DanADaMan

I have a new-to-me 90 vert. I think I have original exhaust with the exception of the exhaust tips/ends which replaced the original mufflers. Basically from the block I have two pre-cats (one on each side) which leads to one other cat (or similar looking thing) closer to the rear of the car, and then separate pipes leading out to the tail pipes.

I think one of the pre-cats is bad. I can hear a slight rattling noise, and when I rev the engine I see very small particles of metal (I mean, very small - almost wouldn't see it unless you really look hard and close).

I live in Alberta, where there is no emision testing. So my question is, do I need the pre-cats? Can I get my mechanic to just cut them out and just run pipe to fill the gap? Will then cause any codes (ie. O2 sensor codes)? Will this increase power? Will this give it a meatier sound?

Thanks

eutu1984

if you remove the precats it will not through a code for the 02 but when cruising on the highway you may get a intermittent code for the EGR.

https://www.summitracing.com/parts/f...model/corvette

cv67

replace
check your mufflers too may be blocked/partially filled wiht pieces

VikingTrad3r

Hi Dan, welcome to the forum!

fwiw, the cat rattle we saw may just be the perforated shroud/shield on the main cat.

your pre cats i think are fine.

and the "jam" your 90vert has is far to high to have any real cat blockage issues.

my advice is not to do anything to the cats in your vert. one issue with gutting cats is your exhaust smell does change, for the worse, and because you have a vert...top down...just not worth it.

post some pics of your ride! it is a very clean original (other than the muffler deletes) example of a well maintained vert.