Cats question
Thread Starter
Drifting
Joined: Oct 2002
Posts: 1,543
Likes: 5
From: Apollo Beach FL
St. Jude Donor '13-'14
Cats question
What will removing the cats do to my C5. Will it enhance performance, better my 1/4 times. Will it mess up the computer program? I am getting Stingers in the near future and I would like to know if I should take off or leave the cats on.
Safety Car
Joined: May 2000
Posts: 4,808
Likes: 344
From: Albuquerque NM
Re: Cats question (lawman34203)
With your mods it will add MAYBE 10 hp, most likely half that. It will also cause you to throw codes unless you add O2 simulators to the rear O2 positions. It will also be very loud, and smelly. Not worth it on a street car, IMHO. Your car may be 1/10 faster in the quarter, this gain will be as much from the weight loss as from the HP gain (minimal). We dyno'd mine with full exhaust and stock cats, pulled 413 rwhp, and with open headers it made 425. 12 hp gain on a heads/cam motor, with NO exhaust restrictions at all. Add in the hassle of finding someone willing to remove them (federal offense, big fine), and the problem passing emissions, why? :cheers:
Thread Starter
Drifting
Joined: Oct 2002
Posts: 1,543
Likes: 5
From: Apollo Beach FL
St. Jude Donor '13-'14
Re: Cats question (6Speeder)
Thanks 6speeder, I was looking around at exhusts for my car and I seen some without the cats. I guess from what you are saying, its not really worth taking them off if my car is a daily driver. :cheers:
Melting Slicks
Joined: May 2001
Posts: 2,596
Likes: 120
From: East Tennessee
Re: Cats question (lawman34203)
I picked up 6rwhp/3rwt with no cats with just boltons and then put them right back on. I had the cats off yesterday with the heads/cam to dyno it today but to be honest I put them back on this morning without even bothering to put the car on the dyno. I dont even want to know what the car picks up w/o them because I will never drive the car like that - just cant stand the smell..
Instructor
Joined: Aug 2001
Posts: 192
Likes: 0
From: Virginia Chesapeak
Re: Cats question (6Speeder)
With your mods it will add MAYBE 10 hp, most likely half that. It will also cause you to throw codes unless you add O2 simulators to the rear O2 positions. It will also be very loud, and smelly. Not worth it on a street car, IMHO. Your car may be 1/10 faster in the quarter, this gain will be as much from the weight loss as from the HP gain (minimal). We dyno'd mine with full exhaust and stock cats, pulled 413 rwhp, and with open headers it made 425. 12 hp gain on a heads/cam motor, with NO exhaust restrictions at all. Add in the hassle of finding someone willing to remove them (federal offense, big fine), and the problem passing emissions, why? :cheers:
I could not agree more.
Le Mans Master
Joined: Nov 2000
Posts: 7,294
Likes: 1
From: Coral Springs Florida
Re: Cats question (lawman34203)
I pulled my cats (all 4) two years ago and never looked back!! They are DEAD WEIGHT , actually about 38 lbs. worth..and very restrictive!! My car sounds better and pulls harder with more torque than before the removal. Does it smell?..once in a while in bumper to bumper traffic IF the wild is blowing in the car you may a wiff ..but that's it. Is it worth it..YES. If you don't pull the cats then at least get a set of Random flow thru cats..otherwise your wasting your maoney on headers and a performance exhaust..what's the point! ....Just my .02:D
For example: Put your hand over you mouth and breath in..Not much air ..huh? Now remove your hand and repeat..alot of air :yesnod:..so this is a very simple analogy..More air..more power..Do it!!:D
BTW..You can see my install of my No cat exhaust on my homepage..besides this is Florida, No emission testing.. :yesnod:
[Modified by vstella, 1:30 PM 1/21/2003]
For example: Put your hand over you mouth and breath in..Not much air ..huh? Now remove your hand and repeat..alot of air :yesnod:..so this is a very simple analogy..More air..more power..Do it!!:D
BTW..You can see my install of my No cat exhaust on my homepage..besides this is Florida, No emission testing.. :yesnod:
[Modified by vstella, 1:30 PM 1/21/2003]
Le Mans Master
Joined: Aug 2001
Posts: 8,145
Likes: 1
From: Bradenton FLORIDA
Re: Cats question (lawman34203)
Zoltan,
You drive that thing at the track good enough already!!! I do know a good local tuner that can do LS1 edit with good results, I recomend you try that for extra HP.
See you at the Corvette Challenge Feb 22nd!
You drive that thing at the track good enough already!!! I do know a good local tuner that can do LS1 edit with good results, I recomend you try that for extra HP.
See you at the Corvette Challenge Feb 22nd!
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Race Director
Joined: Aug 2002
Posts: 16,641
Likes: 1
From: Redacted
Re: Cats question (6Speeder)
It's not worth it unless you are driving strictly on the track in competitive events. Too many legal hassles for too little power in return. Not to mention a car with defeated cats can emit as much pollution as 100 cars with working cats. (yes, it is indeed true).
Le Mans Master
Joined: Apr 2001
Posts: 5,331
Likes: 39
Re: Cats question (larrysb)
I'm thinking about getting another X pipe so I can run without cats on the track (or whenever i want) and using the X pipe with the cats for the street (actually for the emmissions test)
Instructor
Joined: Jul 2000
Posts: 168
Likes: 0
From: Memphis, TN.
Re: Cats question (Gary2KC5)
I took mine off 4 or 5 months ago. No smell what so ever. I don't know what you guys are talking about. No codes being thrown, and no louder either. I was hoping that it would be louder but NO! I still have my stock mufflers until next month, I hope it is louder then.
Anyway restricted dead weight, don't listen to the Tree-Huggers :grouphug:
[Modified by Big Casino, 10:10 PM 1/21/2003]
Anyway restricted dead weight, don't listen to the Tree-Huggers :grouphug:
[Modified by Big Casino, 10:10 PM 1/21/2003]
Melting Slicks
Joined: Oct 2002
Posts: 2,855
Likes: 0
Re: Cats question (vstella)
:iagree: With my heads cam package I got about 20rwhp and could feel the diff I agree its louder but the reason is the trapped air that can't get out I think it depends on your setup how much power you get and I don't spend much time in traffic so its not as bad for me as for some.
Safety Car
Joined: May 2000
Posts: 4,808
Likes: 344
From: Albuquerque NM
Re: Cats question (NEPTUNEBILL)
Hey NEPTUNE: Did you dyno yours with and without cats, or just guessing? I did mine, back to back, with a healthy setup, and only saw 12 hp diff, from bottledup to open headers. You know that not all the restriction is from the cats, so running a full exhaust without cats wouldn't show even that much gain. How high do you rev yours, and what did you dyno with and without cats. I shift at 6400 and pull over 410 rwhp, through the stock cats. just curious. :cheers: