Phantom Knock issue

[91 TSi GP]

I have some hardcore phantom knock going on. I believe it is coming from my exhaust noise/ vibration.. I have a 2-3/4" Downpipe to a 4" dump right below my shifter. Everything is welded solid and there is no rubber hangers or anything. And my car is loud, real loud. Could this be the cause of phantom knock?
I'm almost positive it is but wanted to check with some other people. Also do you thing If I install some new hangers with rubber mounts that it will improve my knock issue by eliminating some of the rattling and shaking?

 

[JayRolla]

You do not want all the exhaust wieght hanging on the manifold/head. You need hangers, rubber mounts and a flex pipe. Yes that can cause your PK issues, expecially the dump tube. It can actually cause it between shifts when it dumps. Also solid motor mounts, bad and or over tightened or loose knock sensor, lifter tick can cause PK.

 

[91 TSi GP]

What I meant from my post was that I dont have the factory rubber hangers, I have solid hangers that offer no give/ flex and make for a TON of vibration. I am going to midify my hangers tonight and see if it helps any.

 

[JayRolla]

I just wanted to make sure its not 100% solid, like having a flex pipe. But yea that vibration can cause PK. You dont want any vibration going from the exhaust through the car to the motor. A lot of downpipes like to touch the transfer case which can cause PK.

 

[91 TSi GP]

Ok I out in the rubber exhaust hangers this weekend and HUGE improvement. I still have the annoying occasional low RPM phantom knock, any other tips to eliminate this any more?

 

[dsm-onster]

A chip or a computer solution that prevents the ecu from reading the knock sensor at lower rpms is the easy fix.

 

[JayRolla]

A chip or a computer solution that prevents the ecu from reading the knock sensor at lower rpms is the easy fix.

Yea that works but PK still can be picked up at mid rpms during wot. It works but its not a real fix.

 

[turboglenn]

Here's the answer i addition to an ECU that can be made to ignore the stock KS

I wouldn't run anything else (didn't even run a KS for 8 years before this baby )

J&S Electronics SafeGuard Indivdual Cylinder Knock Control

Hell, the one i havfe is so old al the new ones have more features but there's a few thigns taht will come off this car when it's either wrecked or parted out and those are my stand alone ECU and J&S

 

[dsm-onster]

Yea that works but PK still can be picked up at mid rpms during wot. It works but its not a real fix.

Ok I out in the rubber exhaust hangers this weekend and HUGE improvement. I still have the annoying occasional low RPM phantom knock, any other tips to eliminate this any more?

Tracking down low rpm phantom knock is time consuming.