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      09-15-2007, 09:04 PM   #18
hotrod182's Avatar

Drives: 07 335i, 06 M3
Join Date: Dec 2006
Location: California

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After all the instrumented testing was done, (and we realized how close our cars were in performance), the side by side runs confirmed it. It also highlights one of the biggest issues of roll on (3 honks) type encounters. When cars are running within a couple tenths of each other in the 1/4 mile, a slight fraction of a second delay on a start will skew your results. As we saw today. A slight jump, and you think you are ahead, and then on the next run the other guy gets the jump ,and the tables are turned. Thats why its always more accurate to instrument your cars at the same time when making a comparison. Even getting a few mph (walking speed) jump on a car can make it very difficult for that car to catch you before 120mph, etc.
Also, I find my car runs closer to 240F when you a cruising for a while, on the fwy, etc. When you are at the drag strip, short trips, etc, it tends to stay around 210F, even after several 1/4 mile runs. Its the opposite of what you might expect. Its interesting how the E92 half way point on the temp gauge is 250F, and on my sedan it is 210F. Maybe the previous scale was inaccurate? I think that car makes it most horsepower in a fairly narrow temperature range. Too cold, and I don't believe it makes full boost. Too hot, and it probably retards timing and/or boost. And the other thing that makes my car different possibly is the occasional long cranking I have had for few months now. I'm wondering if the fuel pump is causing some lean AFR which might actually be producing more HP. Not likely, but just wondering how the fuel pump might affect my performance.

Last edited by hotrod182; 09-16-2007 at 12:29 AM.