Yeesh, so I had to have my Y-pipe professionally installed (didn't have the air tools to remove the old one) and I think the install went wrong.

The exhaust note itself is fairly unchanged; it's a bit more raspy and harsh, but I like it. However, at WOT there is a hissing sound on top of the exhaust note. It sounds like escaping air, or like I'm trying to fake a blow-off valve.

In addition, there's also a tinny metal vibration sound at low RPMs.. it sounds like the heat shield maybe rattling against the Cat.

Any thoughts as to what would cause this? Maybe he forgot to replace a gasket? Or under-tightened something?

 

Could be improper install or could be a bad flex section. Which y-pipe did you go with? No one in my town will touch a y-pipe because its against federal law, so looks like I'll have to do it myself... Good luck whatever it turns out to be.

 

Me too, we can have a ypipe party.

 

try tighteing all the bolts first...sometimes after the first heat up everythign needs to be retorqued

 

When I got my Y Pipe installed (bought from lssexhaust.com) I had the hissing sound too so I turned back around to the exhaust shop and put the car on the rack...We took it up and gassed the car a good 5 times and there was no leak...The sound has faded away in the past 4 months but I had the hissing sound you're talking about...but not the metal sound

 

I went with LSS (budget) Y-pipe. I didn't tell the guy much about the pipe, just that it's a midpipe and pointed to where it needed to go while the car was up on the rack.

I wonder if wrapping it would help? I've heard about some people using industrial wrap to insulate the pipe.

 

hmm... Budget is usually pretty good about their flex sections and keeping BITC away. Try loosening and resetting the y-pipe at all the joints. maybe the gaskets aren't sitting right.

 

Hmm.. the guy hammered the gaskets into the grooves with a rubber mallet.. at least I saw him do one gasket like that. Is that recommended?

 

What in the world did he do that for? I tried forcing it in like that and it ended up not sitting correctly. The only way to make sure it's in the groove is to put it in the groove first then raise the y-pipe to meet the exhaust manifolds. Lemme guess, he installed the y-pipe, then remembered he forgot to install the crush rings and didn't want to remove the y-pipe again.

Edit: Did he do that with the y-pipe partially installed to squeeze them in between the y-pipe flange and the exhaust manifold or did he do this before it was installed? Either way is 'ed but the second one would be extra dumb.

 

Hah! Yeah he hammered the gaskets into the new Y-pipe while it was sitting on the ground. It's not what I would've done but I didn't think much of it.

Sigh.. I'll check for air leaks tonight.. at least, if nothing else, he broke those seized nuts loose so I can get to them w/ hand tools.

 

Give it about 200 miles on the y pipe and if your having the same problem check all the bolts and make sure their tight if they are check and make sure the hanger that goes from the y pipe to your cat is bolted up right.