Went on a small road trip last weekend. On our way back home, started hearing this sound that sounded like an exhaust leak. I can't isolate whether or not its in the front or the back, I usually think its in the back, but sometimes it sounds like it could be coming from the engine bay. It is heard more when lugging in low range...ie 2500rpm or so. For lack of a better way of describing it, kind of like when kids put baseball cards in there spokes on there bike... (doubt kids still do that, can they do it to their playstations?) LOL

Anyway, took it to the dealer, he put it on the rack. Found a little ID plate that had four spot welds, one of them was loose. We just pried it off and I think we're done.... nope. That wasn't it.

My fear is a crack in the exhaust manifold. Visual inspection showed nothing, I'm taking it back in as soon as I can and I'll leave it there until its fixed. Anyone suffered exhaust issues with stock set up? I hope its in the muffler or cats, then I could upgrade!

 

My stock cats disintegrated...it probably had a lot to do with the supercharger, but still...this was with only 8000 miles on the car. It made a sound like small pebbles bouncing around in the exhaust, and usually at high rpm. Not sure if this is what you are dealing with, but the stock cats are prone to early failure.

If the stock ones are bad, I'd definitely recommend the RSC cats...huge improvement over stock.

Stock...


RSC replacements...

 

That wouldn't break my heart if they went... Find out soon. My car might be getting the RSC treatment earlier than I thought.

 

My dad had the cat go in his corvette a long time ago, killed its performance... Mine seems unchanged...

 

I know you're in Seattle now but where did your car live beforehand? I posted in another thread about thermostat failure - if this is the case in colder, wetter climates it does result in the car running richer than it should (which the cats don't like) plus the Vantages seem to run a touch rich anyway.

I hope it's not a cracked header, but if it is, drop me a line, there's a little project I've been thinking about for a while....

 

I'm inclined to agree with Tahoe M3, my money's on catalytic converters. Even though the "baseball card in bike wheel spoke" description sounds like an individual manifold primary exhaust leak, I just cannot imagine what would cause such a leak on a stock manifold Vantage.

If it had aftermarket headers, sure, I could imagine a crack occuring.

I'm curious to hear the diagnosis.

 

If you need cats...I got a used set...

 

[quote=Tahoe M3;2908648]My stock cats disintegrated...it probably had a lot to do with the supercharger, but still...this was with only 8000 miles on the car. It made a sound like small pebbles bouncing around in the exhaust, and usually at high rpm. Not sure if this is what you are dealing with, but the stock cats are prone to early failure.

If the stock ones are bad, I'd definitely recommend the RSC cats...huge improvement over stock.

You think???

 

Yeah, yeah I know...the stock cats are really bad, though and prone to early failure. Even with the SC that's really early...considering that the SC was on for maybe 2000-2500 miles at that point.

Surely the added heat from the SC essentially melted them...but the stock tuning is very rich which is bad for cats. That was actually leaned out with the SC kit.

Stock cats are also very restrictive leading to increased heat...combine that with rich stock tuning and the cats tend to fail early, supercharger or not...at least that's my analysis.

 

I will report back as soon as I get it in to the shop. Stuart, the car is from california.

 

GT650, sent you a PM on those CATS.

 

My RSC cats went on a couple days ago, along with a Larini exhaust, and full mainenance done by the guys at IMA Motorsports. I have not picked up my ride yet, but I am sure I'll be pleased.