Daihatsu Copen Tuning

"All you need to know about performance parts and tuning the Daihatsu Copen engine!"

We were emailed and asked questions for more information on tuning and building a modified Copen and particularly which turbo upgrades work best, so we've put together this feature which covers our go-to modifications for this engine and what we feel are the greatest value modifications you can do.

The Daihatsu Copen is a fantastic small vehicle that has a sense of rarity about it. Even though it's small and technically underpowered, the car's smooth turbocharged engine makes it an enjoyable experience. It feels like it's going 60 mph even though it's just doing 30 mph because it has good traction on the road and cornering is a sheer delight.

We owe the Daihatsu Copen to Japanese K-car restrictions. Honda Beat and Suzuki Cappuccino are just two examples of entertaining, little automobiles that were delivered to us by the same set of tax requirements, but with a nostalgic twist.

Every time I go behind the wheel, it brings a grin to my face and makes me feel a little naughty!
It is built on a shortened version of the Cuore hatchback chassis.

This is a fine project car, with a distinct retro vibe, and we feel it will be a future classic and is one of my favourite Daihatsu models to date.

The Daihatsu Copen make awesome project engines and with the best performance mods like remapping, turbo improvements and camshafts you will certainly increase your driving experience.

Our aim here is to consider Copen tuning and summarise the optimum modifications.

History of the Copen Engine

First generation (L880; 2002)

659 cc JB-DET twin-scroll turbocharged I4
1.3 L K3-VE I4

Second generation (LA400; 2014)

658 cc KF-DET turbocharged I3

Tuning the Daihatsu Copen and best Copen performance parts.

Best Copen parts

When talking about the best modifications for your Copen engine, we are going to concentrate on the parts that provide the best power gain for you spend.

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

Best mods for your Copen

  1. Copen Suspension Upgrades - Upgrading your suspension dramatically improves Copen handling Adjustable coilovers and better bushings are what is needed here.
  2. Internal engine mods - crank, pistons, conrods & compression ratio including balancing and blueprinting
  3. Brake Upgrades - Enhancing your stopping power should be listed in your priority list.
  4. Air Induction kits and Exhaust - NB: on their own these mods will NOT ADD POWER in most applications, but they will enable you to enhance power after other modifications by lessening the restrictive flow.
  5. Tunes - A Remapped Copen ECU gives the biggest gains compared to your outlay, aftermarket ECU upgrades, and piggyback ECUs are all alternatives.
  6. Lightened Flywheels - a lower mass flywheel will improve the engines rev changes. In some cases flywheel lightening is not not a great upgrade for all Copen engines.
  7. Fast road cams are significant power adders, but ideally be setup by someone who knows what they are doing and tracking one down can be a challenge but there might be a local firm to regrind a stock camshaft .
  8. Turbo upgrades - A New Turbo is the most efficient approach to increase air supply, which permits you to combust more fuel and make power gains. Although one of the most challenging mods you'll see massive gains.

Copen Tuning Stages

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

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

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

Copen Handling/Suspension upgrades

Your Copen tuning project should focus on making the vehicle more enjoyable to drive for automotive afficionados and serious drivers. A small light chassis like this is crying out for a decent suspension setup.

Installing lowered suspension and lowering the vehicle by 25-38mm is our recommendation. Larger dips need arch repair, particularly on vehicles that have previously been outfitted with racing-style suspension.

Suspension and steering improvements have been made to the Copen.

One of the most common reasons for customising your Copen is to make it even more manoeuvrable. However, the same blunders and issues keep happening in badly modified projects all of the time.

In order to customise the handling of the vehicle to our liking, we'd go for a pair of Adjustable Coilovers.

While considering suspension upgrades for my Copen, is there anything else I should keep in mind?

Upgrading your Bushes

Bushing upgrades are needed so what's involved?

Bushings, which are rubber mounts, allow the Copen's suspension components to be affixed to the car's chassis. The rubber ones will wear out with time.

