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Old 04-01-2014, 09:40 AM   #41
Mark_T
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Join Date: Nov 2009
Location: Winnipeg MB
Posts: 2,485
Quote:
Originally Posted by Jake Raby View Post
Absolutely not. Manifold vacuum is heavily dependent upon atmospheric conditions and thats what gives the diaphragms inside the AOS their biggest workout.

Before the AOS failure was well known we'd always receive cars with this failure that were thought to have "blown engines" from areas near sea level with California and Florida always having the most, along with the entire east coast. We receive calls and keep logs from all over the USA, its not like we only see local cars, and in fact its quite opposite as we have Porsches here from 30 states now and only one of them is from our own state.

I've never had an AOS failure called in from Denver or any other area of higher elevation. When I travel across the US to instruct my Porsche engine schools I quiz the attendees on several things and one of those is "Who here has seen an AOS failure?". The trend data I have gathered has been priceless.

BTW- Suby engines also have AOS issues, especially those with high boost as the changeovers from + to - manifold pressures are hell on them.
Well, the things you learn as you go through life, eh? Hopefully 750 ft above sea level is enough to not experience this. Thanks for the explanation, Jake!
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