Camber on a MacPherson strut car (Page 1 of 2)

yeesh, that's already a lot for static camber. Focus on roll reduction instead. At the end of the event was it still worn more on the outside? A lot depends on suspension design, but generally -3 is a fair bit for an endurance event due to straight line tire wear, and it impacts braking too. I run less than that, but my car has a much more advanced suspension.... I run about -2.5 on my "real" race car which is struts tho. I'd go for roll control rather than more camber. Run more positive caster too, which gives negative camber in a turn, without the straight line camber penalty.

depending on car, it may benefit to actually raise rather than lower. without custom control arms, mounts, etc, you can ruin geometry wif too much low.

Springs & sway bar(s).

You can also change caster at the strut tower as well.

Just think outside the box a bit and all will become clear.

It's called "poor camber curve", very typical with McStrut suspension.

A proper sports car with a double wishbone suspension (or one of those other more complicated designs that it hurts my brain to think about) is designed such that the camber goes more negative as the suspension compresses so that you can run "conservative" static camber settings for good highway/street wear, but have the negative camber that you need to give you a flat contact patch under cornering. That would be a "good" camber curve... something like a Miata will gain about a degree for every inch of suspension travel (and they only have about 2.5" of travel).

The McStrut doesn't have a good camber curve (in general, it can't), and in non-performance applications (such as most FWD Lemons cars), the camber curve may actually go POSITIVE under compression, as yours does.

As someone mentioned, one way to deal with this is with roll stiffness. Big ol' front swaybar or stiffer springs/shocks. No roll = no camber change. That can be good. But, the big front bar comes with some negatives, such as inducing understeer. You can counter that by stiffening the rear even more than you did the front to get the balance of the car back. Then you won't have an understeer bias, and you'll have camber for a good contact patch... but the car will be super-stiff and unforgiving to drive. Decisions, decisions!

I like dsycks suggestion better. If you simply wanted more negative camber from slotting the top strut mounts, you'd slot inward... to get more caster (and thus more negative camber when the wheel is turned), you'd want to also slot rearward. I'd try slotting the upper mounts inward and rearward at about 45 degrees to get maximum negative AND maximum caster. Set it as far as it will go and see what you end up with and how it feels.

Don't forget to correct your toe after messing with the camber!

Then you're back to...

On our first car we hacked the strut tower tops up pretty bad and finally had to move the lower control arm mount hole out and up to get the last degree, this current build was going to leave the top alone and just move the bottom.. My question, what is the drawback? Wheres the bettterer part?

To break things down even further...

If you look at the lower control arm and the strut at rest:
if the LCA is angled down - as it moves toward horizontal it actually moves the bottom of the strut away from the center of the car and increases camber.
if the LCA is parallel to the ground or angled upward as it continues up it will move the strut toward the center of the car and decrease camber.

Since the LCA is always the same length, and the shortest distance between 2 points is a straight line, the bottom of the strut must move in and out, as the LCA moves up and down, and the camber angle is going to change as it does.

For best results you want it to move from slightly downward to parallel, as that will add camber through its motion.  The change in angle will be least closest to parallel.  If you have lowered it to the point where the LCA is angled up all the negative camber is going to get used up by the LCA changing the angle as it rolls.

How did you lower it?  Cut springs?  What kind of car is it?  Lowering it anyway except with smaller tires still means the LCA angle will change.  Why not raise the front 1/2" and run a 225/50-15 tire for a net change in ride height of zero.

We ended up raising the Cavalier back up a little just to get back on the good side of the LCA angle issue, plus moving the strut tops in with ghetto camber plates (drilling a new set of holes in the strut tower!).
That left reasonably even tire wear and good handling, but strut cars will always have the lack of camber gain problem/workarounds.

We added enough rear spring and sway bar that the inside rear wheel was often in the air, that's pretty much as far as you can go...

Wow good stuff everyone, thanks,

The car is a Maxima, stock wheels are 15", but we bought the car with 17" Z-car wheels , we run 255/40/17 tires, the LCA looks parallel.  The previous owner installed some slightly lower / 20% stiffer than stock springs, stock anti-roll bars front and rear, the car was dropped maybe 1.5" all around (though we did cut the rear springs to drop the rear more) The car still pushes bad, feels like forever before we can pick-up the throttle for corner exit.  Too soon and it pushes off the track (and a black flag), too late and speed is effected all the way to the next corner.  I and my 'mates just don't have the expertise to re-drill the strut tower holes for better camber/castor without running the danger of really messing things up, then again, the springs are so wide, there isn't much room.  To compound the problem, we can never get a residual value under $499.99 so buying even junkyards parts is out. I guess we just have to make do. I have read that a properly set-up FWD racer will lift the rear inside wheel, since our car is so friggen heavy, I doubt that will ever happen, LOL!!

Thanks again, good stuff

Sergio,

Hay, yea, I think I'll give that a try and see if the car rotates better.  That is easy to do at the track and doesn't cost anything, Hmmmm.  Will that cause MORE front roll and MORE positive camber (what we want to get rid of in the first place)?  Definately worth trying

A fully caged maxima should be able to get down to around 2500# and maybe a hint less if put on the right diet.

Also... bump stops as extra damping? Are we putting ALL our secrets on the forums now?