Installing new OEM rubber bushes may dramatically improve the performance of your car.

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

Worn bushes may also quicken the stress 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 minimized.

Some polyeyurothane bushings are hard to locate, but most will find the primary mounts readily available in their areas Custom poly bushes are often made to your requirements.

How low should you go on the Copen?

According to TorqueCars research and testing, the maximum amount of suspension drop for most road vehicles is 25 - 38 millimetres, whereas versions that come with lowered sporty suspension already have a maximum suspension drop of 22 millimetres.

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

While the fact that the Copen being lower allows for less air to travel underneath it may aid in stability, the ultimate goal should always be to enhance handling. When lowering the springs, it is critical to use the proper shocks that match all round.

Adding some negative camber at the front and a degree or two of toe (in for better stability or out to improve cornering), will substantially improve your Copen in handling and cornering.

Putting bigger discs and better high friction brake pads can make for radically improved stopping. (They will brake effectively over longer periods during heavy use than stock brakes will, but grip has more of a bearing on the cars ability to stop).

We should point out that motorsport pads will be noisy and will have to be hot before they are effective.

In every day driving the brakes are occasionally used and won't be as effective at slowing you up so select brake pads which work well in daily use.

Copen Camshaft Upgrades

Fast road cams helps you to boost top end power which makes it a best mod for NASP and turbo petrol engines, but not so much on diesels. We've always seen top end power increases through performance camshafts on most engines.

Significant gains on the Copen can be made from camshaft upgrades. Altering the camshaft profile alters the intake and exhaust durations on the engine and can dramatically change the power band and power output.

Fast road camshafts usually raise the torque through the rpm range, you might lose a little low end power but the high end rpm power will be better.

Competition 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 camshaft will just annoy you whilst driving in heavy traffic.

You should ideally optimize your bhp range to your driving style so for a car driven daily stick with a shorter duration Copen camshaft

Different Copen engines respond differently depending on how well made they are, when cams are fitted depending on the cam being more aggressive cam durations than others as unique due to manufacturing tolerances and quality variations so set your engine up on a rolling road.

The engine timing and fuel delivery and fuel pump and injectors also have an effect on the torque gains you'll hit.

Extending exhaust or intake durations can alter the torque curve, and on most engines there are some advantages to extending the intake or exhaust durations and valve lift.

The Copen power trains are great to work on and thanks to their popularity there is an increase of modifications and tuning parts about.

ECU Mapping Improvements for the Copen

ECU mapping will help fully realize the full potential of all the upgrades you've fitted to your Copen.

(Sometimes flashing the ECU is not an option, so an aftermarket ECU is the route to take, and most of these exceed the specs and performance of your factory ECU's but make sure it has knock protection and that you get it correctly setup.) It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NA (naturally aspirated) engines, but your results usually vary depending on the upgrades you've applied and the condition of your engine.

Air Flow improvements on the Copen

It is the main goal to any engine modification project to push air into your Copen

Intake manifolds carry the air from the intake filter and allow it to be drawn into the engine and mixed with fuel.

Structure and rate of flow of the Intake manifold can make a big change to fuel engine efficiency on the Copen.

I usually find intake manifold are improved through an upgrade, although a few car makers provide well optimised intake manifold.

Increasing valve sizes on Copen, doing a bit of 3 or 5 angle valve jobs and porting and head flowing will also boost bhp and torque, this will give you an improved bhp and torque increase on other tuning mods.

Copen Turbo upgrades

Boosting the induction system with a turbocharger upgrade is a great way to increase horsepower and torque.

It is more simpler and less expensive to replace parts on a turbocharged engine because of the use of stronger materials in the construction of turbocharged engines.

Some engines are exceptionally powerful, while others are only able to handle stock power. There are common points of failure for every engine. To withstand the stress, identify the engine's weak points and reinforce the crankshaft and pistons.

