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voitureltd voitureltd is offline
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Join Date: Feb 2008
Location: Bayside Wi
Posts: 2,549
Originally Posted by copbait73 View Post

I copied a version of the Porsche chart above on the ADVANTAGES OF TWIN PLUGGING thread. The more I studied it for my purposes the more I realized it needed it's own string. (Young guys, bare with me it's old school technical presentation)

I expanded the Porsche chart to higher boost pressure and higher fixed compression ratio. To this I added four starred data points for well know factory engines. There are two factory TURBO engines (middle/left) and two N. A. (lower right).

I added data points from three member's engines representing serious modded street TURBO motors and I added Porsche racing motors (upper/left). These points also show features, C.R., BOOST(or not), intercooled (IC), plugging - single(S/P) or twin (T/P)

Please take the time to understand the chart and the trends it shows. I think it goes a long way toward demystifying relationships and component options as they relate to staying within the confines of stable combustion on the air cooled 911 based motor, N.A or TURBO.

This chart does not predict HORSEPOWER.
Thanks great mapping idea. That indicates my Kremer car which boost to 1.4 bar must be built to the 6.5 of the early 934 935 as it does not detonate with 108 octane and has almost 10K miles on the original build. It has long been my suspicion that Porsche from the early baby 935 and onwards built low compression high boost motors as boost is adjustable for altitude, humidity longivity, etc and compression is fixed. My car was built in 84 and kremer had been king on tracks for many years by then. I do not know if the race cars were still 6.5 in 1984. Andial was competing closely with Kremer by then and my motor from them uses the 1974 factory and 84 Kremer low compression philosophy.

Last edited by voitureltd; 03-08-2008 at 03:28 PM..
Old 03-08-2008, 02:58 PM
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