Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: minilandrover on 27 June 2011, 00:04:21

Title: THROW OUT THE CAT
Post by: minilandrover on 27 June 2011, 00:04:21
Hello All you guys with a 1994-1996 omega diesel 2.5, is you engine still kicking out 130bhp?  need a power boost ? want some fun???
Well after repairing my injector pump that started leaking (see my other posting) i fixed the pump, and made good use of the fact the front of the car was off the ground. i had allready opened up a spare front exhaust Cat pipe and done the cat mod. it takes about 1 hour to modify the pipe and one hour or less to swap pipes or remove and refit a modded pipe. So what's the big deal? Well removing the catalyser or cat for short from it's housing and welding it up again means the engine is no longer wasting loads of energy trying to push exhaust gasses through millions of pinholes in the cat block. Take a look at my photobucket albums and look at the picture  editorial that shown how to de-cat your diesel omega 6 cyl engine. (legal in france as it's not compulsory until 1996 to have a cat on a diesel and mine is a 1994.)
What difference does it make? well forget chipping the car this gave mine a 40bhp boost, faster spin up of the turbo, better acceleration, loads more oomph and cleaner, no puff of smoke when i let go a load of g-g'ees as the old cat would try and clear it's throat.
40bhp is just a guess, but it's like i had been towing another car behind for ever and suddenly the tow rope broke!!! wow i have trouble keeping her to the speed limit's as with the throttle just cracked open she is doing 90kph (60mph) and just a tickle whips her up to 130kph in no time. i shall have to do some timed runs and post them on youtube... anyway have a look at how easy it is and have a think about it, and the cat block removed is done so keeping it intact so you can sell it for re-cycling, they are worth 50 quid.. :y   here is the link..
http://s595.photobucket.com/home/minilandrover
now a mod that can pay for it's self straight away most be a first...
Title: Re: THROW OUT THE CAT
Post by: mrgreen on 27 June 2011, 00:30:36
i wish there was something like that for the 2.2!!!
Title: Re: THROW OUT THE CAT
Post by: minilandrover on 27 June 2011, 19:27:20
Well i am just wondering how many other omega owners have done the mod. and has anyone had the power at the rear wheels measured before and after? There is a nice woods near where i live and a nice long straight. i might just film a run then try and calculate the 0-60 0-100 time and check it against known figures for the standard car, bearing in mind mine has done 330,000 km's  but for a car that weighs 1.5ton's it's going like a bat out of hell, im not bothered how fast  it goes, just how fast it gets going . can anybody time their tired 2.5 diesel 0-60 and 0-100mph? and post some figures.  ;)  so no cheating spare wheel in the boot and a tank of fuel. ok?  :y
Title: Re: THROW OUT THE CAT
Post by: Abiton on 27 June 2011, 21:21:20
I was a bit dubious about your power-gain claim, a cat just can't be that restrictive...

...and then I looked at your piccies.  Your cat appears to be a block of solid carbon!  No wonder you were down on power.    :o

Title: Re: THROW OUT THE CAT
Post by: Kevin Wood on 28 June 2011, 13:58:31
There'll be a few diesel owners desperately looking for cats when the new rules come in. ;)

http://www.omegaowners.com/forum/YaBB.pl?num=1309121813
Title: Re: THROW OUT THE CAT
Post by: VXL V6 on 28 June 2011, 19:20:16
Quote
There'll be a few diesel owners desperately looking for cats when the new rules come in. ;)

http://www.omegaowners.com/forum/YaBB.pl?num=1309121813

Looking at the decat method employed above I think I may go with this approach when I do the my DTi.

I've just got to find someone who will perform the operation...

