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Architecture & Porsche's
Join Date: Jan 2006
Location: Austin, Texas
Posts: 3,189
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Header choice for 3.6: 1-5/8" or 1-3/4"??
Need recommendations, heard the 1-5/8 was a better choice for torque on a 3.6 but with my car under 1900lbs, not sure I need that.
Suggestions? I have cams, headwork: don't want to choke down my modified 3.6. Mark 
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Porsche Club Racing National Scrutineer '89 Andial 951 '82 928R '74 911 RSR 3.6 |
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06-03-2014, 06:25 AM
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Registered
Join Date: Jul 2001
Location: Portland Oregon
Posts: 7,007
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Hi Mark,
I'd need a LOT more details about your engine to offer a recommendation. 
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Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
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06-03-2014, 08:15 AM
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Architecture & Porsche's
Join Date: Jan 2006
Location: Austin, Texas
Posts: 3,189
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1993 Factory 3.6 EFI, 993 Supersprint cams, mild P&P on the heads, stock compression, muffler-less exhaust (going on my race car). Car will be tuned for 93 octane.
BTW what AF's do NA air-cooled cars like the most? A bit rich, say 13:1?
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Porsche Club Racing National Scrutineer '89 Andial 951 '82 928R '74 911 RSR 3.6 |
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06-03-2014, 12:45 PM
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Registered
Join Date: Jul 2001
Location: Portland Oregon
Posts: 7,007
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Hi Mark,
FWIW, you'll make more power with a proper dual-in/dual-out race muffler than none at all on your engine. BTDT and this is especially important unless you have good close-ratio gears. I'd be using 1 5/8" headers for an engine in that configuration. 13.2:1 yields max power, but you cannot run that lean for the engine to survive in hot weather. You should be shooting for 12.7-12.8:1 AFR.
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Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
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06-03-2014, 01:33 PM
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Architecture & Porsche's
Join Date: Jan 2006
Location: Austin, Texas
Posts: 3,189
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Ok I could go high 12's. Thanks for the tip.
Tell you the truth, I'd sacrifice some power for good sound: what configuration is good to getting a higher, smoother pitch out of the 3.6? Most sound like Flowmaster'd bastards  This 3.0 RSR sounded amazing at COTA: flat-collectors & center merge. 
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Porsche Club Racing National Scrutineer '89 Andial 951 '82 928R '74 911 RSR 3.6 |
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06-03-2014, 01:40 PM
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