wantavett

I recently drove my vette to Colorado. (my wife and I are from NH) At see level, my 94 6spd has enough get up and go that it throws me against my seat. When we were in Colorado (Ft. Collins), she felt like a regular car. Had no where near the pick up. I thought maybe it was the long trip, but on our way home, I let her rip and she was like a completely different car. This was definately not in my head. Has anyone else had this happen? Does altitude actually affect performance? It affects everything else, tire pressure, octane of gas (91 out west, compared to 93 & 94 out here) Any input is much appreciated. I am just curious! Thank you!!

wake

It sure does affect performance...

When I drove through Colorado I thought there was something wrong with my car... I went up a very steep grade and it felt like I had a 4 cylinder car in my 88 TPI IROC-Z... I was about ready to pull over and check my car for problems but I came upon and passed an Eclipse/Talon 4cyl Turbo whose motor was just screaming like crazy to maintain speed up the hill... I then also saw an elevation sign that I think at the time claimed ~8000 Ft and realized that it was normal...

I started my trip from an elevation here in CA of just a couple hundred ft, so it took some getting used to... But remember, cool dense air makes power, not thin air... Remember how easily you got winded in the higher elevation??? The thinner air has less O2 content... Bad for you, bad for your car...

Also, remember the older carburator cars??? You had to tune them differently for different elevations... Computerized fuel injection helped make our lives a lot simpler...

drive it

We live at 7000ft in a ski town-so I can relate! You should figure on losing about 3% of your power per each 1000ft gain above 2000ft. Of course on a hot day it's even more. That's why I don't feel too bad about my 0-60mph of 5.0sec. up here! [img]http]//www.corvetteforum.cc/ubb/smile.gif[/img]

wantavett

Thanks guys, you affirmed my belief. It amazes me at how much you lose when the altitude changes. And I guess I should not be surprised because i lost power myself. Thanks a bunch!!

John Row

Another performance hit is cooling. On a recent run up to Mt. Polamar (7600') the outside temp was about 90F, the engine hit 255F when the "check instruments" light came on near the summit. I backed off and shifted to Drive. It was a bit scary, but the temp dropped below 230F in a few minutes.

No air, no cooling!

65Z01

That's why so many records have been set a Raceway Park, we're at sealevel! When the baro dips to -500 feet on a cool day your Vette has wings.

IBEAM700

That turbocharged Eclipse should have been keeping up with your Vette at that altitude.
Why do you think turbocharged airplanes fly so much higher than normally aspirated?

wake

I'm not sure that's true... The turbo will add the PSI, but the air still has the lower O2 content at that elevation...

Jim

BobMachus

Yeah the thin air here plays havoc with power and cooling. At 5000 feet we have about 10-15% less power than at sea level, that is a very noticeable drop. I bought my Vette in MI and drove it out here and boy could I tell a difference. I am working on getting that power back though.

Bob

Timmy!

Try living here and dealing with it everyday! The local dragstrip here is at 5800' and has a altitude correction factor of .9276. Basically you lose a whole second off of your 1/4 mile time.

Tim

IBEAM700

Hey Jim

Yes, the air has less O2, but your force-feeding more air, which in turn equals more O2.
Our vettes cant suck more than a turbo can push, that is exactly what makes the turbocharged vehicles so efficient at higher altitudes

olephart

I had trouble with Red96Coupes 12.0 times compared to my 14.2, both with "stock" lt1.

John's runs were at 36 degrees 27% humidity and 30.47 barometer. Mine were at 90* 70% and 30.01.

I used one of those correction computers and it made over a .4 difference. Another .6 to.7 correction for gears/converter/tires.

Then, if I could match his 60' (he's around 2.0 I'm 2.125) the difference would totally disappear.

I thought he had a "freak" motor or something, but it seems that he has a really nice setup, good driving and the perfect day to race.