Great performance mod, gives tons of horsepower!

[RidgeRunner]

What is this great mod I speak of, and why is this in "Maintenance/repair"?

Simple... I just temporarily removed my catalytic converter. Goofy damn car had gotten to where it had no freaking power. Then it didn't want to even make it up Black Mountain... so I yanked the cat, and sure enough, chunks were falling out. Straight piped it temporarily, and it's a torquey handful as I remember it once being. Didn't think those bastards could so slowly clog up. Figured they just broke chunks off and boom, you have no power.

Sounds like a good excuse for a nicer exhaust system while I'm messing with it.

[dohcfiend]

oh, i was getting ready to say. if this is a tornado or electric supercharger add, i'd be upset.

[SappySE107]

So what you are saying is, i need to install a clogged cat, and then, remove it:P AWESOME!

Yeah, clogged cats aren't very good for gas milage or performance.

[geoffinbc]

Cool. My cat was on for 13 years and it looked fine but was no longer effective when I took it off.

Interesing how some fail differently.

[EspanolaGuitarista]

Hmmm.

So...I could core out my cat. and have more performance and not be breaking the law about removing the catalytic converter? I've seen write-ups for V8 losing as much as 30 horsepower with the cat. on!

[SappySE107]

thats the last thing I would be doing in california. You would want to run a pipe through the middle though, as it will sound like a whirlwind under the car if you just hollow out the cat.

[geoffinbc]

Re: Hmmm.

So...I could core out my cat. and have more performance and not be breaking the law about removing the catalytic converter? I've seen write-ups for V8 losing as much as 30 horsepower with the cat. on!

Maybe an OLD POS undersized cat. On a good highflow you wont lose any measurable power. Keep it on and save mother earth.

[rx191]

a cat will never hurt performance unless it is getting cloged most cats flow 30-50% more CFM than the engine can ever produce. but when they start to clog the flow rating goes down pretty quick. i'm a licesnced ca smog tech, so trust me removeing the cat will not give you any benifit unless it's cloged. also if you have a OBD2 car and remove the cat not only willl the check engine light come on but the computer will put the car in limp in mode to try and keep the emissions down even further so you will lose even more power.

[rx191]

also a cat will never go bad on it's own, something will always cause the cat to go bad like running the engine too hard for too long or a rich or lean mixture. anything that makes the cat run hotter than normal will make it burn up pretty quick. if you had the cat breaking into peices you mite what to check the engine out before putting anther one on the car

[geoffinbc]

a cat will never hurt performance unless it is getting cloged most cats flow 30-50% more CFM than the engine can ever produce. but when they start to clog the flow rating goes down pretty quick. i'm a licesnced ca smog tech, so trust me removeing the cat will not give you any benifit unless it's cloged. also if you have a OBD2 car and remove the cat not only willl the check engine light come on but the computer will put the car in limp in mode to try and keep the emissions down even further so you will lose even more power.

Tis true. Also from my dead cat failing emissions to my new cat causing emissions to be barely readable I think the $300 I spent (all stainless cat you dont have to spend this much) I will sleep better knowing im not dumping tons of unburnt hydrocarbons into my air.

[SHOoff]

oh, i was getting ready to say. if this is a tornado or electric supercharger add, i'd be upset.

Even though the leafblower mod is better. I'm still dissappointed that this thread wasnt about the Tornado/Spiralmax, or Electric S/C

[RidgeRunner]

My temporary fix was too temporary - the downpipe and the straight pipe behind that separated this evening. I couldn't get it back together on the roadside (downpipe is too badly mangled), so I had to just pin the remaining pieces up away from the road and come on back with it deafeningly loud.

This old car rapidly goes between making me happy about it and annoying me no end.

[Fedaykin]

cheers, i got one like that too

[EspanolaGuitarista]

I got a PHR magazine....

in it the where running on a dyno without the cat and then they put it on and 20 hp vanished. Reality doesn't always correlate with theory.

[tractorman]

The wife's old '94 corsica has been getting slower very gradually- so gradually that we haven't really noticed. We just got that 01 lumina, and it's A LOT faster. I'll probably try this 'mod' first. They don't do emissions testing out here in BFE, but maybe I'll hold on to that old cat just in case. I'm thinking of cutting the pipe and welding on a flange so the cat or a straight pipe can just be bolted in.

Anything else I should look for that could cause low power? It runs smooth, is quite reliable... not apparent problems... but lately it's slow and gets a couple MPG less than usual.