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Chad911sc |
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Member ![]() ![]() Group: Members Posts: 80 Joined: 24-September 24 From: Florida Member No.: 28,374 Region Association: South East States ![]() |
I have my short block built and I’m ready to set my deck height. It’s 96mm bore with stock 71mm factory crank. This is a 2.0 2056 build. I have a Web 86a cam calling for approx 9:1 compression. I have 60cc heads with 3cc valve reliefs on my flat top pistons. If I plug all this into the calculator, I get 8.3:1 for my compression ratio if I set the deck height to .040 inch
After I set up the piston on the rod and bolt down the cylinder to the block, I get .053 inch from the piston to the top of the cylinder. My question is, what is the best way to proceed to get the 9:1 ratio with at least .040 inch total deck height. I am thinking that if I take off 6 total cc’s from the head, that will leave me with 54cc heads with the 3cc valve pocket = total 57cc’s. Bringing me now to the correct 9:1 compression ratio with the .040 inch deck height. If I am in the right ballpark, this means I need to have my heads fly cut….correct?? If this is correct, how do I go about calculating how many thousands of an inch do I need to have removed by the machine shop to remove 6cc from the head? I obviously will need to remove at least .013 inch total deck height get to my .040 goal, and that’s with no shims or head gaskets being used. Thanks for your time, Chad |
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technicalninja |
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Advanced Member ![]() ![]() ![]() ![]() Group: Members Posts: 2,531 Joined: 31-January 23 From: Granbury Texas Member No.: 27,135 Region Association: Southwest Region ![]() ![]() |
Chad, I wouldn't spec a "draw through" turbo system on ANYTHING today.
Lots of pitfalls... I wouldn't spec a "Blow Through" on carbs either. One of my Mentors is Corky Bell. I worked for him in the early 80s and he WAS doing blow throughs then. He's dropped "draw throughs" years ago at that point. Mikunis were Corky's go to carbs for forced induction, and they SPEW fuel everywhere past 14psi. He did an intercooled blow through Mukuni on the first gen RX7 that took 100hp to 285! Rotary is more like a 2 stroke than a 4 and they really like boost! The Rotary engine is not robust enough IMO for long life under boost. A mild system is below 15psi now. This was the upper limit back in 83 with all sorts of fuel systems mods, some of which didn't work very well. A serious system goes 20+, some hit 30 today! Digital FI. Injectors pointed at intake valves. Good intercooling, Flex fuel (E/85). Modern turbo (the aerodynamics of the internals has changed BIGTIME over that Rayjay). COP ignition. Piston squirters. The above is the "standard" recipe today. The stand-alone digital FI MADE modern turbocharging possible! |
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Lo-Fi Version | Time is now: 9th May 2025 - 06:17 PM |
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