2nd Gen Non-Engine/Transmission Should I gut the Cat Converter - best method of doing so & reinstall tips ???

[DBazley]

So many of you are more knowledgeable on exhaust than me, keep in mind. Here's what I've got:



Just had a local shop give my '97 a 4" pipe cat back, and the muffler is gone. Sound is better, not too loud, nice, but I'm still 3" from turbo to the cat, and the cat has all it's 'stuffing'.



Can anyone predict the effect, or advise on the benefit (and method) of gutting the cat, and re-installing it ?



Someone said now my muffle is gone, the cat serves as a sort of 'resonator' ???



I fear if I gut the cat it may be too loud, and not sure how much performance benefit is to be gained ?



As we're in "smog all cars California", I've been advised NOT to eliminate it, as we never know when they'll try begin smogging Diesels, too.



Appreciate any advice you guys have ! Oo.



David Bazley

Anza, CA

 

[Nate]

Are you sure your truck has a cat? I was under the impression only the new trucks had one.

 

[DBazley]

It is very confusing to tell which year & model truck do or don't have cat, Nate - for sure. I heard the early ones don't and the 24 valve ones do, but for them it's more of a resonator & less of a CAT. CAT's have ceramic honeycomb interior - resonators have metal packing. (going on what posts I've read last night... )



My '97 is a Non California truck emissions wise (no EGR, etc) and it has a Cat, for sure.



Many shops won't touch it, as it's covered by a Federal Emissions law or somesuch. I did look at more posts last night, and one fellow posted the parts at NAPA that you can get to patch it up, after sawzalling it out. Some 3. 5" pipe & adaptors to make it fit on either end & clamps. Doesn't sound too hard. I'll keep the CAT around in case the trucks need inspecting in the future.



My main question then concens noise - too much ? An awful lot of guys here do the 'straight pipe' thing & swear by it, admittedly.



What it would be if I do this then, would be 3" stock downpipe to roughly the cab / bed intersection, then the new 4" back from there, no CAT, no muffler. Straight piped, 3" to 4"... .



My power mods are modest, (TST 1st plate & Governor spring kit) so I dont' know how much point there would be in getting that 3" out of there - given that the two most restrictive things cat & muffler would then be gone ?



I know this, I like the improvment in both exhaust tone, power & lower EGT's so far ----



Thanks for your thought, Nate or anyone... .



DBazley

 

[mschoenheider]

Your truck will be significantly louder with no cat or muffler. If you are at stock power, there will be very little if any performace advantage to gutting the cat.

 

[NoSeeUm]

Read what Fritz has to say. Cat's were added in 94 and removed in 98.



Jim