Here's are some quartermile times that correspond with mods that I put into my 5at coupe.

I never did drag my 5at bone stock, that's an unfortunate oversight on my part.

With a Z-tube, K&N drop in, grounding kit and Fujitsubo exhaust my best time was 15.2 (actual time, not corrected for the 2200ft elevation). Humid out and about 42 degrees.

Ran it a couple of weeks later with a Crawford plenum added. Best time was down to a 14.9. Humid again and about 47 degrees.

Ran it a couple of weeks after that (last night) with the Crawford High flow cats and got down to a 14.66 quarter. No humidity, and about 58 degrees out.

I know, I know I should have documented the atmospheric conditions better and someone will undoubtedly argue that the humidity is skewing the numbers. Yeah, well maybe, but I think that the lower temperatures from the first 2 nights pretty much make it a wash.

My conclusion is that the Crawford mods are worth the money. I'll try and dig up the slips if anyone wants to see them.

 

The elevation corrected times would be 14.81, 14.51, and 14.28 respectively. And these were all run on the stock 18s in case anyone was wondering.

 

list the trap speeds with the different mods and that will tell a lot about the power you are putting down with each mod.

 

Use this site for all your historical weather data needs:

www.wunderground.com

Then calculate the density altitude:

http://wahiduddin.net/calc/calc_da.htm

Then correct your ET/MPH with NHRA correction factors.

http://www.gnttype.org/techarea/misc/altitude.html

So say you ran last night at Firebird and say you ran at 8pm. According to Weather Underground, the conditions were quite favorable with a very high baro pressure which is a really good. Conditions: 60 degrees, 20% humidity/18 degree dew point, 30.36 pressure. Elevation 2178'.

The computed density altitude is 2299'.

2300' equals an NHRA correction factor of .9731 for ET and 1.0283 for MPH.

Your corrected 14.66 ET would be an estimated 14.26 on a sea level track.

I can't stress how important it is to calculate DA when you go to the track. WAY TOO MANY PEOPLE IN THE INTERNET WORLD mistake their mods for improved ET/MPH when in fact it was very favorable weather conditions that made all the difference. Then next time they go to the track their car is .3 second and 2mph slower and they think something is wrong with the car, but instead it's the weather.