Save cash on fuel

EDITED – See end of text for latest figures!

Since getting my old Audi A4 (1996 Saloon) I have covered over 6000 miles in under 3 months.

I drive over 100 miles a day – and that works out as an average of 76.1 miles a day including my none driving days!

That also works out at £8.04 a day on average…. and 659.8 miles per fill up.

So… I have the perfect chance to try several ways to save fuel.

I didn’t want to do anything over the top. I wanted to make slight changes to see what would happen. The type of changes you could do quite easily without altering your driving style so much.

Firstly I did a few journeys at my normal style. I’m no racer – I keep up with the traffic and drive as the traffic around me drives – so pretty average.

The table below shows a few statistics on my trips. I purchased the car with 113816 miles on the clock – so that is why the first line shows 0mpg – I hadn’t got anything to judge it against.

By the 27/08/09 I had covered 638 miles filling up with 57.63 litres – I had covered those 638 miles at 50.33mpg – a good starting point, as when I chose the car I was looking for 50mpg or more at the very least.

The next entry and I only got 47.03mpg! I knew why though. I was a bit heavier on the throttle and harder on the brakes. I even went around a track which gave the impact of driving the car like a “boy racer” – although that was only for 3 miles…. ONLY 3 miles like an idiot racer and it hammered my economy.

The following fill up gave me 55.66mph – and that was by far gentler driving… but nothing major!

I still drove at the same speeds on the roads as I had done on the previous tests, but this time I didn’t floor the throttle to get to those speeds, and I didn’t use harsh braking to slow down.

I simply put enough throttle down to get the car moving, then as it gathered speed I’d change up a gear – but a little earlier than usual. The time it took to get up to my usual top speeds was a little slower, but it was there that most of the fuel savings took place.

When it came to driving I simply left a bigger gap between me and the car ahead. If I saw the cars ahead start to slow I would come off of the throttle straight away instead of catching up and having to brake.

This way I wasn’t wasting fuel by braking and accelerating all the time – I was just using the throttle to keep me gently at my cruising speed – which was the same cruising speed I had used from the beginning of the test.

As you can see – between harsh driving and gentle driving I had a change in mpg of 8.63 mpg… or 299 miles per tank – at the time that was £6.84 per tank saved. For me that is over £350 a year… which  covers MoT & Tax.

The thing is, the journey to and from work is not taking any longer. Just driving calmly, pre-empting what other cars were doing, having a feather weight foot rather than a lead one… it all added up.

I use the iPhone App – Road Trip to measure all of this. Since using it I have taken a greater interest in my economy – I even have all my expenses set up on it so I can see the true daily cost of my car once insurance, fuel, tax, MoT, services etc are taken into account. Currently it costs £12.21 a day – which is less than half the price of a return train ticket for my work!

Annoyingly the M3 then had months of road works – and the reduced speed took the car out of an economic cruise, so I lost the high mileage economy for a while. Still, I managed to keep the average up over 50mpg.

Yellow: Price per Litre / White: MPG / Blue: Average

I am now trying to hone my driving style to reduce the fuel cost even more. I mentioned that I would simply come off of the throttle if I was catching up with traffic. If I caught up too fast (nothing dangerous)  then I was using the brake. This isn’t the best way to save fuel…. You see modern cars that are aiming at giving better economy are now using engine braking to help save fuel. One way you can do this with older cars is to come off of the throttle, put the clutch in so the revs drop off, then slowly let the clutch out again. The speed of the car will then try to spin the engine revs back up again, and as this happens the energy used to spin the engine up is lost in speed. I am finding I can slow down quite smoothly this way – and in fact don’t need to use the brake unless I am coming to a dead stop, or if there is an event that requires faster stopping.

I also don’t sit on the clutch at traffic lights or on hills. I go into neutral and put the hand brake on. It doesn’t seem like much, but it all adds up. Correctly servicing the car, keeping the tyres to the correct pressure (an important safety check in its own right) – it’s all important in the fight to save fuel bills – and none of it is difficult to achieve.

It’s all about being calm – and it is true to a point, driving faster doesn’t get you there any quicker – but driving there with a bit more thought will save a lot of money.

UPDATE!

Even though I spent some time stuck in traffic due to a huge problem on the M27, the results from clutch braking are showing through. I have just returned my best MPG to date at 56.18mpg – giving my daily running cost (including all bills etc) of just over 15 pence!). If I carried on driving hard, that would go up to £1.15!!! That’s a heck of a difference.

One person pointed out that this may wear the clutch out more… BUT… I am using less brakes and less fuel – which more than makes up for any additional clutch wear. Also. the clutch is gently slipping within a small speed & rev range, so the wear is much less than you would get when changing gear. So clutch wear is a mute point here.