Thread: which gas system right for me?

Depending on what system you get as to how suitable is it for the 4.6. An OMVL will do the 4.6 for example. A smaller gas converter may just limit your peak rpm on gas, not the torque down low. I don't recommend Impco although they are usually OK at higher rpm.

QUESTION: If I buy a gas system which is a Impco system, then then want to upgrade parts say a omvl LPG convertor to make it a better system. Can I do this kind of stuff?? I'm not sure with laws etc.

Originally Posted by nat p

QUESTION: If I buy a gas system which is a Impco system, then then want to upgrade parts say a omvl LPG convertor to make it a better system. Can I do this kind of stuff?? I'm not sure with laws etc.

The laws are quite explicit, you aren't allowed to mess with gas unless supervised by a qualified fitter. Documentation is another matter, no-one demands you account for every change with a certificate! Basically DIY is possible once your vehicle has a system fitted legally, only take care you know exactly what you are doing and don't shout it to the road authorities.

There's no good reason you can't acquire an OMVL off ebay and ask your fitter to install it with the rest of the kit, if that is the way it pans out.

There's lots of gas stuff on ebay...

LPG GAS CONVERTER O.M.V.L R90E IN EC. | eBay

LPG Omvl Twin Outlet Gas Convertor to Suit V8 or Six | eBay

I've seen a "kit" where there was just a converter and then a smaller mixer (it was rectangle and you hardly noticed it,. about 15mm thick). Ever since then I've been trying to find the same system.

It looked like it had a Omvl convertor and thats it.

Any ideas where I can get this from. I;m trying to build the perfect system OR do you recommend Direct injection from the UK that I have noticed people have been puting on their P38.

I was thinking of buying this and puting the LPG on my RRC 4.6.

RANGE ROVER 1989 4DOOR | eBay

What do ya reckon I do?
Cheers NAT

I was thinking of replacing the "carb" with this;

Rover V8 EFi LPG GPL Mixer Venturi Fuel Range Discovery | eBay

So, all up it will be a Omvl converter the the above mixer

Cheers NAT P

The 15mm thick mixers are for installing between flapper style MAF's and the airbox adaptor. They are usually very restrictive. Don't bother trying to fit one on a hotwire efi system.

The UK supplied mixer looks OK but you can get a better one (and cheaper) in Melbourne from AMR Manufacturing, just needs a slight machining where it goes on the throttle body. It's a part no. M352 and is specified for a Nissan 4.2 efi. I bought a bunch off them last time so pm me if you want one, machined to fit. These mixers work great, are 46mm ID venturi's, nearly as good as petrol power.

Go injection if you have doubts about mixer systems but I have been doing these mixers for years and they don't give much trouble for the price. I'm a bit wobbly on self-imported injection systems, I prefer a kit with local back-up myself. You can always go injection afterwards but I doubt you'll need it.

The RRC looks like the goods with the underslung gas tanks.

Edit: M352 mixer:

I'm running a BRC Sequential Vapour injection system on a RR Classic with a Thor 4.0 ltr. I call it a Rangovery. See HERE.

This is a no brainer system that starts on petrol and flicks over to gas once it warms up or has been running for more than 2 mins. It flicks back to petrol automatically when the gas runs out. I honestly cannot tell the difference in power from petrol to gas and fuel consumption in litres is about the same.

Only hassle's are...

1. I've got scuba tanks on the rear floor which limits me to only 55lts of gas. But I put up with that for the savings. This thing is cheaper to run than my old TDI Disco!!

2. Spark plugs - I'm running platinum plugs but they seem to foul up every 20-30K's. First thing I notice is it backfires through plenum when pulling away in too high a gear. I just whip them out and give them a quick clean and off I go again.

An injected gas system should never have a plenum backfire. Where are your injector nozzles mounted?? On the Thor engine they should be in the lower manifold close to the petrol injectors.
Over the years I have found platinum plugs and gas to be problematic at odd times. Don't really know why. I ended up insisting my customers use either NGK standard type plugs or Iridium and no more probs.