znod

Right, the formula still is good. I was just surprised by the anomolous result. And, fine tuning is possible. Also, there is no guarantee that my regression results are the most accurate. I wish there was someway to be sure. At least we can be confident in adjusted 1/4 results. A revised formula might help. Here's to less than 5's tomorrow and less than 8.7 1/8's. I am looking forward to your results. I am lucky to have such a good test site.

grogan545

Hi Zman.Nothing much to report.I tried to make some runs today but only got 1 0-60 of any value(4.98)using my new method of controls "on" in D.I tried some runs with controls off but stiil no traction.The roads have not completely dried from yesterdays rain.I did log weather conditions.
temp 70F
barometer 29.76
dew point 56F
humidity 57%
altitude 400'
Could you please calculate an equivilent altitude for me?thanks in advance.I probably won't get another chance for tests this week,but hopefully by the weekend I can get back to testing.

znod

Here you go.

Your results:
Air Temp 70 (?F)
Station Pressure 29.76 (in)
Dew Points 56 (?F)
Density Altitude 1111.1 (feet)
Correct 1/4 mi. Timeslip with this DA

And, darn, I slept through my testing time this morining. The weather at 3:00 a.m. would have been: 41.0, 34.0, and 30.17--just what I was looking for to get a best unadjusted run. Mabybe conditions will be the same in the morning, but a warming trend is expected. I don't set an alarm to get up, but I had been up for extra-long extended periods both of the prior two nights. Two nights ago I got up and did two passes. Then, to surprise, I got rained on. When I got home, I gently cleaned the dirty places, dried my car, and detailed it--not going back to bed. Night before last we ate our very late for us, and both of us had stomache problems in the night. I got up and spent most of the night doing calculation, posting, and otherwise fiddling around.

znod

Hi guys:

As mentioned above, I have been waiting for the weather to be right to try for a new unadjusted best. The weather today was similar to the conditions mentioned above, but not quite as cool. I made two passes. I was very happy with them altough I did not beat my unadjusted best of 13.594 @ 103.570. However, they now are my 2nd and 3rd bests.

Below are the adjusted and unadjusted data. The weather was so good that my density altitude was only about 800' so I didn't benefit much from adjustment to 500'.

I tried to get to 111.85 on both passes, but fell an mph short on the first one. I wanted to get some higher-speed data for comparing with the 550i test reported on the other thread. If you have not seen post #65 on the other thread, then check it out. I think you will find it interesting.

Unadjusted:
0 to 111.85 (180 kph)........................15.21
1/4 Speed.......................104.190...104.630
1/8 Speed.........................82.870.....82.940
1/4 Time...........................13.635.....13.620
0 to 100............................12.418.....12.331
1/8 Time.............................8.884......8.883
0 to 60................................5.164......5.162

Weather and Altitude Adjusted to 500':
1/4 Speed.......................104.044...104.485
1/4 Time...........................13.591.....13.576

I have been lazy about generating the rest of my adjusted data because neither of today's passes is one of my best five adjusted. I'll finish posting the unadjusted data pretty soon, maybe.

Happy testing guys. I hope.

Edit: Performance data above edited to allow for changed regression coefficients and error correction.

grogan545

Hi Zman.Looks like your testing is coming along fine.Still waiting for better weather here(40 mph winds today).
I don't know if this pattern will hold but it appears that the better weather didn't improve your times as much as expected.Your best unadjusted time was under worse weather conditions.It may not mean anything,but I'm looking for data on how weather affects our cars vs the calculated data from the NHRA formulas.I am still of the opinion that the factors overcorrect,especially if the weather differences are large.I hope to do some research to see if this theory has a basis.

Bokke

Z-Man - that's fast I thought the cars were limited to 155

Cheers,

znod

Yes, I was flying. I forgot to tell you about installing my surplus Mig engine. Just like a Merc they say; the Migs didn't handle well, but boy did they go straight fast. Did I ever tell you about my Kawasaki 500 cc? Same deal. Just kidding about the Kawasaki. I can't exactly remember what a magazine said about them. It was something like the only living Kawasaki 500 cc riders are those that never had to turn. I did think about buying one. But, instead, I bought a Yamaha 350 cc and trashed myself anyway.

znod

g-man: I edited the following post significantly.

