Pad Posted October 30, 2008 Share Posted October 30, 2008 Hi, I filled up my RRC today with gas after having it for a week and travelling about 110 miles and got 50 litres in from when I last filled.. 10 mpg!! Jeez, is that normal? I have been driving very gently albeit in mixed traffic conditions, but I was hoping for at least 16/17 mpg on gas to give me an equivalent cost of 25-28 mpg on petrol. I do have a blowing exhaust manifold gasket but would be surprised if this was a major contributor. Or is this just normal? 3.9 EFI by the way.. Cheers Pad Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 30, 2008 Share Posted October 30, 2008 Given that 15-18mpg is average going with a light foot on petrol, LPG will be lower so 10mpg isn't shockingly unreasonable. Could be a fault or could be perfectly normal. Anything wrong with the car that you've noticed? Quote Link to comment Share on other sites More sharing options...
Pad Posted October 30, 2008 Author Share Posted October 30, 2008 nope, seems to drive well enough... Quote Link to comment Share on other sites More sharing options...
Landowner Posted October 30, 2008 Share Posted October 30, 2008 Hi,I filled up my RRC today with gas after having it for a week and travelling about 110 miles and got 50 litres in from when I last filled.. 10 mpg!! Jeez, is that normal? I have been driving very gently albeit in mixed traffic conditions, but I was hoping for at least 16/17 mpg on gas to give me an equivalent cost of 25-28 mpg on petrol. I do have a blowing exhaust manifold gasket but would be surprised if this was a major contributor. Or is this just normal? 3.9 EFI by the way.. Cheers Pad My V8 Defender was the same giving about 9/10 on gas. I'm hoping for more after upping the T/B ratio from 1.4 which was in my opinion too low for motorway cruising. I also spent most of the time in 5th gear even around town with the 1.4 box so I'm looking for a vast improvement when I eventually get back on the road with raised ratios. Quote Link to comment Share on other sites More sharing options...
Pad Posted October 31, 2008 Author Share Posted October 31, 2008 sadly dont have that option as its auto... I was thinking last night what a significant drop in LPG economy that is if on petrol I should expect 15-18mpg... at current difference in prices it wont make any difference which fuel I use, which is disappointing. Perhaps I should run it on petrol for a while to see what mpg I am get.. Cheers Quote Link to comment Share on other sites More sharing options...
disco_al Posted October 31, 2008 Share Posted October 31, 2008 it could be that the lpg system needs readjusting to compensate for the colder weather, depends on what type of system it is. at the beginning of "summer" when we had a warm snap, my lpg economy dropped through the floor, about 10mpg, i had the system tweaked slightly, and it went back up to 17mpg (3.5 v8 manual disco) Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 31, 2008 Share Posted October 31, 2008 sadly dont have that option as its auto... You can swap the transfer box manual or auto, it's only if yours is a BW and you want to switch to LT230 that you might need to do a bit of fiddling. Quote Link to comment Share on other sites More sharing options...
maxtherotti Posted October 31, 2008 Share Posted October 31, 2008 my rangie takes £32 ish to fill and i get 150 miles so about the same (mostly round town) also dont forget that you will only get 80 ish % of the fuel economy of petrol as gas. on a run i get 170 miles as a steady 85 ish rob Quote Link to comment Share on other sites More sharing options...
DC_ Posted October 31, 2008 Share Posted October 31, 2008 Mines takes about £30 to fill, around 60-65 litres of gas. get about 150 -160 miles on that so it looks pretty normal unless alot of us had tweaking issues? Quote Link to comment Share on other sites More sharing options...
Pad Posted October 31, 2008 Author Share Posted October 31, 2008 nope, you guys are getting considerably better than me (and about what I was hoping for). £30 did me 110 miles.... if I had done 150 miles I would have been pleased. Quote Link to comment Share on other sites More sharing options...
