:. Racing .:. 2005/08/27 - Autocross
Results: *none*
Flashback
After a bit of a break in the racing season, I was back at it for a bit of an "exhibition" fun race sponsored by the BMW CCA. Due to the DIA lot going through its repaving, this event has held at Coors Field, which I haven't been to in a LONG time. Sure brought back a fun memory or two.
This was the first event to run since revalving the shocks to A/B, A+/B+ from B-/C and B/C+. I had tried to get the adjustable front pushrods installed to try zero-drooping the car, but Grant and I mismeasured (oops), so I had the stockers on and "normal" droop settings for this time.
I started with the shocks at -10/-10 on the rebound adjustment, and the bump set in the middle at 3/3. Immediate impressions were that I hardly noticed the bumps at all - the car was *much* smoother. Part of this must be the better Coors surface, but some of that has to be the improved shock valving.
In the morning, the car was *extremely* slidy. On turn-in, the back end of the car would start to break loose almost immediately. Caught several slides on run #1. I tried lessening the rake angle by dropping the car 2 turns, but that did not have much effect. Run #2 I actually spun the car, which was partially turn-in slidiness, and me locking the brakes slightly while eturning. Oops. For run #3, I also dropped the rear bump damping to 1, which also had minimal, if any, effect.
During the break, I reduced the rear rebound to -20, down from -10. In the afternoon, the car was extremely planted, and even had a it of turn-in understeer. Going through the slalom took more "muscling" again to get the car turned and through. However, even with my stiff springs, it appears that the car is still "taking a set" just fine, has good feel, and can be driven hard.
I did notice that even at a relatively high 2 3/8" ride height, there was still a touch of splitter rubbing, so perhaps the zero-drooped front will assist with this.
Lastly, regarding the long-awaited larger front tire size - it definitely helps. I noticed it most under braking, that the car has a lot more front grip before the tires start to lock. It seems to have also made a difference steady-state in the sweeper, although it's hard to say for sure. I'll definitely keep it this way, since there seems to be no downside, other than that I may have to make a little "flare" to cover the tire so that the car remains within the letter of the rules...
Changes for Next Time
Steady-State is still just a bit understeer-y, but not bad, overall. Certainly not like before. I'll have to evaluate this further as I get to do some higher speed driving, and see if the car still feels "safe" or "terrifying". At any rate, I'm going to try the 600# rear spring, to bring the ratio to 0.67, and see if the steady-state feel I'm looking for is finally there. I'll also have to play with rake again to see how I'm doing, and also play with camber to see how my temps are running these days.
Big test of the current springrates is going to try and see how the car behaves over the bumpy DIA lot...we'll see!
NEW CHANGES:
- New Shock Valving
- 20x7.5 front tire
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