Ok im kinda new to the tuning deal so i have a few Questions.... First what is knock/retard? Just recently i bought an aeroforce scangauge and with running about 11.9 afr's and spiking 20psi dropping to 15 the gauge is saying about 6.0 for knock.... and the same for fuel knock. I dont hear anything wierd when in full boost and the car doesnt feel weird so if anyone could explain this to me fast so that I dont mess anything up I would appreciate it.
what are you using to tune with? If its something adjustable I would see exactly were your knocking (like between say 5000-5500rpms), if your A/F ratio is still good there and no lean spots I would pull a degree of timing in that range until the knock is gone.
If you cant make adjustments like that, I would turn the boost down 1psi until it goes away or add some octane.
ok so the afr's are steady all the way through so if I drop boost a little it should go away? Im not sure how to pull timing soo thats the next best thing i guess
Ok im kinda new to the tuning deal so i have a few Questions.... First what is knock/retard? Just recently i bought an aeroforce scangauge and with running about 11.9 afr's and spiking 20psi dropping to 15 the gauge is saying about 6.0 for knock.... and the same for fuel knock. I dont hear anything wierd when in full boost and the car doesnt feel weird so if anyone could explain this to me fast so that I dont mess anything up I would appreciate it.
Do some reading and searching on Google to learn just exactly what knock is. There is a lot of information out there. You need to understand what knock and timing exactly is and how it works before you start trying to tune. 6 degrees of knock is a lot and is bad. Knock is when the air fuel mixture is ignited by the spark plug but the wave formed by the ignition causes the remaining fuel to spontaneously ignite. The fuel does not burn evenly and you get unwanted spontaneous ignitions separate from the spark plug firing. You probably don't hear or feel anything weird because the pcm is able to adjust enough to eliminate the knock. If your engine timing is advanced too much for the fuel you are using you get knock and the pcm retards the timing to try and eliminate it.
ok so the afr's are steady all the way through so if I drop boost a little it should go away? Im not sure how to pull timing soo thats the next best thing i guess
I assume you dont have a way to pull timing or you would no about it. What do you use to tune with? Turning the boost down would probably be the best bet for you. What octane fuel are you runing? A higher octane would help as well.
Ok im wondering if this is my whole problem.... about a little less than a year back i bought a map clamp and installed it since then I have been tuning with that and my WGA should I pull that off and just wait till i get some type of actual fuel mangement sytem?
Naa, you can use it but you need to turn the boost down a little. The car thinks your running less boost than you really are so its leaning the mixture and advancing the timing. Thats ok, but only to a certain point. After that point is when you start to run lean or get knock from advanced timing. For now just put some good gas in and turn the boost down 1psi at a time until the knock goes away.
Mobil 91 octane.... the highest i have been able to find.... i was using an octane booster every once in a while but i didnt have the scangauge at the time so dont know what kind of difference it made then.
i suggest you search GOOGLE! and do a little reading on what knock is. Its a very important part of knowing the engine combustion process. Once you have that down you can think about what your doing to your engine and become a better tuner. instead of posting on here and getting a 100 different answers.
blackbirdrt posted a pretty good post on knock here in the technical forum i think
Do some reading and searching on Google to learn just exactly what knock is. There is a lot of information out there. You need to understand what knock and timing exactly is and how it works before you start trying to tune. 6 degrees of knock is a lot and is bad. Knock is when the air fuel mixture is ignited by the spark plug but the wave formed by the ignition causes the remaining fuel to spontaneously ignite. The fuel does not burn evenly and you get unwanted spontaneous ignitions separate from the spark plug firing. You probably don't hear or feel anything weird because the pcm is able to adjust enough to eliminate the knock. If your engine timing is advanced too much for the fuel you are using you get knock and the pcm retards the timing to try and eliminate it.
well i was more posting on here to find an idea as to how to fix it. I know about combustion and i believe I about got the idea of what knock is... i just have to figure out how to fix it. Im a mechanic in the air force but all i work on is rotary and diesel engines so im still working on learning about the technical stuff. On the stuff i work on just works off compression so i dont have to worry about ignition timing.
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Knock/Retard???
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