 Compression changes |
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| -JR- |
 Dec 16 2004, 07:42 PM
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Life goes faster at 150MPH  Group: Members Posts: 276 Joined: 12-May 04 From: Victoria BC Canada Member No.: 2,055  |
Having never worked on a air cooled engine before I'm wondering if it's possible to increase compression of these motors in the same way you do with a conventional watercooled engine.
IE - Head shaving or piston changes? I've got all the bits from a 2L transporter engine that I'm going to put on my 914 EC case motor. However this will mean I will only have 7.3 : 1 compression still. I'd "like" to see it around the 9.0 region but I'm not sure if I can accomplish this without pistons. Has anyone got some feedback? Can I pull this off? Thanks! |
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| Jake Raby |
Dec 17 2004, 09:09 AM
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
Don't think about increasing CR with the stock cam!! The dynamic CR the stock cam creates is already too much with the factory CR settings!
Thats why a cam change really wakes these engines up in performance, cooling capability and increases the powerband. To increase CR you can flycut the heads, or decrease deck height. The TIV head is severely weakened when the chamber floor is flycut excessively. In some instances the floor can actually burn away and you gain a compresssion leak around an exhaust stud. The design flaw in the heads creates a weak space right behind the chamber where the exhaust stud is drilled. The 2.0 head is the worst in this area. |
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Posts in this topic
-JR- Compression changes Dec 16 2004, 07:42 PM
nebreitling i'm thinking you're gonna want pistons.
a... Dec 16 2004, 07:50 PM Mueller if I figured it out correct, you'd have to mov... Dec 16 2004, 07:55 PM -JR- Thanks for the tips so far.
I imagine that I CAN ... Dec 16 2004, 08:11 PM Mueller the cylinder heads can be cut, but it's the sa... Dec 16 2004, 08:17 PM -JR- Thanks Mueller. I just thought you might have tho... Dec 17 2004, 03:10 AM Joe Ricard Just measure your deck, Then like me measure abou... Dec 17 2004, 06:47 AM redshift I just put a sponge in there to take up some space... Dec 17 2004, 07:00 AM -JR- Thanks Jake. I've heard the 2.0L heads were b... Dec 17 2004, 02:46 PM Dave_Darling Yeah, you really want to be careful about flycutti... Dec 17 2004, 06:02 PM -JR- Thanks Dave, I've read Tom Slider's web pa... Dec 17 2004, 07:14 PM
scruz914 ... Dec 17 2004, 07:47 PM |
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