Went out to the track today, and netted the best as follows. Mods in Sig.

Temp F. 57
Humidity 87
Absolute Barometer 29.52

RT .199
60 1.78
330' 5.157
660' 7.968
MPH 87.18
1000' 10.39
1/4 12.42
MPH 111.18

Best MPH that night was 111.58. This was on Mickey Thompson ET Street Drag Radials @14psi. The track conditions were not the greatest, and I am still working out some tuning issues, but I still think times should of been a lot better. I was launching at about 3-3.5k because any higher, It would just break the tires loose. Any opinions, suggestions? BTW, I just dynoed 390rwhp, with some tuning, but since then, have deleted the o2's and have not went up for tuning again..

 

What's the track elevation? Is that barometer reading the adjusted reading? The kind you would be giving from the weather office?

 

i am trying to figure out the tracks elevation, but am having a hard time. The barometer is what is printed on the timeslip, to tell you the truth I dont even know what "Barometer" is...

 

If you can, next time you're at the track see if you can get a full set of weather numbers from another racer with a weather station. I've found that tracks printed numbers can vary quite a bit from what a weather station shows. Also, be sure to ask for the corrected altitude from him/her.

 

Printed on the timeslip should be an adjusted altitude. As long as you're only using that barometer, you can keep a log. Someone else's barometer reading in the pits could be completely different. A barometer is a measurement of air pressure. The higher the reading, the better the air is (more oxygen to burn making more HP)

What track is it?

 

I'm going to guess you were at Sonoma. That's only 24 feet above sea level. If you went to Sacramento, that's only 50 feet. Not much of a difference and neither are really a factor for density altitude.

Plugging those numbers into my racing formulas tells me it was a poor racing day. The cool temperature was nice but the track was probably also cold. Humidity was high but with the cool air, there still isn't a lot of moisture. 90F and 80% humidity has more water in the air than 60F and 80% humidity so humidity needs to be understood on how it works. The biggest factor now is barometric pressure. 29.52 is very low. Something above 30.00 would be much better.

Based on the weather data and 24 feet elevation, that converts to 547 feet density altitude. Not really a big factor but the higher the density altitude, the slower the car runs. Take your car to Denver and it probably won't get out of the 13's but then with a really good race day at sea level, it's possible you could dip into the 11's..

One more thing is required. Race weight. How much does the car weigh sitting on the starting line? The car, you, helmet, fuel etc. That's how much weight the engine needs to move down the track.

Based on your performance and dyno numbers, my calculations put it around 3800 pounds. If it weighs lighter than that then you're not using all that HP properly to get you down the track. Dyno HP doesn't consider friction with the ground, wind, shift points, traction etc.

 

yea the track was pretty bad that day. It was really windy, cold, and no track prep basically. I have never put the car on a scale, so I have no clue on the weight, but I know its heavy, especially with all the suspension mods, and 12bolt. I was only launching at about 3k, because anything higher would just make the wheels spin out the whole. Also my line lock wouldnt hold the car I need to figure out why. Im sure the car has more potential, I just need to get the tuning bugs out, and go to the track on a better day. Thanks guys!