Honda D Series  D12 D13 D14 Tuning

"All you need to know about tuning the Honda D Series engine!"

We get asked for some tips on improving the D Series and which tuning modifications we rate as the greatest, so we've created an article that covers our go-to modifications and methods of modifying and tuning on the D Series engine.

We were requested for further information on tuning and manufacturing a customized D series, specifically which turbo improvements and engine tweaks work best.

So we've put together this page that includes our go-to modifications for this engine as well as what we believe are the best value additions you can perform. A D Series engine is either SOHC or DOHC and may incorporate VTEC variable valve timing. NB: We have separate articles covering the best mods and upgrades for the D16 D17 & D15 and D12 D13 D14

As with all other Honda engines, the D16 may be upgraded to provide extra power. However, the D16 lacks your typical bolt-on modifications, requiring customization of components for other engines. Swaps with other Honda engines are often the best course of action for a serious tuning effort; our Civic engine swap guide should be beneficial in this regard.

Earlier versions of this engine also employed a single port fuel injection system termed PGM-CARB by Honda, which indicated that the carburetor was computer controlled.

TorqueCars will go through your D15 tuning choices and highlight the best changes. Honda D15s have a lot of potential, and with properly selected aftermarket components like a remap, turbo upgrades, and camshafts, you can definitely enhance your driving experience.

In this article we provide a guide to D Series tuning and highlight the greatest upgrades. Honda D Series are fantastic to work on and with a few sensible motorsport tuning mods like ECU maps, turbo upgrades and camshafts you will greatly improve your driving enjoyment.

Check out our video introduction to Honda Tuning, all you need to know about mods and upgrades on your Honda.

History of the D Series Engine

D12 series engines

D12A

• 1986-1988 Honda Civic & City GG G-Mark Special (JDM Only)
  76 PS (56 kW; 75 hp)@6500 rpm
  10.0 kgm (98 Nm; 72 lbft)@4000 rpm

D12B1

• 1988-1990 Honda Civic (EU)
  74 PS (54 kW; 73 hp)@6300 rpm
  88 Nm (9.0 kgm)@3500 rpm
• D13 series engines (1.3 liter)

D13B1

• 1988–1995 Honda Civic EC (EU)
  76 PS (56 kW; 75 hp)@6300 rpm
  102 Nm (10.4 kgm)@3100 rpm

D13B2

• 1992–1995 Honda Civic DX/EX (EU)
  75 PS (55 kW; 74 hp)@6300 rpm
  102 Nm (10.4 kgm; 75 lbft)@3100 rpm

D13B4

• 1996–2002 Honda City LXi/EXi/DX, 1995-2000 Honda Civic EK2
  95 PS (70 kW)@6500 rpm 119 Nm (12.1 kgm; 88 lbft)@4700 rpm(City)
  91 PS (67 kW)@6,300 rpm 114 Nm (11.6 kgm; 84 lbft)@4800 rpm(Civic)

D13B7

• 1998–2001 Honda Logo
  66 PS (48.5 kW; 65.1 hp)@5000 rpm 11.3 kgm (110.8 Nm; 81.7 lbfft)@2500 rpm

D13C

• 1989–1994 Honda City CE, CE Fit, CE Select, CG, CR-i, CR-i limited, CZ-i, New Fit (JDM Only)
  100 PS (73.5 kW; 98.6 hp)@6500 rpm
  11.6 kgm (113.8 Nm; 83.9 lbft)@5500 rpm

D14 series engines (1.4 liter)

D14A1

• 1987–1991 Honda Civic GL and 1990 CRX (EU)
  October 1989 – 1994 Honda Concerto GL (EU)
  90 PS (66 kW; 89 hp)@6,300 rpm[4]
  88 PS (65 kW; 87 hp) in the Concerto[5]
  11.4 kgm (112 Nm; 82 lbft)@4,500 rpm

D14A2

• 1995–1997 Honda Civic MA8 (EU)
  90 PS (66 kW; 89 hp)@6,100 rpm
  86 lb·ft (11.9 kg/m, 117 Nm)@5,000 rpm

D14A3

• 1996–2000 Honda Civic 1.4i EJ9 (EU)
  75 PS (55 kW; 74 hp)@6,000 rpm[6]
  109 Nm (11.1 kgm; 80 lbft)@3,000 rpm[6]

D14A4

• 1996–1998 Honda Civic 1.4iS EJ9 (EU)
  90 PS (66 kW; 89 hp)@6,300 rpm[6]
  124 Nm (12.6 kgm; 91 lbft)@4,500 rpm[6]

The D14A3 has a restrictive gasket on the throttle body to reduce power in the EU.

