NHRA Altitude Correction Factors Chart

[melly mel]

Saw this on theVboard. Maybe sticky worthy?

For all of you that dont live at sealevel here are the NHRA Altitude Correction Factors.

To convert your Quarter Mile ET and MPH to sea level times, multiply applicable factor times your ET or MPH.

For example 1slowspecv goes to the track which is at 4000ft and runs a 16.2 @ 84 and becomes disenchanted with his car since it does not measure up with the others on the board. Using the correction factors for 4500ft that 16.2 @ 84 becomes a corrected 15.3 @ 88.96. Big difference. Hope this helps you sea level challenged people out.


Alt cr ET cr MPH cr
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

[melly mel]

So my 15.0 at Speedworld would equal 14.1 at sea level? Sweet!!!

Correction: Speedworld being at 1100 ft. would yield a difference of .9887 so I would've hit 14.0603

[DEFYF8]

i don't believe in this at all, sorry

If you want to know what you run at sealevel, go to a track by the bay.

[melly mel]

Why is it so hard to believe? There have been many Specs with similar mods hit low 14's.

[DEFYF8]

but we don't live at sealevel, so why get your hopes up.

i don't know, its wierd

[melly mel]

But it shows what you COULD run at sea level. It's just there to compare times with other cars of the same make, model and mods. Not that I'll be walking around saying, that I actually hit a 14.06 pass. But when someone from another state says they ran faster with the same mods, same conditions it could be a little disheartening.

[Insurgent]

butt dynoed registered a 1-2 HP gain in San Diego doing launches by the bay. I bet you could bust in the high 14's down there, low 14 seems unlikely.

[melly mel]

Yeah, I was thinking mid 14's but they didn't include the 1100 ft elevation in the equation (I kinda guesstimated). Maybe there's a big difference in pressure between 1100 and 1200. Who knows? One of these days I'll drive my car back home to the Bay Area and try to get out to Infineon with an elevation of 500 ft. See how I'll do then.

[SirZyrion]

I gotta agree with Bryan on this one. I'm not feelin' it. If you live in AZ and your car is a 15 sec car, it's a 15 sec car. Going to SD for a pass and better numbers is pointless. I feel the same way about dynoing/racing in heat vs cold. Temp, pressure, humidity, and elevation all affect the car's numbers, but it affects EVERYONE'S numbers, not just one or two, so it doesn't matter to me. With the same drivers and mods, the outcome would be pretty close to the same in hot or cold weather. the oly real difference would come in at the cooling system level.

[jamezpaull]

I think it's a good educational tool. I doubt anyone's gonna see it and be like "you race here and I'll race in San Francisco....then we'll see who's faster".

[zander]

Its more for those assholes on the Vboard that say people in AZ suck at driving lol
Hmm... I think I hit 15.5 once. So 15.3 at sea level? Makes sense to me.

[az03g]

So my 15.0 at Speedworld would equal 14.1 at sea level? Sweet!!!

Correction: Speedworld being at 1100 ft. would yield a difference of .9887 so I would've hit 14.0603
you're math is wrong.... it's not .9887 seconds faster than at sea level... you're run at sea level would be it's 98.87% of your time at the certain elevation. So 98.87% of 15.0 = 14.83... a little more realistic. ;)

[melly mel]

you're math is wrong.... it's not .9887 seconds faster than at sea level... you're run at sea level would be it's 98.87% of your time at the certain elevation. So 98.87% of 15.0 = 14.83... a little more realistic. ;)

Oh okay. Still, 14.8 is pretty sweet considering the amount of money I've thrown down on mods.