Custom Exhausts

[Nate]

Has anyone made a custom exhaust for their car? I have planned what i want to make for mine, and i want to know if i can exclude the cat convertor, the South African R31's dont have cats, and they have more power due to this, so... i dont care for legality really, the permits will come later, i want to do the work while i can over Easter. Any help would be much appreciated.

Thanks

Nate =o)

[GTS-4OrCeD]

You, need a cat, it's the law.

Greg.

[R31 Chick]

Our 31 had two cats in it but we pulled one out and still managed to get over the pits! (had a yellow on it)

[Steve]

Nate, I have heard it is like a $10,000 fine if you dont have a cat. Have also heard that taking to the internals of a cat with a hammer, or welding in a piece of pipe through the middle will have a similar result to a de-cat pipe.

R31 Chick, 2 cats! thats just plain greedy:)

[Nate]

My oh my... must be something with newer cars then, i dunno what the hell a cat does, cep for make it lose power, and filter more crap thru, but its worth keepin it on there then. I made a very nice setup for my old 202 a while back with two - piece extractors joining to one with a single muffler before the diff curve, and a big hotdog at the back. Fully ricey, but the 202 was worked, so i didnt really care. 17" rims too...NOO!!! I Miss em :'(

[Guest crackity]

my old ride never had a cat...got over the pits fine

[Steve]

Think it has a lot to do with when they are made? Ie complience with emissions

[Nate]

Yea, it doesnt say you have to have a cat, just that u have to comply with emission laws, and that the exhaust shouldnt exceed the volume of the std one by a noticeable amount... I dont know how some cars get over the pits... Ive done nearly all my work to my car this holidays Gotta get the permits now before i can drive it anywhere though

[Sneeza]

Nate - a cat converts the exhaust fumes from being very poisonous to be being less harmful fumes. It reduces the carbon monoxide and hydrocarbons from being "emitted" from your exhaust. I think it is mainly for the environment. wow I remembered something from chemistry hahaha

[int21h]

Ok, so what about custom exhauts?

I'm thinking about ditching my kakimoto cat back zaust and getting a custom 3" made up.

Is this good idea or bad idea?

Are the costs more or less?

[Cake]

whats wrong with your curren kakimoto catback? i'd only replace it with a custom, if it was less than 3" or rusted out. if you're lookin for a full custom system, its gonna be $1000 at least. if you want to get the rest of the exhaust done (cat - turbo) just get that custom made, should be well under $400. custom exhaust just means its custom made, to how u want it, not an off-the-shelf item.

[rev210]

bad idea.

If it aint broke don't fix it. Get the dump/front pipe done in stainless (should cost you no more than $450 for both fitted).

If you are evil, then have the old cat removed and stick a matchng 3 inch stainless pipe through the middle of it, so it looks like a fully functional cat from the outside.

BTW, the cat stops working once you use fuel additives (like toluene) and run non-factory fuel mistures. They die remarkably quickly on performance vehicles.

[Steve]

I heard somewhere (cant remeber where) that the cat is totally useless after about 70000kms anyways

[Nate]

Oh well, i dunno about the cat, but im fitting a custom exhaust, cat back...and so far... ive spent... $45 on 2.5" and 3" piping. But this is cost price, as im doing all the labour myself. Also, im getting the bends done at my dads work, they use an oxy torch or somethin the rather, with sand or something in the pipe.. to bend it and keep the same diameter right the way thru! Dunno how mandrel bends work, but this is basically the same thing, (maybe is iunno)

[Nate]

Also, another good thing, is that marlows is asking for $40 for the adapter that goes between the air pod and the air flow meter. The bad thing with the marlows one, is the intake is SQUARE!!! This reduces the flow of the intake, because the square is smaller than the circular channel. Im gettin this done for nothin too just a plate with 3" exhaust pipe stuck on it. EZ! Next problem... heat shield...

[int21h]

My kakimoto has a resonator and isn't loud enuff

[Jengi]

But then you run into droning issues when driving which will get pretty irritating. I have a kakimoto myself and they flow really well...thats all u need, if u want more noise just ditch the turbo-cat assembly, get a new dump and screamer pipe made up and ur set dude.

[int21h]

Yes, i thought it would make it worse if i took the resonator out. I didn't know what these kakimoto zausts are like.

Soon as i get some decent cash flow, i'll do the front pipe and cat.