Re: Elevation=lessBHP?

[The Murphy-Fahlgren Family <efhome@master.adams.com>]

Jason Gray wrote:
> loose power. A system that boost to an absolute pressure level would loose
> no power because the turbo is capable of filling the cylinders with as much
> air as is needed even though outside pressure is reduced. This is why 

Well, not quite, as you are increasing the pressure ratio at higher
altitudes, which can significantly reduce the efficiency of the turbo.
This is especially true for turbos that are running near their PR
peak at sea level, which don't make anywhere near as much power at
altitude, and in fact, will probably overspin and go blooey.

Audi motors (and their ECUs) have a bunch of safeguards to keep this
from happening, even though they are altitude compensating.  If you
have an aftermarket boost controller (like HKS or GReddy or SDS or...)
you are in dire peril at altitude, unless you back the boost down
(I assume that the reason you have one of these is to crank the
boost up, and are running 20+ psi or whatever at sea level).

Eric Fahlgren
-- 
The Murphy-Fahlgren Family            Try to take over the world.
efhome@adams.com                                  Canton, MI, USA