Lpg

hello does anyone know how much mpg you loose roughly running on Lpg compared with petrol

thanks

landy 3.9v8 said:

hello does anyone know how much mpg you loose roughly running on Lpg compared with petrol

thanks

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Depends on which type of LPG setup you have.
Single point LPG is the cheapest, simplest setup but it is the least efficient.
Multipoint, sequential LPG is the more sophisticated and expensive setup but is more efficient than single point.
LPG has a lower calorific value than petrol, so you lose a bit of BHP and MPG anyways.
Reckon on a 2 to 4 MPG reduction depending on which system you have and how you drive it.

the system i have mate is a single i think as it injects it into the inlet manifold and its on a 90 3.9 v8 out of a range rover classic

thnaks

landy 3.9v8 said:

the system i have mate is a single i think as it injects it into the inlet manifold and its on a 90 3.9 v8 out of a range rover classic

thnaks

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If it's a big collar mounted to the inlet manifold with a couple of smaller pipes coming off it as well as the pipe from the air filter, it's definitely single point.
Little tip for you: Get a set of Bosch super4 spark plugs, they were the best ones I found to use.

what does this benifit mate and also is it a better burn with these and how much are they ?

on single point systems the one main pain in the arse is backfiring, you need to make sure the air/gas intake is totaly airtight, also keep on top of your plugs and leads, get good quality leads and change plugs as soon as you notice a backfire or at the maximum 12 months.

bit of info here: Go LPG - Which type of LPG conversion do you need?

that site states that SGi is the most fuel efficient but i have read somewhere that single point can be more efficient on long runs!!

as a reference, i got 280 miles on 94 litres less than £50, this was a trip to ashford in kent and back to rotherham south yorkshire. i wasn't particularly slow either, and there was some town driving around ashford and and back home to use up the gas(second fill) to get the average figure for the trip. the computer indicated a max mpg of 21.5 which would probably equal 35-38 mpg???
this from a 4 litre engine is quite a bargain!!!

mines a 70 litre tank how much roughly do you think iot will take to fill?

usually around 20% less than the data plate on the tank as the gas needs expansion space. so around 56 litres, and i currently pay 49.9p per litre. about 28 quid???

you could get upto 140 miles on a run!!

thats not bad then is it have you got any valve oil into ur system?

I've been getting awful MPG results from both petrol and LPG but it's going down to a guy in south London who I've been told he's top notch, if you live around this area I suggest you check him out.

If you need his number Message me.

landy 3.9v8 said:

what does this benifit mate and also is it a better burn with these and how much are they ?

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Best benefit to fitting these was that it eliminated any backfiring and the difference in performance between petrol and LPG was significantly reduced.
I did not really notice any improvement in fuel consumption.

Here's where I got them from:

Bosch Super 4 Spark Plugs Land Rover/Range Rover 3.9 V8 on eBay, also, Land Rover, Car Parts, Cars, Parts Vehicles (end time 01-Jan-09 14:06:36 GMT)

Have a look see....

do you run k and n filters on ur v8s mate just wondering if it benifital to have one ?

landy 3.9v8 said:

do you run k and n filters on ur v8s mate just wondering if it benifital to have one ?

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I used to, got sick of cleaning it after almost every off road trip.

Went back to paper filters - if they get ****ted up real bad you can throw away and replace for a couple of quid.

K&Ns are washable, but their oily stuff to recoat the element is expensive at a tenner a throw.

I have found that K&Ns are fine for normal use, not so good for wet mud and dust.

Not sure about any BHP improvement - often wondered if a more free flowing air filter (like a K&N) meant less vacuum in the plenum and therefore affected how the vacuum advance worked on the distributor, thus affecting its performance.

ye thats true mate i dont know wat to do about one wat size v8 do you have ?

landy 3.9v8 said:

ye thats true mate i dont know wat to do about one wat size v8 do you have ?

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3.9 Disco, manual box. Does 20mpg (surprisingly) so won't be bothering with LPG this time around.

have u got gas on it or not ? or you just running petrol atm

landy 3.9v8 said:

have u got gas on it or not ? or you just running petrol atm

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NOW YOU'RE ASKING SILLY QUESTIONS......... :hysterically_laughi

BoomerV8 said:

3.9 Disco, manual box. Does 20mpg (surprisingly) so won't be bothering with LPG this time around.

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My previous Disco had LPG, but I'm not going to bother converting this one!

i got 3.9 manual in my 90 and it goes like the clappers its lovely

landy 3.9v8 said:

i got 3.9 manual in my 90 and it goes like the clappers its lovely

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Not surprised at that at all.
So what else are you thinking of doing to yours?

ill show you mine go on you tube then put in my landy for sale and look at the blue one thats the other bloke advertising it before i bought it