I installed a set of GC coilovers and really like the ride and performance. After raising the front of the car a little I noticed a dramatic change in how the car feels on the road. It was not slammed before, however, I noticed a dramatic change in the weight transfer.

Now that I have the option to change ride height what is a good rule for setting up a '00 GSR for autocross and daily driving? Do I want it level, a little high in the back (say 1/2"), lower in the back, etc? People mentioned raising the driver side just a little to compensate for driver weight. This makes sense. It was even recomended to me to have the car aligned with my weight in the driver seat. Ideally, I would like to get the car cornerweighed but don't know if I will in the next severl months.

Suggestions and explinations on the theory of the ride height effecting performance would be appreciated.

 

Did you get an alignment after raising the car? If not, it's likely that you're feeling the change in toe rather than the height change itself.

 

All other things being equal (which they almost NEVER are) a lower center of mass is beneficial. HOWEVER, lack of compliance (bottoming), camber gain, bump/roll steer, and roll center height movement can all result from lowering and conspire to waste any gains - sometimes more.

A LOT of cars on the street are too low - that's a given - but I think the same can be said for some production-based racing cars.

Kirk

 

Right now I have less than a 1.5" drop in the front. I have no clue in the back becuause I haven't had stock springs in so long. One point I was wondering is weight transfer on acceleration. If the car is level the weight would shift back on my softer springs thus pulling some weight off the front and possibly inducing easier tire spin, less traction=less acceleration. With the back up, say 1/2", would it help acceleration?

 

No, if anything it would transfer slightly more weight away from the front wheels by raising the center of gravity slightly. But, weight transfer is really not something you should be trying to fight or control, because aside from lowering your CG there's virtually nothing you can go about it. Work with it, not against it.

edit: just realized I'm sort of talking out my a$$... oh well.


[Modified by robbin, 4:07 AM 3/11/2003]

 

To much rake or rear ride height will promote corner entry oversteer.

 

Is that because of increased weight transfer in the rear, less rear camber... or something else?

Just curious.

 

i would tend to think it's because of too muc negative camber

 

Now I am confused. Carl, wouldn't too much rake or rear ride height reduce negative camber? Wouldn't adding negative camber in the rear decrease corner entry oversteer and push it towards mid corner?

 

Here read this http://www.wtrscca.org/tech.htm

Forget the change in camber! Camber should be adjusted to a constant when ride height is changed.

 

FWIW, when I said "camber gain" I meant dynamic camber gain, rather than static camber - which I assumed one would adjust. When lowered, some suspension designs will gain/lose camber in bump and roll moreso than the do at stock ride height. Extra stiffness usually mitigates this effect to some degree, but... In fact, it isn't unusual to be forced into trading compliance for dynamic geometry control.

K