Valve size to compression loss
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Teching In
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Valve size to compression loss Ok so I'm going to be using the Btr stage 3 can 231/242 .617"/.592" for my 02 ws6 auto with a 3K stall. I am going to send out a set of 243's to tea for a P/P. I'm having difficulty deciding whether to go with there stage 1 or 2 P/P though. So the question is if I went stage 2 they open the valves up so there will be a loss in compression. Now I have stock Pistons still and don't want to mill the heads to much due to piston valve clearance, so will the compression loss be dramatic enough to loose lots of power? Or can I run a thinner gasket and make up for difference? I will be eventually building the motor so didnt wana do the heads twice that's why I ask. Thanks for any input
Most head porters cnc the chambers, thus increasing the cc's of the heads. To get back to the original cc of the head, you will need to mill them. How much? Depends on your current PTV clearance. For instance, TEA opens the chambers to 67cc on the st 2 heads. To get back to stock (64cc), you would need to mill roughly .015. By checking your current PTV clearance, only you can determine if you can mill or not.
1 you're not going to get a significant loss of compression which in turn would not result in a significant loss in power or anything that you would notice
2 you can always mill the heads
3 you can and should be running a thinner headgasket (both for increased compression and better quench)
4 the power gained from bigger valves would more than offset any slight compression loss if you don't do #2 or #3
2 you can always mill the heads
3 you can and should be running a thinner headgasket (both for increased compression and better quench)
4 the power gained from bigger valves would more than offset any slight compression loss if you don't do #2 or #3
Thread Starter
Teching In
Joined: Sep 2015
Posts: 24
Likes: 0
1 you're not going to get a significant loss of compression which in turn would not result in a significant loss in power or anything that you would notice
2 you can always mill the heads
3 you can and should be running a thinner headgasket (both for increased compression and better quench)
4 the power gained from bigger valves would more than offset any slight compression loss if you don't do #2 or #3
2 you can always mill the heads
3 you can and should be running a thinner headgasket (both for increased compression and better quench)
4 the power gained from bigger valves would more than offset any slight compression loss if you don't do #2 or #3