Fuel Saving Techniques

Increase Your MPG

*Never drive the car in automatic. The car seems to rev far too high before changing.

*You will have to drive at least 10,000 miles before you expect 50+MPG as it takes this long for the engine to loosen up.

*Use 12% to 25% acceleration for keeping your speed up.

*Keep the revs between 1500rpm and 2500rpm whenever possible.

*Keep the car in the highest gear possible when maintaining a set speed.

*Optimum speed cruising speed is 45mph to 50mph in highest gear.

*If you have a turbo 451, keep the revs low so the turbo doesn’t boost. When the turbo forces air into the engine, the ECU adds more fuel to compensate and keep the fuel/air ratio level.

*Drive like you don’t have brakes as using the brake wastes the power that the engine has already created. This isn’t as dangerous as it sounds, it actually makes you a better driver as you have to read the road and think ahead. Don’t race up behind slower moving cars or red traffic lights. Easing off the accelerator early and coasting allows time for whatever is slowing you down to clear. Use the inside lane on large “A” roads and motorways, they are the least used lane and usually flow at a consistent speed. This is because BMW, Merc and Audi drivers are in the outside lane and everyone else blindly cruise along in the middle lane because they are idiots. All you get in the inside lane is lorries and the Chinese.

*Making the car more efficient makes it easier for the engine to get air in and waste air out.

Modifications such as silicone air pipes and high flow air filters are a good place to start.

Drilling holes into the airbox and even remapping can increase MPG if you drive sensibly.If you keep the original air filter, ensure it stays clean to keep the engine efficient.

*Front spoilers, side skirts and even lowering the car can increase MPG.

*Check and maintain the tyre pressures, having incorrect pressures increases the rolling resistance of the tyres meaning more energy is wasted making the car move.

*Wider wheels also have a higher rolling resistance so sap more power from the engine.

*Don’t use the air conditioning. When the air condition is running, the compressor needs an extra bit of torque from the engine so it will rev slightly higher when idling and use slightly more fuel to create the extra torque.

*Don’t use the heater blower and headlights (where possible). Not many people realise that the greater the load you put on the electrical system, the more ampage the alternator needs to create, the harder it is to turn. The engine therefore needs to create more power to turn it.

*Keep the windows closed at all times, this reduces the drag on the car meaning it takes less power to push it forwards and maintain speed.

*Keep the roof closed on cabrios, again, this reduces drag on the car.

*Coasting in gear uses less fuel than coasting in neutral but you can coast further in neutral as there is no engine braking. If you are going down a steep hill then you can normally coast in gear and  maintain the same speed. Less steep hills will require you to coast in neutral to keep your speed up. To maintain a set speed on a flat is easy, you just keep the accelerator at a certain position. When you go up or down a hill you have to adjust the accelerator to maintain your speed. If you don’t, you will lose  speed going up hill and use unnecessary fuel going down.

*Don’t carry unnecessary weight. Take all those unnecessary things out of the boot, lose the chav bass box, go on a diet and don’t give anyone a lift. It’s a good reason to be antisocial. In fact, take the passenger seat out. Remember of course that cars become more efficient as the fuel tank empties because the car becomes lighter. 1 litre of fuel weighs approximately 1 kilo so a full tank could weigh 33 kilograms. Filling up just enough fuel every day is going to be a pain but quite possible if your daily route takes you passed a filling station.

*A clean engine engine is an efficient engine, using V-power will clean the engine and Total Excellium is designed to give better MPG.

*Don’t try to accelerate in too high a gear or too low a rev range. Accelerating uses more fuel but the low revs won’t create enough torque to increase the speed of the car. When you need to accelerate, ensure the revs are at least 2000rpm. Dropping down a gear and increasing the rpm uses more fuel but the engine will make better use of it.

*Pulsing the accelerator between 0 and 70% to keep up your speed. This is a new technique. If you are on a 50mph road, you accelerate to 55mph and then let off the accelerator pedal and coast until you reach 45mph. Repeat this over and over. This obviously works best downhill and on flat roads.

