how to trace down knock

[shocker998md]

alright guys heres the scoop with my car. Ive got 009 injectors, TT chip for alky, alky set up, stock turbo, and im running 22lbs of boost. Now from a 30 mph roll and if i ease into the throttle i will not get any knock on the scanmaster. Now if i dont ease into it i will get knock and its not gradual, it will show up 4.8 then 9.0 and i let out of it and it goes back to 0. Now i know for a fact that my alky is working and spraying, so im guessing something is loose.

Im guessing that my down pipe is loose, if i lay down under the car and grab the down pipe i can move it around, but while i do that and i have somebody watch it does not look like its hitting the a-arm. I also held the brake, put the car in drive, and reved the motor up to 2000 rpms and let off it. My buddy that was looking said that the motor didnt really buck or anything that would shout out, broken motor mount.

So where should i start looking now?

 

[SFITurbo]

Lazy fuel pump?
Low octane before alky sprays?
Sensor overtightened or bad?
Alky spray point not set right?

 

[SPOOLFOOL2]

Sounds like false knock. Most likely on the shifts. What MPH does this happen at? What are you recording data with? What are your O2s? The KR that you want to watch for is at peak torque in third gear. This should be about half way through third gear on a 1/4 mi pass. This is where you will be loading the motor the most, and true KR "should" show the most.

Mike B.

 

[shocker998md]

fuel pump is a new walbro 340 and fuel psi goes up with boost.
alky is at the three o clock position as if you where sitting in the car.

Im not sure about the sensors. and ill have to check at what mph it happens, i figure it false knock but i have a bad gut feeling when i step on it because it doesnt seem to be smooth.

Im using a scan master for logging right now, and the 02s are around 790ish. currently im in CA for another 10 days so ill check out the MPH when it happens.

 

[bison]

Put some high octane fuel in there and see if it stops the KR. I doubt its false knock

 

[Just a Six??]

How old are the Motor mounts? They can make weird things happen & are cheap to replace.

 

[shocker998md]

they are factory motor mounts, i have no problem changing them, but i just dont want to shotgun parts just for the hell of it. I had the car in drive, held the brake, and reved the motor up to about 2 grand and my buddy watching said that nothing looked fishy with the motor moving around.

about the high test, even when i max out the alky it will do it when i step on it, but then i can tell its running crappy because of too much alky. But like i said if i ease into the throttle i can work up to a WOT pass, i just have to be gentle with it.