I'm getting alot of knock at half throttle

[DynamicGN]

This only happens sometimes....After I installed the V4 I was boosting 18 psi on 93 octane. My first WOT run was perfect, no knock and 765 a/f then i tried it again and i got alot of knock, so i lowered the boost to 14 psi for daily driving...i notice that at half throttle sometimes the car knocks up to 19 points and sometimes at full throttle too and im only at 14 pounds. I had the chip burned after the motor was rebuilt with je pistons champion heads camshaft, 009's..etc...but i still had the stock turbo and intercooler at the time...could the chip be causing this problem because the program isnt as rich as it needs to be. Should I have the chip reburned for the upgraded turbo and intercooler?

 

[Red Regal T]

I think we all have this problem from time to time. Last time I had this problem was after I put on a stretch intercooler. What ultimately cured the problem was installing a power plate. Something you should try.

 

[Scott231]

Did you retain the EGR function or not? If you didn't, there is your problem.

 

[Kid with a toy]

The Race Plate cured most (80%) of my "false" knock. And I did kill off the EGR function.

I also replaced the rockers, shafts, push rods, keepers, and added braces. And I also put a 6 inch cut of hose on my TV cable, due to the fact that it was sitting dead on my knock sensor.

Overkill with the hose. But I had rather be safe than sorry.

Erik

 

[GNVAIR]

I installed the Power Plate when I had my TA49 on my car and was running 24lbs of boost with some alky with no knock.
Now I have my stock turbo back on running 20lbs of boost and get tons of part throttle knock and a good amount of transitional knock with no changes to anything else.
I am all ears for someone with an easy explanation of this one.

 

[BLACK6PACK]

With the stock turbo @ 20 lbs its putting out very hot air. To run that much boost with a 108 chip I had to have the alky on max.

 

[TurboGN]

DynamicGN, did you check the vacuum line to the fuel regulator. If its not perfect, detonation will slowly get worse until you get knock anytime you're running boost. Once you've found the culprit please let us know. Good luck, Joel

 

[ONLYA6]

I was told that my car does the same thing because building that much boost at anything but full throttle doesn't allow the computer to compensate air/fuel correctly causing some knock. Whether or not that statement is true, I don't know, but it does sound reasonable.

Jacob

 

[sick GN]

What does killing the EGR do?? I didn't drill the hole for the EGR and I get knock at like 15 pounds at WOT but it's OK at part throttle. Could it be cuz of my 97 octane chip?? I am running alky though.

Thanks

 

[DynamicGN]

The vacuum line is fine...this is weird, for some reason the car is running fine now...it stopped knocking at part throttle....at full throttle it is fine too....maybe some knock at high boost....today i raced a ZO6 corvette....i was worried about the knocking problem especially since i was on 18 psi on 93 octane but it didnt knock at all and i beat him by 4 cars...its as if the car fixed itself....im still gonna check it out though...

 

[BLACK6PACK]

Sick GN,
Your chip needs to be set up so that it knows the EGR is disabled.

 

[NC87GN]

Timing tables in some chips are very high at certain MAF counts. I have a 108 chip that has over 35 degrees of timing at part throttle. However at 255 its 26degrees from 3000 rpm's on. You might want to have another chip cut and tweaked for your combo. Be careful as part throttle can be more aggressive than WOT.. HTH


Mike Banas
87GN

 

[lyonsd]

I've currently got the same problem. My problem started after I filled up the tank with 93 octane. And prior to that, I had a couple of WOT blasts on the highway to teach a ricer a lesson.

So I'm figuring my problem is either a tank of bad gas or I screwed something up in those WOT blasts.

I did adjust the fuel pressure a tad and it cured some. It seems to start knocking (according to Scanmaster) as the boost gauge needle approaches 10psi.