high flow cat horse power increase ? 
high flow cat horse power increase ?
depends on if the stock unit is crapped up or not also... I'd say a bone stock car with functional factory equipment isn't gonna gain too much, if you are smelling something weird like sulfur or if its got 200K miles that's a different story....
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Staging Lane
Joined: May 2007
Posts: 80
Likes: 0
i would just cut the cat off and put piping in its place and have no cat at all. jus use exaust cufflings to put piping back together and use a clamp on each side of both cufflings. ive done it before on vehicles and it works great and def makes it breath better. 
I have seen on the newer style cats very little difference if any on horse power. and this was dyno proof. removing cats makes the car louder about it.
Registered User
Joined: Feb 2009
Posts: 21
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Depends on the cat you go with. They DO NOT flow the same, trust me. Random Tech or Carsound cats are the only two I would ever use, and believe it or not the power difference between a good high-flow catted Y-pipe and an ORY is actually pretty minimal.
TECH Senior Member
iTrader: (3)
Joined: Oct 2006
Posts: 7,564
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From: Decatur, TN (N-W of Athens)
And yet the cost of a high-flow is not cheap and the money would be far greater spent on Mids or LT headers.
I'm usually all for cat removal (presuming you have no emissions), but my only reason for not doing it on my car is that it was replaced just a few years back and the apparently huge sound change that happens on LT1s. I love my exhaust note as is and don't want to change it :\ I've been contemplating swapping in a resonator or like a Magnaflow bullet (which is basically a resonator-glass pack hybrid heh). Not sure on what size would be required to attain the same or similar note.
I'm usually all for cat removal (presuming you have no emissions), but my only reason for not doing it on my car is that it was replaced just a few years back and the apparently huge sound change that happens on LT1s. I love my exhaust note as is and don't want to change it :\ I've been contemplating swapping in a resonator or like a Magnaflow bullet (which is basically a resonator-glass pack hybrid heh). Not sure on what size would be required to attain the same or similar note.
EXACTLY the point I was going to make. My 1995 LT1 was 275hp from the factory. It came with the single cat. I had 188,000+ miles on it before I switched EVERYTHING over. Now, I have Mac Mid-length headers (also had them ceramic coated locally in Arlington, Texas), Random Technologies Hi-Flow cat and an SLP Loudmouth 1 exhaust. Heck, I even scrapped those small SLP exhaust tips.. LOL. It is LOUD and proud. I can easily go to any inspection and pass emissions without a problem. DPS troopers (or any other law enforcement agency for that matter) can't write me any tickets for lack of a catalytic converter (or otherwise any type of illegal exhaust). But, my weak point is my exhaust note. It is loud!
Newer style? They stopped making lt1 fbodys in 97. I'm not sure how "new" the cats would be. Mine were clogged to ****. .and I felt a definate power increase after removing them.
TECH Junkie
Joined: Nov 2003
Posts: 3,265
Likes: 1
From: CHITOWN
Emissions doesnt check loudness they check to see if it will pass
And if your cats are clogged they are limiting power, thats why you feel such a big increase.
But if they are working fine, your not going to feel much or gain alot at all.
Long tubes and full 3inch exhaust are worth it!
And if your cats are clogged they are limiting power, thats why you feel such a big increase.
But if they are working fine, your not going to feel much or gain alot at all.
Long tubes and full 3inch exhaust are worth it!
