car MPG help required

rev_henry

This is what you need to be looking at:
http://www.parkers.co.uk/cars/specs/Detail.aspx?deriv=15934

Official combined mpg for a 1.6 lpg astra is thus 30mpg, so your figures are about right, possibly a bit low.

forgotmyname

Depends on the quality of the kit, Dont forget the extra weight of that tank and other bits.

When was the LPG side last serviced? Mixture may need adjusting.

Engine serviced? LPG can be hard on the spark plugs. Correct gaps need to be checked often.

Hammyman

Ukuser wrote: »

Could somebody please explain why im getting such low mpg or where im going wrong in the calculations

thanks

miq

LPG typically gives you 10% less MPG. If you can't drive for toffee, its quite possible for you to get town MPG figures on the dual carriageway.

When was the time you bothered getting your car serviced?

forgotmyname

Reset my trip at the garage tonight and managed to get 69mpg, Damn i was hoping for 70+.

Sorry to any tractor drivers or caravan owners who were stuck behind me. But oh..my the
journey was so boring.. I prefer my 30mpg driving style. At least i dont fall asleep.

Tucker

I drive an LPG car and consistently return 30 mpg on gas.

For my car, combined driving is quoted as 37 mpg, but be honest, that's calculated from ideal driving, not real life driving, so I would be surprised if the true petrol return was 35 mpg, probably less.

LPG by volume (litres) is less efficient but the same as petrol by weight. But of course it is sold in litres.

As has been said, the calibration of your LPG system needs to be right to get optimum return, so if it has not been checked, you should have it done or accept the mpg is what it is.

I get my gas for 67p, so prices vary alot, which affects the savings you can make.

bigjl

We have 51 and 52 plate ex reaponse cars that we use as runabouts, all 1.8 petrol auto, the one i use gets about 29/30 mpg. Mostly round town though.

The 1.6 petrol Astra was never thought to be an economical car even when new. Especially.in 8v or LPG. You will get slightly less mpg using LPG and slightly less power, that is why converting a relatively underpowered car is a bad idea, as you end up hammering it more to make up.for the lack.of power.

I would.say the OP should have the LPG kit serviced and make sure the air filter.on the car is nice and clean. If it is still the same then that is just a result of the above. A low powered car being unwisely converted to LPG. Perhaps the OP could try amd adjust their driving style a bit. It may also be a simple case of leadfoot.

Kilty_2

The Astra G was available in factory LPG/Dual Fuel though, no? ie it's unlikely to be a conversion.

forgotmyname

Not many LPG cars sold though and the price was over what you would pay for the car and an aftermarket
conversion.

Hammyman

forgotmyname wrote: »

Reset my trip at the garage tonight and managed to get 69mpg, Damn i was hoping for 70+.

Sorry to any tractor drivers or caravan owners who were stuck behind me. But oh..my the
journey was so boring.. I prefer my 30mpg driving style. At least i dont fall asleep.

I get just short of 60MPG out of my Ford Mondeo. Most of my time is spent overtaking people.

If you need to drive like a snail to get decent fuel economy, you're doing it wrong.

Goldenyears

Tucker wrote: »

LPG by volume (litres) is less efficient but the same as petrol by weight. But of course it is sold in litres.

LPG is less efficient (by volume) since the density is ~0.50 kg/litre compared with petrol (~0.72 kg/litre) and diesel (~0.83 kg/litre).

Just fewer carbon atoms per litre to oxidise folks and less energy. Notice how half the efficiency gain of diesel over petrol is because you get more of it for your litre.