3.9 Range Rover on LPG
Discussion
Few years ago I used to have a 1994 3.9 Auto with LPG conversion, tanks were under the sills, which I bought with conversion already done around 2 years before I bought it. When on gas it had a bit less power (as you'd expect) but was still plenty enough to tow big trailer with. I used to give it some stick and retured around 11-13mpg average, once got 17mpg ish at sensible speeds. Incidently the car was in top condition. In 15,000 miles the only problem with the LPG system I had was that the valve to allow you to fill up both tanks would keep playing up meaning sometimes I only had one tank available. I would suggest getting the largest tanks you can as the range is not great if you do lots of miles each day and not always passing by an LPG station. I know of people that had lots of teething troubles when they had conversion done so you need a converter that you are happy will be able to sort out these problems and also that the engine is in good condition in the first place.
Also you may want to look into the concerns about the hotter temperature that running on LPG creates which can add to the troublesome block failure as a result of the rear cylinders running very hot thats common on 3.9/4.0 and 4.6 engines and happens even if its not seen LPG! I've not converted my current 4.6 as its running 100% and don't want to "rock the boat" of reliability by adding an LPG system! But then again I don't do enough miles in it to really warrant one anyway.
Also you may want to look into the concerns about the hotter temperature that running on LPG creates which can add to the troublesome block failure as a result of the rear cylinders running very hot thats common on 3.9/4.0 and 4.6 engines and happens even if its not seen LPG! I've not converted my current 4.6 as its running 100% and don't want to "rock the boat" of reliability by adding an LPG system! But then again I don't do enough miles in it to really warrant one anyway.
I have one as a daily driver and weekend toy.
I have fitted larger tyres for better ground clearance and get about 200 miles off £35 (about an 80 litre fill) on average.
When I had 205s on the rims I was getting about 250 out of the tanks.
They need regular oil changes but is a doddle to do as you dont need to lift the car.
Parts are not to expensive and there are plenty of independants about.
I have fitted larger tyres for better ground clearance and get about 200 miles off £35 (about an 80 litre fill) on average.
When I had 205s on the rims I was getting about 250 out of the tanks.
They need regular oil changes but is a doddle to do as you dont need to lift the car.
Parts are not to expensive and there are plenty of independants about.
If you go the LPG route, make sure that you goto a reputable installer who deals in high quality systems. Many of the earlier/cheaper systems can,over time, re-burn the engine map on the ECU after prolonged use and then when you switch over from gas to petrol the bloody thing runs like a sackful of spanners. I've never owned an LPG RR but spoke to an installer near to my office who only does LPG and Air Con work and he explained that there are lots of cowboys doing installations which he ends up having to put right, usually involves binning the system and starting again.
If you live in the SE, one downside is that you will be barred from the Channel Tunnel.....
If you live in the SE, one downside is that you will be barred from the Channel Tunnel.....
Writing from a V8 point of view...
The latest systems with sequential multipoint injection seem to be the ones that are being recommended these days, where the gas mixture gets injected into the rams of the inlet manifold. This prevents blowback etc in the inlet manifold, maybe not so relevant in the the alloy inlet manifolds, but if anyone has something a bit more exotic then it's a must.
These LPG systems have their own ecu that control the gas flow etc., but not sure if this can work with the old 14cux ecu and wiring loom or older versions of. In this case you can pull this out + replace with Megasquirt ECU and loom with which this can all communicate with. With the Megasquirt you can set up fuel maps to suit your driving and will also save £££ as will improve performance/economy. Further improvements can be done with an EDIS 8 ignition set up which replaces the standard coil, distributor and airflow meter with a coil pack (as p38 and on models). Am having this done myself. Cost of kit is approx £250 with fitting etc. over and above. You can offset these costs by selling your dizzy (£80), afm (£30-50), ecu and wiring loom (£100-150) on ebay, which could offset most if not all of these costs. If fitting yourself then you could in effect have money left over, however if not technical would recommend a professional sets it up as lap top work is required.
A few threads on this topic on the TVR Griffith forum and seems that the poster Dax Trojero has something to do with Megasquirt set up, so could be an idea to follow this up further with him to get more insight. There is also a Megasquirt website, forums, technical advice etc., which explains far more than I ever could.
Compatible used Ford Edis 8 + coil packs can be picked up on U.S. ebay with shipping for approx $80 (£50). Also upgrade Bosch yellow top (19 lb/min flow) injectors, again around $80 all in for used/cleaned ones. These have 4 fine nozzles giving better spray pattern than standard lucas hosepipe pattern.
In effect spend a couple of hundred £ and performance economy could well be improved, but all depends on state of engine as to by how much. Can always have lpg slotted in after if this is initialy too expensive.
Will update on mpg etc improvement in a couple or so weeks time mine is done, but this may be slightly improved as having other engine work done over and above this.
Hope some of this info helps.
The latest systems with sequential multipoint injection seem to be the ones that are being recommended these days, where the gas mixture gets injected into the rams of the inlet manifold. This prevents blowback etc in the inlet manifold, maybe not so relevant in the the alloy inlet manifolds, but if anyone has something a bit more exotic then it's a must.
These LPG systems have their own ecu that control the gas flow etc., but not sure if this can work with the old 14cux ecu and wiring loom or older versions of. In this case you can pull this out + replace with Megasquirt ECU and loom with which this can all communicate with. With the Megasquirt you can set up fuel maps to suit your driving and will also save £££ as will improve performance/economy. Further improvements can be done with an EDIS 8 ignition set up which replaces the standard coil, distributor and airflow meter with a coil pack (as p38 and on models). Am having this done myself. Cost of kit is approx £250 with fitting etc. over and above. You can offset these costs by selling your dizzy (£80), afm (£30-50), ecu and wiring loom (£100-150) on ebay, which could offset most if not all of these costs. If fitting yourself then you could in effect have money left over, however if not technical would recommend a professional sets it up as lap top work is required.
A few threads on this topic on the TVR Griffith forum and seems that the poster Dax Trojero has something to do with Megasquirt set up, so could be an idea to follow this up further with him to get more insight. There is also a Megasquirt website, forums, technical advice etc., which explains far more than I ever could.
Compatible used Ford Edis 8 + coil packs can be picked up on U.S. ebay with shipping for approx $80 (£50). Also upgrade Bosch yellow top (19 lb/min flow) injectors, again around $80 all in for used/cleaned ones. These have 4 fine nozzles giving better spray pattern than standard lucas hosepipe pattern.
In effect spend a couple of hundred £ and performance economy could well be improved, but all depends on state of engine as to by how much. Can always have lpg slotted in after if this is initialy too expensive.
Will update on mpg etc improvement in a couple or so weeks time mine is done, but this may be slightly improved as having other engine work done over and above this.
Hope some of this info helps.
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