I road race a 2002 Cavy. I am wondering if anyone has changed camber/caster/toe to their road racer and if so to what angles? I cannot find any literature on this. Also, did you have to change anything in order to change the alignment? It looks like I'll have to mod the housing above the shocks. I run race tires and this is not driven on the street...EVER. Sway bar, shocks and springs are all after market performance, Any info would be great. Thanks!
Road race, or autocross?
I'd be interested in what you did for brake upgrades if you're road racing.
I'm sure you understand suspension theory, but there's tradeoffs.
If you're patient enough over the next couple months I'll be doing a tuned suspension build for autocross. Have you done any measurements on your car?
Roll Center specifically
Wedge?
Ackerman effect?
Caster, and camber curves?
I'm running -1.8 deg. of camber in the front and zero toe for an autocross setup. You will probably want about -1.5 deg to -2 deg of camber. You should also go with some toe out in the front. If you want to shim the rear, I would go with like -1 deg of camber and zero toe.
If you serious about road racing, you should think about upgrading your suspension to Tien SS coilovers. They have built in camber plates for the front which make adjustments pretty easy.
It will be hard to get lots of negative camber with toe out. My camber plates are nearly maxed out with zero toe. Good luck!
Edit: just saw in your profile that you can't run coilovers
Email mcmoney about getting a set of camber plates that replace your front stut mounts if interested.
Mitch Davis wrote:I'd be interested in what you did for brake upgrades if you're road racing.
Stock brakes work fine. Upgrade the rotors to a decent set of slotted if you've got the money (but plain face brembo's work fine too). Put a set of stainless brake lines on, and a racing pad of choice (Bobcats, Axxis Ultimates, etc). I found that NOPI is the cheapest place to get the brembo rotors and axxis pads.
Well, I meant on the brake setup for road racing. I figured it would be pretty easy to get brake fade, let alone heat up your brake fluid.
Eh, but it's all heresay I know :shrug:
What spring rates are you using? Are you still using a front swaybar? What kind of dampers? What kind of tires? All this must be taken into account. Front wheel drive cars have an understeer problem, and here is how to solve it.
Also, something to think about. The optimal camber for braking and accelerating is 0 degrees, because it allows the largest foot print. Negative camber is only required to make up for body roll and tire flex. Idealy, you would run 0 to -1 degree of camber, and have the suspension geometry such that the negative camber gained on suspension compression is equal to or slightly greater than the degree of body roll. Unfortunately in strut type suspensions, This camber gain is hard to come by unless you are running super stiff spring rates and the car is at stock ride height or a little bit higher, so that the roll center is as high as possible. If you are lifting the inside rear through corners, body roll is an issue that needs to be solved before you even think about alignment. Your front spring rates need to be high enough to control the body roll of the entire car....without a front sway bar. On my 1900lb car, with 63/37% weight distribution, I use a 700lb spring on the front to accomplish this. You want to remove the front sway bar to keep the front suspension as independent as possible, which will help keep the inside front tire planted better in turns. Weight transfer to the outside front is never a problem, but is usually excessive and overworks that tire, so we try make the other side stick a little too. If your understeer is still too much, add rear sway bar, two if you need it, and increase rear spring rate (and damping) to make the rear of the car slide a bit....or rotate...to the point where you will have a neutral handling car. Then worry about alignment and suspension geometry. You have to look at how the camber changes through the course of the usable suspension travel.
Draw an imaginary line between the front control arm inner pivot axis and the centerline of the ball joint. In the static state (car sitting there), if this line is level, you will gain positive camber as the suspension compresses.....which is exactly the opposite of what you need to happen. Now draw an imaginary vertical line through the inner pivot point of the control arm, and another vertical line through the ball joint centerline...., and measure that distance between these lines with the car in a static state. In order to gain negative camber under suspension compression (which is what we want) the lines must move farther apart as the suspension is compressed. If they move closer together, you are gaining positive camber, which is counterproductive. The ideal situation is to get the lines as close together as possible in the static state, so that they can only move farther apart as the suspension goes through its usuable travel. This usually requires lowering the ball joint in relation to the inner pivot point of the control arm, which can be most easily done by raising the ride height of the car.....which is a tradeoff because you are also raising the CG which will make body roll more difficult to control. Ideally, the knuckle should be modified to lower to ball joint receptical by as much as possible while still allowing everything to fit inside of the wheel. If the geometry can be modified like this, so that you actually gain negative camber on the outside front through a corner, I would set the static camber around -1.5 to -2 degrees.
Caster is generally used to control the steering effort....more caster (strut leaned back) will offer more steering effort, and better automatic return to center coming out of corners, while less camber (strut leaned forward) will make steering less difficult, but much more difficult to return to center. More caster will also offer up more camber gain as the wheels are turned, which is good, but steering effort increases as well...so you have to find a happy medium where steering effort is acceptable....and stop there.
As for Toe......a good starting point is 0 to 1/16" toe out in the front, and 0 in the rear. If you are still having understeer or push, you can toe the rear out a bit..1/16 - 1/8 of an inch to help reduce understeer.
When using R-compound tires, spring rate needs to increase in order to see the full benefit of what the tires can do.
rubbin' is racin'
STOPIT! Long time, no see. Excellent post. If you need a brake upgrade talk to him (if he is still selling stuff).
