Jump to content
SAU Community

Recommended Posts

hey mate, i have done it on a N/a 4cyl , i wouldnt recommend it for a n/a car and i wouldnt do it on my r33.

i doubt there is much performance ot be had with a street r33 any ways ?? is there?? it would be very minimal if u had a dump full zorst and a high flow cat alrady.

Link to comment
https://www.sau.com.au/forums/topic/134803-cat-punching/#findComment-2505374
Share on other sites

Hey guys,

I am aware of punching the center out of a cat is illegal . Im thinking of punching out the inards of my sports cat and replacing it with a 3 inch pipe.

Anybody got any ideas and comments on the matter?

not sure what info your after. you admit you know that its illegal, thats really all there is to it

theres very limited gains to be had

i had one on my 33 T when i first got it

replaced it and felt or saw no difference on the dyno

a very slight deeper note to the exhaust and a little more stinky thats the only differecne between that and a god quality hi flo item

Jimbo

Link to comment
https://www.sau.com.au/forums/topic/134803-cat-punching/#findComment-2505383
Share on other sites

if you are in qld you will just have to watch out for the hoon squad. when they are doing a blitz they have a epa station setup and they will tell you to go straight to it and escort you there. they did 1 up here in gympie. had it setup for emisions and noise. went right over the car.

Link to comment
https://www.sau.com.au/forums/topic/134803-cat-punching/#findComment-2505525
Share on other sites

lol i saw "cat punching" and the last post by ctjet, it made me think of something entirely different.

I think the noise must depend on the car. A couple of my mates have had theres hollowed out and it sounds sh!t.

Personally I would just get a high-flow.

Edited by shyster
Link to comment
https://www.sau.com.au/forums/topic/134803-cat-punching/#findComment-2505533
Share on other sites

When my old S13 was brought into the country, the CAT had been split at the top - gutted out - exhaust went straight through - and finally the cat sat back around the exhaust and welded at the top where no one could see.

Sensor was still sitting in it - though it was ummm loose and rattled..lol

Went to replace it but when I took it over the pits at the RTA for first rego they didnt even test it!

Link to comment
https://www.sau.com.au/forums/topic/134803-cat-punching/#findComment-2505971
Share on other sites

The RSPCA will be onto you pretty quick for punching your cat.

PS think about what it does to the environment, and whether you are that selfish to do it for the maybe 5kW extra. Just go buy a good new metal substrate cat.

Link to comment
https://www.sau.com.au/forums/topic/134803-cat-punching/#findComment-2506028
Share on other sites

Hey guys,

I am aware of punching the center out of a cat is illegal.

Anybody got any ideas and comments on the matter?

Yeah, I do believe that punching the innards of a cat is illegal. But I don't know, I much prefer punching cats in the face.

Link to comment
https://www.sau.com.au/forums/topic/134803-cat-punching/#findComment-2506572
Share on other sites

knocking the car isnt the bet idea

best to get a pipe.

have a look at it all, the exhaust gas would be mising around something shocking, so possible gain... but a better gain from a straight pipe thats evenly flowing

Link to comment
https://www.sau.com.au/forums/topic/134803-cat-punching/#findComment-2507422
Share on other sites

