Not sure what's going on, but I've gotten a lot slower in the last year, relative to other drivers. I'm not beating people I used to beat handily. Some of that can be attributed to others improving, but I've also been losing ground against drivers who are already top 3 nationals finishers. It's very frustrating. I've been putting my grey matter to work trying to figure it out.
For background, the car:
87 CRX Si, former IT car, now autocross. 27.5 mm bars up front with stock ARB, GC coilovers in the back with a 3/4" ARB and 500 lb springs. Illumina dampers all around. At the beginning of this year it had 255 A7s on 13x9 spun steel wheels. Now it has 235 Ecsta V700s on 13x9 Keizers. The V700s were on the wheels when I got them, I have no idea how old they are.
It started this year. At first I attributed it to the A7s being a season old and having sat the winter, but I'm not so sure. I've had other R comp tires and I didn't experience the same drop off. Could be something odd to Hoosiers.
The steel wheels were heavy, so I replaced them with a set of Keizers with the Ecsta tires. They are definitely less grippy than even worn Hoosiers, but I've done well even with worse tires.
The same time I changed the wheels, I removed a lot of weight (175 lbs) from the car. This included the roll cage. It was 125 lbs by itself and it was a fair amount of weight up high, so it definitely changed the center of gravity. I'm sure it was also making the car a lot stiffer, so maybe this is a factor.
The car definitely handled differently. It was less tail happy, actually tending to push a bit where the back end used to come around. It felt faster, turn in was better, it seemed to corner better according to my butt dyno, but it was ultimately slower overall. Today we were in Blytheville, and the car was VERY tail happy - completely different than before. I've noticed that before on that surface with this car. It was cool - 60 degrees, so I had some trouble getting heat in the tires, but I was ultimately able to turn in an OK time, but I didn't even make the top ten in a 24 car field. Very unusual for me.
The tires definitely don't help, but they aren't totally worthless. I'm revisiting the removal of the roll cage as potentially causing the car to be slower due to loss of stiffness. I did not add anything back, like strut bars. It needs those, I think, but perhaps it needs some other suspension tweaking to match the new lower weight? (estimated to be around 1750 - I knew what the car weighed before and I weighed every piece I took off). I'm kind of at a loss here.