OMVL R90 Reducer: Do I need Power Valves?

[Jamie Taylor]

Hi All,

I am planning on replacing the reducer in the truck with a OMVL R90 Reducer. I note that it has two diaphragms and two outputs. One for high revs/power and one for low revs power.
Do I need to, or should I, install power valves in each of the outputs? Or is this not necessary with this model?

Thanks in advance

Jamie

[Gilbertd]

The two diaphragms are because it is a two stage vaporiser and the two outlets are so you have a choice of using the one at the top or the one at the bottom. It all depends on your pipe runs and layout as to which is most convenient. On both my cars I'm using the top outlet and teh bottom one can then be used to drain any 'heavy ends' although others prefer to use the bottom one and let the heavy ends get drawn in with the gas and burnt.

[Jamie Taylor]

Hi Gibert,

Thanks for your reply. Now I understand. So, I use the most convenient output, and still keep the Y-fork pipe to the fuel input.

Just to note, the engine I have is a V8 460, 7.5L (202kW) in an old American RV. It currently has the At90 which only provides (off the top of my head) 100kw or so of power. I am hoping to give the engine a bit more oomph with this reducer Maybe then I will be able to get up hills without loosing too ,much speed.

Cheers

Jamie

[LPGC]

The more recent R90's don't seem to be as capable as the older R90's in terms of flow ability (i.e. ability to flow enough gas for bigger or higher powered engines). An AT90 may flow as much as a new R90.

What mixer are you using on the 460cube V8? Some mixers (e.g. the old Sprint Gas mixer) do have a vacuum operated 'power valve' on the mixer... In which case you do still use just the one output from the reducer to feed the Y that was supplied with the mixer.

What does it go like on petrol? If power is also down on petrol it could be the mixer itself that won't flow enough air so acts as an additional throttle on the engine thus reducing engine power on either fuel. If it goes OK on petrol but not OK on gas it could be the reducer that lacks flow ability (as you've said) or it could be going lean (or less likely way too rich) on LPG at higher engine loads.

[Pinger]

I'm running a 5.7l SBC rated at 260hp (195kW) and use a (new) R90. I connected both outlets via a Y-piece to the mixer. I also replaced the line from the tank to the reducer. Previously (7mm?) copper, now 8mm poly pipe. If I'm down on rated power (maybe, maybe not) it's due to the mixer not the gas supply side.
I'm using as large a mixer as I dare - any larger causes the mixture to go weak on initial throttle opening. For certain, the torque in the low to mid rpm range is all there.

[Jamie Taylor]

Hi
Sorry both, I just saw your messages!
Currently, the engine is running on an AT90 which I think is rated about 100kW. The motorhome engine is rated at 208kW when running on petrol. So, it seems to be quite a big difference in what power should be supplied and what is. The engine makes a hell of a racket, and from what I understand a poor fuel supply may be the cause of this. The R90 is the single point one and rated up to 360hp, so I am hoping this will do the job.

But, in the first place I need to go and do the exhaust manifold gasket, which is this afternoons job!

Thanks