Jump to content
SAU Community

gutting cat converter


Recommended Posts

If you have a hi-flow cat then the piping should be 3", if you can managed to weld a piece of 3" pipe inside the cat then it wouldn't be restrictive at all. There will be a small performance edge in doing this, but may not be worth your while unless you have a high-horsepower car.

See'ya:burnout:

Please please please don't do this.

It's really bad for our environment, makes your car smell like sh1t, and you can cop a $10,000 fine for it...

Plus unless you have a highly, HIGHLY modified car, you won't gain more than 5-10kw, and that's being generous.

Originally posted by Duncan

Run NOS, the fine is cheaper and the increase larger

AAAAAAAAAAAHAHAHAHAHAHAHAHAHA!!!

:lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:

Works,

Did you notice any difference in performance? I'm planning on doing this cause I'm going to run rotational idle, but I'll still have something which looks like a cat for the cops. I can't imagine that the fumes would be much worse either.

See'ya:burnout:

Due to the age of my car i dont have to run cats (thats what rta said because i did check as the cat adr came in after the yr of my car) and the only time my car smells is on warm/start up.

As Andrew said it is a big fine for a few more KW and it will stand out as all hell if a cop spots the flame out the ass end of your car.

Yes the flame looks dam good but is it worth it in the end? :)

If your going to worry about the environment sell your car and buy a push bike ;)

If your going to the track get a pipe section made up so you can remove the cat (would take 5mins) if it worrys you that much and swap it back to the cat for the street.

definately a louder, crisper note. droning is caused by mufflers/resonators or anything that impacts the flow of your exhaust gas, so removing the cat is more than likely going to reduce the drone of your exhaust.

environmental issues is the usual argument that comes up when mentioning removing cats. fact is... catalytic converters have a limited working lifespan, which is approx 100,000klms for oem units, and usually less for aftermarket items. how many cars on the road do u think replace their catalytic converter every 2-3 years? yep, none. unburnt fuel can also melt the core of the catalytic converter. so those guys with huge camshaft overlap, or running insanely rich mixtures (which will include most ppl with skylines :)), will more than likely have an almost useless cat anyway.

headaches? doubt it, more likely to be an exhaust leak somewhere under the car, maybe the gutted cat wasn't reinstalled with the gaskets?

other than the possibility of a fine, i personally cannot see a reason to not remove your cat... (that is unless it's just for the flames :) )

been tempted to do it with the ute, i used to run hi flowing cats on my auto ute and it had bulk top end mumbo :P

Might get some Cat replacement pipes made up for "drag" usage and then just get my spare set of cats, remove the cover and get put it around the pipe so when i drive to and from the drags i dont get cop hassles :)

For me though cat/no cat is almost pointless as when cold the cats dont work anyway and by time i get to work they only just start heating up ahah..

Eitherway I'd keep 2 sets of pipes for race/drag use and for daily driving. But for fun i'd go no cat for a bit just so i can get footage of flames ;)

flames and quicker turbo spool up. Top end flow is increased as well.

If you look inside the catalytic it is quite a restrictive peice of work. Having a de-cat pipe or better still a flame thrower is good for off street work. If the exhaust joint does a nice 3 bolt flange and give you some spare gaskets its only a 10min job so you can stay legal on the street and go wild at the track.

Does the plex allow you to run dump pipes/flame throwers these days?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • It would be well worth deciding where you want to go and what you care about. Reliability of everything in a 34 drops MASSIVELY above the 300kw mark. Keeping everything going great at beyond that value will cost ten times the $. Clutches become shit, gearboxes (and engines/bottom ends) become consumable, traction becomes crap. The good news is looking legalish/actually being legal is slighly under the 300kw mark. I would make the assumption you want to ditch the stock plenum too and want to go a front facing unit of some description due to the cross flow. Do the bends on a return flow hurt? Not really. A couple of bends do make a difference but not nearly as much in a forced induction situation. Add 1psi of boost to overcome it. Nobody has ever gone and done a track session monitoring IAT then done a different session on a different intercooler and monitored IAT to see the difference here. All of the benefits here are likely in the "My engine is a forged consumable that I drive once a year because it needs a rebuild every year which takes 9 months of the year to complete" territory. It would be well worth deciding where you want to go and what you care about with this car.
    • By "reverse flow", do you mean "return flow"? Being the IC having a return pipe back behind the bumper reo, or similar? If so... I am currently making ~250 rwkW on a Neo at ~17-18 psi. With a return flow. There's nothing to indicate that it is costing me a lot of power at this level, and I would be surprised if I could not push it harder. True, I have not measured pressure drop across it or IAT changes, but the car does not seem upset about it in any way. I won't be bothering to look into it unless it starts giving trouble or doesn't respond to boost increases when I next put it on the dyno. FWIW, it was tuned with the boost controller off, so achieving ~15-16 psi on the wastegate spring alone, and it is noticeably quicker with the boost controller on and yielding a couple of extra pounds. Hence why I think it is doing OK. So, no, I would not arbitrarily say that return flows are restrictive. Yes, they are certainly restrictive if you're aiming for higher power levels. But I also think that the happy place for a street car is <300 rwkW anyway, so I'm not going to be aiming for power levels that would require me to change the inlet pipework. My car looks very stock, even though everything is different. The turbo and inlet pipes all look stock and run in the stock locations, The airbox looks stock (apart from the inlet being opened up). The turbo looks stock, because it's in the stock location, is the stock housings and can't really be seen anyway. It makes enough power to be good to drive, but won't raise eyebrows if I ever f**k up enough for the cops to lift the bonnet.
    • There is a guy who said he can weld me piping without having to cut chassis, maybe I do that ? Or do I just go reverse flow but isn’t reverse flow very limited once again? 
    • I haven’t yet cut the chassis, maybe I switch to a reverse flow. I’ve got the Intercooler mounted as I already had it but not cut yet. Might have to speak to an engineer 
    • Yes that’s another issue, I always have a front mount, plus will be turbo plus intake will big hasstle. I’ve been told if it looks stock they’re fine with it by a couple others who have done it ahahaha.    I know @Kinkstaah said the stock gtt airbox is limiting but I might just have to do that to avoid a defect so it atleast looks legit. Or an enclosed pod so it’s hidden away and feed air from the snorkel and below Intercooler holes like kinstaah mentioned. Hmm what to do 
×
×
  • Create New...