Torque steer? Pulls to one side.

Tiny
FEATHERSTONE RACING
  • MEMBER
  • 2003 CHEVROLET CAVALIER
  • 2.2L
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 150,000 MILES
Hello I'm building a race car it's a 2003 cavalier z24 4 door with 4 speed auto and a 2.2l echo tec. My question is can I set the front end up so I have torque steer to the left and how to go about doing so. I was reading one of your front end alignment segments, were you were talking about torque steer.

Is it possible to set the steer for left pull?

And if it's possible to do so I will freely advertise your site 2carpros. Com
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Monday, January 26th, 2015 AT 10:11 AM

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Tiny
CARADIODOC
  • EXPERT
Torque steer is the last thing you want on any car. It is caused mainly by unequal length half shafts. Chrysler was the first manufacturer to totally get rid of it on their front-wheel-drive cars.

Torque steer occurs during hard acceleration, so you're asking to make your car pull left on the straightaways. Torque steer goes away during coasting, so if you want your car to pull left in the corners, that isn't going to work. What you need to look at is "camber". That is one of the three main alignment angles, and on your car it either is adjustable already or it can easily be made adjustable. Chryslers and GMs use two bolts at the bottoms of their struts. On Chryslers, one of those bolt holes is slotted. On GMs, you might have to grind out one of the holes into an oval to allow the wheels to be adjusted. Also, Chrysler used to use cam bolts that made it easy to get very precise adjustments. You'll have to buy aftermarket bolts to get that luxury on your car, otherwise, you basically kick the tire, tighten the bolts, see what you got, loosen the bolts, kick the tire, etc.

Camber is the tilt of the wheel as you look at it from the front or rear of the car. A tire will want to pull in the direction it's leaning, so both tires would be tipped to the left on top. That will really hurt tire wear so don't get carried away. I don't know what the specs are for your car, but in the '90s, most GM front-wheel-drive cars called for 0.00 degrees which means they were perfectly straight up and down. That is not common on any other brand. Most call for the wheels to be tipped out around 0.20 to 0.50 degrees. (For reference, at 90.00 degrees the wheel would be laying on its side).

A better alternative is to play with "caster". This is what we did with rear-wheel-drive cars on the oval tracks. If you stand to the side of the car and look at the steering pivot points, the upper strut mount and lower ball joint in your case, that upper mount is to the rear relative to the ball joint. In other words, the strut is tipped back on top, just like your seat backrest. Caster has very little effect on tire wear, but it is responsible for steering wheel return after cornering, and on rear-wheel-drive cars it has half as much affect on pulling as camber does.

If you imagine the right front strut tipped back more and more and more until it is parallel to the ground, you'd see that as soon as you put the car's weight on the tire, it would fold up with the top flopping in toward the center of the car. That would be 90.00 degrees of caster. An actual typical value for your car is around 3.00 degrees. Even that is more than enough that the car's weight would make that wheel turn so hard to the left that you would barely be able to pull it back straight if that tire was sitting on a turntable. The goal of the alignment is the left wheel must be doing the same thing. It needs to have the same amount of caster to make it want to pull to the right. When you connect the steering linkage between them, they counteract each other and the car goes straight.

We used to use caster to make the car want to pull left so we didn't have to fight it in the corners. You had to fight it on the straights, but that's when you had fewer other things to worry about, like someone sliding into you! The problem with front-wheel-cars is caster has extremely little affect on pulling. On the street-driven rear-wheel-cars, again, 3.00 degrees of caster was common, and a half degree more on the right than on the left was just right to make up for road crown, (all roads lean to the right so rain runs off), and the cars would go straight. I've had front-wheel-drive cars with as much as 3.00 degrees difference in caster, and they still didn't have a pull. If that were on a rear-wheel-drive car, your arms would worn out after a mile or two from tugging the steering wheel back to center. Besides steering wheel returnability, positive caster causes a wheel to tip in the direction it's being turned, so you'd get the best of both worlds. A wheel could be straight up and down in the straights, and tipped to the left in the corners.

As a point of interest, cars and trucks used to use negative caster, (the upper steering pivot, meaning the upper ball joint, was forward of the lower ball joint). That made for very easy steering in a big, heavy car or truck. But negative caster is very bad for stability and leads to excessive steering wander. As highway speeds went higher in the early '60s, we went with positive caster which greatly decreased wander, and increased road feel, but it took a real lot more effort to turn the steering wheel, so we added power steering. Without power steering it took more turns of the steering wheel to make the desired turn. Once power steering was added, we were able to change the gear ratio in the steering gearbox, so now it just takes a little nudge on the steering wheel to make steering corrections, even at real high speeds. Even most of the NASCAR guys use power steering.

