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I am thinking of removing my CATS on my 98 C5. Along with long tube headers, here are my mods; Kentucky does not conduct emissions testing. I also have a CAI. Any thoughts?
I am thinking of removing my CATS on my 98 C5. Along with long tube headers, here are my mods; Kentucky does not conduct emissions testing. I also have a CAI. Any thoughts?
Can't go wrong with AFR heads. Good choice with 205s. One bit of advice; if you're capable of doing it yourself, measure the installed height on the valvesprings. You'll need a special micrometer, and a valvespring compressor. Call AFR for the installed height spec. It's probably 1.780", or 1.800". I once bought an early set of their 225s. Installed height was off by .100"!!!! Found after I broke a spring at only about 300 miles!!!! Best of luck to you.......
Can't go wrong with AFR heads. Good choice with 205s. One bit of advice; if you're capable of doing it yourself, measure the installed height on the valvesprings. You'll need a special micrometer, and a valvespring compressor. Call AFR for the installed height spec. It's probably 1.780", or 1.800". I once bought an early set of their 225s. Installed height was off by .100"!!!! Found after I broke a spring at only about 300 miles!!!! Best of luck to you.......
Since you're asking for opinions, I'll give you mine:
It's pretty rude to every one of us who breathes air to take cats off on a street car. The horsepower bump is fairly mild over high-flow cats, and since you're here asking us I don't think you're doing anything where the extra handful of horsepower does anything other than give bragging rights. Cats are literally the one emissions component that make a huge, obvious difference to everyone who breathes air anywhere near your car at any time.
Spend the extra couple hundred bucks and get your long tubes with cats in them.
Spoke with my mechanic about headers. He’s a highly regarded racer and performance car builder. He said he has removed a lot of melted clogged cats and suggests I avoid them.
On the other hand, in the year plus I have been reading this forum, probably 90% percent of posts recommend having cats to eliminate gas odors and respect emissions benefits. Quite a number of these members had gone catless, but said the fumes were intolerable, so they had cats installed.
My headers will have high flow cats. If they happen to fail I’ll replace them.
I removed my cats when I went with headers and I cant smell fuel or anything in the exhaust. It smells like exhaust. My guess would be the people complaining about smell need a better tuner.
I removed my cats when I went with headers and I cant smell fuel or anything in the exhaust. It smells like exhaust. My guess would be the people complaining about smell need a better tuner.
Same here. Smells like exhaust and imo sounds better too.
Since you're asking for opinions, I'll give you mine:
It's pretty rude to every one of us who breathes air to take cats off on a street car. The horsepower bump is fairly mild over high-flow cats, and since you're here asking us I don't think you're doing anything where the extra handful of horsepower does anything other than give bragging rights. Cats are literally the one emissions component that make a huge, obvious difference to everyone who breathes air anywhere near your car at any time.
Spend the extra couple hundred bucks and get your long tubes with cats in them.
morals aside, the small horse power bump isnt the only reason why one would want to eliminate the converters bud.
morals aside, the small horse power bump isnt the only reason why one would want to eliminate the converters bud.
What would the other reasons be?
I bought the XS-Power 'Off Road' (No Cats) system in '18 - It was the only set they had at the time and they are no longer making any C5 LT systems. I am just about to the point of lighting it up (lots of Mods / Changes in this project). I would like to have Cats just for the odor I've read about but will not at the beginning. It would require taking it to a Pro once I get it all sorted. The few HP they rob is not an issue with me - It was just the it was the ONLY system they had. The install was pretty smooth - well designed and good quality. just no Cats.
I've read BOTH stories - Stinks like crazy & No smell at all (I agree with the proper tune scenario).
Thanks for any input.
What would the other reasons be?
I bought the XS-Power 'Off Road' (No Cats) system in '18 - It was the only set they had at the time and they are no longer making any C5 LT systems. I am just about to the point of lighting it up (lots of Mods / Changes in this project). I would like to have Cats just for the odor I've read about but will not at the beginning. It would require taking it to a Pro once I get it all sorted. The few HP they rob is not an issue with me - It was just the it was the ONLY system they had. The install was pretty smooth - well designed and good quality. just no Cats.
I've read BOTH stories - Stinks like crazy & No smell at all (I agree with the proper tune scenario).
Thanks for any input.
The most significant benefit to eliminating the cats on a high performance vehicle, especially one that might be modified for higher performance is that it enables the heat from the exhaust to be extracted from the combustion chamber much faster. It keeps the heat out, makes the combustion cycle much more efficient and exponentially decreases the possibilty of knock.
Most people rant and rave about how much extra heat longtube headers create, but its the cats heating up that makes the footwell/ center console area of a corvette so hot. They heat up a lot! When I installed headers, and eliminated the cats, i noticed significantly less heat than when the car was stock. I wouldn't have it any other way, even with the mild extra smell that comes with it.
Thanks for the reply. I probably WILL put them on at some point - just for the smell (which I have yet to experience - not running yet). I am not sure just how much stink I will get - the tune DOES have a lot to do with that and THAT is a Whole Nuther conversation.
I know that they get very hot - they're supposed to. I have personally seen 2 fires started by people parking in tall, dry grass.
Yeah but that was because you still had leaded gas, we don't have that anymore. I think the smell vs no smell crowd depends on your tune but also where you get your fuel. More ethanol means less bad odor. Ethanol burns cleaner and really knocks the smell out. Some of these guy go out of their way to find ethanol free fuel and it makes me wonder. Yeah it is stable longer but it also doesn't burn as clean and will make your exhaust smell worse.
I know with E85 and no cats your exhaust will actually smell pleasant. Methanol will make your eyes water but otherwise doesn't smell bad either.
Yeah but that was because you still had leaded gas, we don't have that anymore. I think the smell vs no smell crowd depends on your tune but also where you get your fuel. More ethanol means less bad odor. Ethanol burns cleaner and really knocks the smell out. Some of these guy go out of their way to find ethanol free fuel and it makes me wonder. Yeah it is stable longer but it also doesn't burn as clean and will make your exhaust smell worse.
I know with E85 and no cats your exhaust will actually smell pleasant. Methanol will make your eyes water but otherwise doesn't smell bad either.
Well it's a moot point, sorry folks. I bought the C5 from a previous owner who didn't have all the specs. Since it has long tube headers, I was told the cats had to be removed. I have not been under the car, I am big guy, and she is lowered. I can't get a look.
I sense no offensive odors.
Since you're asking for opinions, I'll give you mine:
It's pretty rude to every one of us who breathes air to take cats off on a street car. The horsepower bump is fairly mild over high-flow cats, and since you're here asking us I don't think you're doing anything where the extra handful of horsepower does anything other than give bragging rights. Cats are literally the one emissions component that make a huge, obvious difference to everyone who breathes air anywhere near your car at any time.
Spend the extra couple hundred bucks and get your long tubes with cats in them.
Well, I could be wrong. I am not 100% sure I am catless. Some one told me that with long tube headers, the cats have to be removed. That may be BS. My 5th gen SS Camaro had them both. There is no odor that I can tell. She is running rich though, but I think that is all I can smell. I'll get her up on the lift.
Removing Cats
Rose buds of course. 