The MOT test station will presumably only be looking for
the physical presence of a CAT so I would assume that this would pass, especially if the welding is on the upper surface and hence not quite so noticable.
Title: Re: THROW OUT THE CAT
Post by: TheBoy on 28 June 2011, 19:31:14
My old chipped 2.5TD Elite, Automatic ( :'(), could do 0-60 in 9s dead, using stopwatch (not massively accurate). A manual should be noticibly quicker.  Never decatted it though.
Title: Re: THROW OUT THE CAT
Post by: VXL V6 on 28 June 2011, 22:00:24
On a 2.2 DTi you need to give it every opportunity to release all those horses  ;D

Fine when it's rolling, it's just pulling away that's gutless after driving the V6
Title: Re: THROW OUT THE CAT
Post by: Brikhead on 28 June 2011, 23:40:38
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I've just got to find someone who will perform the operation...
I feel more than able enough to offer my surgical experience on this tricky procedure.
I even have a fresh blade in my angle grinder...
Title: Re: THROW OUT THE CAT
Post by: blackviper90210 on 29 June 2011, 07:32:50
Would gutting the "cats" affect the emissions on a petrol?  :-?
Title: Re: THROW OUT THE CAT
Post by: Abiton on 29 June 2011, 07:57:46
Errr, yes.
Title: Re: THROW OUT THE CAT
Post by: blackviper90210 on 29 June 2011, 08:06:59
So I can remove the cat and the car wil be fine, but MOT time, they'll need to be in place.

If thats the case, does it do the car any "harm", ie upset the ecu etc?
Title: Re: THROW OUT THE CAT
Post by: aaronjb on 29 June 2011, 08:14:03
If you did it on a petrol car, aside from failing the MOT every year, you'd have a permanent P0430 'Cat efficiency' code and accompanying light on the dash..

On a diesel (as in this thread) the emissions test is currently visual smoke only (soon to be visual smoke plus the visual presence of a 'CAT')
Title: Re: THROW OUT THE CAT
Post by: blackviper90210 on 29 June 2011, 08:19:17
Quote
If you did it on a petrol car, aside from failing the MOT every year, you'd have a permanent P0430 'Cat efficiency' code and accompanying light on the dash..

On a diesel (as in this thread) the emissions test is currently visual smoke only (soon to be visual smoke plus the visual presence of a 'CAT')
That makes sense, ok. Ref the fault code though, if the cat was then refitted for the MOT, would the codes/light go out, or will it need resetting?
Title: Re: THROW OUT THE CAT
Post by: hoofing it on 29 June 2011, 08:24:21
Quote
I was a bit dubious about your power-gain claim, a cat just can't be that restrictive...

...and then I looked at your piccies.  Your cat appears to be a block of solid carbon!  No wonder you were down on power.    :o

This won't happen if you boot the total crap out of it buy holding the car in second and taking the revs to 4500rpm every 2weeks :D
All diesels need to get a good blast or they soot up :y
Title: Re: THROW OUT THE CAT
Post by: Marks DTM Calib on 29 June 2011, 09:29:47
Quote
If you did it on a petrol car, aside from failing the MOT every year, you'd have a permanent P0430 'Cat efficiency' code and accompanying light on the dash..

On a diesel (as in this thread) the emissions test is currently visual smoke only (soon to be visual smoke plus the visual presence of a 'CAT')

Not on a 3.0 you wont.....only 2.6/3.2  :y
Title: Re: THROW OUT THE CAT
Post by: Brikhead on 29 June 2011, 09:40:40
Quote
If you did it on a petrol car you'd have a permanent P0430 'Cat efficiency' code and accompanying light on the dash..

Aren't the lambda sensors before the cats on the earlier v6's? How would the e.c.u. know?
Title: Re: THROW OUT THE CAT
Post by: Brikhead on 29 June 2011, 09:43:55
Quote
Ref the fault code though, if the cat was then refitted for the MOT, would the codes/light go out, or will it need resetting?

