I'm looking at switching from a company lease car to taking a car allowance.
Basic criteria...
1. 20-25k miles/year
2. Estate
3. Diesel
4. Keep for 3 years
5. I like VAG cars
6. Reliable/Economical
Looked at cars around £7-8k including...
1. A4
2. Octavia
3. Passat
Then I came across a BMW 330i Tourer with an LPG conversion which got me thinking....
1. What's involved in running an LPG converted car - servicing difficulties, costs, long term reliability etc?
2. With the reduced MPG vs. cheaper fuel actually save you any money?
3. HMRC - I'd be claing HMRC advisory fuel rates for work miles - would an LPG converted car be considered petrol or LPG (the rates are quite
different!)?
4. Anything else.....?
Advice and experiences please ladies and gents.
I've had 4 cars on LPG, (v8 mgbgt, 1992 twin turbo 535i BMW, 4.0 Jeep Cherokee, 4.0 v8 RangeRover), and never noticed any real difference
compared to running on petrol.
The MPG is roughly the same, so is performance.
The only time you have any extra expense is when something on the conversion needs repair.
They're fractionally down on power and economy compared to petrol, but it's only ~5%ish on a good injection conversion. Fuel is 55p/litre. What's to lose?! New injectors are generally cheap as chips if you need them for some reason (rail of 4 usually comes in around 70-100 quid). The rest of it is pretty bomb-proof.
quote:
Originally posted by fha772
I've had 4 cars on LPG, (v8 mgbgt, 1992 twin turbo 535i BMW, 4.0 Jeep Cherokee, 4.0 v8 RangeRover), and never noticed any real difference compared to running on petrol.
The MPG is roughly the same, so is performance.
The only time you have any extra expense is when something on the conversion needs repair.
If I were you I'd rate the vehicle as whichever rate means you pay less..
Anyone capable of building a kit/locost/doing some minor mechanics is more than capable of fitting one. You should be able to find someone to certify
it fairly cheaply. There's plenty of installers about but I can't recommend any as we've always done it ourselves. Trade body - not
sure, sorry.
The process involves a bit of tin snipping, drilling and tapping your manifold near the ports, fitting some nozzles, then connecting up hoses, bolting
down the tank, checking for leaks at joints and then cutting your injector wiring as per their instructions. They all should come with instructions on
how to fit them and how to tune them. Tuning is a bit more fiddly, but again the instructions that come with them usually tell you how to tune them to
a reasonable degree, if you want it perfect you can tinker or take it to someone. Ultimately they use your original petrol maps to calclulate exactly
how much LPG to put in (its a direct multiplier) but in reality it varies a little at different RPM due to things like gas dynamics, but you'll
be able to run the car pretty much out of the box IME
Just make sure you get a kit suited to your car. If you have sequential petrol injection you may need a sequential gas kit - the supplier should tell
you that at the start.
[Edited on 31/8/10 by coyoteboy]
quote:
Originally posted by Ninehigh
If I were you I'd rate the vehicle as whichever rate means you pay less..
quote:
Originally posted by coyoteboy
Anyone capable of building a kit/locost/doing some minor mechanics is more than capable of fitting one. You should be able to find someone to certify it fairly cheaply. There's plenty of installers about but I can't recommend any as we've always done it ourselves. Trade body - not sure, sorry.
The process involves a bit of tin snipping, drilling and tapping your manifold near the ports, fitting some nozzles, then connecting up hoses, bolting down the tank, checking for leaks at joints and then cutting your injector wiring as per their instructions. They all should come with instructions on how to fit them and how to tune them. Tuning is a bit more fiddly, but again the instructions that come with them usually tell you how to tune them to a reasonable degree, if you want it perfect you can tinker or take it to someone. Ultimately they use your original petrol maps to calclulate exactly how much LPG to put in (its a direct multiplier) but in reality it varies a little at different RPM due to things like gas dynamics, but you'll be able to run the car pretty much out of the box IME
Just make sure you get a kit suited to your car. If you have sequential petrol injection you may need a sequential gas kit - the supplier should tell you that at the start.
[Edited on 31/8/10 by coyoteboy]
With current LPG systems which use sequential gas injection you do get a loss in power and increase in fuel consumption. Power loss is between 8 and
15% and Fuel consumption increase is between 10 and 20%.
A properly fitted LPG provided it is of decent quality will be reliable and only needs servicing every 15,000miles --- change filters, clean out
accumulated residue, check for leaks and check system is in tune.
With 330i on LPG you will return an real world MPG of 23 to 27. Running cost entirely depend on how far you are from a cheap LPG seller.
Currently my Rover is doing 270 miles to 48 litres of LPG at 60p per litre + £3.00 for petrol ---- say £32
Equvalent mileage cost on petrol £48
I could save a lot more if I was prepared to travel if I travel annother 4 miles for cheaper LPG
SO23
Nearest to home (Shell) = £0.68/litre
Nearest to work (Shell) = £0.68/litre
Don't just look at petrol stations, find local industrial gas suppliers - they often will fill you up, and notably cheaper.
