Autocross vs. Road Coarse suspension setup

[WFO-TSi]

I have done quite a bit of searching on spring rate selection. I have found a lot of useful information from some people with quite a lot of experience at tweaking the suspension of the 2G DSM for autocross. When soaking all of this in I always have a nagging thought in the back of my head..."How much of this applies to road racing?"

The closest road coarse to me is Pacific Raceways, and the surface of that track is hammered. I personally couldn't imagine running spring rates as high as some of those used by the members on this board. I hear a lot of talk from autocrossers about selecting spring rates that will help the car rotate. I am personally trying to increase the cars overall grip instead of unsticking the rear to help it oversteer.

Also, I have to wonder if it is possible to have too much negative camber in the front. For instance the Alignment FAQ for autocross purposes states that –2.5 degrees is recommended. My only concern is that at what point does adding negative camber to the front reduce the straight-line contact patch that I am relying on while slowing down from triple digit speeds?

So my overall question is this...How much of what applies to making a fast autocross car applies to making a fast road coarse car?

 

[jtmcinder]

The good news is that nearly every handling book written has road-racing in mind, so you should get a copy of Fred Puhn's How to make your car handle and read it twice.

As to the specific issue of front camber, the basic rule is the same. If you're serious, you set the camber by taking tire temps. Maybe you'll need 2.5*; maybe you'll want less. If it turns out that you need a lot in the front and little in the rear, then you might want to get a adjustable bias valve, so you can move some braking to the rear, especially if the car is lowered, so less weight transfer is happening. Or maybe you can move braking to the rear by pad choice, such as R4-Es in the front and R4-Ss in the rear. Next Sunday I will be trying R4-Ss in the front and Metal Masters in the rear, in an attempt to do this for autocrossing.

The first decision, however, is how much you are willing to invest, in terms of both money and time. If the answer is "not much," then don't mess with your head worrying about it; just go drive the car. If the answer is "as much as it takes," then start by reading every book by Carroll Smith, along with Puhn, and maybe a few others. If you have questions as you read, post 'em up.

- Jtoby