for those of you with no/hollow cat: yes it is a tbi question
 

My cat finally gave up on me, and I don't have the money to fix it (visual emissons here (if the cops a real @**). anyways my questions are:

did you notice any lose in power?
did you turn up your fuel pressure,? I haven't made mine adustable
did you have any probelms, ex: check engine light, bad start ups...?

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late model 91 rs
fully loaded t-tops, red leather
paint- gm red and yellow blend (light red)
custom painted 16" Camaro rims
305 tbi 14"x3" O.E, hypertech chip, accel super stock plug wires
Edelbrock 3" cat-back
MTX sub and amp, Bose all around
vic_v8@yahoo.com
street kills: a lot of "family" cars, pickups, New v-6 stang, totally killed '86 SC Camaro, 91 z 28 with 305

i had mine removed with the stock muffler and pipes and had no problems and i couldnt tell you if i felt a power gain from it.

thanks for replying, but I would still like some other input.

BTW, I will be putting on a new cat this spring when I have the money.

You can remove it with out any problem!!!!
It will gain a few horses but nothing you can notice. It should not bring up any trouble codes either so don't worry about it just remove every thing.

I don't suppose anyone has before and after times?

i gutted my cat for the same reason, no money. after i gutted it there was only positive gains when i did that it sounded better and it seems like it had to give it a few hp from getting rid of that old cat especially from all of the miles and abuse that the old cat has been though. the negative side that i really havent noticed that i always hear about is it make more of a hollow annoing sound but never had that problem... yet https://www.thirdgen.org/messgboard/smile.gif

i am all for it

I couldn't tell ya because I did mine when I did my headers. But I didn't get any codes but I know I have to boost my fuel pressure bad. I have the afpr but I just need to find time on the side to do it. https://www.thirdgen.org/messgboard/biggrin.gif

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Eric Natzke
91 Firebird 305 TBI
"It Ain't Stock"
http://members.aol.com/j007golden/91firebird.html
For info on certain parts or mods go to the site below
http://members.aol.com/j007golden/modeval.html

when i took my cat out i already had heads, intake, and 1.6rockers. there was a good gain from it. i knocked about .09 off my et's from one week to the next, weather was very similar.
it wasn't anything i could feel just driving around, but it is clearly worth while at the track.
mph was only up slightly.

later
tim

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91 Camaro RS-LO3,Auto.
14.209@95.46mph
Best 60' 1.917
Check Out The East Coast F-Body Nationals Home Page
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When I hollowed out my original TBI cat, it really didn't make much of a difference in power. The bad part was it sounded pretty "ghetto" to me. However, a few months later I ended up putting 350 TPI manifolds on along with the factory 3" y-pipe, cat, and Edelbrock catback system. The 3" cat had seen better days as well, so I hollowed it out too, but this time I decided to weld a straight piece of pipe inside it after hollowing it out. I found that a 2.5" piece of straight pipe fits inside it perfectly. Just had to cut it the right length and weld it at the ends. It ended up sounding way better than the hollow cat with no pipe, and being a full 3" system on top of that, you can actually feel the difference in the way the car pulls. It sounds more like a healthy 350 now instead of a mild mannered little 305! Just a hollow cat sounds all burbly, with the straight pipe in it, it sounds smoother and more tuned. The other nice thing is that as far as visual inspections go, it still looks perfectly legal on the outside. I even hooked the air tube back up to the cat. You can't tell it's been messed with at all. Whether or not you hollow out your cat is really a personal choice, but I can say that going to a 3" system instead of the puny TBI exhaust does make a noticeable difference in power and sound quality. :thumbsup:

I gutted mine and the exhaust leak seems louder, but there were no probs.

i gutted my cat because it broke and was rattling badly so i just dumped the insides out not hard at all. since then i have had no problems with my car or anything at all and thats the only thing i changed. the only thing i noticed after was the tone of the exhaust changed it sounded better IMO didnt sound too bad with my dynomax behind it but it def got louder inside the car not too much. but at least no more rattling.:D

I removed mine and replaced it with a 3" pipe. That with a set of Edelbrock TPI headers, SLP 3" intermediate pipe and a Flowmaster 2 chamber muffler did wonders for both performance and sound. Almost sounds like an LS1 with better exhaust.

:doh: Lol. I guess that's what happens when I stay up all night and respond to posts. Little things like the original post date get overlooked. Kris is right though, it's still a good topic for discussion. ;)

Because it's a 5-year-old thread.

Nor do I, if

1. the post is relevant

AND

2. if the post adds something that hasn't been covered under recent topics already. That includes recents posts + the stickies in the Exhaust forum.

If you're going to take an old thread to the top (TTT) then, as a courtesy to the readers, you state that (A) know you're reviving an old thread (because you actually read the dates), (B) WHY you're doing it, and (C) what the new content is so the reader will know you spent the time to research it first.

I didn't think I had to be that specific in explaining this here -- which is why I gave the brief reminder about the 5-year-old thread above. It also (later) saves the moderators from having to do extensive housekeeping (editing) on the thread archives. Understand?

Moderators dont do "extensive housecleaning".... ever. (at least, i was never informed of that duty :doh: ) we delete threads without tech relevance and move threads not relevant to the board it was posted in into the board that it should have been posted in... usually leaving a link to it in the 1st board. The archives of millions of posts exist so that you could essential answer on your own any question you have if you search long enough.

People dont always do that, nor is it fun to search and sift for hours... if it is a frequently asked question, fine (but should be AVOIDED)... eventually so many posts will come up when people DO search, i think the redundancy naturally falls off.. The history like having threads from 01 still available IS what makes this site great... and having new replies can never hurt... unless they are not tech relevant... SO, this reply and others not relating to the topic will be deleted in a few days.

Pats addition to the thread I view to be helpful to someone doing a search today or in 5 years.. Thanks Pat.

Kdrolt does bring up a good point, though it doesn't necessarily apply here. I've seen guys start bringing back 4-5 year old post one after another. Then post a sentance saying somthing like, "yeah I did that too".

In all honesty, I don't even know how I managed to stumble across a thread that old as I wasn't performing a search at the time. Somehow it was already on the first page of the TBI board I guess. I wouldn't even have bothered posting a reply to it if I'd have noticed how old it was. My apologies for that little oversight! I'll make sure to check the date next time before bothering to post a response. :doh:

I agree completely with Snflupigus. Pat, you did nothing wrong. If you see any relevance or any useful insight or ANYTHING aside from "yeah I did that too" then by all means bring back a however-many-year old thread! Now on the flip side to that, if you question someone's reasoning for bringing back an old thread when the post that brought it back WAS A GOOD ADDITION TO THE THREAD and I see it....your post will be deleted :)

Bruce (90RS305)