kenmohr

What is inside the pre cats on an 89? Anybody have pics?

Need A Vette

Normally there is a ceramic matrix, coated with Platinum & Palladium that heats up and helps to remove the nastys in the exhaust....But they can clog over time, which significantly reduces performance.

D.

RetroGuy

My '96 has a cat on each side after the exhaust manifolds. I promised myself if either one failed/clogged, I'd replace with performance cats from Magnaflow!
https://www.magnaflow.com/catalytic-...ic-converters/

rblakeney

In my case "significantly reduces performance" meant the matrix fell apart and both dumped their contents downstream totally plugging the center main cat leaving me stranded. A local exhaust shop cleaned the center out, blew out the rest with the throttle and all was good. Car sounds better too. My 89 is old enough to not require emissions inspections in my state.

mickey5

some folks call those small round cans "resonators". I removed them when I replaced the main cat. It changed the exhaust note to more of a rumble with a crackle sound when I backed off the throttle. Nice

kenmohr

Did you get more interior noise?

mickey5

Exhaust sounds more aggresive but not objectionable. I removed them and replaced the cat when I lost a couple of injectors a hundred miles from home and limped it back with a constant miss which fouled them.

kenmohr

Thanks. I was told that it would increase drone. Not sure I believe that.

mickey5

Don't notice a drone which I've heard in other Vettes, but then, I don't take her out with the top up.

vader86

Its a regular ceramic matrix, looks like a tiny grid.

Removing and replacing with a Catless front Y probably won't do any droning if youre not increasing pipe diameter. The main cat will tend to cancel it out. It will be more aggressive sounding but not crazy.

DykstraMotorsports

mikeinPA

I went with the catless Y front pipe and magnaflow high flow main cat on my 88. It sounds better and seems to have a tad more kick to it.