Citroen C4 Tuning

"Tuning guide to the greatest Citroen C4 modifications."

A great little car from Citroen, the C4 has proved popular among our members, and we've finally been able to write a C4 Tuning guide.

The smaller size and great choice of engines mean the C4 is a good car modification project to do.

Take your time and research C4 tuning to spare yourself making the usual tuning slip ups we frequently see.

Tuning tips and articles

Engine tuning Transmission tuning Care care Intake & exhaust mods Improve handling Forums

Please watch our video which covers the 5 principles of tuning your C4. Be sure to keep up with our latest YouTube content and subscribe.

Best mods for your C4

  1. Tunes - A tune/remap provides the biggest gains in terms of cost, aftermarket ECUs, and Tuning boxes are all alternatives.
  2. Fast road cams are one of the most significant mechanical changes, but they must be installed by someone who knows what they are doing and they are not always easy to source but you might find a local firm to regrind a stock camshaft.
  3. Intake Upgrades and Sports Exhausts - Note that on their own these mods will NOT ADD POWER in most cases, but they can help enhance power after other mods by removing the restriction.
  4. C4 Suspension Upgrades - Replacing worn bushings and shocks radically improves your C4 handling Adjustable coilovers and better bushings are what is needed here.
  5. Brake Mods - Improve your C4's stopping power needs to be near the top of your Mods list.
  6. Forced induction upgrades - forced induction is the most efficient approach to increase air supply, allowing you to burn more fuel and make more power. It is one of the most costly upgrades it does provide the largest gains.
  7. Head work - The goals of porting and flowing the head are to get air flowing into the engine while removing flow restrictions and turbulence.

C4 Tuning Stages

Typical stage 1 mods often include: Lighter flywheel, Engine Tunes/Remapping, Panel air filter, Alloy wheels, Suspension upgrade (drop 30-40mm), Sports exhaust.

Typical stage 2 mods often include: fuel pump upgrades, Power/Sport clutch, Ported and polished head, high flow fuel injector, Fast road cam.

Typical stage 3 mods often include: Sports gearbox, Competition cam, Engine balancing, Internal engine upgrades (pistons/head/valves), Adding or upgrading forced induction (turbo/supercharger).

Peak power is good on competition cars but for a daily driven car you need a wide power band and perhaps extending the rev range.

In this article we shall give a little insight into the world to the best modifications for your car, but we'd encourage you to spend some time on the site looking into the details of each type of performance mod.

C4 Handling/Suspension upgrades

Many C4 owners uprate the handling of their cars with modified suspension mods as a priority, this will certainly increase your enjoyment of the car.

Fully adjustable suspension allows you to fine tune the handling of you C4 greatly improving your drive.

Improvements to the bushings

Enhancements to the bushings: Things you need to know

Bushes, which are rubber mounts that spin, allow the C4's suspension components to be connected and rotated around the car's chassis. The rubber ones will degrade with time.

By replacing new OEM rubber bushings, you may greatly improve your vehicle's performance.

Because polyurethane bushes are stiffer, the ride may be less forgiving, but the bushes will last longer and maintain the car's handling for longer.

They may also hasten the depreciation of other suspension components due to the increased vibration and play.

With a new set of poly bushes, the excessive play associated with rubber bushes may be eliminated.

Rarer and older models may only have polyurethane versions of the main bushes available as aftermarket bushing kits, however the majority of recent models have a complete set of suspension bushes for all parts of your suspension mounts.

Custom bushes are often built to C4 your requirements.

A common misconception is that a non-adjustable suspension system that lowers the vehicle by 30mm from a franchised component shop is the best option.

Vendors may claim that their C4 suspension kits are compatible with any or all model year C4s.

The 'generic one set for all models' approach is obviously a flawed assumption when it comes to adequately supporting a diverse variety of cars. Engine weights and trim levels, and even alloy rims will affect the handling and require different suspension setups.

How low should you go on the C4?

TorqueCars research and testing indicate that the maximum suspension drop for most road vehicles is 25 - 39 millimetres, whereas the maximum suspension drop for hot hatchbacks with lower OEM suspension is 19 millimetres.

Tolerances may be greatly lowered by altering the diameter of the wheels. Lowering a vehicle, even with 17-inch wheels and stock suspension, may create several issues.

Stability may be improved by lowering the C4, but the ultimate goal should always be to enhance handling. It is critical to use the right shocks when employing lower springs.

If you set the toe out to 0.8 to 1.3 degrees on the front, and add a little negative camber then cornering will usually improve.


Adding meatier brake discs and better high performance brake pads should make for dramatically improved braking.

Bear in mind that motorsport pads can be noisier and will need to be really hot before they bite.

