del91_305

i just found out that our local dragstrip (Bristol Dragstrip) is at 1475 above see level. Should it be hard to run good times at this elevation? I have ran there before but didnt do very good and began to wonder about the elevation.

Jokerman

I don't believe thats really all that bad in terms of elevation. Should only be worth a few tenths i think. (could be wrong of course) How bad was your run? I mean it is still an L03 remember.

automec

i wish i could run at somewhere that low! i live at 4800' and the closest track is at 5800' eleavation.

mike

del91_305

Well the best i could run was a 16.3, But i was having trouble getting my tranny to shift right. I am having trouble with the TV cable. i think that i could have easily ran a high 15, but i was just curious about the elevation.

91gta_tpi

Yeah i ran at the same track with Dustin, and I ran a really crappy best of 16.6, with my 305 tpi stock, with just CAI, and crappy tires.

AlkyIROC

Track elevation is only part of the equation. You also need to calculate in the temperature, humidity and barometric pressure to come up with a density altitude. The higher the track elevation the worse the performance will get anyway.

1475 feet isn't even worth a jet change from a sea level setting.

I'd love to race at such a low altitude. My local track is 3350 feet and like in my sig I usually race at over 5000 density altitude. To have a race day where the density altitude is at or below 3350 is very rare especially during the day. The worst I've raced at is 7000 feet. I've heard that Bandemere, 5800 feet, has had days in the 8000 - 10,000 foot area.

At that high of an altitude, you lose a lot of hp. At least it's not as hard on parts.

TTA850

Bristol is an excellent track and I wouldnt worry about the 1475ft either. My local tracks(Englishtown,NJ and Atco,NJ)are just about sea level and my car performs very similar at Bristol.

Stephen that must suck to see DA's like that, now I feel bad complaining when out DA is 1500-2000ft. In the early part and late part of the season we see DA's of -700 to -1000ft(-1000 is the best I've seen measured). I cant imagine how much youd pick up if you ever ran at a track around here.

HTH,
Steve

IHI

iTrader: (1)

Amen to that. Some freinds went out to Colorado for the division 5 NHRA nationals and some lost a full second with their altitude over there. I definately like the spring and fall series with the -300 to 1400 DA then factor in the NHRA track here with it's max allowed downhill grade, a must hit for your fastest slip!

383backinblack

new england drag way is at 90' above sea level, which is a nice starting point

AlkyIROC

Based on all my calculations, at zero feet I should run 10.11 at 134 mph but that's only theoretical. The only way to know for sure is to get to a sea level track.

Mission BC always has their Hemi and SuperStock shootouts in the spring and fall. The track is 24 feet above sea level and many times the DA is way below sea level making for some fantastic records.

That's why comparing cars around the country is so difficult. Someone has a lot done to their car and only runs high 13 seconds in Denver. Someone else in Florida doesn't do as many mods and easily runs 12's. The Denver car is actually quicker but because of the altitude it's racing at, it runs slower.

I know of a 70 Hemi Cuda A/SA car that runs very low 10's in Mission. During the summer when it's running here locally it barely makes it into the 10's.

Don't get dissappointed at running at high altitude tracks. It's not easy to make a car run quickly when there isn't enough air to make the same amount of HP as a sea level track. Forced induction with a blower, turbo or NOS helps a lot.

Even my 454SS truck only runs 15.0 here when everyone else says it should be running low 14's. It probably would if I was at sea level. Of course it's run low 13's with the help of some NOS.

five7kid

iTrader: (14)

I've only rarely seen it below 7000' DA. We call anything below 8000' "good air today". Last season's logbook, May-August, DA was never below 8000'.

Using the formula: HP=(MPH/234)^3 x weight on the '57, I get 273 at Bandimere and 341 at sea level.

As I was waiting at the gate to sign in for that event, a Pro racer from Brainard ('82 Camaro, 400 SBC, PG, mini-tubbed, 6-point - dedicated race car) was right behind me. I struck up a conversation with him, he was wondering how he would run up here. I asked him what he ran at home - 11.4's he said. Pulled out the calculator, punched some numbers and said, "You'll run 12.3's here." Later in the staging lanes during time trials, I asked him how it had been going. Made some runs and some adjustments, he said, seemed to be running well now. What's it running? Hmmm, let me see, pulls out his last timeslip - 12.33.

