what is a decat?

[skiba]

n00b question but what are the advantages/disadvantages of having a decat? I have an sti exhaust on my 02 wrx and would like to make it slightly quicker. I've been advised a new filter and a decat? Is that the way to go for a few extra hp? Cheers

 

[MrMatteh]

its just a pipe that replaces your (restrictive) catalytic converter in your exhaust

on my car I found it increased torque a bit low down, not sure if peak bhp was changed.

does sound nice though, pops and bangs a treat

 

[adam0bmx0]

You'll also most probably fail an MOT emissions test with a de-cat on, most people swap the cat back in for MOT's.

 

[skiba]

is it an easy swap? low down is exactly where i need the extra grunt...What about the filter? worthwhile?

 

[MrMatteh]

again, ive got a panel filter in my standard airbox and it makes a slight difference

much better than the k&n i had on, as that suffered from quite noticable heatsoak!

 

[BigglesPiP]

Illegal for use on the road.

 

[ci_newman]

Illegal for use on the road.

WTH are you on about?? My de-cat is fully declared to my insurer. A car has to pass emission testing at the time of the MOT - after the MOT there is no way of ensuring that the car still passing emissions other than to retest it.

Some cars will even still pass emission tests with the cat converter removed

 

[McBain]

Illegal for use on the road.

Not true.

 

[Hunders]

I thought that all cars registered 93> HAS to have a cat in order to pass the MOT?

 

[Phil W]

It does, but decats are NOT illegal for road use. If Police decide to do an emissions test and it fails, they can make you go and get the cat put back in, that is all.

 

[ci_newman]

I thought that all cars registered 93> HAS to have a cat in order to pass the MOT?

I doesn't need to have a cat to pass the MOT, it needs to pass a emission test which it's unlikely to pass without a cat. .

 

[Begbie]

Thats why most people use a sports cat, passes emissions and lets more pressure through.

Saves having to swap it over every MOT.

 

[Clarkey]

Thats why most people use a sports cat, passes emissions and lets more pressure through.

Saves having to swap it over every MOT.

since when? I don't know anybody with a sports cat!

 

[austinpowers]

since when? I don't know anybody with a sports cat!

You can get sports cats with 100 cels or 200, tbh some modern cars will pass the mot without a cat, the Rover 827 (92-96, so i've heard) will.

 

[Begbie]

since when? I don't know anybody with a sports cat!

Most people with modified cars, that want there car to pass an MOT. Most forums I use, astra owner club and z22se all use sports cats other than a full decat.

 

[Meridian]

since when? I don't know anybody with a sports cat!

Er....


But you are correct that most people doing exhaust upgrades on scoobs tend to go the decat route. This is partly for perceived performance reasons (on a car which hasn't been remapped there might be a 5bhp difference. If it has been remapped, probably none) and partly to save about £400 for a full system.


But to the OP, yes, a decat will be louder and maybe (MAYBE) 15bhp more combined with an STI air filter.


M

 

[233]

or if your a bit hardcorejust rip the whole exhaust off and go single silencer side exit stylee ) or if your mad fit a straight thru although plod dont like these i found out to my cost with the old nova

 

[Muncher]

since when? I don't know anybody with a sports cat!

I have a 100 cell sports cat.

 

[GeX]

threads like this make me laugh, most people who say it'll fail an MOT haven't actually ever bothered to try and pass an emissiosn test without out..

my car is decat'd and went through the emissions test that it would've done if the cat was in place. nothing wrong with that.

 

[adam0bmx0]

since when? I don't know anybody with a sports cat!

I have a sports cat.