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Does anyone have information about cat converters for high power (say more than 300kw) engines? In NZ it is now a requirement to run a cat and you can't get a cert or a wof without one (except for track cars). I have searched this forum and spent a few hours on the internet. The best cats seem to have a steel or metallic rather than ceramic core but very few state a flow figure or even a power rating and most have a maximum diameter in and out of 3inches with the odd one at 3 1/2 inches. Those that do give a power rating seem to max out at 300kw. This would be enough for most street applications but I am sure that as these regs have been in place in Australia for a lot longer than in NZ and there are quite a few street cars with more than 300kw you must have come up with some solutions or does everyone just replace the cat with a straight pipe? Are there cats bigger than 3 1/2 inches or do you have to run two pipes and two cats to be legal? Would be interested to hear if there are any single cat solutions for big power applications!

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Spoke to one of Sydney's leading exhaust shop a fair while ago. Was told ceramic core cats crap themselves under high hp...gets blown to bits or collapses/melts etc and he recommended a metal cat and said the magic cat brand (or was it metal cat) was the one to go for from memory. I'm pretty sure you can get these upto 5".

Then again, my line at the moment is running a ceramic high flow @250rwkw and it's fine..cats old'ish too.

Greg from sure has sent me the following:

Our Ballistic 100cpsi Racing Cats are available in 4” body, 4.5” body and 5” body.

The 4” and 4.5” are available up to 3” pipe size.

The 5” body are available in 3”, 3.5” and 4” pipe size and the 4” pipe size flows 1023cfm.

The 4” body are $230 each, 4.5” body are $270 each and the 5” body are $340 each + $16 for delivery.

All are in stock. The bigger the body the better they flow.

They are sounding very good. I have a HKS front pipe (3") and HKS cat back (3.5"). I was going to get a 4" pipe but I'm concerned about turbulence?

While they sound very good they aren't old in and need flanges and nuts for the sensor.

This is an easier proposition:

http://www.justjap.com/store/product.php?productid=16440&cat=275&page=1

Just worried it might be too small? But I'm worried 4" is too big for the system. When people say 4" are they referring to the body or pipe?

http://www.justjap.com/store/product.php?productid=16440&cat=275&page=1

Just worried it might be too small? But I'm worried 4" is too big for the system. When people say 4" are they referring to the body or pipe?

That add says 3.5in flanged - that is for a 3.5in pipe, and the cat body is larger than that, probably 4 inch. Check the catco prices as well. The flow measurements are meaningless without stating what be pressure is....

I have this one fitted right now:

http://www.justjap.com/store/product.php?productid=18066&cat=275&page=1

Which has been pointed out as too restrictive for my -5s, HKS exhaust, etc. Currently sitting on 300RWkW and looking for more.

No I'm confused, when Ash et al say you need a 4" cat at least, they are talking about the body not the pipe? LOL

And you're right, pressurising something hard as so it flows is pretty meaningless. Sounds good though.

So i'm looking at getting a Venom cat. What series would best be suited for my skyline , 450 or 500 series ? Has a full 3 inch exhaust system from turbo back & is making 290rwkw at the moment. I want the best flow possible , would the 500 series be to much of an overkill ? :thanks:

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