D14A5

• 1995 - 1997 Honda Civic MA8 (EU)
  75 PS (55 kW; 74 hp)@6,100 rpm

The D14A5 has a restrictive gasket on the throttle body to reduce power in the EU.

D14A7

• 1997–2000 Honda Civic 1.4i MB2/MB8 (UK Market)
  75 PS (55 kW; 74 hp)@6,000 rpm
  112 Nm (83 lbft)@3,000 rpm

D14A8

• 1997–2000 Honda Civic 1.4iS MB2/MB8. UK and (at least) Germany.
  90 PS (66 kW; 89 hp)@6,400 rpm
  120 Nm (12.2 kgm; 88.5 lbft)@4,800 rpm

The D14A7 has a restrictive gasket on the throttle body to reduce power in the EU.

They are also almost identical to the D14A3 and D14A4 engines. Differences are only in the compression ratio and some ancilliary components.

D14Z1

• 1999–2000 Honda Civic EJ9 (1.4i, Europe)
  75 PS (55 kW; 74 hp)
  The D14Z1 has a restrictive gasket on the throttle body to reduce power in the EU.

D14Z2

• 1999–2000 Honda Civic EJ9 (1.4iS, Europe)
  90 PS (66 kW; 89 hp)@6,300 rpm

D14Z3

• 1999–2000 Honda Civic MB2 (1.4i, Europe), MB8 (1.4 SR,UK
  75 PS (55 kW; 74 hp)@5,700 rpm
  112 Nm (11.4 kgm; 83 lbft)@3,000 rpmThe D14Z3 has a restrictive gasket on the throttle body to reduce power in the EU.

D14Z4

• 1999–2001 Honda Civic MB2 (1.4iS), MB8 (1.4SR;UK
  90 PS (66 kW; 89 hp)@6400 rpm 120 Nm (89 lbft)@4800 rpm

D14Z5

• 2001–2005 Honda Civic 1.4iS, LS (EU: ES4 NFL)
  90 PS (66 kW; 89 hp)@5600 rpm 130 Nm (96 lbft)@4300 rpm

D14Z6

• 2001–2005 Honda Civic 1.4 LS (EU: EP1, EU4, EU7, ES4 fl, ES6)
  90 hp (66 kW)@5,600 rpm 130 Nm@4,300 rpm

Tuning the Honda D Series and best D Series performance parts.

Best D Series mods

Just because particular tuning parts are appear in lots of D Series projects it doesn't mean it is good, we shall focus on the greatest tuning parts that will give your D Series the best power gain for you money.

Please watch our video which covers tuning your D series engine. Be sure to keep up with our latest YouTube content and subscribe.

Best mods for your D Series

• Lightened Flywheels - a lower mass flywheel will improve the engines rev changes. Not always beneficial for all D Series engines.
• Remapping/Engine Tunes - piggy back ECU's chips and aftermarket ecus offer more flexibility for highly tuned D series projects.
• Turbo Modifications - Adding a turbocharger is the most significant way to improve intake air supply, allowing you to combust more fuel and make better power figures. Usually one of the most challenging upgrades it does provide the largest gains.
• Flowing and porting the Head - Head work will get air flowing into the engine while removing turbulence or restrictions.
• Air Induction Mods and Sports Exhausts - Please note that on their own these mods won't ADD POWER in most cases, but they will enable you to release power after other modifications by lessening the restriction.
• Sporty Profile cams are are often the best upgrade for an engine, but ideally be setup by someone who can fine tune the cam timing and it is often hard to find a suitable cam near you but we are sure you'll; find a local firm to regrind a stock cam.

D Series Tuning Stages

Typical stage 1 mods often include: Drilled & smoothed airbox, Panel air filters,  Fast road camshaft, Sports exhaust manifold.