*Idling gives 0MPG so if you know you are going to be stationary for more than a minute, turn the engine off. This is the big selling point of the smart fortwo MHD and can apparently save a good percentage in fuel but this is only the case if you spend a lot of time in traffic jams.

*Plan your journey to steer clear of traffic jams, traffic lights, pedestrian crossings, roundabouts, speed bumps etc. Don’t go too far out of your way to bypass these. Large “A” roads are perfect as the average speed is close to the optimum speed.

*Stay off of country roads as you have to use the brakes too often.

I Won’t Remember To Do All Of That!

It won’t be practical to do all of the above steps on every single journey. Do what you can and see what you can comfortably do without using too much brain power. If you are concentrating too hard on saving fuel you  could miss something vital like the illegal immigrant who has just slammed their brakes on in front of you. Once the chosen steps become second nature it becomes easier to add a new step one at a time.

What Returns Can I Expect?

When I first got my 71bhp 451 fortwo I drove it the same way I drove my old 450 fortwo. Imagine my dismay when I started getting 140 miles less per tank in the new car. It was summer so I had the AC on and the engine was a lot quieter so I drove in auto until I learned the new engine noise. Those were the 2 main reasons that I was only getting 260 miles per tank* instead of the 400 miles per tank* from my heavily modified 450.

As soon as I learned the engine and summer buggered off I was getting about 300 miles per tank* which still wasn’t as good as the 320 miles per tank* I got when my first smart was new. I was doing the same journey in the same way, considering that the 451 was supposed to be better on fuel I couldn’t quite work out what was wrong. Then smart did the advert stating that the 451 could drive from London to Edinburgh on 1 tank of fuel, every 451 owner in the UK shook their heads and laughed, even the Advertising Standards Agency got involved. Well, smart won and yet we still couldn’t believe it. The guy who drove the car even posted on one of the forums and explained a few methods to get better MPG. It was this point that people started to believe it was possible. The reason we
were so sceptical was the previous fortwo got good MPG without all these magical methods.I started reading articles on hypermiling (a bunch of methods made by Americans so they could get the sort of MPG we normally get in our small engined Euro cars). I slowly began to implement some of these in my normal driving and saw a slight increase for ever one I did. As each one became second nature I honed the skills to get better results. I’d say you can see a 1% to 5% miles per tank increase for every one of the methods you adopt from the above list, see what works best for you.

*I obviously didn’t run the tank dry. I was usually left with between 2 and 4 litres.

What Methods Do You Do And What Distance Have You Got?

I’ve broken the car in, always drive in manual, light on the accelerator and stay at 50mph when legally possible. I keep the revs down, use the brakes as little as possible, don’t use A/C, keep the windows closed. I coast in and out of gear depending on the slope, pulse and glide on the flats (very rarely). I check the tyre pressures every now and then and use V-Power petrol.

These got me to about 350 miles per tank which was good for me as I drive 330 miles a fortnight going to work. That meant I could fill up on the same day every 2 weeks. I remembered that my old 450 just got better and better MPG when I modified it for higher performance but drove sensibly so thought I’d do the same again. I drilled a few holes in the bottom of the air box, fitted a PiperCross filter (available from smartmods) and fitted a new that I had designed for the non turbo 451. It was designed for superior air flow speed and must be doing something right because the next 3 tanks of petrol took me an average of 380 miles until I had to pull into the petrol station.

Working out my MPG I calculated how far I could have gone until I had fully run out of fuel. It worked out to be approximately 415 miles for the entire tank. That is about 57MPG. That’s almost spot on with the smart figures for the urban cycle, shame I’m not actually doing an urban cycle!

I suspect that this could be bettered with the MHD, not because it stops the engine when you come to a standstill, but because it has a better ratio gearbox.

I will continue to try new things out to see if I can get better figures.

To be honest, I really only try to save fuel when it gets down to half way, when I have just filled up the car with petrol I tend to be a bit slap-dash with my fuel saving techniques. To really test it fully I have decided to use the techniques from fill up all the way through to refill, just to see the numbers.