In our experience, many people spend a lot of money on turbo charger improvements for their Copen just to have the engine block break on their first trip after a lot of hard driving.

At low rpm, large turbo units typically have no power, whereas low-capacity turbo units spool up rapidly but do not have the high end power band improvements.

For better acceleration and lesser lag, variable vane turbo units allow the vane angle to be adjusted based on vehicle speed. This results in more top-end horsepower and a wider power band.

Twin scroll turbochargers are an interesting development but only really suited to the early 4 cylinder engines. Here the exhaust gases are diverted into two channels by dual scroll turbo units, which then send them to the turbo's two sets of vanes at varying angles. They also enhance the engine's ability to scavenge.

Air flow sensor MAP/MAF/AFM limit is prevalent on Copen when a large amount of air is delivered into the engine

There are significant power improvements with 4 bar air sensors, however the OEM air sensor was severely reducing power.

Adding a supercharger or additional turbo will make large torque gains, although more complex to get working. We have this feature on twinchargers if you want to read more.

Copen Fuelling Upgrades

When you raise the bhp and torque you will need to increase to the fuel delivery.

More bhp and torque needs more fuel. Fuel pressure boost valves raise the fuel pressure, providing a more snappy throttle response.Don't forget to be generous with your injectors flow rate.

The rule of thumb is to add 20% when fitting an injector, this allows for injector deterioration and gives some 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.

Copen Intake Tuning.

Breathing mods are usually next up so we'll focus on improving the intake, and then we'll look at exhaust mods and upgrades for the Copen.  Please note that WE DO NOT SEE IMPROVEMENTS WITH INDUCTION KITS, unless you have tuned your car massively and are finding that the standard air intake has become a limitation.

Copen Performance Exhausts

If the current exhaust is causing a flow issue, you may need to update your exhaust.

Even with moderate power improvements, the flow rate on most factory exhausts is adequate. However, when power levels rise, you'll need a better-flowing exhaust.

Generally speaking, sports exhausts boost engine airflow, but don't go too large or you'll limit your flow rate. As a general rule of thumb, you should aim for a thickness of 1 to 1.5 inches.

Most exhaust limitation comes from factory-installed emissions filters; upgrading to a faster-flowing racing aftermarket version will increase flow while preventing the need for an illegal decat. As a reminder, decat or catalyst removal is not a legal modification, thus performance catalysts are an excellent alternative.

Weak spots, Issues & problem areas on the Copen

The Copen engines are generally reliable and solid as long as they are looked after and serviced.

Carbon build up in the head, particularly around the valves which will reduce power and smooth running, this is a very common problem on direct injection engines but should be looked out for on all engines. We have tips on carbon removal guide To minimize this risk only use quality fuel and don't short journeys.

Frequent oil changes are vital on the Copen, especially when tuned and will help maintain the long life of the engine.

Copen Alloy wheel upgrades.

Alloy wheels can help the brakes cool down and are usually less heavy than steel ones. Pay attention to your choice of tyres (tires) for your car, a good soft compound tire can really enhance your cars handling. Large Copen alloy wheels can decrease performance. If you get big alloy wheels you will be changing your final drive ratio.

With this in mind we would advise sticking to a maximum wheel size of 15 inches, although we know some of our members have with bigger wheels with no problems - the 16's work well, but I personally prefer the handling on the lighter 15's but tire choice can make a big difference here also.

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

If you want to disover more, or just get more pointers on Tuning your Copen engine please join us in our friendly forum where you can discuss Copen tuning options in more detail with our Copen owners. It would also be worth reading our unbiased Daihatsu tuning articles to get insights into each modification and how effective they will be.

Please help us improve these tips by sending us your feedback in the comments box below.

We love to hear what our users have got up to and which parts work best for them on each model of car. We use your comments and feedback to improve the accuracy of these Copen tuning guides which get regular updates and revisions.

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