Cat question?

[N8nSM]

First off, thank you again to all that responded in regards to the Z dying after entering open loop. It was the fuel pump (andtuel pressure regulartor as I found also). I've got all that replaced now and back together. I'm still trouble shooting a high idle problem (idling at 3k when started).


At any rate, I've got the Corsa exhaust that is ready to go on one I figure out the idle problem. I was thinking about adding a set of high flow cats but it looks like the cats are connected directly tot he exhuast manifolds. What's the best way to replace these and what part numbers do you have? Do I cut the cats at the exhaust manifolds and weld back in place? What's the best procedure for this?

Thank you all,

-Nate

[ZR1 MK]

Wht are you looking to replace the cats? If they need replacement, the exhaust manifold and cat are one piece for your year car and must be replaced as one unit.

[Z Factor]

I was thinking about adding a set of high flow cats but it looks like the cats are connected directly tot he exhuast manifolds. What's the best way to replace these and what part numbers do you have? Do I cut the cats at the exhaust manifolds and weld back in place? What's the best procedure for this?

Thank you all,

-Nate

You are correct in that they are connected. You can have a shop either cut and replace them, or gut them out but leave the housings there for inspection. If you are going to go to the expense of replacing the stock set up, I'd recommend headers instead, followed by high flow cats attached to them.

:cheers:

[N8nSM]

Headers would be nice, but I'm in CA. Does anyone know of a set of CARB legal ZR-1 headers?

[ZR1 MK]

Whats CA view on cats that need replacement, but stock replacement part isnt available from manufacturer?

[N8nSM]

I don't know what the SMOG Nazzi's say, but I've had exhaust shops weld up the high-flow cats before and they pass inspection as long as they have a registered CARB number (California Air Resource Board).

-Nate

[blackjack]

as anyone ever gutted their cats?
how much power can be expected with this operation?
is it worth the trouble?
blackjack
91/1735

[ZR1 MK]

as anyone ever gutted their cats?
how much power can be expected with this operation?
is it worth the trouble?blackjack91/1735
Theres no reason to disable the cat function. If you want more power, due the many mods available.

[blackjack]

i wasnt planning on doing that,mike....just curiosity:)
blackjack

[Z Factor]

as anyone ever gutted their cats?
how much power can be expected with this operation?
is it worth the trouble?
blackjack
91/1735

In answer to your question, I have gutted the cats on two cars (non ZR-1's)over the years. We use to have a minimal inspection here in Florida and they did a visual inspection to make sure you had cats, hence the reason people left them in place and gutted them.

It will add a little power, and increased the exhaust note as well. It is relatively inexpensive once you find the right muffler shop to do it.

:cheers:

[RedRiderZR1]

Just so you know, there are no Smog legal headers for the ZR1 in California. If you want Hi Flow CATS, one option someone did was to gut the CATS on the manifold and mount high-flow bullet CATS behind those. Although I doubt you would really feel any difference. Really need to go the header route. Maybe you can get lucky and find someone who will be friendly at your next smog check.

[rkreigh]

on the 90s the exhaust manifold and cats are welded together as one parts and the cats aren't serviceable unless you hack them off and use the 93/95 cats and weld on a flange.

for CA emissions look around, you can find alot of cheap factory manifolds with low miles around. from GM they are over 3k for the pair!!!