wolverine

Are your runs East-to-West or are you doing two-way runs, alternating? I've been testing for several years on a stretch of road that looks absolutely flat, and one direction is consistently faster than the other. I mean faster every single time, in every weather condition, usually by about .3 seconds in a 9 second run. So, you really need to do two-way runs to make sure you are getting an accurate measurement.

znod

How about posting some of your results here and joining in? I am sure you would have a great deal to offer.

znod

For my car:

Est 1/8 time = Act 1/4 time - (660/((((.6(Act 1/4 Spd - Est 1/8 Spd) + Est 1/8 Spd)/94.6)138.75)))
.....................= 13.451-(660/((((0.6*(104.083-83.552)+83.552)/94.6)*138.75)))
.....................= 8.753.

Well, that didn't tell be much except that the above value is somewhat more different from the table value of 8.738 than I expected. And, of course, there is no reason that

grogan545

I think since we have introduced correction factors we need a learning curve.I am not totaly convinced of the accuracy yet.When I used the altitude correction from my drag strip run of 3700' equivilent altitude i convert my 14.10 to 13.45.My 0-60 time goes from 5.65 to 5.39.When using the correction factors for my best 2 way average recently I get raw 1/4 13.26 to corrected 13.58.My raw 0-60 of 4.89 corrected to 5.01.
It appears that the corrections from worse than standard weather conditions do not equate with corrections from better than standard weather conditions.How can I have a 0-60 time of 5.39 with a 1/4 of 13.45 and then a 0-60 of 5.01 with a 1/4 of 13.58?I also reviewed some old data from may 05 and have 0-60 runs of 5.00 & 5.03.I didn't log the weather conditions at the time,but mid may here is generally 55 to 65 degree weather with 50 to 70 % humidity.Much less favorable than my latest test conditions.

Zman what I am going to do is run tests periodically as the weather changes(will soon start getting warmer & more humid)and feeding you the raw data along with the weather conditions at the local airport and log the corrected figures.If the corrections are valid the times should only vary according to my start.The 60' time should indicate how good or bad my start was.What are your thoughts?

znod

I pretty much agree with what you say. I also think that we need to keep in mind another variable--that your meter may no longer be calibrated properly for your dragstrip--although I am not sure why it wouldn't be. Still, I understand why you are attracted to the inconsistency of corrections based on actual dragstrip results versus meter results. Also, the inferences you are working with depend on the accuracy of your formula's prediction. Finally, I think we have a serious problem using any values from altitude and weather correction except 1/4 mile results. In this regard, did you agree with my post #200? In summary, your inferences, while reasonable, seem to be based on a variety of things we shouldn't have supreme confidence in.

Regardless, I agree that we should see how things work out given varying weather conditions. I will provide you with whatever data you need. And, I agree with what you say about your times only varying because of your starts. I will be checking the same sorts of things out. But, right now I am not prepared to conclude that my times should vary only because of my starts. It seems to me that my car, while it shouldn't, has some built-in variability. We'll see though as more observations are gathered.

I think we have our work cut out for us. It should be interesting.

grogan545

I do agree with your post #200.I think you are correct in assuming that the correction factors are only for 1/4 mile results.That is the only way the corrections make sense at this point.I will try to find a suitable test road to make full 1/4 mile runs.I researched the road I spoke about previously and it is not suitable.It has an obvious grade and too much traffic.

m630

damn it...quantum mechanics popping up, even in the real world, whats next ...this definitely should be interesting

znod

Bokke

The run's listed were in one direction - west - that day. I have found a "safer" test place but the weather has be lousy for the past week

znod

Here is some data for you to start thinking about.

Unadjusted
1/4 Mile Speed 102.710 103.620 102.910 102.830 102.710 103.020 103.240 102.270 102.860 102.780 Average--102.895
Variance--0.126472222

1/4 Mile Time 13.629 13.744 13.702 13.742 13.720 13.764 13.686 13.742 13.759 13.774
Average--13.726
Variance--0.001921511

Adjusted
1/4 Mile Speed 104.083 105.005 104.285 104.213 103.683 103.996 104.218 103.274 103.870 103.789 Average--104.042
Variance--0.206969822

1/4 Mile Time 13.451 13.565 13.523 13.562 13.593 13.637 13.559 13.61 13.627 13.642 Average--13.577
Variance--0.003461656

Despite having only 10 paired observations, I did matched pairs t-tests on both types of series. The probablilities that the values represent samples drawn from different populations are very small: 2.20097E-08 (Speed) and 1.88427E-08 (Distance). So, I doubt the larger variability of the adjusted data means much at this point.

But, as you were thinking, the adjusted data should be less variable in the long run--ideally showing virtually no variability. I'm going to start reading some of the SMOKEmUP tech articles if I can find time. So much to do, so little time.