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

    • Update 3: Hi all It's been a while. Quite a lot of things happened in the meantime, among other things the car is (almost) back together and ready to be started again. Things that I fixed or changed: Full turbo removal, fitting back the OEM turbo oil hardlines. Had to do quite a bit of research and parts shopping to get every last piece that I need and make it work with the GT2860 turbos, but it does work and is not hard to do. Proves that the previous owner(s) just did not want to. While I was there I set the preload for the wastegates to 0,9bar to hopefully make it easier for the tuner to hit the 370hp I need for the legal inspections that will follow later on. Boost can always go up if necessary. Fitted a AN10 line from the catch can to the intake hose to make the catchcan and hopefully the cam covers a slight vacuum to have less restrictive oil returns from the head and not have mud build up as harshly in the lines and catch can. Removed the entire front interior just shy of the dashboard itself to clean up some of the absolutely horrendous wiring, (hopefully) fix the bumpy tacho and put in LED bulbs while I was there. Also put in bulbs where there was none before, like the airbag one. I also used that chance to remove the LED rpm gauge on the steering column, which was also wired in absolute horror show fashion. Moved the 4in1 Prosport gauge from sitting in front of the OEM oil pressure gauge to the center console vents, I used a 3D printed vent piece to hold that gauge there. The HKB steering wheel boss was likely on incorrectly as I sometimes noticed the indicator reset being uneven for left vs. right. In the meantime also installed an airbag delete resistor, as one should. Installed Cube Speed premium short shifter. Feels pretty nice, hope it'll work great too when I actually get to drive. Also put on a fancy Dragon Ball shift knob, cause why not. My buddy was kind enough to weld the rust hole in the back, it was basically rusted through in the lowermost corner of the passenger side trunk area where the wheel arch, trunk panel and rear quarter all meet. Obviously there is still a lot of crustiness in various areas but as long as it's not rusted out I'll just treat and isolate the corrosion and pretend it's not there. Also had to put down a new ground wire for the rear subframe as the original one was BARELY there. Probably a bit controversial depending on who you ask about this... but I ended up just covering the crack in the side of the engine block, the one above the oil feed, with JB Weld. I used a generous amount and roughed up the whole area with a Dremel before, so I hope this will hold the coolant where it should be for the foreseeable future. Did a cam cover gasket job as the half moons were a bit leaky, and there too one could see the people who worked on this car before me were absolute tools. The same half moons were probably used like 3 times without even cleaning the old RTV off. Dremeled out the inside of the flange where the turbine housing mates onto the exhaust manifolds so the diameter matches, as the OEM exhaust manifolds are even narrower than the turbine housings as we all know. Even if this doesn't do much, I had them out anyways, so can't harm. Ideally one would port-match both the turbo and the manifold to the gasket size but I really didn't feel up to disassembling the turbine housings. Wrapped turbo outlet dumps in heat wrap band. Will do the frontpipe again as well as now the oil leak which promted me to tear apart half the engine in the first place is hopefully fixed. Fitted an ATI super damper to get rid of the worn old harmonic balancer. Surely one of the easiest and most worth to do mods. But torquing that ARP bolt to spec was a bitch without being able to lock the flywheel. Did some minor adjustments in the ECU tables to change some things I didn't like, like the launch control that was ALWAYS active. Treated rusty spots and surface corrosion on places I could get to and on many spots under the car, not pretty or ideal but good enough for now. Removed the N1 rear spats and the carbon surrounding for the tailpipe to put them back on with new adhesive as the old one was lifting in many spots, not pretty. Took out the passenger rear lamp housing... what do you know. Amateur work screwed me again here as they were glued in hard and removing it took a lot of force, so I broke one of the housing bolts off. And when removing the adhesive from the chassis the paint came right off too. Thankfully all the damaged area won't be visible later, but whoever did the very limited bodywork on this car needs to have their limbs chopped off piece by piece.   Quite a list if I do say so myself, but a lot of time was spent just discovering new shit that is wrong with the car and finding a solution or parts to fix it. My last problem that I now have the headache of dealing with is that the exhaust studs on the turbo outlets are M10x1.25 threaded, but the previous owner already put on regular M10 nuts so the threads are... weird. I only found this out the hard way. So now I will just try if I can in any way fit the front pipe regardless, if not I'll have to redo the studs with the turbos installed. Lesson learned for the future: Redo ALL studs you put your hands on, especially if they are old and the previous owners were inept maniacs. Thanks for reading if you did, will update when the engine runs again. Hope nothing breaks or leaks and I can do a test drive.
    • No those pads are DBA too  but they have colors too. I look at the and imo the green "street" are the best.
    • I’m not sure what happened I told them about sonic tunes free OTS tune and the next the I know .. I was booted..   To funny 
    • Yea - I mean I've seen my fuel pump which is decades old and uh, while I'm not saying this with real knowledge... but I sure get the ick at using anything in the fuel system that produced the state of that pump. Many years ago I went through multiple pumps (and strainers) before I dropped the tank to clean it out with extreme violence. I'm talking the car would do maybe 50km before coming to a halt, which resulted in me cleaning out the filter with some brake cleaner and going on my way. None of my stuff ever looked like what came out of your fuel tank. I don't think I'd be happy with it unless every single component was replaced (or at least checked/cleaned/confirmed to be clean here).
×
×
  • Create New...