Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: MickAP on 08 September 2009, 22:15:57

Title: 2.5 or 2.6
Post by: MickAP on 08 September 2009, 22:15:57
Being a tractor owner and never owned a petrol Miggy I just wondered which is the better engine, or more reliable engine 2.5 or 2.6 if any at all. And why did they do a 2.6, after all the difference in cc is small or am I missing something else.............sorry if too many questions.

Mick
Title: Re: 2.5 or 2.6
Post by: tunnie on 08 September 2009, 22:19:50
2.6 replaced the 2.5 due to stricter emissions regulations.

2.6 has all electrical drive system, where as 2.5 was cable driven.

2.6 has snooped plenum, as fitted to later 3.0/3.2s - It actually did not need the extended plenum, but they had to fit it to squeeze the DBW stuff on.

Early 2.6's suffer from leaking steam seals as Vx, in their wisdom decided to use cheaper parts. Later 2.6's don't seem to suffer from this problem.

In short, nothing to chose between them, unless your like me and lazy, the DBW cars have a lighter throttle as its electronic. Its something i notice driving the 3.0, the pedal is harder to press  ;D
Title: Re: 2.5 or 2.6
Post by: tmx on 08 September 2009, 22:20:13
2.6 is a newer verasion of the 2.5 with OBD 2 No EGR Valve Coil perplug ignition and a few other small revisions sort of an improved 2.5 some may say

imho from spending 2 years on this forum theyre both reliable units

the standard 2.5 is 167bhp i dont know the 2.6s bhp i know a Vectra 2.6 GSi is 192bhp though but i dont think the omegas 2.6 is 192bhp
Title: Re: 2.5 or 2.6
Post by: Martin_1962 on 08 September 2009, 22:22:15
2.6 is 178 I think standard, mine isn't.

I think mine is around 190 - 195

2.6 is a good engine, no EGR no SAI, east to fit cruise.

Valve seals the biggest pain
Title: Re: 2.5 or 2.6
Post by: patriotste on 08 September 2009, 22:26:08
Go for th 2.6 its an improved version and is only fitted to the facelift models which also have better corrosian protection.
Title: Re: 2.5 or 2.6
Post by: RobG on 08 September 2009, 22:29:54
Quote
2.6 replaced the 2.5 due to stricter emissions regulations.

2.6 has all electrical drive system, where as 2.5 was cable driven.

2.6 has snooped plenum, as fitted to later 3.0/3.2s - It actually did not need the extended plenum, but they had to fit it to squeeze the DBW stuff on.

Early 2.6's suffer from leaking steam seals as Vx, in their wisdom decided to use cheaper parts. Later 2.6's don't seem to suffer from this problem.

In short, nothing to chose between them, unless your like me and lazy, the DBW cars have a lighter throttle as its electronic. Its something i notice driving the 3.0, the pedal is harder to press  ;D
No problematic ICV either :y
Title: Re: 2.5 or 2.6
Post by: tunnie on 08 September 2009, 22:41:44
Quote
Quote
2.6 replaced the 2.5 due to stricter emissions regulations.

2.6 has all electrical drive system, where as 2.5 was cable driven.

2.6 has snooped plenum, as fitted to later 3.0/3.2s - It actually did not need the extended plenum, but they had to fit it to squeeze the DBW stuff on.

Early 2.6's suffer from leaking steam seals as Vx, in their wisdom decided to use cheaper parts. Later 2.6's don't seem to suffer from this problem.

In short, nothing to chose between them, unless your like me and lazy, the DBW cars have a lighter throttle as its electronic. Its something i notice driving the 3.0, the pedal is harder to press  ;D
No problematic ICV either :y

Nothing wrong with ICV's we had one Omega that did 130k in 3 years, never missed a beat. That was a 4 pot too  ;)

Our 3.0 ICV has also never given us any problems, its all about preventative maintenance  :y
Title: Re: 2.5 or 2.6
Post by: MickAP on 08 September 2009, 22:42:13
Quote
2.6 is 178 I think standard, mine isn't.

I think mine is around 190 - 195

2.6 is a good engine, no EGR no SAI, east to fit cruise.

Valve seals the biggest pain

Sounds expensive to fix if a problem with em?

Mick
Title: Re: 2.5 or 2.6
Post by: deviator on 08 September 2009, 23:43:01
Quote
.....I know a Vectra 2.6 GSi is 192bhp......


The 2.5 GSI vectra is 192 the 2.6 is mid 170's. However the 2.6 has more torque.

As for which to go for, I prefer the 2.6. I will say that some parts are 2.6 specific and can be difficult or significantly more expensive than the 2.5 counterpart (no punn intended). The 2.6 didn't exist for very long.

For example the MAF is 2.6/2.5 specific.
Title: Re: 2.5 or 2.6
Post by: Kevin Wood on 09 September 2009, 10:06:11
Quote
For example the MAF is 2.6/2.5 specific.

2.6 MAF is the same as 3.2.  :y

As said, not much to choose. Main plus point is that cruise enable is very easy on a 2.6. EGR/SAI missing, but SAI is easily ditched anyway and EGR does give some efficiency benefits.

On the down side, around 2001 dodgy stem seals were fitted. DBW throttle is great when it's working but is more expensive than a failed throttle cable when it's not.

You have cat monitoring on the 2.6 so can get into cat efficiency problems, although they are much less afflicted than the 3.2.

Kevin
Title: Re: 2.5 or 2.6
Post by: Marks DTM Calib on 09 September 2009, 12:10:27
2.5
Air Injection - not unreliable
EGR - not unreliable
DIS packs (if they get wet!)

2.6

Cat efficiency Issues
Stem Seal Issues
Coil per plug setup can fail
MAF sensor issues