Does Altitude affect boost pressure?
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From: Edmonton, Alberta
Does Altitude affect boost pressure? I ran (Drag raced) at a track at 600 feet above sea level (Toronto), then I went to a track at 2200 feet above sea level (Edmonton) and I didn't change a thing on the car. Yet I am showing 3-4 less pounds of boost at the higher elevation. I never changed anything on the car from one track to the other. I am using Big stuff 3 and noticed quite a difference in boost between the 2 elevations. If not altatude then what would affect boost pressure?
It's the altitude, your pulley that makes X amount of boost at the 600 ft track will make less boost as you go up higher in altitude, if you go race at other higher altitude tracks just run another pulley to bring the boost back up.
Just with the thinner air at higher altitude it takes more to pack the air, you would probably have to actually up the boost a little to compensate, but I'm not sure what that would do to your A/F if anything.
I say I loose about 1psi per 1000' of elevation. Naturally air temp, barometric pressure and humidity have to be figured in as well. My car really drops off at higher elevation, problem is if your blower is already near maxed out not much you can do about it. Hot temps chip away at it a little more, but since there is less air at higher elevation you can usually lean the car out some and add more timing since its down on power.
I have it pretty well figured out where I may loose .2 in ET going from 500 to 3000' where before I would lose 1/2 a second (without swapping blower pulleys). I use the BS3 wideband correction a lot and its amazing how far the injector duty cycle will drop down to maintain the same a/f on a hot day at a 3000' track..
I have it pretty well figured out where I may loose .2 in ET going from 500 to 3000' where before I would lose 1/2 a second (without swapping blower pulleys). I use the BS3 wideband correction a lot and its amazing how far the injector duty cycle will drop down to maintain the same a/f on a hot day at a 3000' track..
