Omega Owners Forum

Chat Area => General Car Chat => Topic started by: Webby the Bear on 10 August 2015, 19:44:46

Title: Will 3L ''long nose'' plenum bolt straight on to...
Post by: Webby the Bear on 10 August 2015, 19:44:46
...my 2.5?

And is there any advantage in doing this?

Just a question based on one of the comments in my other thread.

I have a 3lplenum and the two shorter bag pipe protrusions so wondering if this is possible and worth it  :)
Title: Re: Will 3L ''long nose'' plenum bolt straight on to...
Post by: TheBoy on 10 August 2015, 20:17:40
It'll fit, but the shorter plenum is better tuned to your engine (which is why they didn't put the longer one on in 1998 when the 3.0l got the longer, better tuned for 3.0l, one)
Title: Re: Will 3L ''long nose'' plenum bolt straight on to...
Post by: Webby the Bear on 10 August 2015, 20:27:58
So no point basically.  :y
Title: Re: Will 3L ''long nose'' plenum bolt straight on to...
Post by: 05omegav6 on 10 August 2015, 21:30:18
So no point basically.  :y
Worth doing if you fit 3.0/G cams and manifolds perhaps... :-\
Title: Re: Will 3L ''long nose'' plenum bolt straight on to...
Post by: Diamond Black Geezer on 11 August 2015, 10:16:51
This is the belief, yes, when you fit the G cams and inlets (and possibly 3.2 man-e-fowlds, too) then you can fit the longer plenum too. As you're sort of '3-liter-ising' the engine. But as said, sticking it on your (and indeed my) 2.5 in standard trim will not do a thing. Presumably lose a little lower end torque?

I'm always fascinated by how the two essentially identical engines require so many little tiny differences and there's so many dos and don'ts to them.
Title: Re: Will 3L ''long nose'' plenum bolt straight on to...
Post by: tigers_gonads on 11 August 2015, 11:11:58
Also remember to fit the long nosed throttle cable and cruise cable if needed  ;)
Title: Re: Will 3L ''long nose'' plenum bolt straight on to...
Post by: Kevin Wood on 11 August 2015, 12:44:15
Beware also that there are differences in throttle pot wiring between the short and long plenum setups. I'm not sure we've completely established what the differences are, but the pot can end up being wired back to front, meaning that it runs like a dog - if at all!
Title: Re: Will 3L ''long nose'' plenum bolt straight on to...
Post by: zirk on 11 August 2015, 12:45:33
Putting aside the Omega and Multi Rams for the minuet, the general rule is a long intake run provides better torque and aids fuel economy at the lower end, a short intake run is better for high rpm and full engine load, hence why intakes are designed and manufactured for overall performance and mpg for each specific engine type, or manufacturers can improve there design by adding variable length intake techniques.
Title: Re: Will 3L ''long nose'' plenum bolt straight on to...
Post by: tigers_gonads on 11 August 2015, 13:09:09
Beware also that there are differences in throttle pot wiring between the short and long plenum setups. I'm not sure we've completely established what the differences are, but the pot can end up being wired back to front, meaning that it runs like a dog - if at all!


True
Best to fit the 2.5 throttle body on to the long nose plenum  :y
Title: Re: Will 3L ''long nose'' plenum bolt straight on to...
Post by: Marks DTM Calib on 11 August 2015, 13:24:52
Putting aside the Omega and Multi Rams for the minuet, the general rule is a long intake run provides better torque and aids fuel economy at the lower end, a short intake run is better for high rpm and full engine load, hence why intakes are designed and manufactured for overall performance and mpg for each specific engine type, or manufacturers can improve there design by adding variable length intake techniques.
Which is what the Omega has  :y
Title: Re: Will 3L ''long nose'' plenum bolt straight on to...
Post by: Webby the Bear on 11 August 2015, 17:19:16
Thanks for the input guys" yeah I shan't bother then unless one day I decide to fit the 3l cams and manifolds. Which, if I decided to do that, I'd prob just stick a 3l in as many have suggested.

Was really just trying to see if any of my spare 3l parts could be bolted on for instant extra performance. As not I shan't bother  :y
Title: Re: Will 3L ''long nose'' plenum bolt straight on to...
Post by: EMD on 11 August 2015, 17:47:36
Trade yours in for a 3.2 thats got lpg , job jobbed  :y
Title: Re: Will 3L ''long nose'' plenum bolt straight on to...
Post by: TheBoy on 11 August 2015, 18:23:49
So no point basically.  :y
Worth doing if you fit 3.0/G cams and manifolds perhaps... :-\
Not sure it would TBH, as the engine's air requirements still won't be anywhere near a 3.0l...