high horsepower handling setup, alignment, etc... (T3 L-body)

[omnigoestohell]

hi all,
has anyone with a fairly high horsepower setup on a street car encountered squirrely handling as the power rolls in?
this is on a Omni GLHS with a T3 and coil over suspension, when the power comes on in 3rd and 4th around 5000-5500 the car really is tough to keep in a lane. the power curve is really extremely peaky right now which I think is contributing to the problem, and I did remove the equal length half shafts but it didn't seem to make the problem any worse.

has anyone had luck with any particular alignment settings to keep the car a little more stable when the power kicks in? this isn't nearly as bad at 15psi but at 18+ on the street it is really wicked. right now I have 1 degree of negative camber front with .05 degrees positive toe. the tires are brand new as are all suspension bushings and springs and shocks, spring rate is 450/350 on the car currently but really it does it regardless of how the shocks are set up.

estimated wheel hp at 18-20psi is about 375,... dyno'd power at 16psi was 332 but like I said it is peaky which I'm sure is a big part of the problem. this isn't really noticable on the drag strip with slicks but with the street tires its a bear.

any ideas?

[speedfreek500]

I have the smae problem with my Glh and even tried the alignment with the front end lifted 2 inches and set toe to .6 and still have same results. I will be keeping an eye on this Thread, sorry i cant help ya out.

[bakes]

What are you running for a diff and what type of bushings ???

[Pat]

hi all,
has anyone with a fairly high horsepower setup on a street car encountered squirrely handling as the power rolls in?
this is on a Omni GLHS with a T3 and coil over suspension, when the power comes on in 3rd and 4th around 5000-5500 the car really is tough to keep in a lane. the power curve is really extremely peaky right now which I think is contributing to the problem, and I did remove the equal length half shafts but it didn't seem to make the problem any worse.

has anyone had luck with any particular alignment settings to keep the car a little more stable when the power kicks in? this isn't nearly as bad at 15psi but at 18+ on the street it is really wicked. right now I have 1 degree of negative camber front with .05 degrees positive toe. the tires are brand new as are all suspension bushings and springs and shocks, spring rate is 450/350 on the car currently but really it does it regardless of how the shocks are set up.

estimated wheel hp at 18-20psi is about 375,... dyno'd power at 16psi was 332 but like I said it is peaky which I'm sure is a big part of the problem. this isn't really noticable on the drag strip with slicks but with the street tires its a bear.

any ideas?

It's the toe. Toe out really does make the car squirrely under power. In tinkering with my car, I've found that zero toe or even a hint of toe in really does make a difference in settling the car under high power. It's definiltey a more conservative setting and will make it a bit slower to respond at turn in, but for a car that will see all 350 hp running through the front wheels drag racing, road coursing or street driving, I think it's worth it.

Autox guys love some toe out for the turn in, but it seems that most of them that love it are also working with 150 hp. :-)

[rx2mazda]

hi all,
has anyone with a fairly high horsepower setup on a street car encountered squirrely handling as the power rolls in?
this is on a Omni GLHS with a T3 and coil over suspension, when the power comes on in 3rd and 4th around 5000-5500 the car really is tough to keep in a lane. the power curve is really extremely peaky right now which I think is contributing to the problem, and I did remove the equal length half shafts but it didn't seem to make the problem any worse.

has anyone had luck with any particular alignment settings to keep the car a little more stable when the power kicks in? this isn't nearly as bad at 15psi but at 18+ on the street it is really wicked. right now I have 1 degree of negative camber front with .05 degrees positive toe. the tires are brand new as are all suspension bushings and springs and shocks, spring rate is 450/350 on the car currently but really it does it regardless of how the shocks are set up.

estimated wheel hp at 18-20psi is about 375,... dyno'd power at 16psi was 332 but like I said it is peaky which I'm sure is a big part of the problem. this isn't really noticable on the drag strip with slicks but with the street tires its a bear.

any ideas?

Yes, turn the boost down to where the tires keep traction. This isn't an alignment issue, its a traction/differential issue. You should have seen me trying to keep Jacksons Iroc RT in one lane @ 35psi at SDAC.....DJ and Slowe got a good laugh.

