View Single Post
copbait73 copbait73 is offline
Registered User
copbait73's Avatar
Join Date: Nov 2003
Location: Chesterfield IN
Posts: 1,316
Compression Ratio vs BOOST - Knock Control

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.

Last edited by copbait73; 03-08-2008 at 01:05 PM..
Old 03-08-2008, 11:38 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)