Question is how much time will I gain from an elevation change? Last time at the track was in Fayetteville, NC at about 500ft above sea level. Now I'm in Boise, ID at about 2800ft. above sea level. Any ideas??

 

http://www.nhra.com/tech_specs/altitude.html

From www.nhra.com, the "Competition" button at the top, then "NHRA ET Quick Reference" from the menu, then on the left is the altitude correction factors. Use the SS/Stock table at the bottom.

The Boise (2700') correction factors are 1.0332 for ET, .9672 for MPH.

(500' is considered sea level.)

 

Holy @#$% a whole frikin second!!!! Great went from slug to a snail. Thanks for the link Five7. Guess I had to find out someday.

 

Look at my sig. If I ever get to Mission and race at sea level, I could drop a whole bunch of ET. My conversion formulas are based off dyno calculations so the only way I'll know if the car will run that much quicker is to actually get to a sea level track and run it.

High altitude tuning is a little different. You can lean the carb down since there's not as much air to use. You can run a lower octane at higher altitudes. You can run more ignition timing. At the higher altitude, you're just not going to be making the same amount of HP so the car has to run slower.

The big thing is you're going to notice the car will be more sluggish and won't sound as crisp as it did at the lower elevations.

Watch the NHRA race in Colorado this weekend. Prostock cars are currently running 203 - 206 mph. Chances are none will be over 200 in Denver. That's how much they lose.

That NHRA conversion number is not a full second. Lets say your car runs 12.0. Multiply by the conversion of 1.0332 for Boise and that 12.0 car now runs 12.398. Now that's also just for altitude. Factor in the density altitude and you're probably going to be racing closer to 4000 feet. That's also why Boise sets a lot of records. In the cool air of spring and fall, the DA can be below 2700 feet but NHRA still uses the 2700 feet factor.

 

i raced at firebird raceway in boise 2 weeks ago. it was 95*, track temp was 140*, and the density alt. was 6100 most of the day. . but last october when i was there they had a denisty alt of 500 feet! (that was fun). what stephen said is right on, on tuning.

 

dude, I went there last Friday and it was a nightmare. I hate firebird. It was around 105 deg. I'm never going back there again. Too many rules and BS. I just wanted to do some passes. I can see why illegal drags are really bad here. Not to mention it was very expensive. When I was at fayetteville, it was $18 out the door. You got a sticker, lined up, and went down the track. First come first serve. The way it should be. Anyways that was my little rant. F*CK FIREBIRD!

 

Yes, your little TGO rules breaking rant.

$18? How much did Firebird charge? Here, it's $30 on "Take it to the Track" test & tune Wednesdays. They get so many cars you're lucky to get 4 passes in. Last year while I was waiting for my turn, some idiot drove down the shut-down area looking for a way out of the place. And that's in a well-attended facility that's trying to get the street racers off the street. At least there were a couple hundred fewer idiots on the street that night.

Or, every once in awhile, they have a Tuesday "Race Car Test & Tune", which costs $40. You're more likely to get more passes in than on a Wednesday night, must have slicks or run faster than 11.50, but it still costs more than the come-one come-all Wednesday T&T.

Do you have an authority problem, or what? What "rules" were so difficult to swallow?

So, how much did Firebird charge?

 

Back off guys, I think what he is trying to say is his car wouldn't pass tech inspection at Firebird.

 

No my car passed the inspection. They were giving me a bunch of crap about a crack on the passenger side of the windshield. Some guy was telling me about how his car didn't pass cause his battery wasn't tied down. Just **** about it. I guess I was expecting the same simplicity that I encountered at Fayetteville Speedway. Which was pull up to the ticket gate. Pay $18. And line up to race. When I got to firebird I had to pick a class and wait till they called it before I could race. Then I had to fill out a bunch of crap on my car. Then I had to buy a number. Run around the pit begging guys to use their shoe polish so I could write my number five different places on the car. Then I had to pass inspection. Then go back to the pit and sit on my butt in the 105 degree weather for three hours only to find out that I had to leave. So I never got to race. Wasted $30 and 4 hours of my time, gas and brain cells from the heat. All my car buddies talk shat about Firebird and now I see why.

 

A battery tie down is perhaps the most common things that a tech guys checks.

There are reasons for the rules. Tracks need to follow the prescribed NHRA or IHRA rules to get insurance and without insurance, I don't think there would be very many tracks for any of us to race at!