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If the car is for street use, I would settle for a Hi Flow steel CAT... BATMBL sells them at a decent price ready to be bolted on... I would much rather spend $350 - $450 for a top of the range CAT then gutt the stocker and be in risk for a $10,000 EPA fine...

If the car is for track use only, Gutt away :)

My friend gutted the CAT in his WRX and the sound was little more droney in the cabin.. thats all... however did make noticable difference in performance... but then bought a hi flow CAT after the boys in blue gave him an EPA notice... he was damn lucky they didnt call EPA on the spot...

Cheers

Edited by QRI05E

mmm, im just think if its done right with the right flanges welded on..it would probably cost less.. make a little more power and not be noticable unless the cat was un bolted..

mmm, im just think if its done right with the right flanges welded on..it would probably cost less.. make a little more power and not be noticable unless the cat was un bolted..

The EPA can very quickly determine if you have a cat on there without unbolting it with an exhaust probe.

If you remove the internals from a cat:

* Yes, of course it will look like a cat from the outside.

* Yes, the car will be louder and probably perform better. The more restrictive the cat, the

bigger the effect from removing its internals.

If you put a pipe inside it:

* You are probably wasting your time and effort. The difference in flow between gutted and

gutted-with-pipe-inside is probably negligible.

If the car is a road-registered car driven on the road in Australia:

* Yes, you _will_ be liable for an eleventy-gazillion dollar fine if you get busted.

If you're talking about doing this because your cat has collapsed (making the car undrivable) and you simply

cannot afford a replacement cat but you must drive to work - well, you have to do what you have to do.

In this situation I'd be trying a wreckers or something to keep me legal, because the fine isn't worth paying.

If you're talking about doing this for _any other reason_ on an Australian road car - don't be silly. Pay the

money, get as high-performance a cat as you can afford, and live with the fact that road-registered

cars need cats.

Regards,

Saliya

Is there an epa in QLD any way? and how do they know that YOU put it on. Im just asking does it make it much louder and what experiences has people had.

Lthlrb can you smell the fumes in the cabin while your driving?

It is a risk no doubt. which i think the owner of the car should take resposiblity for...each to their own really.

If you put a pipe inside it:

* You are probably wasting your time and effort. The difference in flow between gutted and

gutted-with-pipe-inside is probably negligible.

Its ideal to put a pipe in.

I had a noticeable difference as it was causing a bit of turblence inside the cat which wasnt helping things in an already choked exhaust system, so piping the cat can be of benefit if you've knocked it out

You take the risk you pay the price, easier and less stuffin arround to just get a high flow cat bolt it on drive away, if you cant do it yourself well give me $50.00 and ill do it for you, on another note, id like to see results of performance gains of hollowed cat with pipe vs one of batmbl's 5" metal highflow cat, and on another note the time you have to spend on cleaning your rear bar of all the soot and crap, aswell as putting up with that lovely lovely smell, you way the sums up its not that hard, especially with a street car,

And on another note, those lovely lovely defect and fines and stuffing around from doing one home job punch out of your cat vs the once off fee.

Come on people how many times does this have to be covered before people actually work it out

My opinion

Cheers

as stated in title, anyone got tips/ experiences with this?

I doubt whether you'd get a 3in through it, as I *think* the stock cat is narrower than that just inside the flanges. So you're next bet would be a 2.5in pipe - that might fit, or may still be too large. If you go for 2.5in or less it probably wont flow as well as a catco/metalcat style cat, due to the turbulence created when the cross section changes.

Also dont forget that ppl who gut cats are complete ass-clowns, and you dont want to become one of them. They bugger up the environment (contributing to the annual 1200 exhaust emmission related deaths) and leave themselved exposed to heafty fines, all because they're too tight to spend <$400 on good cat.

HTH,

Kot

How about you just do the right thing and buy a new cat...

Think of the environment.

Think of the cancer growing in your lungs from breathing in your un-catalysed exhaust gasses.

Is it worth it all just for gaining a few kW?

You'll have to clean the back of your car a bit harder each time you wash it and you will have twice as much black crap on there. If its white it'll probably stain the rear bar a yellowish colour as well.

I found it made it a bit louder on my old car but as mentioned it'll cause turbulence if you don't put a pipe through it.

Ive got a black car so it won't look that different. It will fit you just have to cut the cat housing a bit. As for cancer and contributing to the death of the environment.. you guys are funny.

I think it evens out for me acually, i ride to work and catch the train to uni so i only drive my rig on the weekends which is alot better for the environment. The lazy cu*ts who drive everywhere and would rather sit for 1hr in macas drive through than walk into the place and be in and out in 5 mins are the ones you guys should be angry at.

cheers.

I had hks dragger cat back (4inch)

i then got a 3inch front pipe made up from the dump to the mid-muffler (no cat).

Suprisingly, it does not sound loud at all. This might have something to do with silent style hks exhaust (more bends on it.)

Bear in mind one of the most restrictions in an exhaust is the catalytic converter aka cat!!!

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