Cats delete
Instructor
Joined: Sep 2010
Posts: 242
Likes: 0
From: Topeka Kansas
My first real job was at a car dealership washing cars. I then started training with a mechanic doing new car service and tune up work. That was 1972. After that I went into the industrial manufacturing field and graduated from a vocational technical machinest school. I have always worked on cars, trucks, motorcycles and have been involved in racing as well as a spectator for the same length of time. I guess I am old school and prefer the smell of high octane, methanol and nitro methane over stinky cats. I honestly have never smelled a car with a catalytical converter that didn't stink. I hate to admit it but I also own a 2010 Ford Fusion (wifes car) and it stinks also.
I left out another little tid bit. I am also a pilot. I can tell the difference between AV gas, pump gas and jet fuel.
I left out another little tid bit. I am also a pilot. I can tell the difference between AV gas, pump gas and jet fuel.
Last edited by bucketlist1957; Oct 28, 2010 at 09:58 PM. Reason: Left something out
Thread Starter
Intermediate
Joined: Sep 2010
Posts: 33
Likes: 0
From: Brownsville texas
So is it worth getting rid of the cats or no? i have the stock cat back on my 97 vette n some friend of mine went straight pipes but used only half of his cat back so sold me his magnaflow but just the muffler itself and all i want is for it to be louder.
Burning Brakes
Joined: Mar 2010
Posts: 1,189
Likes: 4
From: Freeport, FL
It will add to the sound, and of course we all know that the easier the engine can breath and exhale the better it will run. I'd say just get a tune after the delete so that it has the correct A/F ratio. Gotta think, the stock tune is for a stock set-up.
Advanced
Joined: Oct 2010
Posts: 71
Likes: 0
From: Jonesboro, AR
Deleting cats won't affect A/F, just based on deleting them. Front o2's determine a/f, rear just make sure the converter is working. I've ran a converterless untuned 04 Goat for some time and noticed slight torque increase and noticed a gain of about 2mpg. I love the smell of a slightly rich V8 running 93 or better octane, makes my nostrils twinge.
Last edited by bo.benson; Oct 28, 2010 at 11:53 PM.
Pro
Joined: Apr 2007
Posts: 585
Likes: 2
LO PHAT
Pro
Joined: Apr 2007
Posts: 585
Likes: 2
on that one. The slight increase in torque I'll give you, but there is no way that you are going to see an increase of 2 mpg by removing the cats. There have got to be other variables at play...LO PHAT
Advanced
Joined: Oct 2010
Posts: 71
Likes: 0
From: Jonesboro, AR
Say what you want but there are no variables in an average of over 10 tanks of gas on the same drive I do week in and week out. No other mods done in that period of time. And you know that if anything I would be driving it harder with the converters out with the sound difference. I can't explain it either but trip meter doesn't lie.
Burning Brakes
Joined: Mar 2010
Posts: 1,189
Likes: 4
From: Freeport, FL
Removing the cats will increase both sound and power. Sure, it won't add 100hp, but even if it adds 5hp and a healthier sound, that seems worth it to me. Especially when on is not concerned with emissions testing or odor. GM noted that the addition of pup cats cost 5hp, so I would only imagine that the primary cats are worth a few ponies also, right???
Form personal experience, every V8 chevy I removed the cat(s) from also ran a bit cooler. of course they were older higher mileage cars, but the principle is the same.
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Racer
Joined: Dec 2002
Posts: 322
Likes: 0
With a tune you'll see a nice gain from the removal of your cats and yes it will sound louder and better.
How much?
With just the removal of the cats (that's it) I gained 15 rwhp and 11 rwtq.
Worth it? Hell yeah.
Last edited by Tact; Oct 29, 2010 at 09:04 AM.
Thread Starter
Intermediate
Joined: Sep 2010
Posts: 33
Likes: 0
From: Brownsville texas
Last edited by Tact; Oct 29, 2010 at 09:04 AM.
Le Mans Master
Joined: Nov 2005
Posts: 6,993
Likes: 25
The only way you got 15rwhp is if both your old cats were plugged up and you car was barely running to begin with.
