Tuning for High Altitude Performance

[Tony Hoffman]

Yes, they adjust the current to the DPR via the altitude compensation
sensor mounted by the ECU. It's on the side of the glove-box on a
4000Q, not sure on the 5000. The horsepower loss is just due to less
overall oxygen available to the engine, asside from forcing more in
there, you are out of luck :(

I spent 6 years at 5000ft in MT, so I feel your pain.

Tony


>> Yes, it would.  I recall reading (years ago) about modifying (bending) the
>> arm for this purpose... but I'd have to find that book on the shelf
>> (assuming that I'm recollecting correctly).
>>
>> But either way, the flap's "lift" would change with density.  "Force
>> density" if I recall the correct term from basic fluid dynamics.
>
> Of course the lift would change, as it should.  The question is: does
> it change appropriately?
>
> http://www.google.com/search?q=bosch+CIS+altitude
>
> ...seems to indicate that maybe not, and some variants of CIS had
> additional measures for altitude compensation?