diy cat gut

[Nick Bryant]

Right this weekend i was thinking about having ago at gutting my cat.once ive got the cat off whats the best way of gutting it and what size/diameter bolts hold it on, just in case a few heads shear off i was gonna go and buy some and how many would i need

Cheers

[Neil Clark]

Think there about 17mm mate, and probable about 40mm long. I used a really long drill and keep drilling at the comb then a BIG hammer!

Goodluck!

[andygt]

did mine while it was on the car mate bin a plumber used to beatin sh*t outta stuff so i got a 300mm drill bit set the drill to max and away i went driling hole in it then got a bit poky thing and smahed that in to it seemed to fall out or i was able to pull it out with long nose pliers
andy

[Nick Bryant]

Cheers people,Looks like im spending tomorrow on my back in the cold

[Jon S]

It might rain as well

[Nick Bryant]

xxxx cold and wet then lol

[John Rees]

I used a club hammer and an old socket extension, hit it bloddy hard and it will tear from the edge of the pipe.

It took some smashing but it will go

[dai21t]

It'll sound xxxx though. Better off getting a proper de-cat pipe.

[fizz]

It'll sound xxxx though. Better off getting a proper de-cat pipe.

You mean any gutted cats or just the ones with holes in them fromt he 2nd method of gutting it while its still on the car!

Also... can anyone confirm what i have been told by a mechanic chap...

He said that if i gutt the cat i may loose power in the low rev range?

[PW@Woodsport]

He said that if i gutt the cat i may loose power in the low rev range

he may well be referring to the back pressure loss which could reduce bottom end torque very slightly(if at all) but i doubt you'd feel the difference....the advantage of having the exhaust gas exiting faster and spooling the turbo up quicker way outweigh any negatives you might get due to reducing back pressure.

Took me 3 hours,a huge drill bit,12" socket extension,big hammer,chisel,you name it...horrible job...you will probably end up killing the cat temp probe too,doesnt matter though,just unplug it.

whoever said a gutted cat will sound crap should think before typing.

[Nick Bryant]

cheers guys,well its only raining a little bit so i shouldnt get to wet

[fizz]

He said that if i gutt the cat i may loose power in the low rev range

he may well be referring to the back pressure loss which could reduce bottom end torque very slightly(if at all) but i doubt you'd feel the difference....the advantage of having the exhaust gas exiting faster and spooling the turbo up quicker way outweigh any negatives you might get due to reducing back pressure.

Took me 3 hours,a huge drill bit,12" socket extension,big hammer,chisel,you name it...horrible job...you will probably end up killing the cat temp probe too,doesnt matter though,just unplug it.

whoever said a gutted cat will sound crap should think before typing.

CHeers Paul.. thanks for the info...

[Nick Bryant]

Started it at eleven and have just finished,ive got no skin left on my knuckles,im freezing cold and im filthy,if anyone is thinking about doing it whilst the cat is still on the car DONT im sure it will be 100 times easier taking it off and doing it,but its all done now so cheers everybody for your help

[fizz]

bahh... forget all that!..

how does it drive!!!!!!!!!! lol You notice much difference? low end torque gone down a little?

I need details..

[MegatronUK]

Will this be as effective as a proper downpipe? Not knocking it... just curious; I'll be wanting to do one or the other with my motor.

[Fizzy]

leave it as it is! You wont notice the power improvment and the torque will fall through the floor.......

[MegatronUK]

I wouldn't have thought that would be the case with a turbocharged engine - the turbocharger itself probably supplies sufficient back pressure in the form of a restriction to the exhaust gases at a low rpm to negate the affect of the cat - certainly it would make a difference to a n/a ... but I don't think it would adversly affect a turbo.... unless someone would like to say otherwise for the 3SGTE? On the 2JZGTE removal of the cat in the downpipe make a massive difference in the spool up.

[fizz]

leave it as it is! You wont notice the power improvment and the torque will fall through the floor.......

does de-catting not help hold higher boost?

[Fizzy]

YES..IT WILL DO THAT..and spool up is quicker, but remember that unless you have 360 degree bearings you need some back pressure to hold the oil in the turbo. Ive heard many claims of power increases of 20 bhp from this mod but on testing the mt2 tub it just doesnt hold true for a stoch motor. Start modifying and its a different story....aND YOU JUST DONT WANT TO KNOW HOW HARD IT IS TO REMOVE!!!!

[Nick Bryant]

It definately spools up quicker not so much in 1st and 2nd but 3rd,4th and fifth,dont get me wrong though it might not spool up any quicker in the lower gears but it definately aint any slower and my god its LOUD!!!!
No flames yet though