wrightcomputing

iTrader: (5)

I do a lot of Autocrossing and have been trying to get as much camber as possible. I dialed out the camber and caster bolts loosened the upper and lower control arm and jumped up and down in the engine bay to get as much camber as possible then tightened everything up and did some driving with hard braking to settle everything then checked the bolt and added another quarter turn. I have managed to get nearly 2 degree -ve camber. However I think this may be too much as the car corners great yet seems a little unstable at faster speeds and will not brake at all. Every time I brake hard I lock up the tires (which is virtually every time I brake during autocross). I realize the reducing the camber will prevent the tires from locking up but what affect does the caster have on braking.

I am going to lower the camber a little should I,
1. Reduce the camber using the camber bolt
2 set the caster back to a more neutral position which will also reduce camber

Thats for any advice, to be honest I do not really understand the affect caster has on performance. All I know is it moves the wheel forwards or backwards on relation to the car.

wrightcomputing

iTrader: (5)

Ok I have just looked up the affect caster has, and basically the more caster you have the further forward your tires are the quicker your car will turn in. I had noticed sharp turn in so I think I will reduce that a little so the car has a less violent turn in which can sometime get me a little out of shape, then and test test test. Still not sure about the braking any ideas?

dannobre

iTrader: (3)

After all that did you do an alignment again...II would assume so...but just asking

Caster has no real effect in a straight line....only when the wheel is turned..and if effectively increases the camber as the wheel is turned.

It sounds to me that you might have a toe problem...if the toe is out it changes the feel a lot.

If you have too much or too little camber then the tire contact patch will give you less than optimum grip...since that is ideally what you want to have happen with alignment..you want to set up the car to optimize the way the tire interacts with the road

Having too soft or hard springs and shocks can also affect the weight transfer and change the grip as well....


There are lots of good books on suspension out there if you are interested...or find a good shop and become best buddies with someone that knows what they are doing

dannobre

iTrader: (3)

What car is this? RX-8 or E46 BMW.....

Tell us a bit about your setup and we can likely give you better info...there are some talented dudes on this forum

wrightcomputing

iTrader: (5)

Hi Dannobre, I drive an Rx8 it's the Blue one on my profile pic.

My car is completely stock, the only thing different is the forged mazdaspeed wheels with slightly wider then normal tires they are 245/40/18 Dunlop Direzza Star Specs.
I did a toe alignment after adding the camber and I already had 0 toe on the rear and I had 1/8" toe out on the front that I adjusted to 0 toe.
After writing the post I have changes the caster to the neutral setting. (The directional lines pointing towards the back of the car on the cam washer). I am hoping that will make the car brake better and corner a little smoother, having the extra caster seems to give more oversteer, not a bad thing just different.
I went autocrossing today and will be going again tomorrow so I will see how it feels tomorrow. I took it for a quick drive around the block and although the tires will still lock up under heavy braking I can brake harder before it happens. I will see how it goes tomorrow and let you know.

wrightcomputing

iTrader: (5)

Well I went out autocrossing again today and the car felt much better and braked like it should so I think reducing the caster sorted out that problem.