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[doz]

Hi all it's me again. Still finding my way around the mig and I am enjoying it. Now all my experience has been with the vx straight 6 lump so I know the benefits of the dual ram system. I really like my gsi 3000 for it's kick at 4k rpm. As some you know I brought quite a cheap mig and it has a few niggerling faults and I'm working my way through them. I've had a couple of issues with the vac system on the car. One was the vac reservoir which was buggered I currently have a gsi one fitted which seems to be doing a Stirling job until my new mig vac turns up. I also found another pipe dis-connected which goes through the grommet which has the two heater pipes fitted. I've had to make a new hole in the grommet and connect the line in the car so now I have a working vac system. Compared to straight six dual ram system the mig looks a lot more complicated. SO a couple of questions for everybody. What do the 2 lines going through he bulk head do? I'm guessing something todo with the havac. There are 2 dual ram vales fitted. The one at the front I have seen move by revving the engine however I know this isn't a true reading of vac as at wide throttle openings if the reservoir is kaput you will lose vacuum. What does the other valve do at the back of the plenum? I see the vac also controls a valve to do with the auxiliary cooling pump and I'm guessing it also has a connection HBV. Is there anything else it plumbs into? I might as well make a full search of the system to make sure it's all OK. Look forward to all your answers

[Kevin Wood]

The multiram system works on the same principal as the dual ram system. The engine breathes through two separate long channels at low RPM to improve torque and these are bypassed by the valves as the RPM rises to shorten the effective length of the system. Only difference is that there are 2 valves in the Omega system, one in the ducting and one at the rear of the plenum. These are triggered at different RPM to give a smoother torque delivery and this is to some extent why the engines don't give the same "kick in the pants" that the straight 6 did.

The vacuum lines through the bulkhead are to supply vacuum used by the heater controls and a vacuum signal back to the heater bypass valve to control the flow of hot water to the heater matrix.

Kevin

[Marks DTM Calib]

Vac pipe diagrams:

http://www.omegaowners.com/forum/YaBB.pl?num=1152565204

And multiram operation

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

[doz]

Cheers guys looks like I've not missed anything then. I thought the car rev'd very smooth across the rev range compared to the S6.

[Marks DTM Calib]

Cheers guys looks like I've not missed anything then. I thought the car rev'd very smooth across the rev range compared to the S6.

Which sudgests the multiram is working nicely!  

[doz]

Also wheres the first vac tank? is it under the dash some where??

[TheBoy]

Also wheres the first vac tank? is it under the dash some where??

Depends on age - earlier cars only had 1 vac tank by pollen filter. Later ones have one down on the bagpipes, and this feeds the multirams.

[SweetOmega]

Is there a way to check and confirm the valve rear of the plenum is working correctly?

[doz]

Hmmm I keep finding pipes off all over the show. Now found one at the vac tank under the scuttle so I fixed it went for a sedate   drive up he road and the all the waddering came out the exhaust. SO I've just spent the last 2 hours on me back fitting new centres and back box. Oh well fix one thing to break another   I have yet to see my plenum valve move but I've had enough of the ruddy thing for today