On your regular commute to work the brakes are only applied now and then and won't stop you as well so source friction pads which work well in daily use.

Top end power should be your overall aim on the C4 with a nice fat peak torque band.

C4 make good sleepers if you debadge them and fit the most powerful engine upgrades and handling mods you can find!

The best power gains come from larger engine sizes. The more you start with the bigger the return on investment so engine swaps are good value mods for small engined cars.

C4 Tuning modifications.

First generation engines options

  • 1.4 L ET3 I4 petrol
  • 1.6 L TU5 I4 petrol
  • 2.0 L EW10 I4 petrol
  • 1.6 L DV6 HDi I4 diesel
  • 2.0 L DW10 HDi I4 diesel

The second generation from 2010-2018 offered

  • 1.4 VTi: 1397cc, 95 PS (70 kW)
  • 1.6 VTi: 1598cc, 120 PS (88 kW)
  • 1.6 THP: 1598cc, turbo, 155 PS (114 kW)
  • 1.6 HDi: 1560cc, 90 PS (66 kW)
  • 1.6 HDi 16v: 1560cc, 110 PS (81 kW)
  • 1.6 e-HDi 16v: 1560cc, 110 PS (81 kW)
  • 2.0 HDi 16v: 1997 cc, 150 PS (110 kW)

These mods tuning upgrades are usually fitted by our members, decide how far you want to go before you get going.

Getting the correct grade of sports upgrades for your planned usage of the car is essential. Stage 3 motor sport mods just don't work well on the road difficult in stop start traffic.

Fast road cams offer one of the biggest performance gains for your money as far as a bolt on motorsport parts goes on a NA (naturally aspirated) engine.

It improves the intake and exhaust flow and pushes up the power if done right. Ideally you'd add other mods and finish up with a performance chip. We'd also caution you not to go with a motor sport cam as this affects the engines idling and general town driving characteristics.

When pushing up the power you will need to pay attention to the fuelling. More power needs more fuel.

If you find you get flat spots and surges after your modified modifications you should check the fuelling and try a higher octane fuel as well. Larger injectors will enable you to supply sufficient fuel to the engine.

A fuel pump will only deliver a finite amount of fuel, so you may need to uprate this if your injectors are demanding more fuel.

C4 Intake and Exhaust Tuning.

The next area for modification is the intake and exhaust. Air induction kits are only beneficial to increase power if your air intake is struggling! Adding an induction kit to most standard engines will see NO LOW END POWER GAIN AT ALL. If you have heavily modified your engine and it's need for air INCREASES DRAMATICALLY then an induction kit is the answer and will help remove this restriction.

Derestricting the air feed into the engine is a primary goal of car tuners so get a freer flowing air filter if you find that the car is running lean. Induction kits can sound great but due to the warm air in the engine bay they will not add noticeable power and more often than not rob you of power.

Sports exhausts can usually air flow out of the engine but avoid an exhaust that is too big or you might just stuff your flow rate and make things worse. So generally speaking, keep to a size of 1.5 to around 2.5 inches to maximise flow rates, and this should take into account the amount of air your engine is moving.

Head Work & other C4 Engine Mods

Polishing and porting the head will allow you to maximise your air/fuel charge. Leave this to a professional though with a proper flow bench and machine tools A good fast road power clutch will help to keep that power going where it should. Never skimp or ask a standard OEM clutch to cope.

The best mods in our experience for your C4 are Remapping or piggy back ecu, fast road cam and air intake and exhaust.

NA (naturally aspirated) engines do not achieve big power gains if you tune/remap them, unless you have done extensive modifications. With turbocharged engines this is another story. A tuned/remapped turbo will give large power gains and fully release the potential power of the engine.

Adding forced induction will see big power gains but this is usually too expensive to be cost effective. Superchargers are usually easier to add than a turbo. Turbos provide boost in increasing proportion to rising engine speed and this can make mapping difficult.

Superchargers, however will give a boost which is correlating to engine speed so is easier to map. Adding forced induction will nearly always require a lower compression ratio or water injection.

C4 Alloy Wheel Upgrades.

The benefits of alloys include a lower unsprung weight and better brake cooling. Get a good directional tread pattern tire to improve your handling and help improve traction on your C4. We should point out that although they can look cool on the C4 big alloys will actually decrease your performance. The larger you go the lower your acceleration will be - this to the change in your effective final drive ratio.

With this in mind we would advise sticking to a maximum wheel size of 16 inches, although we know some of our members have with bigger wheels with no problems.

If you would like to know more, or just get some friendly advice on Tuning your car please join us in our friendly forum where you can discuss C4 options in more detail with our C4 owners. It would also be worth reading our unbiased Citroen tuning articles to get a full grasp of the benefits and drawbacks of each modification.

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