Citroen XM Tuning

"XM Mods"

The XM is Citroens large executive car. It's futuristic and radical styling has won as much praise as it has critiscism but it still has a lot to offer. Citroen sold over quarter of a million XM's in the 11 year production run.

So what are the best performance modifications for the XM? Handling modifications are usually your first port of call for the XM - the Citroen suspension is generally quite soft, even on the sport setting. Drop the car by as much as 35mm and fit stiffer dampers, bigger drops will need other modifications in most instances. We have seen some good handling benefits from fitting polyeurothane bushings. 

Top end power should be your overall aim on the XM with a nice fat peak torque band. The engines to have for tuning are the Turbo Charged 2.0 inline 4 and the 3.0 24 valve V6. The 2.5 Diesel deserves an honorable mention for its massive torque and nice power band.

Sadly with the 2.0 NASP egnines and the 2.1 12c diesel you are wasting your time spending money on modifications, so if this applies to you get yourself an engine swap then apply the following mods.

Citroen XM Tuning modifications.

Your aim when tuning should be a nice flat torque curve and a wide power band. A fast road cam will be one of the best power mods you can do mechanically to your petrol engine. You will need to ensure that the engine is not starved of fuel so will need to uprate the fuelling if your pushing the power up to the 200hp mark on the Turbo and at around 260bhp for the V6. When increasing your fuelling with bigger injectors you will also need to get a bigger fuel pump to supply it.

Citroen XM Intake and Exhaust Tuning.

The next area for modification is the intake and exhaust. For small XM engine sizes TorqueCars recommend you go with a washable panel sports air filter. On larger engines and turbo vehicles an induction kit will help increase power providing you address the problem of needing cold air. A vent in the bonnet or wing and air box will help to address this. Sports exhausts will certainly help air flow through the engine but do not go too large or you will reduce the flow rate. Stick to 1.5 to 2.5 inches for best results.

Gas flowing 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 expect a standard clutch to cope. Remaps offer significant power gains on all turbo charged cars.

On NASP engines the benefits of a remap are doubtful unless you have done lots of other modifications. A NASP engine remap will help unleash the full potential if you have done a lot of mods. Adding forced induction to the NASP engines will see big power gains but this is usually too expensive to be cost effective. It is easier to bolt on a supercharger than it is to get a turbo working. With a turbo the boost curve is related exponentially to the engine speed making it hard to map. In either case you should lower the compression ratio of the engine.

Citroen XM Wheel modifications.

Alloy wheels will help the brakes cool down and are usually lighter than the steel ones. It is worth noting that although they can look cool on the XM Big alloy wheels 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. Aim to keep the overall rolling diameter of the wheel the same as supplied from the factory. In all cases we do not recommend going above 17 inches.

For more information on Tuning your car please join us in our friendly forum where you can discuss XM options in more detail with our XM 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.