FYI we have a 3.5litre BWM (original economy was 21mpg average) getting 19mpg and with (seat of the pants) virtually no reduction in power. OK, a tad,
but it's barely noticable, you'd have to check it on rollers. A 0-60 timing is imperceptibly different.
quote:
Originally posted by coyoteboy
Don't just look at petrol stations, find local industrial gas suppliers - they often will fill you up, and notably cheaper.
My local is a calor gas supplier, charges 49p/l.
The 8% minimum power loss is mainly down to LPG being supplied to the inlet manifold as a gas, because it is a gas it displaces more air than liquid
petrol droplets.
The Fuel consumption increase is mainly due to the lower calorific value of propane compared to petrol.
Order of calorific values per litre from low to high is
LPG (Propane)
Petrol
Diesel.
quote:
Originally posted by coyoteboy
My local is a calor gas supplier, charges 49p/l.
quote:
Originally posted by nick205
quote:
Originally posted by coyoteboy
Don't just look at petrol stations, find local industrial gas suppliers - they often will fill you up, and notably cheaper.
Good tip!
Any suppliers I might look up (did a quick google, but not overly useful!)
Cheers
Nick
Found a couple of local suppliers via yell.com and waiting on a call back with prices. One of them is actually closer than the nearest filling station with LPG too!
quote:
Originally posted by britishtrident
http://www.flogas.co.uk/gas-finder/south-east/hampshire/west-meon-service-station-petersfield/
Fuel consumption increase will be roughly 20% (due to the lower energy content of the fuel per litre); power loss will be somewhere around 5%. Try to get a quality conversion done. Yes, it costs more but it will save you a considerable amount of aggrevation later. One of the best in the market today is Prins.
Kilbirnie street - I've not actually bought from them yet (still working on finding suitable parts for a 75hp/cyl conversion) but I checked out their prices a month or so ago.
quote:
Originally posted by coyoteboy
They're fractionally down on power and economy compared to petrol, but it's only ~5%ish on a good injection conversion. Fuel is 55p/litre. What's to lose?! New injectors are generally cheap as chips if you need them for some reason (rail of 4 usually comes in around 70-100 quid). The rest of it is pretty bomb-proof.
with the london C charge you only get dicount if its a factory fitted system i believe, so you might have to get a factory fitted vehicle as well, loads about though, you might want to ask if it has to be factory system.
quote:
Originally posted by se7en
I have had several LPG cars and every one that I had was faster on acceleration using gas compared to petrol.
In the BTCC the Ford Focus are using LPG and they are 3-4 MPH quicker than the others.
The gas consumption gives about 90% of MPG compared to petrol. But considering that LPG is about half the cost of petrol it is economic. The down side is that LPG systems need servicing and the components are quite expensive.
HTH
Tom
People keep saying components are expensive. What components? You can buy a full new fuel system for under 400 quid with perfectly adequate
injectors/vap for the majority of cars? That's injectors, vap, electronics, the works. Most 4 cyl injector rails are ~£100. There's no
petrol injectors that come close to that?
quote:
The BTC Fords run on the latest state of the art liquid phase lpg injection which doesn't displace any noticeable amount air and can actually gain power from the liquid gas evaporation cooling the inlet charge.
quote:
Originally posted by bj928
with the london C charge you only get dicount if its a factory fitted system i believe, so you might have to get a factory fitted vehicle as well, loads about though, you might want to ask if it has to be factory system.
quote:
Originally posted by coyoteboy
People keep saying components are expensive. What components? You can buy a full new fuel system for under 400 quid with perfectly adequate injectors/vap for the majority of cars? That's injectors, vap, electronics, the works. Most 4 cyl injector rails are ~£100. There's no petrol injectors that come close to that?
quote:
The BTC Fords run on the latest state of the art liquid phase lpg injection which doesn't displace any noticeable amount air and can actually gain power from the liquid gas evaporation cooling the inlet charge.
I've been waiting for liquid injection to come of age, last time I checked (6 months or so ago) the general consensus was that it was still a long way away as injector freezing is a problem, it requires a dedicated high pressure pump etc etc. I wonder if these ford bits can be had elsewhere or from scrapped cars. Their older gas-phase injection systems were shocking though, so I'm not sure I'd want to go there!
[Edited on 31/8/10 by coyoteboy]
Liquid manifold injection came of age 10 years ago; developed by Gentec (a company created by the university of Gent) for Vialle; a dutch LPG
component manufacturer. Using their technology, a *vast* amount of cars have been built / converted to use LPG. The last generation Ford liquid
injection LPG systems used ICOM parts which are basically crap.
The 100 quid injection rails are also crap; they are either very dissimilar in flowrate within one set (causing bad emissions, bad idle, burnt cats,
etc.), sensitive to flow shifting over their lifespan (causing check engine issues, bad starting, etc). and / or contamination. Steer clear from them
and use quality components from a large scale manufacturer. Prins are one of the best as they use Keihin (=honda) injectors. The others are (in no
particular order)
Landi-Renzo
GFI fuel systems (selling the AG and Necam brands)
BRC
And that's about it....
