Question for you Experienced Guys

[jbrown13]

Went to the track last night, and the DA started out at 1556 FT and ended at 1071 FT. How much should a 500 FT difference in DA impact a pass? I made four passes, all at different DAs, and the spread between the fastest and slowest was only 0.023 seconds. However the slower 2 passes were at the lowest DAs and the 2nd pass was the best ET. All passes were between 11.472 and 11.449. I'm trying to understand if this is normal, and what might have been the reason my ET didn't improve as the DA lowered. There were a lot of cars out last night, putting down all different rubber compounds, and I'm questioning whether that could be causing the upside down trend, even though I could not detect the slightest bit of wheel spin on any of the runs. Sixty foot times varied from 1.624 to 1.645, so most of the 0.023 second difference was in the sixty, and trap speeds varied from 119.23 to 119.57 MPH. Any thoughts that will help me learn to read my slips/logs better?

Thanks,
Jeff

[white ZL1]

500ft isn't much of a change. Other factors could have had more affect on your ET and speed.
I wouldn't read too much into it.

[Camarojt]

Your 60ft variance will affect your ET more than a 500ft change in DA. I would say that IF your 60ft was dead even from pass to pass then 500ft change might equate to half of a tenth.

[Rhino79]

I agree.

[jbrown13]

Originally Posted by Camarojt

Your 60ft variance will affect your ET more than a 500ft change in DA. I would say that IF your 60ft was dead even from pass to pass then 500ft change might equate to half of a tenth.

Originally Posted by Rhino79

I agree.

So, do either of you have any ideas as to why my 60' slowed, since I didn't feel any spin. I allowed 45 min cool down between runs. Or, am I trying to analyze too much out of a small difference that may be due to track conditions, etc.

I guess I'm trying to make this more predictable than it is. For instance my 1st pass was a 1.624 - 60' and 11.458 ET at 1556 Ft. DA, and my 2nd pass was a 1.639 - 60' and 11.449 ET at 1297 Ft. DA and I don't know why. My 60' is 0.015 seconds slower and my 1/4 is 0.009 seconds quicker. Doesn't compute in my analytical brain based on what everybody says should happen. I never thought I'd be considering thousandths of seconds worth measuring and meaningful, until I started drag racing.

By the way, 3rd and 4th passes mirrored each other with 1.645 - 60's and 11.472 and 11.470 ETs respectively. DAs were 1149 Ft. and 1071 Ft. and trap speeds identical.

[LS7 427]

You're only 2/100th's off on 4 passes. Put a .44 on the windshield and run'er all day.

Bryan

[Camarojt]

You will not feel the difference between a 1.62 and a 1.63 60ft. Too many possibilities on what specifically caused the 60ft time variance! Could be tire temp from burnout, track prep changing, not in the same groove as before, different launch from pedal, motor temps, debris on track, bird fart! I threw that last one in for grins lol.

[jbrown13]

Originally Posted by Camarojt

You will not feel the difference between a 1.62 and a 1.63 60ft. Too many possibilities on what specifically caused the 60ft time variance! Could be tire temp from burnout, track prep changing, not in the same groove as before, different launch from pedal, motor temps, debris on track, bird fart! I threw that last one in for grins lol.

This is what I thought, but wanted to be sure I wasn't making a greenhorn assumption. These rules of thumb have a success rate of less than 100% because there are so many variables, and I'm still trying to get a feel for this. We perfectionists want everything black or white, even though we know it is impossible. Thanks.

Probably a gnat fart though, they were pretty bad Friday night. lol

[Camarojt]

Originally Posted by jbrown13

This is what I thought, but wanted to be sure I wasn't making a greenhorn assumption. These rules of thumb have a success rate of less than 100% because there are so many variables, and I'm still trying to get a feel for this. We perfectionists want everything black or white, even though we know it is impossible. Thanks.

Probably a gnat fart though, they were pretty bad Friday night. lol