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Re: High Altitude???

Powells@ezlink.com wrote:
> Friends, since I arrived in Fort Collins, CO (just north of denver) I
> have noticed that the boost in our 1990 200 rarely goes above an
> indicated 1.1 bar.  On occasion I can get the normal 1.3 to 1.4 bar,
> but not dependably.
> I found that gas up here is 91/87/85 (premium/plus/regular) octane,
> as opposed to the 93/98/87 which I found in Texas.  I also found
> that my wife had been filling up at a Sinclair station.  I wondered if
> the Sinclair gas's octane might be too low, causing the engine to
> knock and timing to be retarded, causing in turn a lack of boost...
> I tried filling up on premium at a Texaco station (posted as the
> same octane, 91) and the situation has not improved.
> Any thoughts on the possible cause?  I can certainly check timing,
> etc., but thought I would ask for group wisdon.
> PS:  YES, I have thoroughly checked the intercooler hose, and it
> has no cracks or failures in the area where the oil collects.  BTDT
> already a few months ago.
> TIA for any (constructive) thoughts).  Also FYI - my Audi page and
> Audi FAQ pages should re-appear within a week.
> ++++++++++++++++++++WSU-CSU+++++++++++++++++
> Al Powell
> Powells@EZlink.com
> 1958 Fiat 1200 Spyder "Transformabile"
> 1983 Datsun 280ZXT
> 1990 Audi 200
> ++++++++++++++++++++++++++++++++++++++++++++++
In my opinion you have decreased atmospheric pressure. Less intake
volume therefore less exhaust volume. Superchargers not exhaust driven
can compensate. ECU compensation can address timing and in some systems
spray duration but not air (molecules) volume.