Typical stage 2 mods often include: high flow fuel injectors, fuel pump upgrades, Fast road cam, Sports catalyst & performance exhaust, Suspension (Sports), induction kit.

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

Getting Started with Remapping or Engine Tuning

For enthusiasts eager to dive into DIY remapping, acquiring some essential tools and knowledge is the first step. A little knowledge is a dangerous thing, so don't start playing with this yourself unless you actually know what you are doing.

A cheap programmer, like the TL866, becomes a valuable asset, allowing you to read and write to the ECU’s memory chip.

Combine this with a free software, like HTS (Honda Tuning Suite), and you're equipped to start the remapping journey. Additionally, integrating a wideband O2 sensor into your setup is crucial for real-time air/fuel ratio monitoring, ensuring your engine runs optimally and safely under its new tuning parameters.

Remap Options and Brands

When considering ECU upgrades or remaps, especially to complement your existing Viper Stage 3 chip and other modifications, several reputable brands stand out:

Hondata

• We always like the Hondata S300: Which is perfect for OBD1 setups, this module enhances the factory ECU unlocking some power options. If you have an OBD2 ECU, Hondata's offerings like the K-Pro or FlashPro systems might be more suitable. These systems offer comprehensive tuning options, including fuel maps, ignition timing, VTEC control, and more. Their compatibility is often geared towards specific engine codes and ECU versions.

Viper performance

• The Viper 4x stage 3 chip makes quite a difference and improves acceleration. It is branded a Chip Sprint Throttle booster and OBD programmer module.

AEM Infinity

• A powerful and versatile option, the AEM Infinity ECU offers a wide range of tuning capabilities suitable for various vehicles and engine setups. Its compatibility with older and newer models makes it a strong contender, it can be more costly but it proves to be very capable.

Haltech

• Haltech ECUs, like the E6k, provide a plug-and-play or universal solution, adaptable for numerous applications including Honda engines. Their user-friendly interface and extensive tuning capabilities make them a favorite among performance enthusiasts.

Accel DFI

• Accel DFI systems are another option worth exploring. They offer robust engine management solutions that can cater to a wide variety of tuning needs, from basic adjustments to advanced fuel and ignition management.

If you have experience of these or other offerings from Apexi or Greddy on the D series please let us know in the comments sections below and we can pass these tips on.

Moving Forward

Choosing the right ECU or remapping solution depends on several factors: your specific performance goals, the current modifications on your Civic, and how far you wish to push the envelope. If you plan lots of mods and upgrades you'll struggle to extract power on the OEM ECU.

D Series Camshaft Upgrades

Fast road cams raise the higher RPM power so are more suited to petrol engines, than diesel ones. In most cases you will see peak power increases through performance camshafts on most engines

We've seen quite a few projects using Skunk cams in the D series, skunk2 stage 2 cams seem to be the popular choice and really do lift the top end power.

If you have VTEC, you can set it to cut in at lower RPM ranges, giving you a sportier cam profile over more of the engine's power band.

It is simpler to get VTEC to come in early than it is to find and install a fast road cam, therefore this is our preferred choice for individuals wishing to improve the cam profile on their D series.

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 power band gains are on offer for camshaft upgrades.

Fast road cams usually boost the torque over the rpm range, you may lose a little bottom end torque but your higher rpm power will improve.

Race cams, boost the higher rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

A Competition camshaft won't do well if in heavy traffic.

You should ideally match your power band to your driving style so for a car used daily stick with a fast road D Series camshaft

Each engine responds differently primarily due to the airflow when camshafts are fitted depending on the camshaft being more or less aggressive camshaft durations and cam duration as unique due to manufacturing tolerances and quality variations so set your engine up on a rolling road.

The Carb/Throttle body and fuel delivery and fuel pump also have a large bearing on the bhp gains you'll get.

Longer valve durations can alter the bhp band, and on most engines there are some advantages to extending the intake or exhaust durations and valve lift.

Air Flow improvements on the D Series

Enhancing the performance of your D Series engine involves a multifaceted approach, focusing on maximizing the efficiency with which air and fuel are introduced and utilized within the engine.

