mexicanzcar Posted July 12, 2009 Share Posted July 12, 2009 think you may have problems with knock using RC 11.5:1 in L28E? according whit the L28 engine calculator .. with flat pistons, head MN47 and felpro gasket. Quote Link to comment Share on other sites More sharing options...
Savage42 Posted July 12, 2009 Share Posted July 12, 2009 Not if you are running 100 octane fuel & your timing curve & fuel mixtures are correct. Quote Link to comment Share on other sites More sharing options...
sweetleaf Posted July 12, 2009 Share Posted July 12, 2009 Yes, without some high octane. Quote Link to comment Share on other sites More sharing options...
mexicanzcar Posted July 12, 2009 Author Share Posted July 12, 2009 yeah i know..but i want the car for daily drive in mexico we using 93 oct. with a timing conservative think you can bring daily driving ? Quote Link to comment Share on other sites More sharing options...
Savage42 Posted July 12, 2009 Share Posted July 12, 2009 You might get away with that if you have a larger cam, make sure it's not running lean and run close to stock ignition timing. Hot air temps can also cause detonation. Typically, 10.5:1 is all I've seen safely run on our 91 octane here, so 11:1 would be pushing it on 93. I guess 93 with a little octane booster make it safe. The piston rings are the things that will take a beating. Always the issue of head gasket longevity with that kind of compression, as well. Good luck. Quote Link to comment Share on other sites More sharing options...
mexicanzcar Posted July 12, 2009 Author Share Posted July 12, 2009 thanks for coments... so i better put the oem head gasket .. this is because of 11.0:1 one question ..a engine turbo and N/A(high compression) using the same AFR? about 11.5-12.5 Quote Link to comment Share on other sites More sharing options...
David K Posted July 12, 2009 Share Posted July 12, 2009 Avoid using the L Engine Calculator. Its for entertainment purposes only. It doesnt mention all the parts, testing and tuning that go into a high compression engine. That little piece of software is fun, but a worthless tool while building an engine. Quote Link to comment Share on other sites More sharing options...
Savage42 Posted July 12, 2009 Share Posted July 12, 2009 As for the head gasket, I've never used anything but Felpro and have not ever had a failure, so I'm not saying OEM is any better. You can also run a copper head gasket shim and lower the compression down a little more. As for compression ratios, a turbo engine is best suited to be between 8:1 and 9.5:1, depending on boost levels and desired characteristics. The highest you typically want to go on any NA street motor would be 10-10.5:1 range. It's interesting, as a turbo motor running 15 psi is actually running 16:1 compression under that boost and can run on pump gas. You could never run that with a NA motor. Different rules for different setups. Hope that helps. Quote Link to comment Share on other sites More sharing options...
mexicanzcar Posted July 13, 2009 Author Share Posted July 13, 2009 okay, I have been resolved some questions but then it is more advisable to do. in the event of 11.0:1 which Air / fuel ratio should I use .. maybe it solves the knock with a little extra gasoline Quote Link to comment Share on other sites More sharing options...
MAG58 Posted July 14, 2009 Share Posted July 14, 2009 Savage, I think what he's asking is if the AFR for a high comp motor should stay about the same as for a turbo motor, and the answer is every motor is different, but way richer than the stock curves would definitely be best and help knock, especially in hot Mexican summers so 11.0 would probably be a pretty good place to start and tune to. Quote Link to comment Share on other sites More sharing options...
cockerstar Posted July 14, 2009 Share Posted July 14, 2009 Would e85 be a viable option for a high compression n/a? Quote Link to comment Share on other sites More sharing options...
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