Means almost nothing in regards to the original question. Factors of 324 that add up to negative 36. Looks like I have alot to research. Many owners who operate vehicles designed to operate on 87 octane fuel experience ping and knock. RPM heads, RPM intake, FiTech EFI, Comp XE266HR roller cam, EDIS/Megajolt ignition, long headers), T5Z w/Steeda TriAx shifter, 9" Trac Loc w/3.89:1, 31 spline axles. I have the dual plane stealth intake. A cam has a big effect on compression. What are the differences between a male and a hermaphrodite C. elegans? It's my understanding that they should all be within 10 psi of each other so in that regards I'm good. No doubt, I am very familiar with that combo though. 70 Maverick Grabber, 5.0 (Perf. 7.0 to 1 = 140 psi 8.0 to 1 = 160 psi 9.0 to 1 = 180 psi 10.0 to 1 = 200 psi etc. In general, 215 psi is 10.0 to 10.5 with a stock cam. A forum community dedicated to Nissan and Datsun Z car owners and enthusiasts. WebTo find the compression ratio (CR) you divide the total swept volume with the total compressed volume. But I did request all this when it was being built. NOT the .050" timing data. This compression ratio calculator can be used to work out the compression ratio of your engine. If I know my cranking pressure and I know all the internals. A 1:1 ratio is equal to 0 PSI. a KLUTZ in a Auto Shop is like a bull in a China Shop. A 200cc can trap 220cc for example. http://www.gregsengine.com/cylinder-compression-testing.html I bet your compression comes up when done this way. WebCompression Calculator. Changing the rod length will affect the piston location in the bore relative to cam timing everywhere except at TDC and BDC thus changing the dynamics of the engine. I think he was in reference to 12:1 static compression. The builder must have used custom pistons only way to really find out is call the builder of the motor.. Yea he used Venolia pistons. Healthy engines should have compression over 100 psi per cylinder, with no more than 10 percent variation between the highest and lowest readings. google_color_bg = "FFFFFF"; I have read that for 91 oct I should keep it under 170. The results would only explain either psi or compretion ration. To calculate the pounds per square inch (psi) from the compression ratio, one needs the compression ratio and the atmospheric pressure measurement. vs.. a fixed compression engine like a diesel that operates with the throttle wide open all the time, speed controlled by how much fuel you add. If your compression ratio is 12:1 theoretically that means the compression is 12 times atmospheric pressure. You should start to worry if one of your cylinders is getting close to 100 psi. I'm trying to use the best piston, head to get the best quench possible to help. you have what you need for static pressure vs compression ratio. Furthermore, that reading should be above 135 PSI. If you don't have a leak tester, you can squirt a little, Powered by vBulletin Version 3.8.8 Beta 1.