Need Help !! Cats or no Cats
Thread Starter
Instructor
Joined: Aug 2004
Posts: 136
Likes: 0
Need Help !! Cats or no Cats
Hey C5ers
Need some suggestions on if I should go with cats or no cats on my 97 Vette. I'm going to put some new mods on it such as Lunati 224/224 554 114 cam, TEA stage 2 heads, Holley intake manifold, and a undetermind brand headers. Currently I have a Borla rear section on the car. What would be best for max HP gain and drivability for me? Any help would be great. Thanks in advance fellow forum members.
oh Yeah, Long tube or shorty headers?
What's best?
Need some suggestions on if I should go with cats or no cats on my 97 Vette. I'm going to put some new mods on it such as Lunati 224/224 554 114 cam, TEA stage 2 heads, Holley intake manifold, and a undetermind brand headers. Currently I have a Borla rear section on the car. What would be best for max HP gain and drivability for me? Any help would be great. Thanks in advance fellow forum members.
oh Yeah, Long tube or shorty headers?
What's best?
Last edited by Nvd97C5; Feb 23, 2005 at 04:36 PM.
Le Mans Master
Joined: Jul 2002
Posts: 7,370
Likes: 8
From: Slave to the evil empire
Cruise-In V Veteran
St. Jude Donor '04
Well if you live in California then the only answer to your question is keep the cats, unless you have friends that can fake your emissions inspection 
Melting Slicks
Joined: Dec 2001
Posts: 2,040
Likes: 0
From: Collin County Texas
You'll get tired of the sound, believe me. I have had a number of cars w/o cats, and it sure gets old after awhile (if it is a daily or near daily driver).
Here in Texas, if the State Highway Patrol catches you w/o cats, they impound the car. It's a long walk back from out in the boondocks!
I'd keep them on just to somewhat muffle the sound. The extra pickup in HP will be pretty small.
Here in Texas, if the State Highway Patrol catches you w/o cats, they impound the car. It's a long walk back from out in the boondocks!
I'd keep them on just to somewhat muffle the sound. The extra pickup in HP will be pretty small.
Instructor
Joined: Dec 2004
Posts: 205
Likes: 0
From: Regina Sask
I just took mine off this weekend and I hate the sound.... simply because it didn't get any louder at all. This is running through the stock exhaust. I really do not like the stock sound of the Vette. It is wayyy to quite for me. I did not notice any smell difference at all. I plan on doing the a&a mod this weekend and that should make it sound a bit better. If that doesn't work then I will be getting an aftermarket exhaust. I was also told that removing the cats might cause resonance in the cab but I couldn't get it to resonate at any rpm. With your mods I think it might get loud but it's all personal preference. It depends how much your mufflers kill the sound.
Last edited by Rizzo1; Feb 23, 2005 at 04:35 PM.
Melting Slicks
Joined: Dec 2001
Posts: 2,040
Likes: 0
From: Collin County Texas
Originally Posted by Nvd97C5
Hey thanks runamuk and RWhite.. any suggestion on a good high flow cat that won't hurt my wallet?? 
Race Director
Joined: Mar 2000
Posts: 17,602
Likes: 20
From: Palm City Florida
Originally Posted by Nvd97C5
Hey C5ers
Need some suggestions on if I should go with cats or no cats on my 97 Vette. I'm going to put some new mods on it such as Lunati 224/224 554 114 cam, TEA stage 2 heads, Holley intake manifold, and a undetermind brand headers. Currently I have a Borla rear section on the car. What would be best for max HP gain and drivability for me? Any help would be great. Thanks in advance fellow forum members.
oh Yeah, Long tube or shorty headers?
What's best?
Need some suggestions on if I should go with cats or no cats on my 97 Vette. I'm going to put some new mods on it such as Lunati 224/224 554 114 cam, TEA stage 2 heads, Holley intake manifold, and a undetermind brand headers. Currently I have a Borla rear section on the car. What would be best for max HP gain and drivability for me? Any help would be great. Thanks in advance fellow forum members.
oh Yeah, Long tube or shorty headers?
What's best?
I polled 2 years ago and most people said don't do it.. Its not worth the gain if any.. And it will Stink..
Well I was determined to prove everyone wrong and gutted my own cats.. The Good news... It sounds NASTY!!!!
I love getting on it... 
the Bad news... It Stinks like schit! It has taken me over a year to get USED to the smell.. It reaks all over your clothes.. DOn't let ANYONE convince you that tuning will make the stink go away.. YOu cannot TUNE Idle the car is closed loop..
I am putting some high flow cats on the 1st chance I get..
But my guess is you will need to do it and get it out of your system
Safety Car
Joined: Mar 2002
Posts: 4,928
Likes: 1
Cruise-In V Veteran
St. Jude Donor '09
Originally Posted by chuckster
I will start off by saying that "Every Generation must learn for themselves that the stove is hot"
I polled 2 years ago and most people said don't do it.. Its not worth the gain if any.. And it will Stink..
Well I was determined to prove everyone wrong and gutted my own cats.. The Good news... It sounds NASTY!!!! I love getting on it...
the Bad news... It Stinks like schit! It has taken me over a year to get USED to the smell.. It reaks all over your clothes.. DOn't let ANYONE convince you that tuning will make the stink go away.. YOu cannot TUNE Idle the car is closed loop..