On Sunday, it was real, real cold (quickest time at altitude to date that morning), he was running 12-teens. He ended up runner-up for the event (IIRC, his dial-in for the finals was 12.25).

In 2002, I was running 14.6's at Bandimere, best time had been 14.53 on a particularly "low" day. NHRA altitude correction factor for 5800' is .9276, translating to a 13.48 best @ sea level, 13.5's "normal". In September, I went to the Div V finals at Topeka (700' elevation), I jetted up 4, no other changes; my first run was a 13.80 (storm front was moving in, DA was 2300'). Got rained out all day Saturday, at 7:09 a.m. Sunday morning DA was 900', 1st run was a 13.44. Next run was at 2 p.m., DA up to 1400', I ran a 13.53.

The NHRA correction factors are pretty good - at least for this racer's '57 Chevy...

unknown_host

iTrader: (1)

Southern Oregon Dragway is at 1500 feet, I have always wondered what my car would run at a Sea Level track... If I get into the 12.1's or 12.0's on the motor this season I will tow the damn car to another track to get my 11 second motor pass (if it even is capable heh).

AlkyIROC

Mission isn't that bad of a pull from Medford. I know that entire west coast area swaps racers around for different events.

If I want to race at sea level I have a minimum of a 16 hour pull over all the mountains. I'm right on the east side of the rockies. I suppose the only good thing is that every regional and semi regional track I can visit are all at lower elevations so no matter where I go, the car will run quicker.

unknown_host

iTrader: (1)

That does suck have you ever taken yoru car just to see?

AlkyIROC

I went to Yakima Wa a couple of years ago. Different camshaft, tranny, compression ratio and was running on 92 pump gas. The car was running 11.6's here. I went 11.09 in Yakima and because of the lower elevation (1100 feet) I ran out of rpm before running out of track and bent a couple of valves when they started to float at the 1000 foot mark. The car was maxed out to run at high altitude. My best 60' time was in Yakima. Even with my new engine I haven't been able to get such a good 60' time locally. I think if I took the car to a lower elevation track now I'd get a low 1.4 60' time.

High altitude tuning needs a few things to consider.

Because you make less hp, you need more gear in the rear end to make more torque. At high altitude you don't need as much octane or you can run lower octane in a higher compression engine. You can also run more advance in the distributor. The fuel system needs to be leaned out since there isn't as much air to burn (smaller jets).

My car, although it sounds great, sounds even better when it's at a lower altitude track. The engine sounds crisper and throttle rersponse is higher. That's mainly because of the extra hp it's producing.

Right now the NHRA is in Pomona for the winter nationals. Check their web site to see how fast the cars like ProStock and Stock Eliminator are running. Wait until they go to Denver and compare the difference on what they run. All these professionals know how to tune for high altitude but they still can't produce the amount of power they get at lower elevations.

A good example is ProStock. Right now the number one qualifier ran 205 mph. In Denver I don't think any one of them has broken 200 yet. 5 mph in a prostock car is a lot of hp.

Pony Killer

i'm in the same boat as tta850 we race at the same tracks.

my best run in my car was at atco on a night where it was 50* and 87% humidity. .. starting off at 50ft or whatever it is.. i'm sure it's pretty close to 0 DA

ChrisFormula355

You know, maybe its just me, but I prefer telling people the time I actually have on the timeslip, even though I know my 3,200 elevation track is at a disadvantage. It just feels like a bogus copout. The only time I quote corrected times in fact is on this website because everyone else does.

unknown_host

iTrader: (1)

I dont.

rich3114

The DA here varies so much during the year, the only way to judge whether your mods are working is by figuring it out, even though I don't post corrected times. DA during the summer is around 4000, and in November, it was -299, so that's a big difference to try to compare without using DA. I go out to track test new mods, and the only way to accurately compare times is to correct for DA.

I don't post my track times at all, come to think of it.