Knocking Out Cat Guts

[Nothing(V)an]

i am buying a JJ dump/front pipe this week and am wondering what to do about the cat, i already have an aftermarket cat-back. I have been told to knock out the inside of my current cat-back to get most airfolw out of it (yes, i know it would then be illegal). Im wondering how much louder would it be (current loudness is sounds great but not loud enough to get unwanted attention)? And would doing this be the equivelent, if not better (air flow wise) than buying a hiflow cat?

[ali-turko]

buy an high flow cat, i knocked the honey comb out of my cat and i always got unwanted flames at the wrong time, its only a matter of time till a cops sees u pop a flame, and also u get that black shit on your bumper

[sinistaGTR]

mate wont be louder car smells a bit more and you dont get unwanted flames at all its only when you give it too it and back off its not like they just pop out all of a sudden.

[AndyMac]

f**k I hate threads like this.

A gutted cat is only going to get you maybe 5kw more.

- Is it worth the fine ?

- Is it worth the showoff attention it attracts (ie flames) ?

- Is it worth dump raw exhaust fumes directly into the atmosphere ?

Seriously, anyone who does this on a street car deserves a slap.

[Kinks]

^^ you forgot the most important part. flames are cool.

yeah there's no point doing it on a street car. i'd rather not be polluting the atmosphere any more than I have to.

[Dean_HR31]

Panzy's.

PUNCH IT OUT!

However if u drive ur car daily & ur worried about police go for a hi flow..

Cos the comment above about it blowing flames only when u gun it and back off is incorrect..

They seriously blow flames at any time! im talking to the extent where a little blue flame will pop out

changing into second gear at 2500rpm....

[MANWHORE]

all you enviro lovers. that is all

[nisskid]

get a metal pipe, hammer/mallet and hit, repeat step 1 untill complete.

[Dean_HR31]

haha good man..

[Blitz]

Unless you are talking about a hard tuned big HP car, there is no point punching out your cat, nevermind the fact that its illegal.

Get yourself a good quality high flow cat and that will be more than ample

[MZTRBO]

If yous are worried about punching a cat out cause of the effects to the atmosphere, do not modify your car and get an aftermarket computer which is illegal in NSW as it plays with the emissions, thus effecting the atmosphere.

I think a stock cat or hi -flow cat vs a hollow cat is a very free performance gain, especially at higher hp levels.

Im sure it could be easily a 5-10kw gain at anything over 220rwkw.

Its up to the individual and thier princibles.

MY2C

[DivHunter]

My CAT craps out black shit already (not hollow), think I need a new one

[Adriano]

Ive seen 860RWKW with a pair of 4inch cats, this was a horsepower hero dyno beast, if there was any real gain to be had, it wouldn't have had cats

"If yous are worried about punching a cat out cause of the effects to the atmosphere, do not modify your car and get an aftermarket computer which is illegal in NSW as it plays with the emissions, thus effecting the atmosphere."

Plenty of aftermarket computers can be tuned to be more fuel efficient and better emmissions than the factory 9.5:1 AFR at full load, i remember reading that 60% stock cars 5 years old would fail the drive cycle.

[MZTRBO]

Fair enough, My point was that they must enforce it for a reason. They need quite substantial reasonable cause to bring in legislation like that.

[arbess]

Dont punch your cat guts out in the first place and you have solved your own problem with the cops. Simple... why make it complicated.

I'll tell you now, if you punch them out, you are a prick, and deserve a huge fine.

If you want to know what pollution is like, move to asia and live there 24/7, then come here and tell me that you still want to punch your guts out.

not taking it out on you, but be a little more considerate and forget the 13 year olds that you will please with flames coming out your pipe.

Edited May 24, 2007 by arbess

[Nismo_God]

i want flames....burn my fully sick body kit....which is already scrapping the ground.....

seriously it will stuff up the rear end making it black....shoot flames, buy a lighter...and 5kw...learn how to drive better and u wont need those 5kw....

[nisskid]

whys everyone worried about getting black carbon on their bumpers, i thought carbon body kits were all the rage these days...

*watches the tumbleweed

[Nothing(V)an]

Thx for the input, you guys love your flames, i didnt know it would blow flames, was just asking in regards to having a bit more power and also coz i dont have and wont have a spare dollar any time soon to buy a cat. Might just leave the one i got as i have a kit fitted and car is getting resprayed next week, dont wanna burn that fresh paint.

[Nic19]

what bout with a bee-r limiter or anything similar. wont these just tear a cat apart?

[r_speedfreak_r]

id hate to go against the crowd but going from my own personal experience i belive it makes a huge difference. even if thats true and on paper it only makes u an extra 10kw but an extra 10kw at the wheels is still pretty good. And i didnt notice a difference in top end power but i thought the way the engine felt overall was a well worth improvement. Felt more agressive and i dont belive it makes much difference to the db reading but i think personally the note is alot better. Generally speaking most skylines sound the same but with the combination of having a straight through pipe and a titanium exhuast everyone who knows my car can tell its mine just by the note. And yes it does smell pretty bad if your behind the car but im never behind my own car and yes it does pop flames but ive been told it looks awesome not becuase you can see flames coming out the end of the car but because you can see it coming towards you in a blue flame down the pipe and then watch it turn yellow once its through. I think ill stick with my decision