airborne84000

correct me if I'm wrong, but I believe that a stock pulley set up on a jackson supercharger on a civic will push 6-7 psi. but unless I am mistaken, my autometer guage is reading 8. My buddy said that since I live in Utah w/ 5,000 elevation, that will have an effect on boost readings.... any help would be cool
thanxxxxx

V-SPEC 1

I know for sure that if you live in a high elevation, you would loss some psi/HP with the same setup on the sea level.

TEAMGENDAI

intresting???

airborne84000

seriously guys it is reading right on at 8psi. it sure as hell doesnt feel like 8, so maybe my guage is a pos

lazerus

Elevation will highly affect PSI. For every 1000 ft. subtract .5 PSI for your air pressure.

so to get the same power (or close) you would have to run .5 PSI more boost for every 1000 FT.

(it won't be the same power, but it will definately feel better!)

Brad

b18cya

you may have the 10 psi pulley installed?

FFormula1

Check the barometer in your area to get an accurate measurement of your air pressure.

Bottoz

Yes, altitude will definatly affect your boost pressure. Im at 6000ft/Colorado. Your mechanical boost guage will read what your pully/boost controller/wastegate is set at. Example, you have a 9psi spring on your wastegate (or a 9psi SC Pully). Your Boost guage will read 9psi, because you are building 9psi of pressure above the static air pressure. BUT, the static air pressure of your altitude is lower than sea level air pressure. At 6000ft, Im about 2.5 - 3 psi below sea level air pressure. 12 instead of the sea level 14.7. So, even though the mechanical boost guage reads 9psi, its actually about 6psi of sea level air. This is all verified by reading MAP voltages. With the key on, but engine not cranked, the MAP reads -2.7 psi. When I reach full boost as indicated by the mechanical boost guage (9psi on the guage) my MAP sensor reads about 6psi. This is also why vaccum reading are lower at high altitude. There is less air. Vaccum @ idle is around 14-16, as compared to about 20 at sea level.

Sooo, your Utah 5000ft elevation could subtract about 2psi of pressure. If your SC Pulley is an 8psi pulley, then its actually moving about 6psi of sea level air.

Bottoz

airborne84000

ahhh ok then, well thanks alot fellas!!!!
greatly appreciated!!

Bottoz

Sure thing. So....when you ask someone how much boost they're running you'll have to find out 2 things:

1. Elevation.
2. Mechanical or Electronic Boost guage.

Bottoz

ringgold

This is some cool info! People always ask me how much boost that Im running on my car. it levels out at about 10psi or so but Im at 5500' elevation or more at all times because I live in Albuquerque, NM now. So when people ask now I should say that Im running 10psi but the altitude affects it and its more like about 7-8psi? I wander how much this effects my 1/4 times? How can I figure this out does anyone know

ringgold

someone else with alot of racing experience from both high and low elevations chime in on this and tell us maybe something else that hasnt already been said.