Hay has anyone made their CAT convertor straight through. I was thinking of buying a high flow through unit but i can just punch the inside of mine out.

Has anyone got rid of their cat inside. Have you noticed much improvment.

Watch out with removing guts of catalytic converter - its a $2,000 fine from the EPA...

Ouch.

Cheers
Heath Young

doin that is illegal in most states
cat's r there 4 a reason, if nething just get a high flow one, not clean out the inside

I know what it's purpouse is, and yes it's illigal but i was just asking. Anyway what are the benifits oh having a high flow cat, how much in kW.

Cheap Alternative : Get a Commodore or a Falcon Cat as they are usually Big enough for most Exhaust Jobs..
They don't impede the flow of the exhaust but still do the job.


DO NOT HOLLOW OUT THE CAT!!!!
Hollowing out your existing cat is Dangerous and silly and has no Kw Benefit..
( It has been proven on many Import four Magazines)

The thing is the other night I replace my system with a RedBack exhaust system from the cat back and when we had the exhaust off we started the car and with the cat in place it wasn't all that loud, therefore this means that it impedes the flow quite a bit. I have had two cares with no cats so to speak and there was a huge difference in kW.

A cat converter is on of the most restrictive parts in any exhaust, well for normal cars, a Porsche etc, use a completely different design, where the gas is not blown through a honeycomb like media, but a flow trough mesh with 3 different metal, these metals cause a chemical reaction to occur, and bobs your uncle. I just want more sound and more pickup.

Whilst i agree that the cat converter can be one of the most restrictive parts of any exhaust system i disagree with your statement about the exhaust flowing better because it sounds louder. :nuts:

Whilst I agree that the cat converter can be one of the most restrictive parts of any exhaust system I disagree with your statement about the exhaust flowing better because it sounds louder. :nuts:

Well there is a whole dam definition for it and equations to follow, but it basically comes down to that sound pressure is a direct translation of acoustic power. The higher sound pressure means that the power behind that sound pressure wave is higher. This translates to the input power of that sound. Of course there is a limit to here this principle no longer applies, this is usually anywhere above 95dB(A). The sound pressure level is then directly translated to radiated sound power, where the power does no longer obey the 20log(SPL)^10)=OSPL, so there. I think that's right.

But all I meant was that the cat was restrictive to the point that the car was marginally louder with the cat in place with no exhaust.

I've heard that using a 3" cat on a 2.5" system is a good idea also, obviously a bit of welding would required to conenct everything up properly to the cat inlet/outlet but it allows for slightly better flow again through the cat, especially if it is a high-flo unit.

i just replaced every part of my exhaust BUT my cat......sounds sweet, pretty *** loud and definately an increase in power which was proved at the drags