Best way to increase compression?
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From: SoCal
Best way to increase compression?
I will be having a cylinder head worked on with new stainless steel valves, etc. The domed valves will decrease the compression.
I understand the jdm gasket will increase compression. Is this a reliable amount? Should I just have the head milled down slightly and put regular gasket in?
I understand the jdm gasket will increase compression. Is this a reliable amount? Should I just have the head milled down slightly and put regular gasket in?
Joined: Oct 2000
Posts: 9,033
Likes: 21
From: South of the pier, Huntington Beach, CA
I was absolutely astounded by how much variation the factory head had between combustion chamber volumes. Some as low as 53.3cc and some as high as 53.8cc. This is considered good and the best in the industry. ( http://www.vtec.net/articles/view-article?...0&page_number=2 ) If you ended up at 53cc your compression ratio would be in the neighborhood of 11.3 or 11.4 or so. How high do you want to go? 11:1, 11.5:1? As you know, the higher you go, the more octane you need or timing retard . You might have to start storing gas at home and that may not go over well with the wife. 
I don't think milling should be a problem but check with Joe Alaniz, he is very knowledgeable and as I mentioned before, UL thought there would be no problem with milling a bit.
I have experience with running 13.5 to 1 back when 106 octane was available at the pump (I won't tell you how many years back that was) and it sure makes the engine perform if you can get the mixture and timing correct.
The valves to my knowledge do not have to be concave but it does lighten them. Material can be added to the combustion chamber but I am not aware of anyone that has done research in that area with the F20C head. You can't just add material anywhere and it would take mucho research to get it right.
If you want to go all out I guess you could change pistons but that is a very major step.
Anyway, keep us posted...I'm very interested in your efforts. Good luck be with you.
I don't think milling should be a problem but check with Joe Alaniz, he is very knowledgeable and as I mentioned before, UL thought there would be no problem with milling a bit.
I have experience with running 13.5 to 1 back when 106 octane was available at the pump (I won't tell you how many years back that was) and it sure makes the engine perform if you can get the mixture and timing correct.
The valves to my knowledge do not have to be concave but it does lighten them. Material can be added to the combustion chamber but I am not aware of anyone that has done research in that area with the F20C head. You can't just add material anywhere and it would take mucho research to get it right.
If you want to go all out I guess you could change pistons but that is a very major step.
Anyway, keep us posted...I'm very interested in your efforts. Good luck be with you.
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