Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: rhydV6 on 03 October 2006, 08:47:53

Title: 2.5 V6 Decat(s) Options??
Post by: rhydV6 on 03 October 2006, 08:47:53

Think one of the CAT's on mine is screwed, rattly sound from exhaust under acceleration.

So was thinking of chopping the CAT's off and welding in some straight pipe instead for the time being.

Are there decats available to buy from anywhere?

Also will an MV6/Elite etc (Twin Tailpipe) Backbox fit on to my 2.5? I've looked at the exhaust system diagrams and they both look identical even with the same bore exhausts, so as far as I know one should fit, is this correct?

Cheers
Title: Re: 2.5 V6 Decat(s) Options??
Post by: nixoro on 03 October 2006, 08:53:48
Not sure if its any help to you but I'm sure Tezray on here had a pair of decats he made for sale.

Might be worth investigating.

HTH :)
Title: Re: 2.5 V6 Decat(s) Options??
Post by: Marks DTM Calib on 03 October 2006, 09:25:26
Lambda sensor might not be to happy with the lack of back pressure.

And you can fit the 3.0 tail pipe to the 2.5
Title: Re: 2.5 V6 Decat(s) Options??
Post by: nixoro on 03 October 2006, 10:09:40
Not sure if these would be any use for you but for a quick fix maybe.

Spotted these on ebay

http://cgi.ebay.co.uk/VAUXHALL-OMEGA-PAIR-OF-CATS-CATALYTIC-CONVERTER-FOR-V6_W0QQitemZ290035266420QQihZ019QQcategoryZ10404QQrdZ1QQcmdZViewItem

Be sure to find out the History of them if you go for them.

HTH :)
Title: Re: 2.5 V6 Decat(s) Options??
Post by: Marks DTM Calib on 03 October 2006, 10:14:50
Must be a fair age...absolutely no heat shields left on them.
Title: Re: 2.5 V6 Decat(s) Options??
Post by: nixoro on 03 October 2006, 10:19:53
Quote
Must be a fair age...absolutely no heat shields left on them.

I thought they were the aftermarket type like mine, only mine is missing the Heatshield but its relatively new, it didn't come with one.

Thought they maybe a good purchase if they passed on the emissions during MOT time, although I guess it depends on the condition of the car they came off.
Title: Re: 2.5 V6 Decat(s) Options??
Post by: nixoro on 03 October 2006, 10:32:52
Maybe a better option Heatshields included.

http://cgi.ebay.co.uk/VAUXHALL-OMEGA-EXHAUST-CATALYTIC-CONVERTERS-X2-V6_W0QQitemZ250034534791QQihZ015QQcategoryZ10404QQssPageNameZWDVWQQrdZ1QQcmdZViewItem#ebayphotohosting
Title: Re: 2.5 V6 Decat(s) Options??
Post by: Admin on 03 October 2006, 10:56:04
Check it is not the baffles in the centre section gone first. They rattle too.

Tapping the different parts may help identify the problem area.

Decatting will cause problems, not least of which the reduced back pressure, which will actually decrease power.



Title: Re: 2.5 V6 Decat(s) Options??
Post by: Marks DTM Calib on 03 October 2006, 11:47:24
I think Mr McB had a set of cats that were in good nick.....80 quid is to much for a pair .....50 quid is closer to the money.
Title: Re: 2.5 V6 Decat(s) Options??
Post by: Jimbob on 03 October 2006, 12:15:08
Hijack alert!!!

On the subject of heat shields...

My other car (Mazda 626), the heatsheild came loose while I was on holiday, rattled like god knows what!

Went to a local garage who wrenched off the knackered sheild with 'you dont need one anyway'
only cost me a fiver!

Any problems from running without one?

Cheers
Title: Re: 2.5 V6 Decat(s) Options??
Post by: nixoro on 03 October 2006, 12:16:36
Quote
Hijack alert!!!

On the subject of heat shields...

My other car (Mazda 626), the heatsheild came loose while I was on holiday, rattled like god knows what!

Went to a local garage who wrenched off the knackered sheild with 'you dont need one anyway'
only cost me a fiver!

Any problems from running without one?

Cheers

Mine doesn't have one and seems to be running alright. :)
Title: Re: 2.5 V6 Decat(s) Options??
Post by: Tezray on 03 October 2006, 13:37:07
As Nixoro very kindly said yes i have got a custom pair of decat pipes sat in my garage. However when i had them fitted they were too loud for my liking and i can't recall any major power gains. I think in order to see any power gains you'd need to have a remap when they were fitted so the lambda's wouldn't get upset....If you want them you can have them for next to nothing. Let me know  ;)
Title: Re: 2.5 V6 Decat(s) Options??
Post by: rhydV6 on 03 October 2006, 14:14:16
How much matey?