A friends car ran these two times at the same track and similar atmospheric conditions. No changes to the car. Serious mods made to driver after several disappointing launches.

60'___2.45____2.18
330'__6.56____6.13
1/8___9.85____9.41
mph__74.61___75.51
1000'_12.70___12.24
1/4___15.065__14.644
mph__95.90___94.32

Why is the 1/4 mph lower in the second run when the 1/8 mph is higher than the first run?

Any other observations?

 

The MPH is down becuase of less tire spin. The 2.1 to the 2.4 is a huge diff.. Other than that the good second run. Just another number to compare I run a 14.0 with a 96 mph trap on a 1.9 60'. All of the 14.6 time slips I have are with a 92-93 mph trap and 2.1 60's.

 

what do u think about my 2 times ive made.

first run....

r/t... .957
60'... 2.928
330'... 8.101
1/8... 11.960
mph... 65.91
1000'... 15.142 temp. 47*
1/4... 17.824 humidity. 66%
mph... 84.56 baro. 30.59

second run i made....

dial... 15.99
r/t... 1.079
60'... 2.316
330'... 6.701
1/8... 10.257
mph... 69.39
1000'... 13.342 temp. 50*
1/4... 16.003 humitiy. 55%
mph... 83.98 baro. 30.45

what do u think about my times. i know i need to work on my reaction time. the first run was against a 87 monty arocoupe and second run was aganist a new Acura 3.2TL. i lost both runs but i let off alittle before the finish line becuz i didnt know exactly where the finish line was. and the first run i spun off the line becuz the cars before me and the monty spilled some water on the track i think it was water.

 

Brent: MPH is a result of HP. Many variables can change the HP results. Simple things like a wind change or shift points will change the MPH.

Doing a breakdown of the 2 runs to see how they compare. These times are the differences between each point on the track.

#1
60' = 2.45
1/8 = 7.40
1000' = 2.85
1/4 = 2.365

#2
60' = 2.18
1/8 = 7.23
1000' = 2.83
1/4 = 2.404

First of all the second run will be faster just because of the better 60' time. You'll notice that the second run is also faster between the 60' mark and the 1/8 mile. Since all the shifting should be done before the 1/8 mile, I'd say some shift points were different but they were at a better rpm and it made more HP in the first 1/8 mile. The distance between the 1/8 mile and 1000 foot mark were almost the same. The difference between the 1000 foot mark and the 1/4 mile dropped off in the second run. Maybe the car got a head wind or the engine maxed out or the driver lifted slightly. Even atmospheric conditions can change the available HP. Something slowed it down in that last 320 feet. That could also lower the mph in the second run.

"Similar atmospheric conditions" means nothing without hard data. Just because it was a nice day doesn't mean much. I've watched the barometer drop enough in 6 hours that cars slowed down enough to notice.

 

thats what i kinda see at the track also.