4* off launch knock.


May 25, 2001
ever since i put in the power plate i noticed an increase in launch knock up to 5* , but it goes away right after i hit 2nd gear, my question is.., Is low end knock bad for the motor, can it damage the motor yes or no?
yeah, i have kinda the same problem...only i don't have a power plate.:confused: :confused: :confused:
I would think low end knock is the worst kind. At say 2000-2500 rpm you are at max torque, which means you have high cylinder pressure. What boost level is this knock occurring at
i am getting the knock at.

18 psi to 20 psi, i really dont pay attention but i would assume that is where it happens, for some reason i thought high top end knock is the worst kind, that is what i have been told so far. i would say around 3k to 4k rpm range.
i would think high end knock would be alot worse. Parts are being stressed more at higher RPM's. I don't see too many pistons shooting out of motors at low RPM's:confused:
You think its false? What scantool? If its scanmaster, remember its kinda slow. What mph is it the knock occuring at? You say it goes away in the next frame? If so, I wouldnt worry about it. Just my .02
hey neil.

the knock is ocurring right off the line at WOT I have a scanmaster 2.1, i would assume around 20 t0 30mph, i talked to Lou and he said not to worry about it, that usually happens and its nothing to worry about as long as it goes away within the next couple of frames which it does he said something on regards to the computer trying to adjust the the load of full WOT blast so it retards the timing just for a second but then it adjust and works fine... i was just concerned about it that's all, i really dont like any type of knock whether is at low or top speed.
Torque peak is when the engine is working the hardest, no matter what the engine or the mods. The reason parts fly out at high rpm is because you are factoring in the centrifugal force of spinning at 5000 times a minute. The pistons will melt at 2000 rpms just as easy or easier then they will at high rpm. Wicked87GN I am with you I dont like any knock whatsoever, but 4* is not the end of the world. An engine is more likely to knock at peak torque then at any other time so I agree with Lou, as long as it goes away as rpms come up it should be OK but if not then you may have a problem
Most likely false Knock. Some cars have real problems w/false knock on hard launches . If the engine is not knocking in third gear on a 1/4 mi pass then it is false knock on the launch.
Could be a couple things at 20-30mph...

1) wheel spin can cause false knock and around 25mph is where my GN breaks loose (full boost).

2) depending on the chip programming, it could be momentarily lean. I think some chips are programmed to lean out at TPS of 1.8-2.2V to aid turbo spool.

3) could be the engine mounts, downpipe, hard downshift to first gear, loose torque converter bolts, TV cable hitting the knock sensor, or other mechanical banging going on...

Just a few thoughts. HTH.