Another false knock thread, could it be this?

[Ruiner46]

I'm chasing false knock on my 2016 GT with a whipple, long tubes and return fuel system. The knock started after installing the headers and fuel system at the same time. I know it is false knock because I get the same +7 or so with E85 or pump gas, and sometimes it doesn't happen and I can get a nice run where it is adding timing. Tonight I was tapping on the exhaust with a rubber mallet and checking for rattles while also removing some other parts that didn't have much clearance to the x pipe. My exhaust is full Corsa with Corsa headers.

This video is the sound from the passenger header while tapping on the driver's header. It seems to be coming from the primaries themselves. If I squeeze two primaries together by hand near the collector, it stops. I'm not sure if this is enough to cause knock.

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[Jackson1320]

Put a hose clamp around the 4 tubes and tighten it up. Drive it and look for knock

 

[markmurfie]

I had a bolt fall in between all four of my headers and slide all the way down near the collector. It made a similar noise when tapped upon. Lots of random knock sensor activity. It was a BITCH to get that bolt out of there. Lots of air blast, and dental tools to drag it back up and out, it was hard to even see it in the small gap between the pipes. I almost gave up on doing it in place.

If the other side header doesn't make that noise, you may have something stuck in the middle of the four of them, and its very likely what is causing your knock.

 

[Cory S]

I'm chasing false knock on my 2016 GT with a whipple, long tubes and return fuel system. The knock started after installing the headers and fuel system at the same time. I know it is false knock because I get the same +7 or so with E85 or pump gas, and sometimes it doesn't happen and I can get a nice run where it is adding timing. Tonight I was tapping on the exhaust with a rubber mallet and checking for rattles while also removing some other parts that didn't have much clearance to the x pipe. My exhaust is full Corsa with Corsa headers.

This video is the sound from the passenger header while tapping on the driver's header. It seems to be coming from the primaries themselves. If I squeeze two primaries together by hand near the collector, it stops. I'm not sure if this is enough to cause knock.

Yes, that reverb/rattle you hear before the sounds stops, is what the knock sensors are picking up. Find it, and get rid of it.

When I hit my exhaust anywhere with a mallet, it sounds like I am hitting cordwood.

 

[DRKHORS]

Put a hose clamp around the 4 tubes and tighten it up. Drive it and look for knock

This! I did this very thing with my headers. The primaries were just close enough that under heat they would slightly touch causing a minor vibration at certain RPM's and right at throttle lift off.

While I haven't performed the fix yet, if that is your issue a small tack weld between the primaries should fix the issue.

 

[Ruiner46]

Thanks for the ideas. I'm definitely going to try the hose clamp, and try to make sure nothing is stuck in between the pipes.

 

[slime_bullet]

I went through 2 sets on the drivers side that did this bad when they were hot. I've tried it all, wedging in between the primaries, tack welding, band clamps, etc. Finally having success on a 3rd set they sent me. Passenger side was always fine

 

[Ruiner46]

I've been all over the car tapping on things and moving stuff around. I removed my driveshaft safety loop just in case, tightened up a bunch of exhaust clamps, and I have a band clamp on each header. I'm still getting false knock, but it's only when I stab the throttle wide open. If I gradually roll on it, the knock sensor is happy and adds timing. I may try multiple clamps per header... I don't know what else to try at this point.

I took this log today with 3rd gear runs back to back. First one was stabbing the throttle and the second was gradually getting to full throttle. Funny thing, after this, I couldn't get it to knock again, but I'm sure it will be back tomorrow.

 

[andrewtac]

I've been all over the car tapping on things and moving stuff around. I removed my driveshaft safety loop just in case, tightened up a bunch of exhaust clamps, and I have a band clamp on each header. I'm still getting false knock, but it's only when I stab the throttle wide open. If I gradually roll on it, the knock sensor is happy and adds timing. I may try multiple clamps per header... I don't know what else to try at this point.

I took this log today with 3rd gear runs back to back. First one was stabbing the throttle and the second was gradually getting to full throttle. Funny thing, after this, I couldn't get it to knock again, but I'm sure it will be back tomorrow.

Mine does this too, sort of gave up. The only thing I could say for sure was it didn't happen when I rolled into it. I also looked at some logs from the track and it didn't seem to do it then either. But stabs, yes almost always now. Sometimes a little positive, Sometimes it just doesn't quite add as much timing. But roll into it and almost instantly it adds 4 degrees.

 

[M-Driver]

The rattle reminds me of my Bellhousing Spacer Plate between the motor and the transmission, but it doesn't make sense it stops when you squeeze the headers. Another source of rattle might be the line near the cat.

 

[slime_bullet]

Mine does this too, sort of gave up. The only thing I could say for sure was it didn't happen when I rolled into it. I also looked at some logs from the track and it didn't seem to do it then either. But stabs, yes almost always now. Sometimes a little positive, Sometimes it just doesn't quite add as much timing. But roll into it and almost instantly it adds 4 degrees.

Aed tuned?

 

[andrewtac]

Lund

 

[slime_bullet]

Lund

I can say I had a tune that did this. Stabs of the throttle and instant positive kr reading. Rolling on the throttle a tad before stabbing it reduced the occurrence. Could even get it in neutral blipping the throttle. Some say too aggressive "throttle tip in". Idk, but I went to a different tuner and it cleared that up.

 

[andrewtac]

Well it didn't do it in the past, and I have added so much. I did not do one thing at a time like I should have.

 

[Zrussian13]

My issues are similar. Only happens to me in 2nd (occasionally) and 3rd more often. Mines a manual though so I figured it was something in my tranny getting ready to let go. Been like that for 15k miles now. First 5k boosted it never did it. Doesn't happen very often now but I noticed if I slam gears over 7k I'm fine. If I slam 2nd or 3rd around 5500-6500rpm, good chance it will happen, but if I shift smoother and get into the gas gradually at those rpms I'm good.

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