On Vx's the e.m.l. should go out soon after the fault has been rectified, only a.b.s. and s.r.s. systems need re-setting.
Title: Re: THROW OUT THE CAT
Post by: blackviper90210 on 29 June 2011, 10:40:44
Your the man Brikhead, cheers  :y
Title: Re: THROW OUT THE CAT
Post by: aaronjb on 29 June 2011, 10:41:54
Quote
Quote
If you did it on a petrol car, aside from failing the MOT every year, you'd have a permanent P0430 'Cat efficiency' code and accompanying light on the dash..

On a diesel (as in this thread) the emissions test is currently visual smoke only (soon to be visual smoke plus the visual presence of a 'CAT')

Not on a 3.0 you wont.....only 2.6/3.2  :y

Ahh - didn't realise the earlier cars weren't .. whatever standard it is that brought that in ;D (Euro III, was it?)
Title: Re: THROW OUT THE CAT
Post by: Cotty on 29 June 2011, 12:49:11
Quote
i wish there was something like that for the 2.2!!!
  You'll find that like the V6's your 2.2 would be easy to change the engine management chip.
For the V6 there's a phase 7 motorsport chip which is simple to install as no welding is needed so its out with the old and in with the new with a claimed extra 30bhp.
I decided against the idea due to the insurance increase and also fuel consumption!!
If your happy with what you've got,it runs well and has good mpg then stick with what you have.
I've had 34mpg out of my previous 1998 2.5V6 but that was cruising between 60-70mph on the motorway but I did that as a one off to test consumption because I like to use the performance that I've paid for and it's amazing how many V6 Omega's I've flown past on the m-way so the majority of owners can't afford to use the car for what it was designed for!!
Do any mods then let the insurance comp know as I guarantee you that if you don't and it comes to claim time you'll find that you're not covered.
Your engine was designed with the components you have so any altering has no guarantee it won't damage your car!!
Anyway he sold his cats to pay for a K&N ;D
Title: Re: THROW OUT THE CAT
Post by: Kevin Wood on 29 June 2011, 14:14:35
Quote
Quote
i wish there was something like that for the 2.2!!!
  You'll find that like the V6's your 2.2 would be easy to change the engine management chip.

It's only the early V6s that have a removable chip. 2.2, 2.6 and 3.2 all have flash based ECUs so no chip to replace.

Besides, the best way to tune a 4 pot is to replace it with a V6. ;)
Title: Re: THROW OUT THE CAT
Post by: blackviper90210 on 29 June 2011, 14:40:21
Quote
Quote
Quote
i wish there was something like that for the 2.2!!!
  You'll find that like the V6's your 2.2 would be easy to change the engine management chip.

It's only the early V6s that have a removable chip. 2.2, 2.6 and 3.2 all have flash based ECUs so no chip to replace.

Besides, the best way to tune a 4 pot is to replace it with a V6. ;)
If thats the case, is there any benefit on changing a 3.0 chip or best to stick with whats fitted?
Title: Re: THROW OUT THE CAT
Post by: Kevin Wood on 29 June 2011, 17:14:12
Quote
If thats the case, is there any benefit on changing a 3.0 chip or best to stick with whats fitted?

On a 3.0, yes. The point is that the map on the later V6s (2.6 and 3.2) isn't stored on a removable chip, but on the 2.5 and 3.0 it is.
Title: Re: THROW OUT THE CAT
Post by: sticka_v8_init on 29 June 2011, 17:44:23
Just searched this "phase 7 motorsport chip " and found it for about £30. Is it really a case of out with old, in with new = + 25odd Bhp? Any possible side effects?
Title: Re: THROW OUT THE CAT
Post by: blackviper90210 on 29 June 2011, 17:47:20
Is it just a case of getting a different chip and plug 'n play, or is there other changes to be made?

In that case where can I find these and rough costing?

