R34 Gt-t Cat Replacement Pipe

[R34_Wong]

Hi everyone,

I was wondering what would be the effects of removing the standard cat and replacing it with a 3" stainless steel on a one would be on a near GT-T?

I've heard that this may result to a huge loss in lower end power.

Can anyone advise? Thanks in advance!

[R31Nismoid]

Whoever told you you'll loose power/top end is a moron

If the car is stock, probably no real increase as the rest of the exhaust needs to be upgraded.

Apart from the fact its illegal, and it will cause your car to get a lot of build up on the rear bar (in less than a week if daily driven)... you wont loose power or anything. Its the non-legal hi-flow cat basically

[R34_Wong]

Whoever told you you'll loose power/top end is a moron

If the car is stock, probably no real increase as the rest of the exhaust needs to be upgraded.

Apart from the fact its illegal, and it will cause your car to get a lot of build up on the rear bar (in less than a week if daily driven)... you wont loose power or anything. Its the non-legal hi-flow cat basically

Well the exhaust system is turbo back stainless steel. I've noticed it's a lot smoother to drive now (is that odd?), but I dunno if its me, I feel as if theres a loss of power lower end (do excuse my error). The build up will be an issue I guess... but I've got a black car so maybe not as noticable... (more whipping every day?)

[R34NRG]

why on earth would u replace just the cat? thats just stupid? your doing a half ass job, why not do the whole exhaust.

if it is a turbo back exhaust the only reason that i can think of as to why it might feel not as powerful is the power is alot smoother in delivery rather then a light switch on/off situation.

for example\

by 3,00rpm you might be makn only 80kw with the standard cat and only 60kw with the bigger cat.

but at 4,000rpm your makn 90kw but with the bigger cat your at 120kw.

but basicly who ever told u your losing power by gettn a bigger exhaust is a MORON

im very very very sure you got more power, it justs just proberly bringing the power on smoother.......

best way to find out is dyno it

Edited April 14, 2008 by R34NRG

[Scottydoo]

You should just get one of the Catco 3" cat's with the 5" body,they flow not too much less than a de-cat pipe anyway really and they r legal and your exhaust wont stink... you can get them off this forum i think the guys user name is Batmbl or something like that, I have one on my car (with a 3" turbo back exhaust) and its making more power everywhere

[R34_Wong]

You should just get one of the Catco 3" cat's with the 5" body,they flow not too much less than a de-cat pipe anyway really and they r legal and your exhaust wont stink... you can get them off this forum i think the guys user name is Batmbl or something like that, I have one on my car (with a 3" turbo back exhaust) and its making more power everywhere

Thanks guys, been a great help. I was thinking that I didn't feel a large loss for lower end power. Definately have a smoother ride. Need to get some cash up I think. Anyway, once again thanks for all the help.

[limpus]

why on earth would u replace just the cat? thats just stupid? your doing a half ass job, why not do the whole exhaust.

if it is a turbo back exhaust the only reason that i can think of as to why it might feel not as powerful is the power is alot smoother in delivery rather then a light switch on/off situation.

for example\

by 3,00rpm you might be makn only 80kw with the standard cat and only 60kw with the bigger cat.

but at 4,000rpm your makn 90kw but with the bigger cat your at 120kw.

but basicly who ever told u your losing power by gettn a bigger exhaust is a MORON

im very very very sure you got more power, it justs just proberly bringing the power on smoother.......

best way to find out is dyno it

Read the post above and you will see he already has an aftermarket exhaust...

[R34_Wong]

Read the post above and you will see he already has an aftermarket exhaust...

Indeed your right. I was driving the car today and it really does feel like its lost a lot of lower end power. Theres definately a smoother ride, moving through the gears, the car doesn't thrash as violently as I remember it being and when boost kicks in, its definately not what it used to be (maybe I'm getting used to it?). Would this actually be the case or am I being too obsessive? I had a look at the cat I removed and from what I can tell, it may have actually been a hi flow cat (looks a lot larger anyway, bugger!). What would everyones thoughts be?

[R31Nismoid]

probably need a tune more than anything

[some_cs_student]

Just be warned that in some states having a de-cat pipe can be a huge fine. Victoria is somewhere around 10K if the EPA catches you...

Batmbl sells quality metal cats, although I'd recommend the extra $$$ to get one with flanges from him, as I found getting someone to fit flanges carefully was expensive

[R34_Wong]

Just be warned that in some states having a de-cat pipe can be a huge fine. Victoria is somewhere around 10K if the EPA catches you...

Batmbl sells quality metal cats, although I'd recommend the extra $$ to get one with flanges from him, as I found getting someone to fit flanges carefully was expensive

Damn! Thanks for the heads up. Thats a scary thought to have looming above me... I'll be sure to do some checking out soon~

[r33cruiser]

10K if the EPA catches you

here in qld only the COMPANY that installed it gets that fine. e.g an exhaust shop.

if u are caught u are defected and off to court u go.

keep it in the garage for the track mate. u can smell a decat'd exhaust a mile away.

Edited April 14, 2008 by r33cruiser

[R34_Wong]

here in qld only the COMPANY that installed it gets that fine. e.g an exhaust shop.

if u are caught u are defected and off to court u go.

keep it in the garage for the track mate. u can smell a decat'd exhaust a mile away.

I agree with you there. Looks like more than likely I'll get myself a high flow cat and replace the pipe. A shame... I'll miss that roar. Thanks for the genuine advice once again, its good to hear the pros and cons from everyone