Landowner Posted October 31, 2008 Share Posted October 31, 2008 nope, you guys are getting considerably better than me (and about what I was hoping for). £30 did me 110 miles.... if I had done 150 miles I would have been pleased. Make sure the timing has enough advance for gas, mine went considerably better on gas after advancing. Quote Link to comment Share on other sites More sharing options...
paintman Posted November 3, 2008 Share Posted November 3, 2008 What system do you have? Single point or multipoint? If single point & there is a flow adjuster (often called a power valve) in the line between the vapouriser & mixer is this set up correctly? If fully open all the time you will just be wasting gas. I too get 160 to 190 on around 65ish litres depemding whether its town driving or motorway cruising. Quote Link to comment Share on other sites More sharing options...
Pad Posted November 3, 2008 Author Share Posted November 3, 2008 Its a single point... is it just a matter of adjusting the valve in until it starts running rough? Quote Link to comment Share on other sites More sharing options...
V8david Posted November 3, 2008 Share Posted November 3, 2008 Its a single point... is it just a matter of adjusting the valve in until it starts running rough? Try half a turn. Doesn't take much, I noticed a big difference in power/consumption with just 1/4 turn. Don't try making it run rough, may get backfires and risk the AFM. Is it leaking anywhere? I had a slight leak from the plastic Y piece which lost a fair bit of gas. Lot of trial and error really mate. Like everyone else I expect 160-170 miles from £30-32. 200+ miles on a good motorway run (without jams!) Or go to an autogas place and have the system serviced/checked/setup. Shouldn't be too expensive. Good luck. Quote Link to comment Share on other sites More sharing options...
Highway_Star Posted November 3, 2008 Share Posted November 3, 2008 'Kin elL!! What are you boys doing? I have a 100l tank in the boot which fills to about 85l, as you'd expect. That'll cost me about £40 to fill from the point it starts to splutter and kicks back to petrol. Now, on the motorway I'll get 250miles from that, easy. Round town more like 200. That's about 14 mpg on the M'way, 11 round town. These are real numbers, not me driving like a nun. If I drive like a nun and change the tyres to AT's it's noticeably (probably 2-3 mpg) better. My lpg system is OMVL Leonardo, closed loop, single point mixer. I'm running standard ignition at 16º BTDC at idle, vac pipe clamped. It may well be the closed loop system that makes the difference, but I'm very retentive about servicing the vaporiser, filters and ignition. I noptice the drop in performance when the filters are clogging, for example. Quote Link to comment Share on other sites More sharing options...
V8david Posted November 3, 2008 Share Posted November 3, 2008 'Kin elL!!What are you boys doing? About 150 miles+ off £30. You're doing 200 miles+ off £40. So to answer your question... same as you pretty much?! Same ratio. i.e. we'd both get about 50 miles from £10. 'kin ell indeed... Quote Link to comment Share on other sites More sharing options...
Pad Posted November 3, 2008 Author Share Posted November 3, 2008 thanks, gives me some hope at least.. Quote Link to comment Share on other sites More sharing options...
cooper Posted November 3, 2008 Share Posted November 3, 2008 I was getting about the same as V8David from a 3.9 efi auto hope that helps Cheers Shaun Quote Link to comment Share on other sites More sharing options...
Highway_Star Posted November 3, 2008 Share Posted November 3, 2008 David, What tyres are you running on? Bear in mind my numbers are on Machos, if I put my AT's on I'll get another 2-3mpg, I was pleasantly surprised when I found that out! Quote Link to comment Share on other sites More sharing options...
paintman Posted November 4, 2008 Share Posted November 4, 2008 http://www.lro.com/forum/viewtopic.php?t=22292 Quite a lot on LPG in the LRO LPG forum. Quote Link to comment Share on other sites More sharing options...
