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      04-27-2010, 02:22 PM   #46
Bob MG
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Drives: like a muppet
Join Date: Oct 2009
Location: Dubai

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Checked boost pressure today.

My calculations were 100% correct

Sea level pressure 1019hpa
5300 ft pressure 839hpa (this can be worked out for any altitude)

The percentage of air pressure at 5300ft compared to sea level is *
derived by 839/1019 = 0,82

I lose 18% at my altitude.

This is the ratio you must apply to the boost a pulley generates at *
sea level.

95mm pulley
6 psi x 0,82 = 4,92 psi

On my runs with the boost gauge connected, the maximum recorded boost *
was 0,33 bar = 4,78 psi
This proves my theory beautifully.

92mm pulley
7 psi x 0,82 = 5,7 psi
7,5psi x 0,82 = 6,1 psi

Based on what we saw with the 95mm pulley boosting at the bottom of *
the 6-6,5 range, I believe the 92mm will boost at 7

808E90 (Ricky) dynoed at 440HP with 4,5psi and he had full ericsson *
exhaust.
Mine dynoed at 443 HP with 4,78 psi, and i have a full akrapovic. *
Makes sense.

Therefore on a SC, power is directly proportional to amount of boost, *
regardless of altitude, making the effective delta gains compared to **
stock car, much higher at altitude

Last edited by Bob MG; 05-02-2010 at 07:59 AM.