Anyone have real world experience with altitude vs boost?

[Konaboss302]

Hey All,
I'm getting ready to move back near home (Montana) from the Baltimore, MD area due to PCS orders (Marine Corps). At sea level with just the 2.65 upper, my Stage IV Eaton is seeing about 15psi. Now I'm looking for someone WHO ACTUALLY RUNS THEIR COBRA AT ALTITUDE to give me a heads up on expected boost loss. I know by "the math" that I would probably lose 1-2 pounds... but the barometric pressure reported by weather stations at 4500 feet matches that at sea level, so I'm at a loss. If someone could give me a heads up on what I can expect to happen, that'll let me know if I need to step back to a 2.76/4lb combo or if I need to start sweet talking the wife about getting that 2.3 Whipple... Thanks guys!

 

[97SaleenCobra]

I live at a 4800 feet, with a corrected altitude of 7000 for most of the summer.. You don't necessarily lose boost. You lose air density therefore you lose power. Elevation sucks.

 

[Konaboss302]

Yeah, figures... I probably won't be hitting the track a whole lot though. I loved Montana when I was still there before I enlisted, should be fun to go back. Even with the elevation, I should still be solidly above the 450/450 mark at the wheels, plenty for a street car.

 

[SVT GI]

I'm in Great Falls, I went from sea level in California running 24lbs to 3500ft in Montana running 22lbs. Running a KB Mammoth.

 

[97SaleenCobra]

Yeah, figures... I probably won't be hitting the track a whole lot though. I loved Montana when I was still there before I enlisted, should be fun to go back. Even with the elevation, I should still be solidly above the 450/450 mark at the wheels, plenty for a street car.

you should easily be at those numbers, my 97 has a Vortech V1 with only 5 lbs and I'm 426 at the wheels.

 

[Konaboss302]

Did that end up making your car run rich? Or did the MAF compensate for the lower boost levels? I've been thinking about grabbing a 2.3 Whipple for a while now, I figure if I pulley it for 18-19, then I'll realistically get about 16 at that altitude and be good for 91 octane, then when I move back to sea level, it'll already be set up for the extra 2-3 pounds it'll see but with the 93 thats available everywhere else...

 

[oldmodman]

17psi at the beach.

11psi at Whitney Portal, 9714ft.

Altitude doesn't matter if you are still the fastest car around!

A Vette tried to pass me going up that hill and couldn't even gain on me, never mind going around.

Boost is good.

 

[gargstang]

I'm at 5300 and run about 2 pounds less on my Whipple and on my old Procharged 93.

 

[untitledreality]

Did that end up making your car run rich? Or did the MAF compensate for the lower boost levels?

You wont need to change your tune at all, it will compensate for the lower air density. I went from 600ft to 5400ft with no issues whatsoever.