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View Full Version : Problem with knocking



lateshow
21-02-2011, 09:52 PM
I have been tuning and seen results in several vr4:s here in Finland. There seems to be one common rule. Auto's knock more than manuals. Basic rule is that under heavy load ignition has to be taken 2-5 steps back to prevent the harmful knockin. But in some cases (manual transmission) only 0-2 steps will do the trick (Boost is around 0.9-1.1 bar) How can this be? Fuel is just perfect, goes with 11.5:1 ratio under heavy load. But to think of it: 5 steps retarded ignition from stock-> a very lazy car. Here is a link to some of my logs. It seems we are getting the knock mostly commonly at 4000rpm. I haven't listened my own car with earphones yet but they seems to knock less than the knock sum says. If you get 1-2 knock you hear nothing... I'm using a better and bigger FMIC, RPW downpipe, self made 3" exhaust and a k&n panel. Other vr4:s have a similar setup.

Could one reason be bad ignition? I am using plugs with 6-heat value (or what the correct word is) and its jerking a bit now with heavy loads. One reason could be faulty engine mounts as the engine "hits wall" every time you lift the gas pedal, dont know. Heres a link to one of my logs.
http://users.tkk.fi/~lylirost/vr4/EvoScanDataLog_2011.02.19_16.51.34.csv