Ok so my engine builder the other day when he heard i was having problems with the knock retard told me to just get rid of it completely, just get it tuned out of the system and never worry about it again. Just have perfect timing at all times, as long as the tune is correct there shouldnt be any REAL knock. Just noise from rockers and headers. How bad is this? Will it effect anything? Or if I just get it removed from the computer will all be well again with my motor? PLEASE help on this one

 

When you tune, you have to tune for ALL possibilities.... poor fuel, high coolant temps, high inlet air temps, etc. Some of these are taken care of in the base timing maps and offset tables, but the knock sensor is a "safety net" for those cases you didn't plan for. In effect, you might have to run a little less timing without the knock sensor for protection. Why give up the extra performance all the time, when you can let the knock system take the performance away only when it would harm your engine.

Not a lot of risk here, if you can control your environment.... fuel, temps, driving conditions, barometric pressure. And, if you can do the level of hands-on tuning that you need to insure you have it set up correctly. I don't run a knock system, and really can't with a solid roller setup, but I've got more than 40 dyno pulls to insure that I have everything set up correctly. And I know the specs on the fuel that comes out of the big blue drum with "VP Fuels" printed on the side is not going to be "a bad tank".

This really belongs in "LT1 Engine Tech"...... moving it there.

 

It sounds like you may be getting some false knock. I have the same problem and have been researching fixes for it. From what I've found the best idea would be to bypass the knock sensor with a switch(do a search for "knock sensor resistor mod" or something like that), so you can have it function 99% of the time and then bypass it at the track or when you know you have good fuel. I get false knock even at idle, which is pretty pathetic. I'm going to try the mod in a couple weeks and check the results with the Tech II.

 

I don't use the KR system either. Like Fred, my car has been carefully tuned and I use it in a controlled manner.

Rich Krause

 

I bypassed mine as well. Was picking up 3 at idle and 8-10 at WOT with 100 octane in the tank. Got tired of trying to figure it out and my tune is dead on. Even when I opened the cutout I got even more knock. Did the by-pass last year a 0 problems.

 

i dynoed 386rwhp and had 16 degrees of knock at wide open throttle, iam going to have pcmforless desensitize or tune it out if they can.

 

how do you bypass the system??? does anyone know of a web page that explains how? or can some explain it to me??

Thanks!

 

Ok so where's the writeup or some more info on the "switch" cause the switch would be much better than just gettin the knock sensor outta the system. PLEASE someone let me know, I can't find it anywhere

 

I would assume that you would wire a switch in so that when it was on, it would tie the needed resistors into the knock sensor wire and essentially "turn it off".

In my case, with a 100k ohm knock sensor (OBD2), If I measured the knock sensor's resistance at 97k ohms, and wanted a 100% desensitization, I'd want to use two resistors, 1 with a value of 97k ohms between the senor and the PCM, and another with a value of 194k ohms that goes from ground to a spot between resistor 1 and the PCM. The trick I guess is getting a switch that basically cuts the resistors in when the switch is on, otherwise they are left out of the system...

 

I've seen two ways to do it. One was a complete by-pass (which I did) and a "desensitzation" one. I did a search last year and found plenty on it. I can check my resistor pack at home and see what I am using.

 

I probably wouldn't do it with stock cast pistons, they won't last long with real knock.

I have zeroed out all KR with LT1 edit. I have forged pistons and a custom tune though.