Decat, lpg and emission's?

**Mental Wealth Doctor** · Sunday 4th October 2009, 18:18

Im sure last mot i had, the emissions test was only done on lpg, making me wonder whether i could decat my car without worrying about mot emission's test? anyone got any thoughts on this, i have heard the cat is very restrictive on the engine

, anyone know what kinda bhp gain there is to be found here??
and will it sound louder? i've got twin rear exhaust but i swear my old 2.0 glt was louder
2.5 lpt/mbc 855 AWD

**Volvostorm** · Sunday 4th October 2009, 20:20

Mine's on LPG, and its been de-catted. For MOT proposes you don't need one for a emissions, as the limit is 3.5%CO on gas.

Mine seems quicker to spool up on boost, and it is slightly louder, more of a burble on tickover, to a bit of a throaty growl higher up, but the could be because I have a powerflow system.

**Mental Wealth Doctor** · Sunday 4th October 2009, 20:57

sweet thats what i wanted to hear thankyou

**Wombatbomb** · Sunday 4th October 2009, 20:59

However, running without a CAT means you are breaking the Construction & Use Regulations, so best to avoid any roadside checks by VOSA.

**Volvostorm** · Sunday 4th October 2009, 21:09

Originally Posted by Wombatbomb

However, running without a CAT means you are breaking the Construction & Use Regulations, so best to avoid any roadside checks by VOSA.

Thats very true, but then 'mainly' go after trucks and vans, so, you could be ok

**Mental Wealth Doctor** · Sunday 4th October 2009, 22:17

say no more lol

**readview** · Monday 5th October 2009, 11:35

Hi Owain,if your going this route make sure you dont go and buy a de-catted front pipe for a t5 as it wont fit.You will need to convert your original front pipe and cut the cat out as the awd cat/front pipe is a different shape to enable it to route round the transfer box.I have a de-catted s70r with a three box powerflow system and it is way too loud for me so it will be coming off very soon,but it's all down to personal prefence.

Originally Posted by Mental Wealth Doctor

Im sure last mot i had, the emissions test was only done on lpg, making me wonder whether i could decat my car without worrying about mot emission's test? anyone got any thoughts on this, i have heard the cat is very restrictive on the engine

, anyone know what kinda bhp gain there is to be found here??
and will it sound louder? i've got twin rear exhaust but i swear my old 2.0 glt was louder
2.5 lpt/mbc 855 AWD

**cameron** · Monday 5th October 2009, 13:15

Will that exhaust fit mine Adam

Sorry for the hijack

**readview** · Monday 5th October 2009, 15:46

Hi Lee,yes it will go straight on,still on the car at the mo if you want to hear it.Full powerfow system,de catted,stainless with lifetime warranty,fitted to the car before i bought it on 30.04.2009.Receipt for £500 present.I'll be needing £240 for it as i am going to have to shell out for a new exhaust.

**Jamest5r** · Monday 5th October 2009, 15:51

Sorry to jump in and i know im behind Lee on this one but could a 100 cell race cat be put in to make it legal??

If so second in line please readview.

**cameron** · Monday 5th October 2009, 15:54

All yours jim, agency are being very tight with the work this week, so no money

**850 2.5 10v** · Tuesday 6th October 2009, 10:26

De catting a car is both illegal and bad for the environment.

Furthermore its a mod and its that usual "you must tell your insurance company".

Its not worth the hassle - put in a race / performance cat and be done with it.

**RollingThunder** · Tuesday 6th October 2009, 13:13

Originally Posted by jamest5r

Sorry to jump in and i know im behind Lee on this one but could a 100 cell race cat be put in to make it legal??

If so second in line please readview.

I fitted a 100cell competition spec cat to my old 940T and it passed the MoT no problem. BIG improvement in turbo spool up response though - well worth it.