Chamber porting for dropping compression
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Chamber porting for dropping compression
Jim V is going to be porting my combustion chambers to help reduce the compression on my Promaxx heads in preparation for boost. They start at 119cc, does anyone have any experience on how many cc’s can be removed on a head like this?
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Rob, When Valako chamber ported my heads he got me to 129cc on Darts combustion chambers. Did you tell Jim where you wanted to be at? He didn't just do a fluff and buff on my chambers. It was strategic to optimize flow and ward off detonation. I'll assume he'll do the same for you. I run 87 octane in my engines. I actually gained RPM after I removed 0.70 of compression.
Last edited by Rookie; 01-13-2019 at 04:49 PM.
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Jason, I spoke with Jim on Saturday regarding my project. I am sitting around 9.8 right now and would like to get down in the 8.5-8.75 range. I understand this will not be doable with the porting alone but am hoping he can remove as much as possible while helping flow. I will still have to run thicker head gaskets but I am trying to run the thinnest gasket possible after the porting to get me to my desired compression ratio. Jim was thinking he could get them into the upper 120’s while increasing flow. I would be very happy with 10cc’s but a little more would be even better!!
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Jason, I spoke with Jim on Saturday regarding my project. I am sitting around 9.8 right now and would like to get down in the 8.5-8.75 range. I understand this will not be doable with the porting alone but am hoping he can remove as much as possible while helping flow. I will still have to run thicker head gaskets but I am trying to run the thinnest gasket possible after the porting to get me to my desired compression ratio. Jim was thinking he could get them into the upper 120’s while increasing flow. I would be very happy with 10cc’s but a little more would be even better!!
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