 1966 GTO

put jack stands under rear frame and floor jack center section looking at tubes for movement

I had it up on the lift and measured everything if there was any movement I think I would of found it.

[Formulas]

they are fairly rigid even when roset welds are broken but the joint will flex under power then rear wheels dont track truely straight steering the car

supporting the frame and jacking the center punkin will make it visually flex if broken

if you say their solid then they are solid

[blueghoast]

Your rear end is gona try and rotate under accleration that's probly why your getting rear steer ajustable shocks or ajustable sway bar should help.

GT

[Tim Corcoran]

Originally Posted by blueghoast

Your rear end is gona try and rotate under accleration that's probly why your getting rear steer ajustable shocks or ajustable sway bar should help.

GT

Adjustable sway bar?

[blueghoast]

Originally Posted by Tim Corcoran

Adjustable sway bar?

With adjustable links.
I have adjustable upper arms aftermarket lower arms solid bushing on the
lowers air bags and 4-speed brackets and old 3-way adjustable shocks.
I pre-load with my air bags to get the car to go straight and quit a bit of
negetive pinion angle for traction on the street, No front sway bar either.
90-10's up front for shocks. Hope this will help a little.

GT

[Formulajones]

With 3.08's and second gear that's a ton of wheel speed, almost like scating on ice at that point. The rear of the car may drift where ever it wants lol.

Doubtful there is any real cure for it when doing burnouts like that. What's most important is does the car launch nice and straight with sticky tires on a prepped track. That's where suspension tweaking should be done.

Our cars are nice and straight at the track but when we horse around on the street they for sure can be ditch hunters if I'm not careful. Lots of factors play into that like wheel speed, the crown in the road, different types of surfaces. Ya just gotta be on your toes lol.
Me personally I try to keep wheel speed under control with my right foot so the car is easier to catch and manage.
Sounds to me there is probably nothing wrong with your car.

[ta man]

Does it go straight under full traction? With my car I try to avoid burnouts on the street..it can get out of shape real quick..at the track a nice controlled burnout for a short distance can even go slightly crooked, but the car goes down the dragstrip straight and easy every time.

[Tim Corcoran]

Funny thing, I put in a rear sway bar and new shocks and it exaggerated the issue.

[lust4speed]

Without getting yourself killed, do a burnout on the other side of the road to rule out the crown of the road making the rear drift right pushing the car left.

I would say that the passenger wheel is exerting more downward pressure and during spinning it has more force to push the car left. Too much preload on passenger side or suspension binding keeping the passenger tire from traveling up the same amount as the left.

[johnta1]

Under heavy acceleration with tires spinning in 2nd gear car goes to the left hard enough that I have to let off to maintain control.

Is this when doing a burnout?

[Tim Corcoran]

Originally Posted by johnta1

Is this when doing a burnout?

Yes, tires spinning = burnout

I hammer it from a dead stop tires spinning shifts into 2nd tires still spinning car goes left pretty hard can't correct it and I let off.

[PAUL K]

Put an LS on it!

[srmmmm]

On hard acceleration, the pinion is trying to "climb" up the ring gear which reduces the effective weight on the passenger side tire. (Which is why an open differential usually only spins the passenger side tire) As a result, the driver side tire experiences a higher coefficient of friction, compressing the control arm bushings on that side and inducing a rear wheel steering effect that makes the vehicle want to go left. You might try running a few pounds more pounds of air pressure in the left tire to reduce the contact patch slightly to even out the tractive effort between the two sides.

[Tim Corcoran]

Originally Posted by PAUL K

Put an LS on it!

LS???