Cats or NO Cats?????
On The Tree
Joined: Jul 2008
Posts: 187
Likes: 0
ya know how much it costs to make a 700+ emissions legal engine and btw you didnt mention any engines that make that much power. It's cheaper just to rip the cats off and reduce exhaust impedence then it is to build up an LS1 to retain its "federal legality" and remain emissions friendly.
Yes, I do know how much it costs to build, since I've done it.
Removing the cat on a stock or mostly-stock engine will not improve power. It will only increase emmissions. This has been proven on multiple dyno tests. It's certainly true that when cats first started being used they destroyed power (althought much of that can be blamed on the decrease in static CR that occured at the same time) but on modern engines there is no benefit to removing the cat on any remotely streetable engine.
Removing the cat on a stock or mostly-stock engine will not improve power. It will only increase emmissions. This has been proven on multiple dyno tests. It's certainly true that when cats first started being used they destroyed power (althought much of that can be blamed on the decrease in static CR that occured at the same time) but on modern engines there is no benefit to removing the cat on any remotely streetable engine.
TECH Enthusiast
Joined: Jan 2002
Posts: 531
Likes: 0
From: Helendale, Ca (SilverLakes)
Since the Cats only use up 3-5HP (dyno proven) I would not mess with them.
Besides, if you live in a Smog Testing State, if you remove/modify them or move them from stock location.....you are screwed.
Besides, if you live in a Smog Testing State, if you remove/modify them or move them from stock location.....you are screwed.
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I would leave them. The exhaust smell of running no cats gets old. Even if it doesn't bother you, it might bother your passengers (girlfriend/wife.... mother?)
Plus if you need to get an emissions inspection every year or so, you may run into problems.
Plus if you need to get an emissions inspection every year or so, you may run into problems.
If you are going to mod your car at all don't you want the "MAX"? 
No. I, and many others on here, already make more power than can be used on street tires.
And I rather like the idea of my children and grandchildren being able to breath without sticking a filter in their nose.
And I rather like the idea of my children and grandchildren being able to breath without sticking a filter in their nose.
TECH Apprentice
Joined: May 2004
Posts: 318
Likes: 14
From: Chicago, IL
Sorry if it's a dumb question...but can you get highflow cats separate from a catted Y? Is there any benefit to doing that? Does that mean you get an ORY and do a lot of cutting, fitting, and welding to get them on?
Last question...is there any value to it, or any cost savings?
Last question...is there any value to it, or any cost savings?
On The Tree
Joined: Jan 2009
Posts: 199
Likes: 0
From: Waco, Tx/ Houston, Tx
Thread Starter
On The Tree
Joined: Nov 2007
Posts: 143
Likes: 0
From: Tyler ,Tx
Well know more than have done to my car I believe I will leave it as is for until I find a job and can do it the right way, I was just considering taking the cats off and putting pipe in place of them and just run o2 simulators but Ive changed my mind.
I just installed True Duals, and i dont have cats as of yet ( i have high flows, just need to get a shop to install them on my system) and i cant say the exhaust smells bad. It smells like an old muscle car. But i do think im going to install them, just so its "closer" to being legal. ha ha And it does rasp a little. which bugs the **** out of me
A lot of people have them and don't have them. The choice is yours. I will most certainly be using them. I don't feel like coming across the right cop that will look for them. Or the inspection shop that will notice they aren't there.
To me, its just safer to have them. I doubt removing them would be worth that much more power. But I could be wrong.
To me, its just safer to have them. I doubt removing them would be worth that much more power. But I could be wrong.
You all are on crack!
Taking the cats off decreases power? Absolutely not! Without a tune maybe, otherwise not.
The smell is unbearable? No way. If your old yes or if your running the car inside tunnels or garages. The rest of us who run their cars outside barley notice the smell. I had the cats off my GTO for a year and no one was the wiser. Not Mom,Dad, girlfriend, or my uncle had a clue.
Having the cats off is a good way to free up some extra ponies. Yes, It can make your setup raspy (unless your TDs), yes it does smell a little, and yes if your state has emissions don't even think about it. Otherwise id do it. Id recommend a tune too.
Good luck.
Taking the cats off decreases power? Absolutely not! Without a tune maybe, otherwise not.
The smell is unbearable? No way. If your old yes or if your running the car inside tunnels or garages. The rest of us who run their cars outside barley notice the smell. I had the cats off my GTO for a year and no one was the wiser. Not Mom,Dad, girlfriend, or my uncle had a clue.
Having the cats off is a good way to free up some extra ponies. Yes, It can make your setup raspy (unless your TDs), yes it does smell a little, and yes if your state has emissions don't even think about it. Otherwise id do it. Id recommend a tune too.
Good luck.