Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: stemon on 26 July 2009, 23:18:15

Title: decatting 3.0 v6 ? to do or not...
Post by: stemon on 26 July 2009, 23:18:15
Is this worth doing? ive got 2 decats but have been told i will loose back pressue due to having a cat back exhaust allready with no centre boxes just a back box.

whats everyones view on this?

Title: Re: decatting 3.0 v6 ? to do or not...
Post by: Kevin Wood on 26 July 2009, 23:25:57
Cats really aren't as restrictive as some make out. I'd say the hassle come MOT time every year would outweight any advantages.

"back pressure" is also a bit of a myth, IMHO. The best exhausts are tuned to suck gases from the engine, so no back pressure there at all.

Kevin
Title: Re: decatting 3.0 v6 ? to do or not...
Post by: NiallyV6CDX on 26 July 2009, 23:36:23
If you can be bothered to switch it back round everytime you put it through an MOT, then why not. :y

I have a question for you actually, did removing the mid section silencers improve performance at all and how noisy is it now? I am thinking of doing the same modification to mine but if its really loud I won't bother.
Title: Re: decatting 3.0 v6 ? to do or not...
Post by: stemon on 26 July 2009, 23:36:27
interesting thanks kevin, just spotted you have a tech 2, are you able to disable my egr system as removing the system.


anyone else with different views on this decatting?
Title: Re: decatting 3.0 v6 ? to do or not...
Post by: stemon on 26 July 2009, 23:39:45
Quote
If you can be bothered to switch it back round everytime you put it through an MOT, then why not. :y

I have a question for you actually, did removing the mid section silencers improve performance at all and how noisy is it now? I am thinking of doing the same modification to mine but if its really loud I won't bother.

Thanks for the responce, removing the 2 centre boxes made a small difference, ive now got a single pipe all the way through rather than the twin setup.

it is noisy but has gained power up the rev range.
Title: Re: decatting 3.0 v6 ? to do or not...
Post by: Kevin Wood on 26 July 2009, 23:48:25
Quote
interesting thanks kevin, just spotted you have a tech 2, are you able to disable my egr system as removing the system.


anyone else with different views on this decatting?

Are you talking about EGR or SAI?

EGR can just be blanked off under the valve, but feedback from the valve is required by the ECU so it must remain connected. SAI can be removed but, again, the solenoid should remain connected to keep the ECU happy. I'm not aware of a way to disable either of these systems using a Tech 2.  :-/

Kevin
Title: Re: decatting 3.0 v6 ? to do or not...
Post by: stemon on 26 July 2009, 23:52:10
Quote
Quote
interesting thanks kevin, just spotted you have a tech 2, are you able to disable my egr system as removing the system.


anyone else with different views on this decatting?

Are you talking about EGR or SAI?

EGR can just be blanked off under the valve, but feedback from the valve is required by the ECU so it must remain connected. SAI can be removed but, again, the solenoid should remain connected to keep the ECU happy. I'm not aware of a way to disable either of these systems using a Tech 2.  :-/

Kevin

Have removed both systems but as you said they have to stay plugged in, i was interested in disabling them as have noticed the european x30xe didnt have egr/sai
Title: Re: decatting 3.0 v6 ? to do or not...
Post by: NiallyV6CDX on 27 July 2009, 00:03:59
The EGR is pretty easy to blank off.
Think I might just try that exhaust mod, although I'll keep it twin pipes all the way through.
Title: Re: decatting 3.0 v6 ? to do or not...
Post by: Kevin Wood on 27 July 2009, 00:06:19
Quote
Have removed both systems but as you said they have to stay plugged in, i was interested in disabling them as have noticed the european x30xe didnt have egr/sai

Interesting. Maybe there's a variant code that could be changed. Problem is, it could change other things too. :-/

Kevin