MKIII Alignment Settings?

[Spaniard]

My supra rides on some spongy eibachs and high pressure shocks. I will be going coil-overs later but right now I need an alignment. I was told that it would be best to ZERO out my camber all around and get as much CASTER (adjustable from stock?) as possible in the front for a more direct feel. I have driven a Supra with more caster and it was really nice.

Can anyone recommend some good alignment settings that can be done to my MKIII. It's a street car with some weekend race fun, but nothing technical.

Getting it done tomorrow, any suggestions people?

 

[Wiisass]

Alignment is going to depend on ride height and suspension setup.

It would not be best to zero out your camber, are you sure they didn't mean toe? More caster can be good for steering feel as it will increase the moment arm of the torque acting around the steering axis. But too much caster can numb steering feel at the limit but that is also based on tires.

I'm assuming you got this done already. So what settings did you go with?

Tim

 

[SPD TRP]

I have been wondering this as well.

My caster is 7.7 left and 7.6 right, my car feels a little darty to me. Just the slightest input sends you that way, kinda hard to keep tracking straight.

camber is -.3 left and -.1 right, toe is zeroed out left and right.

The range for caster is 8.2 to 7.2 and I know that if the caster is equal and too negative the car will wander and the steering will be light and diffilcult to keep in a straight line, and too positive will make the steering very heavy.

I am thinking that my caster is too negative.

Would like to hear some feedback on other's alignment specs.

Wayne

 

[Wiisass]

I think you should be running a little more camber than you are. At least -1* in the front depending on ride height and the rest of the suspension setup.

Never run negative caster. But I'm sure you just mean lower caster when you say that. But yes, less caster will make the steering lighter and it will not return as quick. More caster will make the steering heavier, but it will return quicker. This is because you are adjusting the mechanical trail of the suspension. Mechanical trail is the distance from the point that the line connecting the upper and lower ball joints intersects the ground and the center of the contact patch. As you increase caster, this moment arm gets bigger and therefore there is a greater moment about the steering axis from lateral force.

Also, too much caster is bad and will affect the steering feel. The right amount of caster will allow the driver to feel when the front end is losing grip due to the way the tire behaves at the limit. Also, caster affects the amount of camber gain you get with steering angle.

Tim

 

[SPD TRP]

I think you should be running a little more camber than you are. At least -1* in the front depending on ride height and the rest of the suspension setup.

Never run negative caster. But I'm sure you just mean lower caster when you say that. But yes, less caster will make the steering lighter and it will not return as quick. More caster will make the steering heavier, but it will return quicker. This is because you are adjusting the mechanical trail of the suspension. Mechanical trail is the distance from the point that the line connecting the upper and lower ball joints intersects the ground and the center of the contact patch. As you increase caster, this moment arm gets bigger and therefore there is a greater moment about the steering axis from lateral force.

Also, too much caster is bad and will affect the steering feel. The right amount of caster will allow the driver to feel when the front end is losing grip due to the way the tire behaves at the limit. Also, caster affects the amount of camber gain you get with steering angle.

Tim

Yes you are right, I should have said less positive camber. Do my caster numbers seem to be in the ballpark in your opinion or should I run a little more or a little less?

By the way when I did my 1j swap I installed a brand new toyota oem rack and poly-u rack bushings. My front end is pretty tight, already replaced upper and lower bushings with ply-u's and changed lower balljoints with oem toyota.

I think I just need to get some happy alignment corrections to improve it's characteristics.

What are you caster and camber numbers if you remember right off hand?

Thanks

Wayne

 

[Wiisass]

Caster sounds like it would be fine. I dont' remember what my brother's car is set at right now.

Something seems off though. If you're toe is really 0 at each wheel and your caster is about even, a 0.2* difference between camber wouldn't make the car feel like that. Definitely add a little more camber though, it might help just because of camber gain with steer angle.

Also, make sure your steering rack is centered, if not it could be contributing to this.

But the ideal alignment would depend on the rest of the car setup.

 

[SPD TRP]

Caster sounds like it would be fine. I dont' remember what my brother's car is set at right now.

Something seems off though. If you're toe is really 0 at each wheel and your caster is about even, a 0.2* difference between camber wouldn't make the car feel like that. Definitely add a little more camber though, it might help just because of camber gain with steer angle.

Also, make sure your steering rack is centered, if not it could be contributing to this.

But the ideal alignment would depend on the rest of the car setup.

The car is set up as stock with staggered wheels, 9.5 rears and 8 up front both with a 42 offset if I remember correctly. Would like to get some coilovers but would like to get this sorted out first.

As far as the rack goes, I put it in when the 7m was out before the 1j went in. It went in very easily, it seemed pretty clear that is was in correctly because there were no obstructions in the way so there was a clear line of sight to check it out fully.

I may have my alignment guy add some more camber, it is presently at
-0.3* left and -0.1* right.

How much in your opinion should I add? Maybe bring them both to 0.2*?


By the way, thanks for responding!!!

Wayne

 

[Wiisass]

Well if you're getting coilovers soon, then you're going to have to get the car realigned anyway.

For centering the rack, I don't mean that the assembly is in the correct spot in the car. I mean that the rack itself, the part that moves when you turn the wheel, is centered with the steering wheel straight. A quick way to check is measuring turns to lock from the steering wheel being straight ahead.

But has this always been like this? Or did you get it aligned and it started doing this? How was it aligned before when it was acting like this?

I would run more camber than that, but I didn't realize that stock specs were that low. If it were me, I would run closer to -1* of camber with a stock suspension, at least to start. -0.1 seems too low based on how much the car rolls and how much the wheel gains camber during roll.