Last edited by Tact; Oct 29, 2010 at 09:04 AM.
Le Mans Master
Joined: Mar 2004
Posts: 8,700
Likes: 298
From: Ft. Lauderdale Fl
My first real job was at a car dealership washing cars. I then started training with a mechanic doing new car service and tune up work. That was 1972. After that I went into the industrial manufacturing field and graduated from a vocational technical machinest school. I have always worked on cars, trucks, motorcycles and have been involved in racing as well as a spectator for the same length of time. I guess I am old school and prefer the smell of high octane, methanol and nitro methane over stinky cats. I honestly have never smelled a car with a catalytical converter that didn't stink. I hate to admit it but I also own a 2010 Ford Fusion (wifes car) and it stinks also.
I left out another little tid bit. I am also a pilot. I can tell the difference between AV gas, pump gas and jet fuel.
I left out another little tid bit. I am also a pilot. I can tell the difference between AV gas, pump gas and jet fuel.
My wife owns a Lexus, one year old, and at times, it also stinks.
Le Mans Master
Joined: Nov 2005
Posts: 6,993
Likes: 25
Team Owner
Joined: Jan 2004
Posts: 22,185
Likes: 65
From: NJ
This thread is become pretty comical.
My observation from experience is that the cats keep the raw exhaust smell down as well as keep you within the law in case you ever get a roadside inspection. I actually spent more money than I needed to to put cats on my LG Street system because I cant stand that raw fuel smell when you start the car cold, and when you are sitting at idle. I had the car tuned recently and the tuner (very well respected) said that if I remove them its only going to be good for a few HP, so I saw no good reason to take them off.
Lots of people have this Billy Bob 70's mentality when it comes to emissions control and don't realize that the newer cats (and emissions control in general) aren't like the older, restrictive pancake style cats GM used to use. If you want to rip apart all the technology that makes these cars great street cars and mimic a 1970 Nova, why not just get a 1970 Nova?
For an all out race application, there are certainly better cars to start with, but its understandable. I dont think anyone in this thread has a race only car.
My observation from experience is that the cats keep the raw exhaust smell down as well as keep you within the law in case you ever get a roadside inspection. I actually spent more money than I needed to to put cats on my LG Street system because I cant stand that raw fuel smell when you start the car cold, and when you are sitting at idle. I had the car tuned recently and the tuner (very well respected) said that if I remove them its only going to be good for a few HP, so I saw no good reason to take them off.
Lots of people have this Billy Bob 70's mentality when it comes to emissions control and don't realize that the newer cats (and emissions control in general) aren't like the older, restrictive pancake style cats GM used to use. If you want to rip apart all the technology that makes these cars great street cars and mimic a 1970 Nova, why not just get a 1970 Nova?
For an all out race application, there are certainly better cars to start with, but its understandable. I dont think anyone in this thread has a race only car.
Last edited by Chevy Guy; Oct 29, 2010 at 12:50 PM.
Pro
Joined: Apr 2007
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Racer
Joined: Dec 2002
Posts: 322
Likes: 0
Wrong and wrong. But you're obviously one of those guys who knows more than the average branch. Too bad you're stuck in Lo Phat's dark place.
Pro
Joined: Apr 2007
Posts: 585
Likes: 2
Dougbfresh is correct. You could not have gotten 15 additional horsepower by removing the cats. While this might be possible to attain on some old truck with plugged up pellet-style cats, removing the cats on a C5 will typically give an increase of only 1 to 3 horsepower.
Before you make any additional comments that need to again be removed by a moderator, use the search function of this forum. There are dozens of threads that have documented this topic. If you saw an increase of 15 horsepower after removing your car's cats it was likely due to a tune or variances in the dyno(s) used.
I'll go back to my dark (i.e. enlightened) place now...
LO PHAT
Melting Slicks
Joined: Jun 2008
Posts: 2,283
Likes: 16
From: Katy Tx
I think you will find you have traded an occaional slight sulphur smell from the cats for a much stronger skunk-like smell of untreated exhaust. There have been Lots of posts on CF about the smell. High flows are a good compromise.