I went to the track last night to see any increase in performance from my new exhaust (x-pipe and axelbacks). Below is my best run against my previous best.
7/2/08 4/24/08
r/t .179 .256
60' 2.199 (+0.078) 2.121
330 5.977 (+0.094) 5.883
1/8 9.042 (+0.096) 8.946
mph 80.37 80.29
1000 11.664 (+0.09) 11.574
1/4 13.883 (+0.08) 13.802
mph 101.13 100.83

I have read that x-pipes typically give you less torque and more hp (top end). This seems to be the case for me. I was losing time until the 1/8 and then began to gain some back. Had the highest trap speed to date.

I also wonder how much of my 60' performance was hurt going from the 17" premium wheels to the 18" polished bullits. There is a decent amount of weight difference there. Any thoughts? Anybody else have some et's from before and after wheels swaps?

Thanks,

Scott

 

Those are really consist runs and don't think 18" wheels had any impact. Since there are some many variables like weather temp. and humidity, traction, etc. You will need more runs to come to any conclusions.

 

A larger rim will usually hurt performance a bit. more rotating mass further out on the radius of the wheel. I dont know how much of a difference it would account for. but the difference in your times is so small its not meaningful IMO. the bigger issue would be what were the DAs of the days. that could easliy account for the difference or more!

 

The 1/8 mi results are because of the worse 60. The car made up the speed by the 1/8 mi mark due to making more power even with having to spin 20 lb additional reciprocating mass.

However to have the complete story youneed to have density altitude for both occasions.
You could easily have 0.4 second difference in conditions.