I know the subject of LPG is discussed quite regularly on this forum ??.but I don?t think anybody has asked this question before.
I?ve trying to investigate the various types of LPG conversions available and their respective advantages/disadvantages over the last few days and am now even more confused than when I started.
There seems to be 2 main systems available;
1. Induction systems
2. Injection systems ? which are divided into
a) single point injection
b) multi-point injection
Information suggests that the induction systems have been around for a while and seem to be ?tried and tested? but the injection systems seem to be at the stage (3rd generation) where almost any type of petrol engine i.e. multi-valve, turbo, variable valve timing etc. can be converted and they will comply with the strictest emissions regulations. However there seem to be a lot of horror stories, mainly regarding ?blowback? causing air boxes to explode. Does this phenomenon apply to both types of systems ? Also in some cases it seems to wear out valve seats and stems where they are not ?hardened? enough to cope with combustion qualities of LPG. Recent engines don?t seem to suffer from this problem so much (???).
Petrol Land Rover owners will be glad to hear that the venerable LR V8 in it?s various guises is very popular with LPG converts. However an awful lot of them seem to be complaining about very poor consumption on LPG, for example mpg on petrol is 20-22, therefore with LPG you would reasonably expect 15-17 mpg, but owners are only getting 10-12 mpg on LPG which makes the conversion almost redundant. I?m not sure whether this is due to installation problems or otherwise.
Also a lot of DIY installers don?t seem to be doing their homework and matching the LPG system to their cars engine/power requirements, leading to problems such as loss of power, no revs etc.
Finally, ( I heard that sigh of relief ! ) which system would backroomers recommend for the BMW 3.5ltr 12 valve straight 6 ? (circa 1984-1992)
Regards,
Chad.R
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>Petrol Land Rover owners will be glad to hear....... V8 in it?s various guises is very popular with LPG converts. However an awful lot of them seem to be complaining about very poor consumption on LPG, for example mpg on petrol is 20-22, therefore with LPG you would reasonably expect 15-17 mpg, but owners are only getting 10-12 mpg on LPG which makes the conversion almost redundant. I?m not sure whether this is due to installation problems or otherwise.
Chad,
That translates to the fact that V8 LR owners are absolutely desparate to improve their fuel consumption and so fork out £750-£1500 on various systems that have an unacceptable level of faults.
For that reason I advise extreme caution unless you know a particular company has used a particular system on a particular vehicle and it has run for months with no problems.
David
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A friend of mine runs a land rover repair business and has been doing conversions for some years.
He now recommends an Italian system which has a higher level of engine management - he claims a 10-20% increase in "mpg" as a result - I will ask him for the details...
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I'd be very suprised at this claim...
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to clarify - an increase in range over a standard LPG system, not petrol...
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From my "research" the Italians seem to to well up on LPG systems and there seem to be alot of Italian systems on the market - Tartarini systems seem to be quite popular.
Chad.R
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Induction is crude (i.e. like mine!) and blowback can be avoided by fitting a nrv or "fart-flap"
Friend of mine at D&N Autogas has converted a 1990 BMW M5 to gas with an injection system. Induction lpg systems won't work on motas such as this!
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Anyone that claims to get 20-22 mpg from a V8 Landy is talking through their proverbial ass.
I have a V8 90 which with careful driving averages around 18. If I drive normally it will be around 16. And with the minimal (relative) weight of a 90 that's about as good as it gets. So a drop to 12 for LPG ain't bad.
Incidently, 'er in doors drives a 4.6HSE which just luvs the flammable stuff.....about 14. Just proves my point that 20-22 is pie in the sky.
It could be a diesel of course in which case it won't run particularly well when converted to LPG.
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On my vehicle, a carina e 2.0 litre, I had an installation done in Poland. It cost £300 there, plus the extra £50 here to put the extra permanent UK filling adapter as the temporary adapters work very badly in the UK.
In two years, it has saved £550 in fuel,
The consumption is lower on gas as was expected. I do an average of 27.5 mpg on gas, vs. 35 mpg on petrol. So a difference.
Because it is the carb version, I think it drinks more gas in town, and a lot of the miles are done in heavy london traffic which is not good for consumption.
So there is a saving, and this is based on 5000 miles per year mileage.
The reliability of the installation is good. It has cut out at times, but that is to do with the idling on the gas being a little too low. But apart from this very minor problem, it performs well, with only a slight difference in performance.
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I've got a golf mk3 1996 1.8 SPi estate and it does 31 mpg at 75 mph, with a NECAM MEGA LPG G3 multi point system. The multi point systems are more economical and environmentally friendly than the others.
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Got a carina e 1.8p installed omvl LPG injectors, bit noisy injectors, but works well. Installed in 153000 and now 182000 still running strong -)). But regular services.cant faults it at all. I plan to run it until it goes. Get bat 27 mpg on LPG and used to get 38mpg on petrol if I drive like a grandpa in 60-65 mph speed. Get abt 25-27 mpg on LPG in motorway speeds. Glad I converted.i also have valve saver and dense iridium plugs
Edited by nafede on 11/01/2014 at 22:24
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