Power FC knock increases with speed (mph)
#1
knock increases with speed (mph)
at idle my knock readings are 0-1 then as i drive the knock readings increase with the speed of the car. The faster i go the higher the knock readings. Up over 100 knock at 70+. around 30 mph the knock readings are alot lower. The revs don't seem to make much difference. I retarded my timing alot to see if that would change anything but it's the same so i put it back. I can't test under boost yet cause the engine is still being broken in.
I've determined its most likely noise. But what could cause the knock to be determined by speed? If it's drive train noise it seems it would be high regardless of speed. My cruise AFR's are fine, and i have a transmission brace which i heard can increase knock readings.
I've determined its most likely noise. But what could cause the knock to be determined by speed? If it's drive train noise it seems it would be high regardless of speed. My cruise AFR's are fine, and i have a transmission brace which i heard can increase knock readings.
#2
94 Single Turbo FD
Join Date: May 2006
Location: Calgary, Alberta, Canada
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well it must be drive train noise due to the fact that your not even able to boost the engine. try taking your tranny brace off and go for a drive to see if that fixes the knocking. let us know your result if u do this cause i want a tranny brace aswell but having false knock readings is a pain in the ***.
what tranny brace are u running? i am having trouble finding one.
what tranny brace are u running? i am having trouble finding one.
#3
I made my own brace. I just cut 3 rectangle pieces out of steel. Drilled holes then ran half inch steel to each rectangle tack welded it bolted to the car then took it loose to finish welding it. Painted and bolted back up.
I won't be able to remove the tranny brace for a little while, the pit i use to work on the underside of my car is flooded right now. If that removes the false knock readings i might try some rubber washers.
if the knock is speed dependant more so then rev dependant, would that seem like a noise coming from the driveshaft or rear end? could it travel that far to the engine and be picked up as knock? cause if it was something in the transmission or something loose it seems like that would be more based on revs. Thoughts?
I won't be able to remove the tranny brace for a little while, the pit i use to work on the underside of my car is flooded right now. If that removes the false knock readings i might try some rubber washers.
if the knock is speed dependant more so then rev dependant, would that seem like a noise coming from the driveshaft or rear end? could it travel that far to the engine and be picked up as knock? cause if it was something in the transmission or something loose it seems like that would be more based on revs. Thoughts?
Last edited by Dudemaaanownsanrx7; 05-17-08 at 01:16 PM.
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#8
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iTrader: (24)
Not a stupid question. Every car is a little different, you'll have to sort out what is noise VS what is a real knock. Once you have a couple of datalogs for your setup you'll know right away by looking for spikes in the time trace. Some say 40 knock is bad. Others say 60, on and on.
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