 

[SPD TRP]

Well if you're getting coilovers soon, then you're going to have to get the car realigned anyway.

For centering the rack, I don't mean that the assembly is in the correct spot in the car. I mean that the rack itself, the part that moves when you turn the wheel, is centered with the steering wheel straight. A quick way to check is measuring turns to lock from the steering wheel being straight ahead.

But has this always been like this? Or did you get it aligned and it started doing this? How was it aligned before when it was acting like this?

I would run more camber than that, but I didn't realize that stock specs were that low. If it were me, I would run closer to -1* of camber with a stock suspension, at least to start. -0.1 seems too low based on how much the car rolls and how much the wheel gains camber during roll.

I understand now about centering the rack in the housing. I will check more closely the relation between left and right lock to lock.

I had the toe so far out when the new rack went in that I really didn't drive it until I had it aligned.

As far as caster goes, -1* isn't going to wear my front tires abnormally?


Thanks

Wayne

 

[Wiisass]

So you had never driven the car before?

Do you have any friends that are good drivers or know any supra guys? Have one of them drive the car? Darty to some people, might be responsive to others.

-1deg of CAMBER shouldn't wear your tires unevenly. But I don't know what you're doing with this car, if its just street driving, then leave it alone I guess. Or try -1*. I mean on a stock suspension, doing street driving and nothing performance related, I guess the stock specs for alignment would be fine. It just seems weird to me, knowing how much the body rolls and how the wheel cambers in, but if you aren't pushing the car, the body won't roll as much, so you won't have the problem.

So if it's just a commuter car, then leave it alone and have someone who's there feel the steering issue. Maybe a better description from someone else or maybe just more description from you would help.

Tim

 

[SPD TRP]

So you had never driven the car before?

Do you have any friends that are good drivers or know any supra guys? Have one of them drive the car? Darty to some people, might be responsive to others.

-1deg of CAMBER shouldn't wear your tires unevenly. But I don't know what you're doing with this car, if its just street driving, then leave it alone I guess. Or try -1*. I mean on a stock suspension, doing street driving and nothing performance related, I guess the stock specs for alignment would be fine. It just seems weird to me, knowing how much the body rolls and how the wheel cambers in, but if you aren't pushing the car, the body won't roll as much, so you won't have the problem.

So if it's just a commuter car, then leave it alone and have someone who's there feel the steering issue. Maybe a better description from someone else or maybe just more description from you would help.

Tim

Yeah, I had driven the car before I put the new rack in. I may not have understood what you meant.

It seemed to drive better than it has lately. I think what I will do is buy some new tires as the rears are worn on the center patch from the guys at discount tire over-inflating them. I'm hoping this is related issue, but I hardly ever get that lucky with a simple problem fix.

As far as what I am doing with it is--the answer is mainly commuting with some spirited bursts here and there, and the occasional high speed travel on a sweeping freeway on or off ramp. The suspension set up is tokiko illumina II's, stock springs, and suspension teqniques sway bars front and rear.


When I say "darty", it seems like I am consistently sawing at the wheel.
I wish I could be more descriptive, and check things right now but the car is in the body shop getting some work done. Should have it back next week.

I read somewhere that if the caster is too positive, the steering will be very heavy and will have the tendancy to bump steer--kick when you hit a bump.
This is what made me start to wonder and searching the boards for any information on alignment specs. I do know that it seems to be more of a handfull when the pavement gets rough.

Thanks Tim.

Wayne

 

[Nick M]

I have been wondering this as well.

My caster is 7.7 left and 7.6 right, my car feels a little darty to me. Just the slightest input sends you that way, kinda hard to keep tracking straight.

I think the problem is you. Not that you are doing something wrong. But 7 1/2 degrees of caster on most street cars is a lot. Perhaps you should ride in an 88 Mustang instead of an 88 Supra with 1 1/2 degrees of caster, and see what darty is.

You are getting really good advice, follow it.

 

[Yblegal91t]

The suspension set up is tokiko illumina II's, stock springs

...

 

[cry4me_sky]

I just had my suspension redone (eibach springs and kyb shocks) IT was my girlfriends dad who did it. When he was aligning it he said the front passenger side has quite a bit of negative camber but the adjustment is pushed all of the way out. He said he can put it on the framing machine and pull on it a bit to get it set correctly and put the adjustment more towards the middle, but he didnt know what the stock front end specs are supposed to be on an mk3 supra. He said some foreign cars have more negative camber... basically he told me to find out what the stock camber is supposed to be (or what you guys recommend for the suspension i am now running) And let him know before he starts pulling on the frame.

I didn't see the stock specs listed above but i'm sure one of you guys has some info for me, someone always does.

Its just a dd i don't race it...i drive it a little hard every now and then for the fun of it but i'm not autocrossing or dragging or anything like that in it.

p.s.
i believe he said the front left camber was like -2/3 of a degree... he didn't say what the right side was.

thanks a ton.

 

[Wiisass]

-2/3* is nothing. That would be fine for your setup if you can get the other side to be the same. Stock specs are for not much camber at all, it's low, but it's also in the TSRM, so you can find it there.

And does he mean that the adjustment is all the way in? Like towards the center of the car? Because if they were all the way out, as in towards the outside of the car, then you would have the full range to take away negative camber.

 

[cry4me_sky]

i didnt look at it so i guess its all the way in then.

the left wheel is neg 3/4 i guess and the front right is negative 1 1/2