Are my calculations correct?

[BigM]

Hi
My way of thinking is if I'm paying 72p per litre for gas, but loosing 20% efficiency compaired to running on petrol then I am running my car as if petrol was currently costing 86.4p per litre (as I'm having to use 20% more fuel to cover the same milage).
i.e 72+20%=86.4
Are my calculations right?

So to travel the same distance would use 20% more gas than petrol.
If my car used 10 litres of petrol to cover 100km then it would use 12 litres of gas.

[billynoband]

Not far off, you may only lose 10%. Depends on the car and the system fitted. You may also need valve saver fluid at 50p per tank.

[Gilbertd]

Blimey, somebody thinking about it logically. I worked out that if petrol stays the same price (around £1.25 a litre even though I saw £1.29 tonight with the extra VAT), gas would need to get to £1.10 a litre before it costs me the same no matter which fuel I run on.

[e301988325i]

Hi
My way of thinking is if I'm paying 72p per litre for gas, but loosing 20% efficiency compaired to running on petrol then I am running my car as if petrol was currently costing 86.4p per litre (as I'm having to use 20% more fuel to cover the same milage).
i.e 72+20%=86.4
Are my calculations right?

So to travel the same distance would use 20% more gas than petrol.
If my car used 10 litres of petrol to cover 100km then it would use 12 litres of gas.

If LPG MPG = 80% of Petrol MPG then;

LPG is 80%, to get to 100% would be:

LPG price: divided by 4 x 5, divide by 0.8 x 1.0 or x 1.25 (+25%)