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copbait73 copbait73 is offline
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Join Date: Nov 2003
Location: Chesterfield IN
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Desirable INTAKE/EXHAUST Port and Valve Sizes?

Ok, I'll admit it, these threads about Kremer and RUF cars and Porsche porn made me hit the books published in the 70-80s. From my research I'm questioning accepted wisdom regarding desireable intake and exhaust port and valve sizes on these 30 plus year old engines.
1) Yes, the street TURBO uses X and Y sizes but these were driven by emissions, fuel ecomony, part throttle response and CIS system AT a specific (low 260-300HP) horsepower level.
2) Factory racing TURBO engines have larger intake ports BUT more importantly they have huge exhaust ports. Before you say they would have no response on the street reread Bruce Anderson's book. Several 962s were adapted to the street in the late 80s. They were responsive and VERY powerful.
3) I stopped by a local P-car engine builder, 36 years at it. He has flow bench, fixed dyno and has been porting and flow benching for years. He says he's porting 930s and getting 75HP for the effort. He didn't elaborate (obvious, he wants to get paid for his work) but mentioned EXHAUST.
Ok, what do you guys know based on actual back to back testing. What has been done, this looks like uncharted territory.
This has an point, I have a Superflow 110 flow bench and I'd like to start doing some testing.

Last edited by copbait73; 02-17-2008 at 02:20 PM..
Old 02-16-2008, 01:34 PM
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