Drag Strip Guru's - need a crash course on weather and racing
 

TIMESLIP WEATHER REPORT - Posted below are my best times at the local tracks around here. I dont understand the weather and the relationship with helping or hurting performance. If its cold outside, and the humidity is low. I usually say, hey its a good day to race !

Does the pressure have a big impact also ? Wanted someone to look over this in relation to my best times and explain (if possible)


no problem**** state capitol*** hub city****finishline
Time
14.16 ----------- 14.25 -------- 14.29 -------14.14
Temp
60----------------53-------------69------------51
pressure:
30.3--------------30.2-----------30.9----------29.9

humid:
48%--------------86%-----------24%----------76%

wind:
6 mph E----------10mph E--------calm---------10mph ENE

In my opinion, the factors listed in terms of importance are: temperature, humidity, baro. pressure. All 3 together are variable enough to affect your times, assuming that all other conditions are constant (ie, your driving style and track conditions).

All that being said, I think that the track condition of the different tracks would be the largest factor in your times in this case... they are all quite close to each other in terms of weather conditions. Are the tracks all that different?

I've had the opportunity here to compare quite contrasting temperatures (I have never looked at baro. pressure when I go racing though) and that is what I have found.

It would be interesting to see what some of the other guys think.

all 2.1 60 foots on these runs

That does not necessarily mean that the tracks are equal. Last year I would have thought the same as you, but this year I found out (even after consulting with other people) the following:

St. Thomas, Ontario:
Track yields horrible 60' times but trap speeds are higher

Cayuga, Ontario:
A "bad" 60' time here = the best 60' time at St. Thomas, however trap speeds are always 1-2mph slower at this track, if not more. My buddy gets about 4mph slower traps in his Mustang between the two tracks (better 60' here, and similar ETs).

This is all, weather conditions approximately equal. Elevation is about the same +/- 100m... or less.

Grrr all this track variation sucks and with our weather it is hard to maintain the tracks... I wish I could come race at your no problem track... where is it exactly??? :D

Its in the Baton Rouge, LA -- New Orleans, La area.

Assume windage and trackprep are identical. Then remove launch differences for the different temps (sunny, overcast, etc.). That leaves only power differences right?

Correction factor for power looks something like this.
CF = 1.18 * (29.22/Bdo) * ((To+460/537)^.5) - .18

Bdo = absolute pressure (not relative)
absolute pressure = realtive hum - (elevation / 1000)
To = outside air temp

Using corrected power your last run is .44sec faster than run #3 if I got it right. I agree temp is always the most important but maybe that ENE wind had something to do with it. Does the track run southward?

these guys are all right. The best racing conditions are:

sun shining on the track which warms the surface and helps traction.
cold temperature.
low humidity.
high pressure.

The best temps seem (for me at least) to be in the low 40's. Any colder than that and traction suffers terribly. I have run in 20 degree weather and although I trapped well, I never ran a new best E.T. Humidity is the second most important. Pressure does make a difference, but it is the least important of the factors. I have around 300 timeslips and I have been tracking weather conditions, these do seem to correlate pretty well.

Elevation

No Problem Raceway - 23

Hub City Dragway - 161

State Capitol - 53

Finishline - 487

im messing around with this calculator thing at http://wahiduddin.net/calc/calc_hp_dp.htm

cant make much sense out of it, is there something better to use ?

It appears to me Hub City and then No Problem were the best days to race, but then again im not sure about any of this. Also after looking at some of this stuff and my timeslip from finishline dragway im not sure my times are accurate at all.

Ceasar,

Is your 2.1 60ft on street tires or radials? I apologize in advance for going OT.

ceasar is on street tires.

hey no problem about OT, i found out much of what i needed to learn. pretty cool ! toyo proxes t1-s is what im using