What is the best fuel for your next car?

What is the best fuel for your next car?

The switch to electric driving is accelerating, as more manufacturers than ever are offering electric cars alongside their combustion-engine counterparts.

Although the development of EVs has accelerated in recent years, it is still difficult for some buyers to add up the amounts. One obstacle to this is that comparing EVs and combustion engine cars on a comparable basis isn’t as straightforward as it could be, especially in terms of cost. But fear not, Auto Express is here with a trio of cars that will help you determine the best powerplant for you.

Today, the Stellantis Group is one of the few car manufacturers to sell models with a choice of petrol, diesel or electric power. It’s offered in several Citroën, Peugeot and Vauxhall models, but here we’ve lined up three Citroën C4 hatchbacks to analyze the differences. We focus on the driving experience, day-to-day usability and all-important operating costs to see which strikes the best balance of talents.

Design & technique

Whether you choose petrol, diesel or electric, the Citroën C4 uses Stellantis’ Common Modular Platform (CMP) which is used on a wide variety of models, from the Peugeot 208 to the Vauxhall Mokka. The C4 is one of the bigger cars to use CMP, and it’s an interesting looking crossover. Our three C4s are Shine Plus trim and are largely identical, except the e-C4 has a unique wheel design and metallic blue trim inside and out.

All three are front-wheel drive and front-wheel drive, and the only other visual clue to the e-C4’s alternate setup is in the trunk. To make room for the battery under the passenger compartment, the spare wheel well is half the size of the petrol and diesel models. This means you can’t add a spare wheel to the e-C4, but it’s also not an option on the internal combustion engine cars.

The biggest difference between them is something you can’t see: weight. The e-C4 is considerably heavier than the other two. It weighs 1,541 kg, which is 263 kg more than the petrol C4, or the equivalent of always driving around with three large adult passengers on board. Weight is an issue to keep in mind when making an EV, and for the moment, Stellantis has opted for a 50 kWh battery for the best compromise between mass and range.

Diesel engines are often heavier than petrol engines and the BlueHDi car here weighs 46 kg more than the C4 PureTech. While not as big as the e-C4s, this difference still has an impact.

The driving

While all three cars use the CMP platform, their powertrains make them all drive differently. Go for a petrol C4, and you get a 1.2 PureTech three-cylinder turbo engine, which produces 129 hp here. Diesel models use a four-cylinder 1.5 BlueHDi engine that matches the power output of the PureTech, but at 300Nm there’s more torque and it’s made from 3,750rpm; the PureTechs make 230 Nm at 5,500 rpm.

The e-C4 has a 134 hp electric motor and 300 Nm of torque that is available almost immediately as soon as you press the accelerator pedal. Our two combustion engine cars also came with Citroën’s EAT8 automatic gearbox, so they are just as easy to drive as the single-speed e-C4. The lighter curb weight of the C4 on petrol means that the time from 0 to 100 km/h from 9.4 seconds is 0.1 second faster than that of the diesel. By comparison, the e-C4’s instant response means it sprints off the line, but then its weight comes into play, so 0-100km/h takes 9.7 seconds. The e-C4 sprints away with minimal fuss and noise, just the faint whine of the electric motor as the car picks up speed. In contrast, the C4 diesel is quite rattling, but it is only overly loud on cold starts, while the C4 petrol has a sporty three-cylinder.

A disadvantage of the cars with combustion engine is the Citroën EAT8 automatic gearbox. It’s not a great automatic, as it’s slow to respond and has hesitant shifts, so it’s harder to make smooth progress than in the e-C4. Shine Plus models are for cars only, but a manual gearbox is available in lower specification C4s. However, Citroën’s six-speed gearbox isn’t the smoothest to use either.

The weight difference between these three cars has a profound effect on the way they drive. The PureTech-powered C4 feels most lively and turns eagerly, while the BlueHDi tends to understeer faster, thanks to the extra weight in its nose. The e-C4 doesn’t suffer in the same way because all of its extra weight is placed low and between the axles. It doesn’t feel as lively as the petrol C4, but the extra weight gives it better stability, so it has less bumps in the middle of the corner. This stability is also felt when cruising, as the e-C4 is much more comfortable than its stable mates at all speeds and smoothes out most bumps with ease.

