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aerohead · 03-31-2011, 04:16 PM

On the Bug,since it's air-cooled,you're most likely going to have to respect engine cooling first.When I did my VW bus,I purposely left the bottom of the boat-tail 'empty'.I had no facility to evaluate cooling performance and since the #3 exhaust valve, stretched-failure-mode is very real,I was reluctant to take any chances on that.
Aside from that,the diffuser angle should be as shallow as the studies encourage,and THEN,as reality intrudes on our wishes,make compromises to keep the thing alive,i.e. make it steeper in order to preserve it!
GM licked this problem with it's EPCOT car which had a variable-pitch diffuser.

03-31-2011, 04:16 PM	#61 (permalink)
aerohead Master EcoModder Join Date: Jan 2008 Location: Sanger,Texas,U.S.A. Posts: 15,909 Thanks: 23,994 Thanked 7,227 Times in 4,654 Posts	diffuser On the Bug,since it's air-cooled,you're most likely going to have to respect engine cooling first.When I did my VW bus,I purposely left the bottom of the boat-tail 'empty'.I had no facility to evaluate cooling performance and since the #3 exhaust valve, stretched-failure-mode is very real,I was reluctant to take any chances on that. Aside from that,the diffuser angle should be as shallow as the studies encourage,and THEN,as reality intrudes on our wishes,make compromises to keep the thing alive,i.e. make it steeper in order to preserve it! GM licked this problem with it's EPCOT car which had a variable-pitch diffuser.