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Registered
Join Date: Jul 2003
Posts: 846
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Help me understand C/R
For our 911's nobody recommends higher than 10:1 C/R for pump gas, but the new Porsches have much higher C/R:
Cayman S - 11.1:1 997 Carrera S - 11.8:1 !!! Please enlighten me. TIA. |
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Registered
Join Date: Jul 2001
Location: Portland Oregon
Posts: 7,007
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Hi:
These engines have: 1) VERY sophisticated Engine Management systems with active knock-sensing. 2) These engines use 4-valve, pent roof chambers with a centrally located spark plug that are FAR more detonation-resistant than the air-cooled engines. 3) These engines are all water-cooled which brings FAR greater control off those all-important cylinder head temps. All these things permit these engines to operate safely on pump premium while using over 10:1 CR. In short, apples-to-oranges (compared to any air-cooled engine),.... ![]()
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Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
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Registered
Join Date: Jul 2003
Posts: 846
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Thanks for this.
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