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copbait73 copbait73 is offline
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Join Date: Nov 2003
Location: Chesterfield IN
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Originally Posted by kenikh View Post
Bottom line, keep the engine cool. Best mechanism? Water.

Does this mean a water jacket around the head? No. There are 911 racers in the SouthWest that use water misters behind the fan that blow misty air down around the heads, using the heat transfer capability to cool the engine in a open circuit (vs. closed circuit of a water cooled head), keeping temps way down. Also the use of alcohol and water in the intake tract keeps charge temps down, mitigating heat.

Even an air cooled motor can be water cooling assisted.
Check my recent 2.4L TURBO install and you'll see I agree but these are solutions and we are still digging for details to get an understanding.

Ok, here is some information that may be relevant. If so, we need to do some real digging to find the “limit” for our Porsches.

An old “How to HOTROD Volkswagen Engines” from 1970 book:

“We do not know of any published figures for the VW cylinder-head temperatures (sound familiar?) but some Corvair figures may be of interest. A Chevy dealer bulletin advised cylinder-head temperatures for the turbosupercharged Spyder models as: 200 to 300 degrees at idle, 350-475 at 30 to 60 MPH cruise, and 460 to 575 degrees from 3,000-5,000 RPM at full throttle.”

I’ve never owned a Corvair but according to this book they had a CHT overtemp limit switch that lit an idiot light at 575 degree. They were on Spyders(Turbo), 140HP motors and those with A/C. P/Ns 1993599 or 1993547.

Last edited by copbait73; 08-03-2009 at 05:23 PM..
Old 08-03-2009, 05:21 PM
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