Sorry for the million questions, I just believed there wasn't a cheap (ish) way of improving the 3.0  :o
Title: Re: THROW OUT THE CAT
Post by: blackviper90210 on 29 June 2011, 17:48:04
Quote
Just searched this "phase 7 motorsport chip " and found it for about £30. Is it really a case of out with old, in with new = + 25odd Bhp? Any possible side effects?
Beat me to it, lol  :)
Title: Re: THROW OUT THE CAT
Post by: TheBoy on 29 June 2011, 19:04:11
Quote
Just searched this "phase 7 motorsport chip " and found it for about £30. Is it really a case of out with old, in with new = + 25odd Bhp? Any possible side effects?
Aside from the fact you'll never get that sort of increase in a month of Sundays, yes.

The downside is, there are a lot of inappropriate, poor chips out there, esp those off egay, that many I've seen have been disappointing.

A good chip, of which there are a couple will, at best, give probably just shy of 10%...  ...these tend to cost a couple of hundred quid.
Title: Re: THROW OUT THE CAT
Post by: TheBoy on 29 June 2011, 19:05:43
I would add this phase 7 whatever is not one I've heard of, and is probably one I'd give a wide berth to.
Title: Re: THROW OUT THE CAT
Post by: VXL V6 on 29 June 2011, 19:38:38
The best results seem to come from remapping diesels, once i've de-catted my DTi (Must get SWMBO's done first along with replacing the rest of the exhaust) I am looking at getting it remapped.

Title: Re: THROW OUT THE CAT
Post by: minilandrover on 26 June 2012, 22:48:08
Hi Guys  im the cat man and back to let you guys know if it hurt the car....NO it didn't... it's still going like a bat out of hell, and im loving it... saving fuel, though to be fair it did cost me a tire, cos coming out of my drive i booted it ( again) and went squealing down the road and tore off a strip of rubber from my tire. Im wondering if the omega has a limited slip diff cos even in the snow or mud i never get one wheel spin,and loose drive, i always get drive to both wheels or enough to pull my self out of the mud. Anyway im diverging or something, the cat mod works just fine, turbo power is on tap at 2000 rpm, and the power available from 2000 to 4250 is usually enough to leave everyone else behind, no need to go screaming up to 5000+   the turbo limits it's self to 2 bars? the pressure guage sweeps up to full power in a couple of seconds then gives a little negative kick as the limiter valve pop's open but the pressure stays up there. then it's time to back off or find another gear to play with.   So have any of you guys tried it yet?  I do however have a big problem with the car today. it would not let me in. i had to unlock the door by key and the infra red key and transmitter are working but i am unable to do a reset or get the reciever ( i popped in a spare one i had) to talk to the cpu and let me drive home.

So i posted a question, if i swap the cpu unit for my spare one will it accept my key ( doing the reset manouver) or will it expect and demand the old key code? I have the old infra red transmitter but have stripped the board for the buttons and battery spring, I can rebuild it but would preferre sticking with my repaired keyfob. the key is working as ive tested it with my phone and i can see the ir pulses. can anyone help? mt topic is posted earlier today
Title: Re: THROW OUT THE CAT
Post by: Brikhead on 26 June 2012, 23:24:37
I do however have a big problem with the car today. it would not let me in. i had to unlock the door by key and the infra red key and transmitter are working but i am unable to do a reset or get the reciever ( i popped in a spare one i had) to talk to the cpu and let me drive home.
Were the engine management light or the emissions control light flashing whilst you were trying to start the vehicle?
If so then check you still have the immobilizer chips inside your key fob's...
http://www.google.co.uk/imgres?q=vauxhall+immobilizer+chip&hl=en&sa=X&biw=1609&bih=899&tbm=isch&prmd=imvnsfd&tbnid=5ZqVIjWPmBncLM:&imgrefurl=http://www.astraownersclub.com/vb/showthread.php%3Ft%3D243624&docid=ep_jO6gHhR61vM&imgurl=http://i151.photobucket.com/albums/s127/rudemonkee/My%252520car/DSC05409.jpg&w=800&h=600&ei=sjPqT472HOnJ0QWo-thw&zoom=1
It may be worth starting a new thread regarding this problem.