So you can't use caster to get your pull to the left because it doesn't have the same affect as on a rear-wheel-drive car, but also, the upper strut mount sits in a sheet metal pocket that would need to be seriously reworked, otherwise the coil spring will rub on it.

There's something else you have to be aware of related to the alignment. That is centering the engine cradle, and this only applies to GM products. The cradle is held to the body with four bolts, and it has to be removed and dropped down to remove the engine or transmission. Before doing that you have to mark those bolts in some way so the cradle is reinstalled in exactly the same position. If it is stuck back in off-center by as little as 1/16", you will have the most horrid handling car you've ever experienced, and no alignment will fix it. That is, unless the mechanic knows to check it and adjust it.

The angle is called "steering axis inclination", (SAI). There is no spec given for any car. All that is critical is it must be exactly the same on both sides. With SAI, you stand in front of the car and look back at to see how the struts are tipped in on top. A typical value might be around 28 degrees but again, you only care that both sides are the same. When you loosen the bolts for the cross member, then slide it to one side with a pry bar, the bottoms of the struts move to the side, but the upper mounts don't move because they're bolted to the body. The alignment mechanic can watch the SAI numbers on the computer screen as he moves the cross member.

When SAI is unequal, the car will dart to one side or the other when the suspension height changes, meaning going up and down as you go down the road. It can never be made to be predictable, and the car will never act the same way twice. You have to experience this to appreciate how extremely miserable it is to drive a car this way.

Also, since moving the cross member to one side moves the lower ball joints, that makes the wheels tip too, and that is camber. An inexperienced mechanic will immediately see the unequal camber and assume you hit something or someone just replaced the struts. He will try to adjust camber back to specs and equal on both sides, then the numbers on the computer screen will look fine, but that handling problem will still be there. SAI has to be corrected first, then camber has to be set to specs.

I would recommend setting camber on the left about half a degree positive, (tipped out on top), and the right side at about half a degree negative, (tipped in on top). That would give you a one degree pull to the left. The right edges of both tires are going to scrub off, and leaning the wheels to the left on top will lessen that. One degree pull to the left will tire your arms on the straights, but you won't be fighting as much on the corners.

Look at the tire wear after a few races. If more tread has scrubbed off the right edges, you can tip the wheels more to the left. The goal is to have cornering forces make the tires flat on the track in the corners to get the best grip. That will result in them running on the left edges on the straights, but traction isn't a concern there for the front tires.
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Monday, January 26th, 2015 AT 11:24 AM
Tiny
FEATHERSTONE RACING
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Thanks for the reply, I was thinking about adjusting that cradle, Now I won't

The track is clay so I'm not to worried about tire wear.
The straight away is maybe 8 cars long
The track is in a form of a " D "
So there is more cornering then straight away driving
That's why I'm trying to get the car to turn left on its own

I can move the top of the struts 1/4 inch either way or close to that.
So the right I moved it back and inwards
The left I moved it forward an out wards
Left side looks almost straight up and down now

The strut bolts I have to grind them an 1/8 inch to get camber, as the suspension has to look stock,

I'm. Also looking at right side tire towing it out 1/8
Left tire 1/4
Or would that be to much drag
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Tuesday, January 27th, 2015 AT 9:26 AM
Tiny
CARADIODOC
  • EXPERT
It sounds like you're suggesting 3/8" total toe out. That is done on asphalt because the right tire will have a lot of weight so the car will follow it, and the left tire is pulling harder to the left. Even though the left one is skidding, it's sliding anyway so we want it to pull to the left while it's sliding. On dirt, both tires slide a bunch anyway so there's less benefit from total toe out.

Toe out can be considered normal on the race track for front-wheel-drive cars because the forces tug on the steering linkage and tend to pull the wheels toward 0.00 toe.

I wouldn't move the upper strut mounts in or out because those are the steering pivots, just like upper ball joints when those are used, and that changes SAI the same as when moving the cradle. You can move the right one to the rear to increase caster and make the right wheel want to turn left harder than the left one wants to counteract it and turn to the right, and moving the left one forward will make it want to pull right less than the right one wants to pull left, (that was a mouthful), but remember that unequal caster has almost no affect at all on pulling on a FWD car.

I should also point out that while we can't measure it directly, when you turn left, caster increases on the left wheel and decreases on the right one. Both of those make each wheel tip a little to the left, AND, it's what makes the steering wheel come back to center when you release it after a turn. Like a balanced teeter totter, both wheels come back to the point where caster on both wheels is equal. What you're designing in with unequal caster is that balanced, or equal point is to the left of the center-line of the car, so, in effect, the wheels are balanced when they're steering to the left. That's one of five different ways of describing caster. I don't use it often, but it applies more in this application than when trying to describe the concept of caster to beginning suspension and alignment students.
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Tuesday, January 27th, 2015 AT 6:41 PM

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