EMPTY CAT
When I was doing some exhaust work on my 92 SSEI, I discovered that the cat was just a shell with nothing in side of it and I know there should be something! Should i replace it or is it really necessary on this year. I would guess it went bad and the owner before me gutted it out.
I replaced my cat with a magnaflow a while back because I got the "low catalyst efficiency" code. Figured my cat was plugged. When the guys brought the old one back to me it was completely hollow like yours. I am 100% no one gutted it, everything just burnt out. You don't HAVE to replace it just yet if you're short $$... but you'll be missing a lot of gas mileage and power if you don't
It made a HUGE difference for me in both those areas.
It made a HUGE difference for me in both those areas.
You MIGHT notice going from a stock cat to a hi-flow cat. 5-10hp.
You WILL notice going from a plugged old stock cat to a hi-flow.
You WILL notice going from no cat or a gutted cat to a hi-flow. You've lost low-end torque by decreasing your exhaust gas velocity.
You WILL notice going from a plugged old stock cat to a hi-flow.
You WILL notice going from no cat or a gutted cat to a hi-flow. You've lost low-end torque by decreasing your exhaust gas velocity.
Senior Member
Posts like a Northstar
Joined: Aug 2007
Posts: 620
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From: Ladysmith B.C. Canada

My day is complete, I learned something alread and I haven't even had breakfast yet.
I am surprised that a Cat will actually add power and fuel economy. In the past, I've actually gutted cats to save a few $$ instead of replacing them, but that was on cars with a lot less power to start with.
I am surprised that a Cat will actually add power and fuel economy. In the past, I've actually gutted cats to save a few $$ instead of replacing them, but that was on cars with a lot less power to start with.
The secret there is as Bill W. described and has to do with exhaust velocity.
I've seen many a person make the mistake of automatically assuming that a larger than stock diameter exhaust will gain them power, when in fact they end up losing low end and sometimes more, depending upon how big they went.
I've seen many a person make the mistake of automatically assuming that a larger than stock diameter exhaust will gain them power, when in fact they end up losing low end and sometimes more, depending upon how big they went.
UNBELIEVEABLE!!! It is like a brand new car. I picked up a Magnaflow cat. and installed it, when I got done, I drove her WOW! It is like the difference between night and day. It is hard to believe a bad cat. would weaken the engine so, but it did. Thanks for the advice.





