staimy

Hello, I have a 1989 corvette c4 convertible, I live in Portugal, I need new catalysts for it, from what little I've researched I think it needs 3 catalysts, right? 2 in front and one in the middle? I would have to buy it on ebay to order, could anyone here help me? which would be the most recommended...

vettehardt

If you don't have to worry about emission tests, then you can eliminate the two front cats by buying a new Y-pipe without them. Then run a new main cat in the middle. The new cat technology is better that what it used to be and a single cat is all that is needed.

I went through this a couple of years ago on my 91 when my pre-cats started breaking down and clogged up the main cat in the middle. I had to keep all three cats due to the rules in my racing organization. It isn't cheap or easy to find a new y-pipe with the two cats in them. I was lucky and found one on Ebay. Cost me $470 when a catless y-pipe is only about $250.

staimy

Unfortunately here in Portugal we have vehicle inspections that we have to do every year so that the car can be driven on the road. So all you need is one catalyst the one in the middle is ok perfekt. I have to see what I can find on ebay

vettehardt

You have to read your rules. Does the exhaust and emission systems need to be exactly as they came from the factory. Or do you just have to pass an exhaust sniffer test where they analyze what comes out the exhaust pipe? If just the sniffer test, then you can eliminate the two pre-cats and it should still pass. If it must be as from factory, then you need to have the two pre-cats.

staimy

Yes, they analyze what comes out of the exhaust pipe due to gas emissions. They use Infrared gas analyzer (analysis of four gases: CO; CO2; O2; HC; NOX and Lambda value.. , that's why I needed a cat..