Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: JamesV6CDX on 26 December 2009, 17:30:28

Title: multiram / vacc temporary bodge. Acceptable?
Post by: JamesV6CDX on 26 December 2009, 17:30:28
Ok, firstly, my front vacc tank was broken.

In order to start the car after the rebuild, I just plugged the vacc feed to it.

Upon a  test drive (with no working rams) she drove very well indeed, however economy hasn't been as great as my previous 2.5s.

Not sure if this is a co-incidence. As a temporary thing, I have rigged the vacc pipes  up in the same way as the early Omegas - eg multirams connected, without the vacc tank.

I now see both rams operate, when the engine  is revved VERY hard.

Not sure if this is a co-incidence, but since connecting them (albeit in a non-ideal way), and re-setting the MID, she seems to now think she's doing 29mpg around the city... a huge improvement.

Could connecting the rams help MPG that much, under  careful / long distance driving conditions?

Last question, promise! - while generally pokey, she still feels  a bit flat when hoofing it  from 70 to 90mph - will the addition of a shiney new vacc tank help with this? No other obvious issues anywhere....
Title: Re: multiram / vacc temporary bodge. Acceptable?
Post by: JamesV6CDX on 26 December 2009, 17:33:45
Just to add, the EGR is currently all connected up as normal, however there is no "feed" to it from the manifold - as 2.6 manifolds are fitted!

Any advantage of blanking this off?
Title: Re: multiram / vacc temporary bodge. Acceptable?
Post by: CaptainZok on 26 December 2009, 17:37:48
Quote
Just to add, the EGR is currently all connected up as normal, however there is no "feed" to it from the manifold - as 2.6 manifolds are fitted!

Any advantage of blanking this off?
That's going to give you a huge airleak when the EGR is active  isn't it?
I would have thought it needs blanking at the plenum James.
Title: Re: multiram / vacc temporary bodge. Acceptable?
Post by: JamesV6CDX on 26 December 2009, 17:39:54
Quote
Quote
Just to add, the EGR is currently all connected up as normal, however there is no "feed" to it from the manifold - as 2.6 manifolds are fitted!

Any advantage of blanking this off?
That's going to give you a huge airleak when the EGR is active  isn't it?
I would have thought it needs blanking at the plenum James.

Thanks, Cap'n.

Will it not just "recirculate" air from the engine bay, as  opposed to the exhaust manifold?

Or is it different, because the manifold would be forcing  fumes into the EGR?  :)
Title: Re: multiram / vacc temporary bodge. Acceptable?
Post by: CaptainZok on 26 December 2009, 17:59:21
Quote
Quote
Quote
Just to add, the EGR is currently all connected up as normal, however there is no "feed" to it from the manifold - as 2.6 manifolds are fitted!

Any advantage of blanking this off?
That's going to give you a huge airleak when the EGR is active  isn't it?
I would have thought it needs blanking at the plenum James.

Thanks, Cap'n.

Will it not just "recirculate" air from the engine bay, as  opposed to the exhaust manifold?

Or is it different, because the manifold would be forcing  fumes into the EGR?  :)
You'll be getting unmetered air not combustion gases as the ECU expects which is just going to add to your problems I would have thought.
Title: Re: multiram / vacc temporary bodge. Acceptable?
Post by: Kevin Wood on 26 December 2009, 23:48:16
Yep, EGR needs to be blocked or it will totally screw up what the Lambda sensor on that bank sees.

Multirams without the reservoir will only work on part throttle. Floor the throttle and the vacuum disappears and they stop working. This is what the reservoir is for, and why it feels flat on full throttle.

Kevin
Title: Re: multiram / vacc temporary bodge. Acceptable?
Post by: JamesV6CDX on 26 December 2009, 23:51:13
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Yep, EGR needs to be blocked or it will totally screw up what the Lambda sensor on that bank sees.

Multirams without the reservoir will only work on part throttle. Floor the throttle and the vacuum disappears and they stop working. This is what the reservoir is for, and why it feels flat on full throttle.

Kevin

Kev, many thanks  :)

The EGR bit makes perfect sense, I'll blank this off.

Re. the Rams- does this mean the multirams are not at all effective, on the earlier models (without the vacc tank) then?
Title: Re: multiram / vacc temporary bodge. Acceptable?
Post by: Kevin Wood on 27 December 2009, 00:05:40
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Quote
Yep, EGR needs to be blocked or it will totally screw up what the Lambda sensor on that bank sees.

Multirams without the reservoir will only work on part throttle. Floor the throttle and the vacuum disappears and they stop working. This is what the reservoir is for, and why it feels flat on full throttle.

Kevin

Kev, many thanks  :)

The EGR bit makes perfect sense, I'll blank this off.

Re. the Rams- does this mean the multirams are not at all effective, on the earlier models (without the vacc tank) then?

IIRC on the earlier cars the rams were fed from the same reservoir as the climate control - so still had air supply when flat out.

Kevin