Quote:
Originally Posted by marolf101x
Camber:
Shocks (coil overs) have nothing to do with camber gain. . .only the actual suspension points can do this.
First you set "static camber" using shims on the upper control arm. This is the amount of camber at ride height. Typically -0.5 to -1.5 degrees.
Then you look at the actual pickup points of the suspension:
By using a tall spindle you move the control arm further up the "arc" created by the rotation of the suspension (if you look at the suspension from the front, draw a circle with the center point at the upper control arm pickup point at the frame, and the outside of the circle at the upper ball joint.)
The Guldstrand mod accomplished the same thing by moving the upper control arm point at the frame down. Do not use this mod and a tall spindle or you'll have too much camber gain.
Essentially, when the suspension compresses the upper ball joint follows this arc and pulls the spindle in toward the engine, providing dynamic camber gain (or how much additional camber is added to the static camber when the suspension is compressed).
So if you have a static of -0.5 degrees, and you gain -0.7 degrees per inch of compression travel you'll have:
ride height = -0.5
compressed 1" = -1.2
compressed 2" = -1.9
compressed 3" = -2.6
***these are just numbers for examples. actual numbers depend on tires, wheels, caster, just about everything.
So the REAL question becomes "how much camber do I need?" Well, that depends on everything. . .tires, wheels, roll angle, etc. The idea is to keep the tire flat on the pavement while the car is turning and rolling toward the outside with the goal of keeping both tires flat no matter what the body is doing.
Parts from multiple manufacturers:
When using parts from different manufacturers you have to make sure you know everything you can about each part. For example, our tall spindle may encounter ball joint bind on a stock upper control arm. We adjusted the ball joints in our control arms to correct this issue and provide complete articulation of all suspension components. I've never tested the GW arms, but I've been told they are fine. If it were me I'd stroke everything just to make sure. You DO NOT want to snap a ball joint.
Suspension Travel:
3" compression is typical in these cars. You only get about 5" of wheel travel total (even in most "modern" cars that's all you get). We set most of our coil overs so 60% of available travel is used for compression (or 3") as you compress the car more than you extend it (unless you live in Hazzard County and have a "magic bush" just in front of the washed out bridge across some creek).
The shock is bolted to the middle of the control arm, so it cannot possibly move 1" when the wheel moves 1". . .this is called motion ratio. Typically around 2:1. So when the wheel moves 1", the shock moves 0.5".
Don't get confused with the "long shock" options you see. The shock still moves the same. So you could have a 10" stroke shock on the car, but the wheel will still only move 5".
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Thank you for this.
I understand that coilovers have nothing to do with camber gain but I stated it because it's relevant to what you nailed on the head of "how much camber do I need" If the car sits low with coilovers, this will have an affect on how much camber I in fact do need for my set up. like you said too much camber is not a good thing and I'm trying to figure out if I can just get away with tubular arms.
SO to answer my question of how much camber I need, will just tubular control arms be enough for the street say if I start with -1.5 static?
Would the addition of the tall drop help me gain more usable camber with a car that sits at your typically low Pro Touring height on the front?
My set up is this, stock subframe, QA-1 's and I want to be moderately low, 18's with a 255/35.