With Citroën’s focus on comfort, the e-C4 makes a strong case for itself when compared to the combustion engine cars; it is more comfortable, easier to drive and also quieter.

Practicality and running costs

In terms of everyday usability, there are few compromises with the e-C4. Apart from the smaller wheel arch under the split-level boot floor, the space on board is identical to that in the other C4s. All three have a luggage capacity of 380 liters which can be expanded to 1,250 liters with the rear seats folded, while the space in the rear seats is also identical. Up front, the auto-equipped C4s use the same style of drive selector found in the e-C4, but the latter does without paddle shifters behind the wheel for its single-speed transmission.

The practicalities of using electricity instead of fossil fuel do affect how far you can go with filling. Although the e-C4’s battery takes up more space than the tanks in the C4s, the lithium-ion cells are not as energy-rich as petrol or diesel. Citroen quotes a WLTP-tested maximum range of 217 miles, but if you can match the petrol’s WLTP fuel economy of 48.7mpg, you’ll have a range of 536 miles. Go for the C4 diesel, and with an average of 64.5mpg WLTP, you’ll get a healthy 709 miles from the 50-gallon tank. For some buyers, the lack of stops the diesel needs will still be attractive.

It does cost something. Based on an electricity price of 26 pence per kWh, you’ll spend around £576 to travel 12,000 miles in the e-C4 using 5.4 miles per kWh. To cover the same distance in the petrol C4 (with an average fuel price of £1.63 per liter in the UK), you would have to pay £1,826, while the diesel (with an average of £1.50 per liter in the UK) UK) costs £1,497. Of course, there are many variables when it comes to charging electric cars, with some slower public charging stations offering free energy, while fast chargers tend to be more expensive than a household power supply. Then there’s the impact of cold weather on range, which can be drastically reduced in some cases.

There’s no escaping the fact that EVs are more expensive to buy than their combustion-engine counterparts, but the gap is narrowing and the lower daily running costs are where the savings are made. A list price of £34,995 for the e-C4 is reduced to £32,495 when you add in the Government’s Plug-in Car Grant (PiCG), but it’s still £5,635 more than the petrol C4. If you don’t have a wallbox for a home charger, you should also take that into account; budget at least £400, maybe more if you need to upgrade your home electricity supply.

Using the PiCG price and based solely on the cost to refuel (3p per mile for the e-C4, 14ppm for the petrol car), you would need to travel approximately 50,000 miles to get the list price difference between the e-C4 and the petrol C4.

However, there are further savings elsewhere with the e-C4. Free road tax (compared to £155 per year for combustion engine cars), exemption from congestion charges and cheaper maintenance costs will appeal to private buyers, while business users will see their benefit-in-kind rates fall. The fiscal year 2021-2022 will have a BiK rate of one percent, rising to two percent for 2022-23, but that is still a fraction of the cost for the diesel, which itself offers modest savings compared to the petrol C4.

Buy one of these cars directly from Citroën’s online store and enjoy additional savings. The e-C4 is £4,000 off the list price, and on a three-year PCP deal with a £5,000 deposit and an annual limit of 10,000 miles, monthly refunds are £355. The petrol C4 costs £40 a month less than the e-C4 for £315, but the diesel C4 is relatively uncompetitive, costing £365 a month, £10 more than the electric model.

Of course, the other appeal of the e-C4 is the environmental impact of its zero-emission operation, which some people are happy to pay for, for a clear conscience.


A comparison of three models whose only difference is their power source sheds light on the development of electric propulsion. In the case of the Citroën C4, the electric version delivers a better driving experience than the combustion engine cars, with excellent refinement, and the extra weight improves the car’s handling.

The only reason we would choose diesel is to cover a lot of miles without the inconvenience of having to stop as often as in an EV. For an enjoyable driving experience, petrol still leads the way, and here it delivers the running costs and range that make it a tempting alternative to diesel.

Buy on financing and the main obstacle to electric ownership – a high purchase price – has been largely removed. Add in daily running costs that are only a fraction of petrol, and the e-C4 makes a strong case for itself. Even if you buy outright, those savings will go a long way in justifying the higher initial cost of the car, while the company car rates are just too good to ignore.

Read Andy Palmer’s take on electric car charging infrastructure and why it needs improvement…