Catalytic Converter Replacement
Thread Starter
Racer
Joined: Jun 2004
Posts: 313
Likes: 0
From: Macomb MI
Catalytic Converter Replacement
I have a 91 Coupe L-98 (87K) with pre-cats and a full sized one. Took it to a dealer who said I need a new catalytic converter but they couldn't do the work because of my sidepipes. In looking around I found a DynoMax kit with Y-Pipe to replace the pre-cats and a new converter. Anyone have any experience with this?
http://ecklers.com/product.asp?pf_id=34198&dept_id=1777
http://ecklers.com/product.asp?pf_id=34198&dept_id=1777
Melting Slicks
Joined: Apr 2002
Posts: 3,305
Likes: 2
From: Havelock NC
You can't get the dealer to do that work, but most muffler shops would probably be willing to cut out your old cats and replace it with one single main cat. I had that done on my old 87 and it ran great that way.
Safety Car
Joined: Jul 2008
Posts: 3,966
Likes: 4
From: Made In America
St. Jude Donor '10-'11
High flow cats are the way to go. Newer technology, filter better, and there is a chance your old ones are partially clogged which is robbing horsepower and could cause you to fail emissions providing you have them. Some people choose to remove all cats and weld in test pipe in there place for the sound and horsepower(small gain). I would suggest: Random tech, Catco, Magnaflow, or some other name brand high flow cat.
Instructor
Joined: Apr 2008
Posts: 105
Likes: 1
From: New Ulm MN
If you do not have emissions testing in Missouri, gut the old cat (do not remove it). Take it off and with a 12 inch screw driver clean it all out. You will retain the stock look. I would also suggest getting a pair of LT headers (TPIS) so you could be done with the pre-cats as well.
Le Mans Master
Joined: Mar 1999
Posts: 7,996
Likes: 0
From: McAlester Oklahoma
If you pre-cats are bad just replace the whole Y pipe with stainless. Don't gut your main cat. I did and I lost a lot of MPG and it was way to drone sounding. Put a high performance cat back in and the MPG came back up and it sounds better. Still loud but better.
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
I have (SideEffects) sidepipes too. I'll tell you what I did if you like. And, address the 2-part cat system vs 3-way replacement issue. However, with no add'l post -- 10 days after your OP, I'm assuming it's already handled.
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