Hmmmmmm? 13.564 is my best unadjusted--with a density altitude of 787.9'. Today's passes, which are my second and third unadjusted bests, were with a density altitude of 801.3'. So, actually my best had the biggest good-weather penalty. And, my second and third bests had my next to biggest good-weather penalty.

But, still, as you are thinking, the weather formula may be over correcting us. If not, then why don't my best unadjusted passes translate into my best adjusted passes? So, if the formula over corrects for good weather, then it must over correct for bad weather too, and not as good unadjusted runs turn out to be the best adjusted runs. It all should average out over time--assuming equal numbers of runs with good and bad weather. So, the averages across many passes, reflecting differing weather characteristics, should provide the best measures of performance. Of course, we would have assumed so anyway--i.e., even without weather over correction. That is, we know that the weather formulas will not fit each car equally well; thus, no matter what it seems to me that we would want to focus on averages as being the best providers of info.

And, recall that you mentioned that all corrections should lead to the same results with everything but weather held constant. I can't do much with this idea, however, because I have no idea if I am holding everything but weather constant enough. I'll keep thinking about this possibility though.

Incidentally, do we have proof that our cars' abilities to adjust actually produce performance enhancements? I definitely wonder. I had crummy results this morning (13.7's--and, of course weather and altitude adjustments would make a great deal of difference--density altitude = 2,085.6), and it is only 10 to 15 degrees warmer. Also, after my first pass, I realized that somehow I had not relieved DTC of its duties. Maybe my car just wanted to sleep in today. Sometimes it feels like it is tired--like this morning.

I just checked things out. My density altitude of 2,085.6 yields a 13.478 @ 105.327--adjusted to 500'. Adjusted to sea level I get 13.407 @ 105.893. I guess my car did well even though it felt tired. Darned weather. I'd rather my car didn't feel tired and, thus, I'd get get better/worse unadjusted/adjusted data.

grogan545

I agree that we should continue to use the weather correction factors.They are far more accurate than ignoring weather altogether.I guess I'm nit picking because my figures don't look nearly as good when corrected.This cold dry weather now gives me super times and I am having a problem letting go of them.
I did manage 1 full 1/4 run today,its still pretty windy but I'm getting the urge to test.Here are my numbers for today I think the weather was a big help.
60' 1.93
330' 5.62
0-60 4.90
1/8 8.65/82.4
1000' 11.20
0-100 11.63
1/4 13.35/104.65
weather conditions were
temp 40 F
barometer 29.80
dew point 18 F
humidity 40%
altitude 400'
If you would be so kind as to crunch the numbers I would appreciate it.

znod

Hi g-man:

We are just leaving the house, and I just now saw your great results. Below is your density altitude. Did you want me to do more than work with your 1/4 results. If so, then I won't be able to do so possibly until tomorrow. And, if so, how did you want be to go about it--using my regression values or the tables?

Your results:
Air Temp 40 (?F)
Altimeter Setting 29.8 (in)
Dew Point 18 (?F)
Altitude 400 (Feet)
Density Altitude -591 (feet)

Here are your basic data corrected to sea level.

Your results:
Density Altitude -591 (feet)
Uncorrected ET 13.35 (sec)
Uncorrected MPH 104.65 (mph)
Corrected ET 13.433
Corrected MPH 103.985

Here they are corrected to 500'.

Your results:
E.T. 13.433 (sec)
Trap Speed 103.985 (mph)
Measured DA 0 (feet)
Corrected to 500(feet) DA
Corrected ET 13.504 (sec)
Corrected Trap Speed 103.429 (mph)

I am wondering if it would be better to present our weather adjusted data at 1,000' feet rather than 500' feet. I am thinking that maybe we should use an altitude that would be "unquestionably" higher than the altitude any magazine would ever be tempted to test at. Another reason for doing so is that it turns out that 1,000' is the average of out altitudes. So, we would be adjusting toward each other. I am pretty sold on this idea. What do you think? I am sure that all of my sub 5 second 0 to 60's would go away, but, regardless, we virtually always would be presenting more conservative data than the magazines.