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

    • GCG is a good company, they're a major distributor for Garrett in Japan as well.
    • Nah, OEM washer bottle and brake fluid reservoirs are fine I don't know what it is with the plastic that Mazda used, some plastics, like the washer bottle and brake fluid res are fine, and still look new after 20 years use, where as the coolant expansion tank, and PS reservoir, that I replaced with new OEM items when I first got the car, turned yellow and started getting brittle a few years later If the dirty yellow stained plastics didn't trigger me there wouldn't be an issue, but they did, much like the battery bracket....... Meh As for going back to work full time to support car stuff, nope, why, because I own a Mazda NC MX5, not a Nissan R series Skyline 🤣
    • I've never heard of CJ-motor, so can't advise you on them. I'd just go straight to GCG for a GCG highflow though. Seems no point to use a middleman. I'm somewhat surprised that the price on the CJ site is lower than the GCG retail price. Even though CJ would get a discount of some sort, you would hardly expect them to give up so much margin. Maybe the price is out of date? Having said that "I'd go to GCG"...when I did my highflow, I went to Hypergear. I did this https://hypergearturbos.com/product/rb25dethighflow/#tab-dyno-results with the R34 OP6 450HP profile. With the BB centre (extra $400) and intially with the standard boost actuator, but I eventually got him to send me the high pressure one when I got to the point of being able to actually use it. Ends up costing the same sort of money as the GCG highflow, but this is, of course, the turbo that I KNOW has a shorter length core and so moves the comp cover rearwards. The GCG apparently doesn't do that. My mechanic also swears by the GCG highflow, given that we have another turbo rebuilder who does something essentialy the same as theirs, using Garrett wheels. He says it stands up at really low revs and makes good power. I haven't pushed my HG highflow past ~240-250rwkW yet (should have a little more in it, but unclear how much) and it does have a fairly gentle boost ramp. OK, it's much better now that I have gotten my boost controller tuned up on it.  A lot of my earlier unhappiness was because I couldn't keep the wastegate flap as closed as it needed to be (including some mechanical issues). I'd still prefer it to boost up nearly as quickly as the stocker, and it certainly a bit slower than that. So maybe the GCG one is worth the first look (for you).
    • Ok thanks 🙂 I will higly consider this. Any "known" company for a good reviews and experience to send that off? Is that CJ-motor good one? Or go straight to GCG site? I need to use VPN to even find some of those "shops" let alone access them 🙂 
    • You can literally put in as much WMI as it takes to quench the combustion totally (and then back it off a little, obviously), and it will keep making more and more power. The power comes from the cooling effect of the water (and the meth) and the extra fuel (the meth, which also has massive octane). It is effectively exactly like running E85. One might be slightly better than the other, but they are damn close. But with either you can lean on the boost or the timing (or both) waaaay more than with just petrol and the results are similar. Here's the first thing I googled for an anecdotal bit of evidence. Can't access the attachment without being a gold member, but it is there for the getting if able to, or searched up elsewise perhaps. https://www.hpacademy.com/forum/general-tuning-discussion/show/wmi-vs-e85/
×
×
  • Create New...