[Pat]

You should have seen me trying to keep Jacksons Iroc RT in one lane @ 35psi at SDAC.....DJ and Slowe got a good laugh.

Rookie....

[rx2mazda]

Rookie....

LOL shut up Pat! We tried 0 toe with Jacksons car, no difference. On slicks it was fine, on street tires it was a nightmare.

[turbovanman²]

As said, what bushings or engine mounts? An LSD helps big time. What tires, and agreed with Pat, try to keep it a 0 toe or a bit negative.

Rookie....

LMAO.

[omnigoestohell]

Carroll, I did see you trying to keep it in a lane, I was behind you in Jackson's black Iroc. Also got some spray from the coolant in his Spirit hehe.

So tires are 140 treadwear Hankook RS-3's, the diff is a Quaiffe, tranny is a 568 w/ 3.50fd and the bushings are all poly... engine mounts are a mix of home brew and spiva's stuff but all good and solid.

Pat, I'm glad to hear you say something although Gus had always explained kind of the opposite, I seem to recall he liked some toe out and the power pulls the wheels together/straight but I'm not sure what he actually was using to measure this or if it was based in any scientific fact. Do you suspect that Gus may have been wrong in this conclusion?

I'm probably going to get some alignment tools myself and play with that to see if it makes a differnece. What do you recommend for starters?

[turbovanman²]

The tires want to push out from the front when driving down the road, this makes it more squirelly, RWD are much worse as they can move the toe alot more. If you set a bit of neg toe, they will straighten out hence making it less twitchy. FWD's don't have much toe change except if the front end moves up and down alot.

[BadAssPerformance]

The Quaiffe and Quaiffe style OBX diffs make the car edgy... will allow you to change lanes by throttle alone. This is more on an uneven street surface than a smooth track, but still can happen. Even my slow T2 Shadow does on street tires. Good idea on toe in.

[omnigoestohell]

Yes, JT I should have stated it is WAY worse on old pavement than on the sections that have been recently repaved. I will try some toe in. I know if I do it myself with the tape measure it gets measured in fractions of an inches, if I have an alignment shop do it what should I try one degree neg to start?

[BadAssPerformance]

No, not that far... I would start with 0°

Yeah, being used to it in my Shadow, had a blast driving Craig's GLHS (more power, twice the squirley) at the Shelby Bash a couple years ago. Anyone else that drove it thought we were crazy tho LOL

[rx2mazda]

An LSD helps big time.

This is not true. An LSD actually makes torque steer worse!

This is due to the way a ATB differential operates. You ever heard of guys complaining about torque steer with an open diff on street tires? No. When that one tire looses traction under power, all the power is sent there and you have a nice peg leg burnout. Your not fighting the steering wheel. In an ATB LSD when that one tire starts to loose traction it gets less power, the one that has traction gets more - then that tire starts to loose traction so back to the other tire the power goes. This transfer of power/wheelspeed is not seamless and thats why you are fighting the steering wheel left and right. On slicks and a flat surface(the track)you don't get these problems but, on street tires and a crowned/uneven road its a problem.

You have a torque steer issue, not an alignment issue. Can you make you torque steer issue better with an alignment tweak? Maybe.....a little IMO. Be sure to keep us posted on what you find out!

EDIT: JT posted up a shorter version of this post while I was typing! lol

[Pat]

Ca
Pat, I'm glad to hear you say something although Gus had always explained kind of the opposite, I seem to recall he liked some toe out and the power pulls the wheels together/straight but I'm not sure what he actually was using to measure this or if it was based in any scientific fact. Do you suspect that Gus may have been wrong in this conclusion?

Gus may have been right if he had crappy old rubber bushings in the control arms, which knowing Gus was likely the case! God knows how much his control arms were moving in those bushings!

Front end up and down movement will definitely alter the toe. Look at the tie rods, if they are roughly parallel to the ground at rest, any suspension movement up or down will pull the toe out a bit.

I did have an issue with my quaiffe a few years ago, but the symptoms were a bit different. If I was on the gas, it pulled one way, off the gas, it pulled the other way. It sounds like your issue is more alignment based to me.

---------- Post added at 01:57 PM ---------- Previous post was at 01:54 PM ----------

This is not true.[B]
You have a torque steer issue, not an alignment issue. Can you make you torque steer issue better with an alignment tweak? Maybe.....a little IMO. Be sure to keep us posted on what you find out!

