This is very simple, and it is what the NHRA teams use to get an idea of what they will run at various tracks. To get your corrected time, simply find the track elevation and multiply your ET by the corresponding ET number, and multiply your mph by the mph column. example...at PRP the mirada ran 12.47@105.82, which is 1180 feet above sea level.

So, I take 12.47*0.9874(1200 foot correction number)=12.312, and take the speed, 105.82*1.0129=107.19, and these times are estimated corrections to sea level. Again, this is by no means perfect, or set in stone, and quoting these numbers as what your car WILL RUN makes you a ricer... Also, keep in mind that things like barometric pressure, humidity, and air pressure all play a big role.


Altitude above Sea Level (Feet) Elapsed Time Factor (ET) Trap Speed Factor (MPH)

feet ET mph
-----------------------
1200 .9874 1.0129
1300 .9861 1.0143
1400 .9848 1.0157
1500 .9835 1.0171
1600 .9822 1.0185
1700 .9809 1.0199
1800 .9796 1.0213
1900 .9783 1.0227
2000 .9770 1.0241
2100 .9757 1.0255
2200 .9744 1.0269
2300 .9731 1.0283
2400 .9718 1.0297
2500 .9705 1.0311
2600 .9692 1.0325
2700 .9679 1.0339
2800 .9666 1.0353
2900 .9653 1.0367
3000 .9640 1.0381
3100 .9627 1.0395
3200 .9614 1.0409
3300 .9601 1.0423
3400 .9588 1.0437
3500 .9575 1.0451
3600 .9562 1.0465
3700 .9549 1.0479
3800 .9536 1.0493
3900 .9523 1.0507
4000 .9510 1.0521
4100 .9497 1.0535
4200 .9484 1.0549
4300 .9471 1.0563
4400 .9458 1.0577
4500 .9445 1.0591
4600 .9432 1.0605
4700 .9419 1.0619
4800 .9406 1.0633
4900 .9393 1.0647
5000 .9380 1.0661
5100 .9367 1.0675
5200 .9354 1.0689
5300 .9341 1.0703
5400 .9328 1.0717
5500 .9315 1.0731

 

I likegetting thedensity altitude then using the NHRA table, it's much closer.

 

i agree, but not many part time racers are going to be able to get that, unless the track list it on the timeslip.

 

True, I just wanted to put the info out there so these guys could look into it.