which gas system right for me?

[nat p]

MOrnin all, I'm running a 4.6 with a 3.9 top end in my RRC. I love it but it is STUPIDLY expensive to run. Like 250km out of a tank if I'm lucky. So gas is it for me OR im going LS1.

The quiestion is I've been looking for an RRC to buy as a whole car and then put that gas on my car. BUT I just realised that it is probably the wrong system. ANy ideas can I modify a RRC to suit my later model engine.

Cheers NAT P

[bee utey]

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.

[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.

[bee utey]

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 (http://www.ebay.com.au/itm/LPG-GAS-CONVERTER-O-M-V-L-R90E-EC-/110737723964?pt=AU_Car_Parts_Accessories&hash=item19c87b923c)

LPG Omvl Twin Outlet Gas Convertor to Suit V8 or Six | eBay (http://www.ebay.com.au/itm/LPG-Omvl-Twin-Outlet-Gas-Convertor-Suit-V8-Six-/260847740525?pt=AU_Car_Parts_Accessories&hash=item3cbbbca66d)

[nat p]

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 (http://www.ebay.com.au/itm/RANGE-ROVER-1989-4DOOR-/160646447268?pt=AU_Cars&hash=item25674640a4)

What do ya reckon I do?
Cheers NAT

[nat p]

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

Rover V8 EFi LPG GPL Mixer Venturi Fuel Range Discovery | eBay (http://www.ebay.co.uk/itm/Rover-V8-EFi-LPG-GPL-Mixer-Venturi-Fuel-Range-Discovery-/150657874305?pt=UK_Cars_Parts_Vehicles_Other_Vehic le_Parts_Accessories_ET&hash=item2313e8b981)

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

Cheers NAT P

[bee utey]

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:

http://www.aulro.com/afvb/attachment.php?attachmentid=38990&stc=1&d=1315746232

[wozzlegummich]

I'm running a BRC Sequential Vapour injection system on a RR Classic with a Thor 4.0 ltr. I call it a Rangovery (http://www.aulro.com/afvb/classic-range-rover/134735-ultimate-rr-classic-3.html#post1542091). See HERE (http://www.aulro.com/afvb/classic-range-rover/134735-ultimate-rr-classic-3.html#post1542091).

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.

[farmport]

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.

[bee utey]

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.

I actually had a dual fuel Falcon XG 6cyl on petrol backfire while I was under the bonnet, I could see the air filter lid jump up (low fuel pressure problem). So while port injection definitely stops the kind of massive backfires that ruin air intakes, small ones are still possible. As for the platinum plugs, I agree, they don't always perform as expected. I tend to only use them with hidden plugs where you have to get off manifolds to replace them.

[wozzlegummich]

I actually had a dual fuel Falcon XG 6cyl on petrol backfire while I was under the bonnet, (low fuel pressure problem). So while port injection definitely stops the kind of massive backfires that ruin air intakes, small ones are still possible.

Now that's interesting.

This system has a fuel filter between the converter and the injectors. I don't think it has been changed since the system was fitted in 2006 (previous owner) . I wonder if that is partially blocked and is unable to deliver fuel quickly enough on initial acceleration. I'll order a new element tonight and see how I go.

[bee utey]

Now that's interesting.

This system has a fuel filter between the converter and the injectors. I don't think it has been changed since the system was fitted in 2006 (previous owner) . I wonder if that is partially blocked and is unable to deliver fuel quickly enough on initial acceleration. I'll order a new element tonight and see how I go.

Actually the Falcon backfired on petrol, however any lean mixture will raise the possibility of a backfire. On your gas system it depends on where the gas pressure sensor is. If it is after the filters it should self adjust. If before, yes there is a case for filter change. I believe that filter changes are recommended at around 40K anyway. Notwithstanding this, some of the systems I have fitted the vehicle ignition system cannot cope with full throttle off idle on gas only. I program in a dash of petrol that cures the stumble completely. (Toyota Prado in particular)

Another question is, if you are running the Thor system, are you using the coil packs? I found they perform best with smaller plug gaps, around 0.6mm/0.024".

[wozzlegummich]

Another question is, if you are running the Thor system, are you using the coil packs? I found they perform best with smaller plug gaps, around 0.6mm/0.024".

Interesting you ask. Yes it is running the coil packs (Is there an alternative?)

When I first got the vehicle all seemed OK and would only "pop" through the plenum on take off if I was lazy and took of without any throttle. (OK on petrol though). This gradually got worse to the point where unless I gave it a footfull it would pop on take off (it's a manual).

So I popped the plugs out, gave them a clean, dropped the gaps to .030". After refitting it had a massive flat spot when revved from idle (on gas - OK on petrol).

Again I regapped the plugs, this time back to where I thought I started at about .035". Still had a massive flat spot off idle when revved in neutral.

Jumped on the interweb and read in several places that platinum plugs shouldn't be cleaned. ****! So I jumped in the car to get some new plugs at the local Autobahn. It flat spotted once on take off then was OK. No sign's whatsoever of the flat spot or the backfire (pop) through the plenum. Hasn't missed a beat since. WTF??

All I can put it down to is the computer has "re-learnt" itself and adjusted the mixture according to plug voltages and/or O2 sensor readings. (I think this system uses the original computer in tandem with the gas computer) Maybe needed input from speed sensors to start that process??

Any thoughts?

(I will be dropping the plugs back down to .024" this weekend - be interesting to see if the flat spot returns until I drive it again).

[bee utey]

Interesting you ask. Yes it is running the coil packs (Is there an alternative?)

Some people have used the Thor inlet manifold in conjunction with the distributor front cover. There are many aftermarket ECUs availabe to run anything you want.


All I can put it down to is the computer has "re-learnt" itself and adjusted the mixture according to plug voltages and/or O2 sensor readings. (I think this system uses the original computer in tandem with the gas computer) Maybe needed input from speed sensors to start that process??

Any thoughts?

(I will be dropping the plugs back down to .024" this weekend - be interesting to see if the flat spot returns until I drive it again).

All things are possible, the vehicle computer will self learn as it warms up. If the gas mixtures are originally off then running much on petrol may unlearn them. Only running the gas software can tell how much difference there is between petrol and gas settings. Software and adaptor available here:

eBay Australia: Buy new & used fashion, electronics & home d (http://www.ebay.com.au/itm/230662646857'ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649)