Jferrante

Hey guys - been quickly transforming my car into the dedicated track car it is in the below video for the past year now. Car has been phenomenal and sometime after going to straight pipes I have noticed the "noise" in the video that almost sounds like something from a rotating component.
I have new plugs torqued correctly, coils, exhaust gaskets (even fixed an exhaust leak this morning from a header flange), full boost leak tested, new tensioners pulleys, water pump, ps pump etc.
The secondary air pump is also deleted.
My question is does the noise in the video sound simply like a compression backfire due to the straight pipes? If not any other ideas for what it could be? Has been like this for the whole season so far and once again am having no issues with 8 days or so already completed.

My initial thought was exhaust leak but even fixing that didn't change any of the noise. This seems to only occur at idle also - if you listen to my other video of me catching the slide the noise is not present so more leaning me to idle compression or sticking valve, bad lifter?
Thanks - hopefully I am just over thinking it.

fpb111

Lazy chain tensioner? The "What the !!??@&$@ is the noise in my Mezgar engine noise?

https://rennlist.com/forums/996-turb...ine-noise.html

Jferrante

hoping something stupid like that. going to bring it in to my indy this weekend and we are hoping it's not a bent rod...could really be a variety of things.

mffarrell

That doesn't sound good. In a way it sounds like an exhaust leak, but I can detect something metallic slapping around. I would not run it until you have your mechanic check it out.

Good luck, and I hope it is something benign like an exhaust gasket.

Jferrante

I checked the exhaust yesterday and no leaks, actually fixed 2 as stated in the original post. we are leaning worse case with bent rod or head gasket. either way would suggest new rods.

powdrhound

That's not healthy Joe. If it's a lifter you will be able to isolate it easily as it will be coming from one bank or the other and will be isolated to one side of the engine. Use a stethoscope. Good luck. If you end up splitting the engine to do rods, I would install a GT3 pump and crank for a track use engine. Much better than the turbo crank

Jferrante

thanks will keep you posted.

Mike Murphy

That sounds exactly like an exhaust leak to me. I know you said nothing's leaking, but that's what it sounds like to me. Like a puff of air out the side gasket of an exhaust manifold.

Jferrante

Yep pressure tested it no leak from there - we think it may be head gasket - will know soon

Macster

Sounds like an exhaust leak to me. Almost certainly not a head gasket leak. The CEL would be on with a misfire error code.

Sounds like a leak at a cylinder exhaust port either a gasket is bad there or a pipe is cracked.

Be sure you have replaced all the metal o-rings that are used to seal each turbo to its exhaust system. My tech sources tell me these should not be reused.

Third-Reef

Sounds like exhaust leak at the flange at the head or a burnt exhaust valve. You could isolate which cylinder it was (if this is what it is) by using the durametric to turn each injector off and see if it stops. Nice car!!!!!

T10Chris

Are you running stock manifolds? Previous owner installed headers on my car and when I cracked a header primary tube it sounded like that...

If that isn't it, I agree with John's advice above.

edit: nevermind, I see you've already covered those bases... Good luck and keep us posted with what happens

Jferrante

I am with all you guys - I swore it was exhaust and thats the only reason why I continued to track it with no issue (I am also ruling out bent rods for this exact reason - the engine would be kaput if that were the issue since I have a few days on it since the noise) - I replaced all ring gaskets etc on turbos and what now. tested for leaks and found the header flange leaking and fixed it - noise still there. I am going to double check it again tonight on the lift and make sure no cracks or anything are present and report back.

Gofishracing

Block off tail pipe to see if exhaust leak increase. sounds like a lifter to me

Jferrante

Well I just double checked everything and there is another exhaust leak - it is at the turbo and waste gate and it seems like a little waste gate shaft play but probably isn't causing it. See video. Also some other smaller leaks so i am going to try and fix them all tonight and see what happens