9D4Z28

anyone know how much of a horsepower gain i will get from a highflow catalytic converter on my 94 z28 bone stock

RamAir95TA

iTrader: (2)

A handful.

Swift_01_z-28

iTrader: (1)

I would say 3-5.

multmigs

iTrader: (2)

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....

ss.slp.ls1

iTrader: (36)

^ +1.

WhitePhoenix99

iTrader: (12)

Not as much as you would if you just got rid of it all together

multmigs

iTrader: (2)

X2^^^^ I'd do this if you are after el cheapo HP

wrd1972

iTrader: (12)

Practically none.

hitmanws6

iTrader: (20)

only do this if your cats are going bad and need to be replaced

harner

iTrader: (16)

I like the way you think.

Black93_Formula

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.

WhitePhoenix99

iTrader: (12)

Why? Hell I had my cats cut out the 2nd day I had my car lol. The only use for them is if you have to pass emissions. . otherwise they are just restricting airflow

xx_ED_xx

iTrader: (17)

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.

hitmanws6

iTrader: (20)

right i meant if you want to stay emissions friendly

RedFire04

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.

Formula350

iTrader: (3)

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.

officermartinez

iTrader: (1)

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!

WhitePhoenix99

iTrader: (12)

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.

slick1851

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!

xx_ED_xx

iTrader: (17)

Yes since some of you are not familar with them not all cats are the same. Earlier ones you could knock the guts out of them. Newer metallic honeycomb cats you can not. And if they are clogged up and got almost 200,000 miles on them then yes you will notice a difference.