MPG AC belt

[mancunian]

Any thoughts as to why my fuel consumption dropped form 24mpg to 29mpg after the AC belt had been taken off the pump? Faulty tensioner pulley meant the belt was taken off prior to repair. On a long run at 75mph+ I got 28mpg when last year with belt fastened I got 24mpg on a similar run.
#Mancunian

[dipstick]

If my fuel consumption went from 24mpg to 29mpg I would say it was an increase, MORE miles to the gallon.

The reason probably is that the engine is not having to drive the AC therefore the power being usually absorbed by the AC is now going into propelling the Bongo.

So don't run your AC when its not really needed, or you will consume more fuel.

[Aethelric]

interesting though. Even with the aircon switched off the engine is still turning the pump. Maybe removing the belt in winter may be a good idea to save fuel, but general opinions are that you should run the aircon for a short time weekly to keep it working.

[trevd01]

If my fuel consumption went from 24mpg to 29mpg I would say it was an increase, MORE miles to the gallon.

Consumption is less, therefore it is a reduction. But it is more miles to the gallon.

That is because we in the UK we express consumption in miles/gallon. You are expressing distance travelled per unit of fuel.
A bigger number the less fuel you are using.

If we expressed our consumption like most of the rest of Europe - in Litres/100km, the figure would go down. You are expressing fuel used per unit of distance.
A smaller number the less fuel you are using.

25mpg = 11.2 l/100km
30mpg = 9.4 l/100km

Calculator here: http://www.tdiclub.com/misc/conversions.html

I'll fetch me anorak...

[dipstick]

Hi Rev, That was too much to take in after a Sat night session at the local. But I do see where you are coming from, I think.

Aethel, the aircon is engaged by an electric clutch I think so although the belt is turning the pulley it is not under a large load until you turn on the AC.

[Aethelric]

Hi Rev, That was too much to take in after a Sat night session at the local. But I do see where you are coming from, I think.

Aethel, the aircon is engaged by an electric clutch I think so although the belt is turning the pulley it is not under a large load until you turn on the AC.

Oh, thanks dipstick, so with climate control, is the clutch engaged in econ mode? - This is a great forum.

Dave

[oglivy0]

Anything the engine drives uses fuel,removing the belt = better fuel consumption.

[trevd01]

Hi Rev, That was too much to take in after a Sat night session at the local. But I do see where you are coming from, I think.

The US does mpg, too, but they more accurately talk about 'gas mileage'. Of course their gallons are smaller, just to confuse things