Tuning the Citroen ES9

"Comprehensive guide to tuning the Citroen ES9 engine!"

We are always getting emails requesting information on the premier ES9 modifications. So let us look into Citroen ES9 modifications and outline the best upgrades on this great engine and point out some problems along the way.

The Citroen ES9 great bases for a tuning project and with a few sensible tuning upgrades like ECU maps, turbo kits and camshafts you will certainly improve your driving fun.

Our aim here is to provide a guide to ES9 tuning and highlight the best mods that work.

Just because particular upgrades are are common on ES9 it doesn't mean it is good, so we'll optimum upgrades that will give your ES9 the best power gain for you spend.

The camshaft profile plays a big part in the engines power output so camshaft upgrades make quite a large difference. The intake and exhaust durations will alter depending on the chosen camshaft profile, so large engines power gains are on offer for camshaft upgrades.

NB: Fast road camshafts normally raise the bhp through the rpm band, you might lose a little low end torque but your high end rpm power will be better.

Race camshafts, raise the high end rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

A Motorsport and race cam is not great driving in heavy traffic.

You should ideally match your torque band to your typical driving style so for a car used daily stick with a mild fast road ES9 cam

Each engine responds better to extreme cam durations check your engine on a rolling road.

The engine timing and fuel pump and injectors also have a large bearing on the power gains you'll achieve.

Altering valve durations can alter the power band and on most engines the exhaust and intake durations do not need to match, although most cams and tuners use matched pairs there are some advantages to extending the intake or exhaust durations.

ES9 Tuning Stages

Stage 1 ES9 modifications: Remaps/piggy back ECU, Fast road camshaft, Panel air filters, Sports exhaust manifold, Drilled & smoothed airbox, Intake headers.

Stage 2 ES9 modifications: Sports catalyst & performance exhaust, high flow fuel injectors, induction kit, Fast road cam, Ported and polished head, fuel pump upgrades.

Stage 3 ES9 modifications: Engine balancing & blueprinting, Adding or Upgrading forced induction (turbo/supercharger), Competition cam, Internal engine upgrades (head flowing porting/bigger valves), Twin charging conversions, Crank and Piston upgrades to alter compression.

Carefully think through your options and then acquire your upgrades and set yourself a power target to void expensive mistakes.

Mapping allows a tuner to unlock the full potential of all the upgrades you've done to your ES9.

It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but the outcome may differs on the upgrades you've applied and the condition of your engine.

Pushing air and fuel into the ES9 engine is the aim to any engine upgrade task.

Intake headers take the air from the intake filter and allow it to be sucked into the engine cylinders.

The size of bore and shape and flow characteristics of the Headers can make a substantial change to fuel mixing and power on the ES9.

It's not uncommon that intake headers are in desperate need of performance upgrades, although some OEM provide fairly well optimized intake headers.

Larger ES9 valves, getting port matching and head flowing will also lift torque, and as an added benefit will permit raising the torque increase on other parts.

Turbo upgrades for the ES9

NASP engines need quite a lot of work when you add a turbo, so we have a separate guide to help you take into account the pros and cons of going this route on your ES9

The more air you can get into an engine, the more fuel it can burn and uprating the induction with a turbocharger upgrade makes significant power gains.

When your motor has a turbocharger parts are going to make more power and you'll see that turbocharged engines are built with better components.

There are weak spots for every engine, with some being over specified and some only just able to handle stock power

Research these limits and fit higher quality crank and pistons to utilize the power.

We've seen people spending a loads of money on turbo charger upgrades on the ES9 only to suffer the humiliation of seeing the ES9 explode on it's first outing after it's completed.

Big capacity turbo units will usually experience low end lag, and low capacity turbo units spool up more quickly but don't have the high rpm torque gains.

In recent times the market of turbochargers is always developing and we commonly find variable vane turbochargers, permitting the vane profile is altered according to speed to lower lag and increase top end power.

Twin scroll turbochargers divert the exhaust flow into two channels and push these at differently designed vanes in the turbocharger. They also help the scavenging effect of the engine.

It is common that there's a restriction in the air flow sensor (AFM/MAF/MAP) on the ES9 when loads more air is being fed into the engine.

We see 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor limited bhp at a much lower level.

Adding a supercharger or additional turbo will make large bhp and torque gains, although more complex to configure. We have this in depth look at twinchargers if you want to read more.

Uprating ES9 fuel injectors

When you boost the bhp and torque you will need to look at to the fuel system.

More bhp and torque needs more fuel. We strongly recommend you to be generous with your flow rate on the injectors.

The rule of thumb is to add another 20% when fitting an injector, this allows for injector deterioration and gives a little spare capacity should the engine require more fuel.

We think this one is common sense, but you'll need to match your fuel injector to the type of fuel your car uses as well.

Best ES9 performance exhausts

You only need to to boost your exhaust if the existing exhaust is creating a restriction.

On most factory exhausts you'll see your flow rate is still good even on modest power gains, but when you start pushing up the power levels you will need to get a better flowing exhaust.

Sports exhausts increase the flow of air through the engine.

But if your exhaust is too large, ie: it's over 2.5 inches bore, you will lose a lot of the exhaust flow rate and end up sapping power and torque.

Typically exhaust restrictions can be located the catalysts installed, so adding a higher flowing performance alternative will help avoid this restriction.

Problems and issues to look out for on the ES9

The ES9 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the ES9, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your ES9 engine please join us in our friendly forum where you can discuss tuning options in more detail with our ES9 owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.

We need your help to complete and improve this page, so do give us your feedback in the comments box below.

We really like hearing from our readers, and hearing about which mods were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our ES9 guides and tips are kept up to date.

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