How much does elevation affect 1/4 mile times?

[Pickle's Camaro]

I occassionally race my '96 Camaro at a track tucked in the mountains of Pennsylvannia (Numidia Raceway) and my times are horrible compared to the times I read on this board. Granted I don't have nearly as many mods as most of you have. But, still my times seem way off. I usually run between a 16.8 and a 17.1! WTF! My best is a 16.6 and that was with my friends wife riding with me screaming "Faster, Pickle, Faster Pickle, Faster, Faster!!!!!". That was pretty cool considering she is a pretty attractive blonde! Anyway, before that run I let the car cool as much as I could in the staging lanes with the hood popped. Also, it was at night and the air was cooler. I wouldn't consider myself a beginner (although I'm far, far from being a pro). I actually won a reaction time contest up against some real pros! I cut a .502 light! I know the basics at the tree. I have an automatic and I try to tach it up past two grand but sometimes the tires start to break loose and I back off because I don't want to red light. The only thing I can think of is the elevation of the track. You do have to drive up a pretty steep mountain to get there. As for the car it only has 53,000 on it and I've had it since day one and its constantly babied (oil changed every 3,000).Also, I have an SLP CAI sitting in a box in my garage. It's been too damn cold to install it! Anyway, sorry this is so long but just wondering what the problem could be.

[Pickle's Camaro]

Oh by the way, the only mods that I do have is a Dynomax muffler (Z28 Tips) and a K&N filter. Thanks.

[DEE97GTP]

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

This is a good estimate. You must also figure in humidity and temperature, and traction(60ft time) to be able to make a valid comparison with someone else.

DEE

[Redsix]

Alot!!! Why do you think people run the times they do at HRP (Houston) [img]tongue.gif[/img]

[Only4U]

<blockquote>quote:</font><hr>Originally posted by Redsix:
Alot!!! Why do you think people run the times they do at HRP (Houston) [img]tongue.gif[/img] <hr></blockquote>

hey man, a bunch of cv6.com guys are getting together at RCR@seguin this friday, you should come!

lemme know!

[Only4U]

jesus, 5500 elevation and 1200 elevation is a 1 second difference when your start time is 15 flat. ima go quick and find out the difference from hrp and rcr...

[Only4U]

ok, i just read that the elevation in houston at the HIGHEST point is 90 ft above sea level. so, let's round that number to 100 feet for simplistic's sake.

i also looked up and read that the elevation for austin (which is pretty near seguin [where rcr is]; looked for austin, cause nothing came up in search for seguin) is 750 feet. once again, for simplistic's sake, we'll round that number up to 800 (i've also heard, but am uncertain of, that seguin is higher in elevation than austin; so i could be right on, i could be off, but i wouldn't guess by any more than 100 ft).

now, if you look at that table, you'll see the difference between any 100 feet is the same, -.0013

therefore, since their chart begins with 1200 feet, we will have to add .0013 to that 1200 ft e.t, which is .9874, and we will have to do that not once (take us to 1100 ft), not twice (take us to 1000 feet), not 3 times (900 ft), but 4 times (800 ft), to get the right multiplication factor for houston, tx.

so...

.0013 x 4 = .0052

and, the multiplication factor for houston is a mere...

.9874 + .0052 = .9926

and likewise, for austin, we would have to take the .0052, and add (7 times .0013 and then add the .0052) to get the correct multiplication factor for houston.

that would go something like this...

(.0013 x 7) + .0052 = .0091 + .0052 = .0143

.9874 + .0143 = 1.0017

so...

15.00 s x 1.0017 (austin) = 15.0255 E.T.

you must take the extra .0255 s and subract that from 15.00 now to get your time at hrp, which would be....

15.00 s - .0255 s = 14.9745 E.T. HRP

15.00 s x .9926 (houston) = 14.889 E.T.

vice versa, add the (15.00 s - 14.889 s = .111) .111 s to the 15 flat to get the rcr time...

15.00 s + .111 s = 15.111 E.T. RCR

a .1365 second of a difference.

i did my math backwards, and that's why i used hrp's elevation to acquire rcr's e.t.; and vice versa. my math is just a bit funky, even though i'm pretty sure it's correct; but hey, it's late, and i did this all at once, and it's pretty easy to math more than one way, especially if you don't plan it out beforehand ;) and i also didn't set where the hell the exact 1.0000 multiplication factor elevation was, so we can just assume it's just somewhere in between 100 and 800 elevation feet, but obviously, very close to 200 ft. since at 100 ft the factor is 1.0017, then adding .0013 would bring the elevation to 200 ft and the multiplication e.t. to 1.0004; however, this information is completely irrelevant, unless you are just curious ;) .

i think i did this correctly, not 100% positive though, feel free to correct me if you wish [img]smile.gif[/img] btw, this is also assuming conditions/weather/ect is the exact same. this is solely basing results on elevation only.

so basically a summary of what i did:

i ran a time (15.00 s) (also, all under same conditions, keep in mind) at this majical 1.0000 multiplication factor place around 200 ft elevation. then i converted what that time would be in seguin, tx at rcr (15.111 s), and also what the time would be in houston, tx at hrp (14.9745). now i need to stop cause all this is confusing me [img]graemlins/rofl.gif[/img]

[ January 15, 2003: Message edited by: Only4U ]</p>

[Only4U]

<blockquote>quote:</font><hr>Originally posted by Young Tae Byun:
My 1998 Camaro Z28 ran 13.7s all day long at an elevation of 250 feet above sea level.
Living here in Colorado ... I've seen '98 Z28s run 14.7s to 14.9s and even 15.1s!
Altitude will affect naturally aspirated cars. We lose about 60 to 70 HP here in Colorado.
Stock F-Body's will dyno around 250 to 260 HP uncorrected.<hr></blockquote>

omfg dude, your sig is longer than my damned math equation!