OPINIONS: Removing CAT from D40 2.5td auto

Hey guys I am about to remove the CAT from my navara next week.. I am going to unbolt it from turbo back to DPF and get a 3" pipe made up for it as I already have 3" from DPF back... I would like your opinions about doing this.. the real reason for this is to see if I can get a note out of the exaust as you D40 owners know that there quiet asssssss.... im also doing it to improve flow rate and power gains Thanks for taking your time to read this and hopefully answers!

Removing the DPF is illegal, so mum should be the word.

Watch the sensors before and after - the ECU monitors those to see if there's a pressure differential and if there is, it triggers a regen cycle (injecting diesel into the chamber during the exhaust stroke of the cylinder). If there's enough differential, it will put the vehicle into limp mode.

yeh im not going to remove the DPF thats staying.. im just pissing off the cat..

Is removing the cat legal in QLD?

I hate cats, if were up to me i'd remove the creepy little buggers from my life all together, i'd never even think about letting one in the nav!

Mine works fine and has a sweet note too.

That's it.

I'm moving to QLD.

Krankin nah it is illegal but no one would know.. unless you get pulled up by a cop with a sniffer but yeh a chance ill take to see the difference...

Its illegal in vic too but mine still looks like its on there.

LOL, apparently the fine for welding on a 'fake cat' is higher than no cat as well.

Jason said:

The fine for welding on a 'fake cat' is higher than no cat as well.

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I know. Dont tell anyone.
Mine is the original cat just nothing inside it.

Got another IDEA!?! What if I sat there for about 2 hours with a big ass screw driver and punched out the guts of it...? i wounder how much the fine is?

Put a high flow one on, and stop poisoning everyone!

Solid.. we must have posted at the same time.. lol

Mine is gone, it runs fine.

4BYFOR said:

Got another IDEA!?! What if I sat there for about 2 hours with a big ass screw driver and punched out the guts of it...? i wounder how much the fine is?

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Punching out the cat will actually not make your Nav's performance any better.

Why? Since the cat is wider than the rest of your exhaust system, by hollowing it out, you create a 'chamber' for the exhaust gases to accumulate and 'swirl' around.
Exhaust gases entering the cat will expand to fill up the cat and hence slow down in velocity. This creates a 'bottleneck' effect but in reverse. The sudden slowing down of the gases as they enter the cat and then acceleration of the gases as they exit the cat causes a fluctuating effect which robs you of power.

In my years of modding skylines and turbo cars, if you're gonna hollow out a cat, you must weld a straight through pipe (which is the same diameter as your exhaust) inside your cat.
It's basically a cat with all the guts removed, with a pipe through it.

Mine felt like it revved better at high rpm without the cat.
If you had to add up the gunk taken out of the cat its virtually blocking more than half the cat.

4BYFOR said:

Got another IDEA!?! What if I sat there for about 2 hours with a big ass screw driver and punched out the guts of it...? i wounder how much the fine is?

Click to expand...

It doesnt take 2 hours I noticed an improvement on mine.

From what I have been told by exhaust fitters, I wouldn't smash the guts out.

The crap inside is said to be highly poisonous.

Dave.

hold your breath?