But, if you do go for a conversion from a reputable manufacturer and have it installed properly you won't have any problems. Go for it!
Sebastiaan
quote:
Originally posted by coyoteboy
People keep saying components are expensive. What components? You can buy a full new fuel system for under 400 quid with perfectly adequate injectors/vap for the majority of cars? That's injectors, vap, electronics, the works. Most 4 cyl injector rails are ~£100. There's no petrol injectors that come close to that?
quote:
The BTC Fords run on the latest state of the art liquid phase lpg injection which doesn't displace any noticeable amount air and can actually gain power from the liquid gas evaporation cooling the inlet charge.
I've been waiting for liquid injection to come of age, last time I checked (6 months or so ago) the general consensus was that it was still a long way away as injector freezing is a problem, it requires a dedicated high pressure pump etc etc. I wonder if these ford bits can be had elsewhere or from scrapped cars. Their older gas-phase injection systems were shocking though, so I'm not sure I'd want to go there!
[Edited on 31/8/10 by coyoteboy]
With respect, we've been using cheap-ish injectors in one car for a LONG time with no issues at all, perfectly good emissions (certainly those
checked at MOT) and no drift in tuning (checked with LC-1 after 12 months). The biggest problem I've seen with them is that most can't
deliver the spec they claim, top end flowrate-wise, even with the nozzles correctly sized.
Still never seen liquid phase injection parts for sale anywhere, and every factory car I've seen them on appeared to be gaseous? I've been
looking in the wrong places.
britishtrident - fancy pointing me in that direction? I could do with a system with twin injectors per cyl and at that price I could do it nicely
Fleabay- my god...
[Edited on 31/8/10 by coyoteboy]
With equal respect; running them in one car says nothing. I've been in the LPG business as a design engineer between 2003 and 2009, so should
know what I'm on about.
quote:
Originally posted by coyoteboy
With respect, we've been using cheap-ish injectors in one car for a LONG time with no issues at all, perfectly good emissions (certainly those checked at MOT) and no drift in tuning (checked with LC-1 after 12 months). The biggest problem I've seen with them is that most can't deliver the spec they claim, top end flowrate-wise, even with the nozzles correctly sized.
Still never seen liquid phase injection parts for sale anywhere, and every factory car I've seen them on appeared to be gaseous? I've been looking in the wrong places.
britishtrident - fancy pointing me in that direction? I could do with a system with twin injectors per cyl and at that price I could do it nicely
Fleabay- my god...
[Edited on 31/8/10 by coyoteboy]
quote:
Originally posted by coyoteboy
britishtrident - fancy pointing me in that direction? I could do with a system with twin injectors per cyl and at that price I could do it nicely
Fleabay- my god...
[Edited on 31/8/10 by coyoteboy]
First of all Prins aftermarket systems are the best and good for 100,000 miles plus without anything other than servicing, this is mainly due to
the quailty of the injectors, sensors and electrical connections.
However the LPG kit market has developped at an amazing rate. Three or four years ago most of the cheaper kits on the market were experiencing cases
premature gas injector failure at around 15,000 miles. This was to a large extent y due to quality and design issues but was mainly triggered by the
sourcing of LPG from eastern europeean supplies which were heavily contaminated with "heavy ends" (i.e. wax and paraffins ) and
particulate matter. Due to design issue Matrix injectors had a particular problem with contaminated gas, while early Valtek & Rail injectors
suffered from burnt out solenoid coils and wear
Since then electrical and material specifications have been improved and the lpg is filtered in both liquid and gas stages and reliability and
longevity has increased greatly. On my car I have a Valtek type 30 which I would expect to last for at least 50,000 miles perhaps a lot more (it
has already covered 20,000 miles without any attention.
In any event replacement injector rails are available for around the same cost as a set of platinum/iridium spark plugs and rebuild kits and
replacement coils are available and simple to fit.
One thing known to increase injector life is to ensure the the gas reaching the injectors is at high temperature at all times.
The problem that exists in all system that use gas injectors is the injectors need to be much physically larger than petrol injectors but need to
operate in the same time window as the petrol injector --- a bit like squaring the circle, particularly on high output engines.
Ford and Vauxhall factory fit dual fuel cars used a different gaseous system which used a gas distributor, these systems have also suffered from
problems caused by contaminated gas which can usually be fixed by flushing out the system with a mixture of thinners and WD40.
A link that may be of interest http://www.ac.com.pl/en/
The PDF manuls for the Stag 300 premium are worth downloading and reading.
http://www.ac.com.pl/en/doc/346/instructions-and-manuals
[Edited on 1/9/10 by britishtrident]
^^^
As I've commented before BT, you seem to have an almost Encyclopaedic Knowledge of things auto related!
quote:
With equal respect; running them in one car says nothing. I've been in the LPG business as a design engineer between 2003 and 2009, so should know what I'm on about.