Question: catalytic converter for california in 1996 grand sport

[wayneb661]

has anyone replaced their CATS with new and found one better then another one. it has to be CARB but since I want to replace them and TIG in better ones. stainless is the way I want to go. Everyone have a Merry Xmas and a safe holiday Wayne

 

[Hib Halverson]

Why are you replacing your cats?

Car flunk the smog check?

How many miles on the car?

Be careful with aftermarket cats. Very few are better than the OE units. They either flow poorly or they are poor catalysts or both.

The existing cats are stainless steel but likely not the type of SS you are thinking about.

 

[wayneb661]

thanks Hib Halverson

Thanks Hib for showing interest in my question.no the 96 grand sport passes with flying colors (smog) but always looking for that 1%-2% that hides.I tell young guys that we started with indexing spark plugs and different motor oils back in the days of SFV drag strip. my 1959 vette parts are much more available than my C4 that are still made in USA. would like to try some high flow cats and maybe get the mpg to 21-23 range. right now its 19-21 mpg with B&B 3" stainless exhaust, K&N, holley balanced injectors ,a new map for air/fuel ratio ect.ect, I think we should just grab one of the black/red stripe drums 112-116 sportsman leaded drums for the 59/blown flatbottom and call it a day.but times they are a changing here in so-cal.so if you have any good venders that supply SS cats (and yes their is more than one grade of Stainless Steel) please forward to me info Wayne. Wishing you and your family a happy and safe XMAS

 

[Hib Halverson]

Keep in mind that much of the "high flow" cats sold by the aftermarket don't really flow better than the stock units. That's not to say that there are no cats which outflow the stockers but they are rare.

The other problem with aftermarket cats which are truly high flow is that they are poor catalysts meaning they may increase exhaust emissions compared to the stock units because they have less catalytic reactant due their small sizes or they will have poor durability compared to the OE parts.

Finally, by the letter of the law, in CA all aftermarket cats which do not duplicate the stock cats are typically not approved for sale, installation or use in California and thus are illegal. Now, in practice, only real observant smog stations will flunk you for aftermarket cats but some may. The key is finding a smog station which will just see cats and sign off rather than looking at what type of cats they are.

Lastly, if you decide to replace the cats on your 96, give them to me. I'll pay the shipping.