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[Entwood]

Sorry to ask such a daft question ... but I'm slightly puzzled ...

The airflow through the plenum, after passing through the twin throttle bodies, does the air "mix" or remain totally seperate left bank/right bank ?

Logic says it remains seperate otherwise why have 2 throttle bodies ... but I need confirmation of this, and I can't find a piccie of the underside / internals of the plenum chamber....

When you've all stopped laughing if someone could advise this numpty  ...    

[hotel21]

Try this....

http://www.omegaowners.com/forum/YaBB.pl?num=1153840176

 

[Marks DTM Calib]

It depends on what the multiram is set to....have a little look at the diagrams in the multiram operation maintenance guide and all will become clear!

[Kevin Wood]

Depends on the position of the rear multuiram valve. At low RPM the two banks breathe separately through each half of the plenum. At high RPM (and idle, I believe) the multiram valve is open and this connects the two halves of the plenum so it behaves as a single volume.


Kevin

[Entwood]

Thanks for that .. sort of helps ...   so below 3400 but above idle the banks are virtually seperate .... ie .. most of the time under normal cruising....

The reason for asking ... the LPG conversion also includes "valve lube" - which a lot of folks say is not needed, but came as part of the package - but I've noticed that the "valve lube" injection is to only one point, on the right hand side of the plenum, and it occured to me that perhaps this means that only one set of valves are getting the benefit .... the diagram seems to confirm that is the case for most of the operating range.

Methinks a call to the installer is required ...  

[Kevin Wood]

I think you do need to talk to the installer. It would need to be injected into both halves of the plenum to be effective, as you say, and also the points at which it's injected would be critical. I would go for somewhere immediately after the throttles in the neck of the plenum where the air velocity is still high and it stands the most chance of being atomised and distributed evenly between the cylinders. If it's injected somewhere where the airflow is dead it'll most likely pool on the plenum floor or all end up going in one cylinder.

Kevin

[Matchless]

Another intake quirk is that the left-hand butterfly feeds the right-hand cylinders and viceversa

[Kevin Wood]

Another intake quirk is that the left-hand butterfly feeds the right-hand cylinders and viceversa

Oh, yes. Took a little head-scratching when we LPG'd James' V6. :-/

Kevin

[TheBoy]

Another intake quirk is that the left-hand butterfly feeds the right-hand cylinders and viceversa

eh? me no understandy?  Does it swap over somewhere then?

[HerefordElite]

Another intake quirk is that the left-hand butterfly feeds the right-hand cylinders and viceversa

eh? me no understandy?  Does it swap over somewhere then?

look closer at M-DTM's pic and you can see where the flow crosses over - the inlet runners are offset with the cylinders - better for flow i think as it's a smoother bend rather than air coming in above cylinder and turning sharply through 90deg

[Entwood]

Another intake quirk is that the left-hand butterfly feeds the right-hand cylinders and viceversa

eh? me no understandy?  Does it swap over somewhere then?

look closer at M-DTM's pic and you can see where the flow crosses over - the inlet runners are offset with the cylinders - better for flow i think as it's a smoother bend rather than air coming in above cylinder and turning sharply through 90deg

Sorry .. I can't see this .... perhaps I need to go to spec-savers .. but I see straight lines in all the piccies ..

[Kevin Wood]

The intake manifold runners run from left side of plenum to right bank of engine and vice versa to make the path as straight as possible from intake valve to plenum.

Kevin

[Entwood]

AHHH got you ... found this picture in the guides .. now makes sense

Unable to contact the installer yet ... I'll try again tomorrow ... but the more I look/think about it .. the more I'm convinced the "valve lube" is wrong    Thanks for the thoughts  

[HerefordElite]

AHHH got you ... found this picture in the guides .. now makes sense

Unable to contact the installer yet ... I'll try again tomorrow ... but the more I look/think about it .. the more I'm convinced the "valve lube" is wrong    Thanks for the thoughts  

perfect - pic 2 is exactly what we're talking about