I am putting some high flow cats on the 1st chance I get..
But my guess is you will need to do it and get it out of your system
I polled 2 years ago and most people said don't do it.. Its not worth the gain if any.. And it will Stink..
Well I was determined to prove everyone wrong and gutted my own cats.. The Good news... It sounds NASTY!!!!
I love getting on it... the Bad news... It Stinks like schit! It has taken me over a year to get USED to the smell.. It reaks all over your clothes.. DOn't let ANYONE convince you that tuning will make the stink go away.. YOu cannot TUNE Idle the car is closed loop..
I am putting some high flow cats on the 1st chance I get..
But my guess is you will need to do it and get it out of your system
And you can't tune the stench down Open Loop either - believe me I've tried!
Lossed HP with the new Metal Matrix RT cats is supposed to be minimal.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Le Mans Master
Joined: Jul 2002
Posts: 7,370
Likes: 8
From: Slave to the evil empire
Cruise-In V Veteran
St. Jude Donor '04
Originally Posted by Nvd97C5
Hey thanks runamuk and RWhite.. any suggestion on a good high flow cat that won't hurt my wallet??
Headers
Safety Car
Joined: May 2000
Posts: 4,824
Likes: 351
From: Albuquerque NM
Not only will it stink, and eliminate you from passing emissions, you won't gain much power. I dyno'd mine (heads/cam) with open headers and got 425 rwhp. Bolted on stock cats, x pipe, and Corsa Indy's and got 413 rwhp. The cats may be the majority of the restriction costing 12 hp, but not all. It's not worth it for a street car, IMHO. Keep the cats.
Thread Starter
Instructor
Joined: Aug 2004
Posts: 136
Likes: 0
I'd like to thank everyone for taking the time to post a reply... After reading the replys, I will spend the extra $$ and install a high flow cat. I'll learn from others mistake and invest on the high flow now then regreting it later.. Thanks again everyone..
After reading the replys, I will spend the extra $$ and install a high flow cat. I'll learn from others mistake and invest on the high flow now then regreting it later.. Thanks again everyone..
Race Director
Joined: Jun 2004
Posts: 19,459
Likes: 48
From: Schaumburg IL
CI 7-8-9-11 Veteran
St. Jude Donor '06-'10, '13
I posted about the same thing about 2 weeks ago, here is a link to that thread
http://forums.corvetteforum.com/show....php?t=1001507
http://forums.corvetteforum.com/show....php?t=1001507
Instructor
Joined: Dec 2004
Posts: 205
Likes: 0
From: Regina Sask
Wow..What did people do back in the days of carburators and mufflers with no emmisions stuff on? They all must of stunk pretty bad...LOL. I had the car running again last night and went right to the back of the car. I could smell exhaust but I can smell exhaust behind my daily driver as well. It certainly was not obnoxious or anything that I would get annoyed with. I'll be leaving the cats off for now. If for some reason it starts to stink then I'll get high flows. I've got a 57 Chevy with headers and straight pipes and as long as it's running outside there's no problem. In the garage it stinks.....so does my 99 Concorde and my bike and my sled... if the door is closed. Try it without. If you don't like it then add the high flows later. Just my thoughts...
Race Director
Joined: Mar 2000
Posts: 17,602
Likes: 20
From: Palm City Florida
Originally Posted by Rizzo1
Wow..What did people do back in the days of carburators and mufflers with no emmisions stuff on? They all must of stunk pretty bad...LOL. I had the car running again last night and went right to the back of the car. I could smell exhaust but I can smell exhaust behind my daily driver as well. It certainly was not obnoxious or anything that I would get annoyed with. I'll be leaving the cats off for now. If for some reason it starts to stink then I'll get high flows. I've got a 57 Chevy with headers and straight pipes and as long as it's running outside there's no problem. In the garage it stinks.....so does my 99 Concorde and my bike and my sled... if the door is closed. Try it without. If you don't like it then add the high flows later. Just my thoughts...
Good point... However one flaw... In the old days cars burned leaded gas... this stuff smells SWEET... I could pull up a chair right behind a car burning leaded gas...
Unleaded.... different smell all together...
another point....some people have a much better tolerance for the unlead no cat smell.. I bet most of them smokers... It just wreaks on your clothes... makes you smell like a mechanic...
Instructor
Joined: Apr 2002
Posts: 221
Likes: 0
From: Michigan
Originally Posted by jo8243
Cars without cats stink horribly...... smells like an old POS... keep the cats.
Find the 5HP somewhere else, you can get just about as much by going to a carbon fiber fuel cap door...
Thread Starter
Instructor
Joined: Aug 2004
Posts: 136
Likes: 0
Hey, thanks again guys.. I'll just invest on some high flow cats.. I would hate to pay for the extra labor if I took the cats of and realize that the smell is too bad to deal with.. Thanks for all your replies..
Safety Car
Joined: May 2003
Posts: 4,961
Likes: 2
From: Vette-hid.com Lost in DFW texas
Cruise-In V Veteran
Cruise-In VI Veteran
Cruise-In VII Veteran
St. Jude Donor '06-'07
see sig for sound clip.Put long tubes on do not not bother with putting on shorties. I have a 226 grind cam long tubes no cats and corsas