I'm not suggesting that an alignment will make it straight as an arrow under hard acceleration, but some toe out is making it way worse.

[turbovanman²]

This is not true. An LSD actually makes torque steer worse!

This is due to the way a ATB differential operates. You ever heard of guys complaining about torque steer with an open diff on street tires? No. When that one tire looses traction under power, all the power is sent there and you have a nice peg leg burnout. Your not fighting the steering wheel. In an ATB LSD when that one tire starts to loose traction it gets less power, the one that has traction gets more - then that tire starts to loose traction so back to the other tire the power goes. This transfer of power is not seamless and thats why you are fighting the steering wheel left and right. On slicks and a flat surface(the track)you don't get these problems but, on street tires and a crowned/uneven road its a problem.

You have a torque steer issue, not an alignment issue. Can you make you torque steer issue better with an alignment tweak? Maybe.....a little IMO. Be sure to keep us posted on what you find out!

I don't have that issue, except when the control arm bushing's wear, it was worse with an open diff, for me, anyhow.

[Force Fed Mopar]

Engine side-to-side positioning plays a big part too. Take the wheels off and remove the axle nuts. Now use a screwdriver/extension/whatever to push each axle inwards as far as you can and measure how much it moves. Should be the same on both side. Not sure why it makes a difference, but it does. Have done this on both mine and DodgeZ's cars, along w/ a tape-meaure alignment and camber setting, and have very little torque steer, if any. And his Omni was making 315/370 at the wheels w/ a OBX diff.

[shadow88]

It's the toe. Toe out really does make the car squirrely under power. In tinkering with my car, I've found that zero toe or even a hint of toe in really does make a difference in settling the car under high power. It's definiltey a more conservative setting and will make it a bit slower to respond at turn in, but for a car that will see all 350 hp running through the front wheels drag racing, road coursing or street driving, I think it's worth it.

Autox guys love some toe out for the turn in, but it seems that most of them that love it are also working with 150 hp. :-)

I agree it's toe that makes it twitchy, but I found it's negative toe or toe out that makes it better.

I found when the front raises, the camber moves toward negative and the toe moves toward positive. I set my shadow at .5degrees negative camber and .2 degrees negative toe. Although most friends who drive my car find it unbearable, it's an improvement.

Other fixes are better tires, but you seem to have that covered with your 170 treadwear rating. Sometimes it's just the road.

[BadAssPerformance]

Good point Jamie...

Not for cornering, but for drag racing, jack up the front to about as much as it lifts during launch (will vary from car to car) and then put camber and toe at 0°

[GLHNSLHT2]

It's the toe. Toe out really does make the car squirrely under power. In tinkering with my car, I've found that zero toe or even a hint of toe in really does make a difference in settling the car under high power. It's definiltey a more conservative setting and will make it a bit slower to respond at turn in, but for a car that will see all 350 hp running through the front wheels drag racing, road coursing or street driving, I think it's worth it.

Autox guys love some toe out for the turn in, but it seems that most of them that love it are also working with 150 hp. :-)

Gus may have been right if he had crappy old rubber bushings in the control arms, which knowing Gus was likely the case! God knows how much his control arms were moving in those bushings!

Front end up and down movement will definitely alter the toe. Look at the tie rods, if they are roughly parallel to the ground at rest, any suspension movement up or down will pull the toe out a bit.

I did have an issue with my quaiffe a few years ago, but the symptoms were a bit different. If I was on the gas, it pulled one way, off the gas, it pulled the other way. It sounds like your issue is more alignment based to me.

---------- Post added at 01:57 PM ---------- Previous post was at 01:54 PM ----------



I'm not suggesting that an alignment will make it straight as an arrow under hard acceleration, but some toe out is making it way worse.

+1 on the toe. Set toe at zero. Also what is your sway bar setup like? The stock style bushings all the the sway bar to bind up, and keep the control arms from moving when they need to. Heim joint the ends like this. http://www.pnw-sdac.org/gallery/v/Me...Bar+End+Links/ Allowing the control arms to move will help to keep the traction more even. The sway bar still functions and functions like it should have.