Header - noise question -

Reply Subscribe

Thread Tools

Search this Thread

Jul 19, 2004 | 04:51 AM

Hawkeye2

Thread Starter

Staging Lane

Joined: Apr 2004

Posts: 71

Likes: 0

Header - noise question -

Installed PPC headers, Y pipe, Random Cats and Borla. After the header
install I get a rapping type sounds that varies with the RPM. It's not
a leak, I've checked all connections. I don't see any clearance issues
under the car. The only thing that I can imagine it is - is the AIR check
valve. However, there is no noise while in neutral. The engine must be under
some type of load to have the noise. No noise under mild acceleration,
however when moderate to hard accelaration you can really hear it.

A friend driving beside me could hear it from inside his car. Does the
AIR check valve noise depend on load of the engine? Any drawbacks to
making a restrictor plate for both sides?

Thanks.

Jul 19, 2004 | 08:55 AM

JamRWS6

TECH Resident

Joined: Feb 2003

Posts: 827

Likes: 0

From: Dallas, TX

Can you explain the noise in a different way? Is it a ticking noise or a vibration?

I just made the AIR restrictors for mine and I really couldn't tell too much of a difference. I think most of the ticking noise is just the exhaust gases pulsing in the primaries which since they are much thinner than the stock manifolds you can hear them more pronounced.

Also, do you have ticking from an exhaust leak?

Jul 19, 2004 | 09:36 AM

Hawkeye2

Thread Starter

Staging Lane

Joined: Apr 2004

Posts: 71

Likes: 0

Quote:

Originally Posted by JamRWS6

Not really a ticking sound, more like a rapping as if you vibrate your tongue
off the roof of your mouth! (sorry for the description) I've met other owners
of LS1's with same noise, different header brand, and others with no noise.

The restrictor plates are easy enough to try, just doesn't sound like a leak
or a ticking sound. If I open the hood and work the throttle manually there
is no leaking sound or ticking sound. It must be under load. And, if moves
with the RPM of the engine, so I don't think it's hitting the floor or the
sub frames, that would not vary exactly with RPM, and would be more
of a bang. The only other thought I had was the driveshaft hitting the
loop I installed at the same time, but there are no marks on the shaft at
all???

Last edited by Hawkeye2; Jul 19, 2004 at 07:18 PM.

Jul 19, 2004 | 10:31 PM

S2002S

On The Tree

Joined: Oct 2002

Posts: 120

Likes: 0

From: Albuquerque

I'm still having some minor leaks with the cat connections, and I suspect I have a clearance problem somewhere because under some conditions, I think I can feel/hear a slight knock.