Oh No The Jägermobile Broke Today!

[Jake Raby]

but atmospheric pressure at sea level causing repeated AOS failures?? That seems a bit of a stretch.

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.

[DennisAN]

Originally Posted by Jake Raby

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.

Well that's good to know...for me personally. Boise is at about 2,700 ft elevation. It's the lowest point in the area, with the roads over the Rockies quickly getting to above 5,000 ft. Highest pass likely to see here is Galena Pass on Hwy. 75 at 8,900 ft.

[Mark_T]

Originally Posted by Jake Raby

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!

[Jager]

Thank you for the information Jake... I will keep a spare AOS available for the next time... There will be a next time.

I installed the new AOS today and got the Jägermobile back on the road... Sure was smoky for a few minutes. I will probably change the spark plugs this weekend.

I cut the AOS diaphragm casing to take a look inside and here is what I found:









The material of the diaphragm was flexible but tore very easily. There were at least three holes that were visible.

[Paul]

Looks like a $20 part, wonder why they cost so much?

Glad you are back on the road.