octane rating qs

[Stealthee]

Track prep makes a HUGE difference. The first 60' makes or breaks a good run.

Right here NHRA only allows half altitude correction for supercharged and turbocharged cars.

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

As it is LV is still at 2100ft so if your car was suffering due to altitude it would still suffer in Vegas.

Its also been discussed many times on 3si how altitude does not effect FI cars by people like Monet. If FI cars suffered from altitude then airplanes would be fucked considering thats where SC and TC's came from originally.

EDIT: Found a formula (note this is for NA's)

hp loss = elevation x 0.03 x hp @ sea level
1000

So a 320 hp NA engine at sea level would make about 280 hp 4200 feet. A forced induction engine may lose 10 hp at that altitude.

[quackmandude]

yea, the higher the altitude, the thinnr the air, thats not a 3s fact, but a fact of the universe. the higher the alt, generally, the less power u produce, thats physics, and fact for an internal combustion 2 and 4 stroke engine, even rotorys. if matt ran at the sa trak, near sea level hell prolly imprve his time..physics is on his side anyways. but altitude is not everything, colder air is denser air, notice matts runs r at night, where in roswell can be really cold. but during the day at roswell its super hot, if he ran in the heat of the day it wouldnt be as quick of a ride. but the night air doesnt balance out the altitude difference, altitude, is a bigger factor
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[Stealthee]

Originally Posted by quackmandude

yea, the higher the altitude, the thinnr the air, thats not a 3s fact, but a fact of the universe. the higher the alt, generally, the less power u produce, thats physics, and fact for an internal combustion 2 and 4 stroke engine, even rotorys. if matt ran at the sa trak, near sea level hell prolly imprve his time..physics is on his side anyways. but altitude is not everything, colder air is denser air, notice matts runs r at night, where in roswell can be really cold. but during the day at roswell its super hot, if he ran in the heat of the day it wouldnt be as quick of a ride. but the night air doesnt balance out the altitude difference, altitude, is a bigger factor
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Matt himself has even said he'd be lucky to pick up 1 tenth by racing at sea level. Its a FACT that forced induction is not affected much at all by altitude.

[quackmandude]

wait, ok, so because the turbos compress the air right??? so the only thing that would be happening differently is the compressor wheels would spin faster since they have to compress thinner air, am i right?
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[Stealthee]

Exactly. The boost curve would be slightly altered but power difference would be minimal. A NA car suffers because it can only use the available oxygen.

[quackmandude]

so this means i should find a vr4 engine and tranny befori go, hahah well dam
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[Stealthee]

You will feel a difference. I dont know the altitude difference between Kingsville and where you are heading but it may only turn out to be a 10-15 hp difference.

[quackmandude]

0 to 9000 feet...the mountain road there is insane in the membrane. hey alil off thread topic tho, snce im not gonnahave the awd powertrain loss of a vr4, what should i expect a dyno run at?
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[Stealthee]

I assume you'll be on RT 82 since it climbs pretty high?

According to the formula if you made 210 hp (closer to actual hp, not 222 rated by Mitsubishi) you would be down to 153 hp at 9000 ft. Thats about 125 whp. Your car will be a slug.

[quackmandude]

lol dammm ok then im waiting till i find a tt engine. r there any reliable engine dealers, either through ebay or other website, that have relisble engines??? i no its risky, but im planning to haveit on stands and overhauly it all before i put ir in
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[vr4choke]

Originally Posted by quackmandude

wait, ok, so because the turbos compress the air right??? so the only thing that would be happening differently is the compressor wheels would spin faster since they have to compress thinner air, am i right?
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but would the stock turbos be able to effectively compensate for the thinner air? it seems like the guys who dont feel a difference all have big ass turbos

[Stealthee]

A turbo is a turbo and they act the same. The boost curve will slightly change but peak power will remain almost unchanged.

[vr4choke]

would you be able to run higher boost at a higher altittude?

[Stealthee]

Monet runs 32-35 lbs of boost.

[vr4choke]