V8david Posted November 4, 2008 Share Posted November 4, 2008 David,What tyres are you running on? Bear in mind my numbers are on Machos, if I put my AT's on I'll get another 2-3mpg, I was pleasantly surprised when I found that out! I fitted the wheels off 2 old road bikes, stripped everything except the driver's seat, windscreen, instrument panel and lights, and drilled holes in the chassis No, fair play mate. That is good. I'm on goodyear wrangler ATs on the front and kumho ATs on the back. And I haven't stripped anything... Quote Link to comment Share on other sites More sharing options...
Highway_Star Posted November 5, 2008 Share Posted November 5, 2008 That's my point. My Range Rover is not running in the most fuel efficient setup. I have chunky tyres on, 4 antennas and a light bar on the roof, and a ton of carp in the boot. I'm still getting similar mpg to you guys. If I were to set the car up a bit more standard, lose the lights and antennas and fit the other wheels. ie Run as you do I'm getting better mpg. Without nun 'esque driving either! Now there's a whole lot of other factors to consider, closed loop LPG system will help, engine and transmission condition, even altitude above sea leve and air temperature & humidity! Quote Link to comment Share on other sites More sharing options...
mickeyw Posted November 5, 2008 Share Posted November 5, 2008 I'm running standard ignition at 16º BTDC at idle, vac pipe clamped. What's with the clamped vac pipe? Are you preventing vac advance? I've not heard of this before It may well be the closed loop system that makes the difference, but I'm very retentive about servicing the vaporiser, filters and ignition. I noptice the drop in performance when the filters are clogging, for example. I too have the two-stage OMVL vaporiser. What does your servicing consist of? Quote Link to comment Share on other sites More sharing options...
Highway_Star Posted November 5, 2008 Share Posted November 5, 2008 Sorry, to clarify. 16º BTDC, vac pipe clamped = The timing was set up by an old experienced engine tuner, by ear, vac guage, sniffing the exhaust and power runs on the rolling road. When we measured the timing after tuning, for reference purposes, we found it to be 16º BTDC (according to the marks). When setting or checking timing with a strobe, standard practice is to disconnect and plug, or clamp the vac pipe, so that the vacumn A/R mech is not affecting the timing at idle Once I year I strip the vaporiser, cleaning out any heavy ends and generally checking it over. I replace the diaphragm and springs (you buy a service kit which includes everything you need). Also remove and clean out the filter in the solenoid valve, replacing the filter pack. Once that's all back together, out with the laptop and set up the mixture again. LPG engines with vacumn operated vaporisers need a bit of resistance in the air filter, K&N free flow filter is no good, conversely a choked air filter will knock the mpg down, so that get changed regularly too. Quote Link to comment Share on other sites More sharing options...
mickeyw Posted November 5, 2008 Share Posted November 5, 2008 Sorry, to clarify.16º BTDC, vac pipe clamped = The timing was set up by an old experienced engine tuner, by ear, vac guage, sniffing the exhaust and power runs on the rolling road. When we measured the timing after tuning, for reference purposes, we found it to be 16º BTDC (according to the marks). When setting or checking timing with a strobe, standard practice is to disconnect and plug, or clamp the vac pipe, so that the vacumn A/R mech is not affecting the timing at idle Once I year I strip the vaporiser, cleaning out any heavy ends and generally checking it over. I replace the diaphragm and springs (you buy a service kit which includes everything you need). Also remove and clean out the filter in the solenoid valve, replacing the filter pack. Once that's all back together, out with the laptop and set up the mixture again. LPG engines with vacumn operated vaporisers need a bit of resistance in the air filter, K&N free flow filter is no good, conversely a choked air filter will knock the mpg down, so that get changed regularly too. Okay, now I understand I think, just clamped during tuning. Now I fully accept that filters should be kept clean, but if you have a lambda controlled system, as I do, I would have thought that would be able to take care of some variations in running conditions (within reason). I have also read here on other threads that changes in weather can upset the mpg, but again wouldn't the lambda control be able to compensate? Who, apart from RPI, sells service kits for OMVL vaporisers? Thanks, Quote Link to comment Share on other sites More sharing options...
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