A key component in achieving this is the induction kit, and the inclusion of a Pipercross Viper rally induction kit or pipercross AEM or K&N are popular choices on the D series.

Let's delve deeper into how this, along with other modifications, contributes to the overall tuning strategy.

The Role of the Induction Kit

The induction kit is specifically designed to replace the car's standard air filtration system with a high-flow, performance-oriented setup.

This induction kit not only increases the volume of air available to the engine but also improves the quality of the air by ensuring it's cooler and denser.

You must fit a cold air feed and isolate the induction kit from the engine bay heat to get the maximum benefit.

Cooler air contains more oxygen, which is crucial for the combustion process, allowing for a more powerful explosion within the cylinders.

Intake System Upgrades

The intake system's primary job is to carry air from the filter, through the induction kit, and allow it to be pulled into the engine cylinders with fuel for the combustion phase.

The design and flow characteristics of the intake manifolds are critical in this process, as they can significantly impact fuel atomization. Superior fuel atomization ensures that fuel mixes more thoroughly with air, leading to a more efficient combustion process.

Upgrading the intake manifold on your D Series engine to one designed for performance can greatly enhance this effect. While some manufacturers provide decently flowing intake manifolds out of the factory, it's not uncommon for these components to be in dire need of a performance upgrade to meet the demands of high-performance tuning.

Enhancing Valve and Port Performance

To complement the improved air intake from the induction kit and intake manifold, consider upgrading to larger intake and exhaust valves. This allows for greater air and fuel flow into and out of the combustion chamber.

Additionally, getting port work and head flowing done can further enhance this effect by smoothing out the paths the air and fuel take, reducing resistance and improving flow efficiency.

Such modifications not only improve torque but also create a foundation that increases the effectiveness of other tuning parts.

This synergistic effect means that each component doesn't just add to the performance in isolation; it amplifies the impact of other modifications, leading to a more significant overall improvement in engine performance.

The Cumulative Effect

In engine tuning, it's the cumulative effect of all modifications that leads to a noticeable improvement in performance.

By starting with a high-quality induction kit like the Pipercross Viper rally, and enhancing the intake system and valve train, you're setting a strong foundation for further modifications.

Remember, the goal of any engine tuning job is to efficiently force more fuel and air into the engine, and then optimize how that mixture is combusted.

Through careful selection and upgrading of components such as the induction kit, intake manifold, and valves, you're well on your way to achieving a more powerful, responsive, and efficient D Series engine.

D Series Turbo upgrades

NA (naturally aspirated) 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 D Series

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

There are common areas of failure for every engine, with some being very over engineered and some only just able to handle stock power. It is important to find these limitations and fit higher quality crank and pistons to handle the power.

We see many drivers spending a lot of money on turbo charger upgrades on the D Series only to suffer the indignity of watching the D Series throw a rod soon after it's been enthusiastically driven.

Large turbochargers commonly experience a bottom end lag, and small turbochargers spool up more quickly but don't have the top end engines power gains.

You'll commonly see there's a limitation in the air flow sensor AFM/MAP on the D Series when a lot more air is being pulled into the engine.

We note 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped performance at a much lower level.

Adding a supercharger or additional turbo will make large bhp and torque gains, although more complex to setup. We have this article on twincharging if you want to read more.

D Series Fuelling Upgrades

You will need to ensure that the engine is not starved of fuel so need to pay attention to the fuelling when you start going beyond 20% of a bhp increase.

Removing the restriction in the intake that was fitted to some EU models is a good way to add power (restoring that lost power).

Carbs can be upgraded to enhance fuel delivery and if you set up a twin throat carb properly it can make really good power gains.

The early carbureted D series engines may be modified to dual carbs or multiple throttle bodies for increased power.

You'd be better off upgrading to fuel injection since it's simpler to tune and set up for higher power improvements.

Because it enhances throttle responsiveness, the fuel pressure regulator is an excellent addition for injected versions.

The fuel injected engines are more powerful, easier to tweak and offer better economy so conversion to fuel injection makes a lot of sense on the D series engines.

Boosting the fuel pressure provides a more snappy the acceleration responsiveness.Don't forget to over specify your injector capacity.

The rule of thumb is to add 20% capacity when fitting an injector, this takes into account injector deterioration and provides you some spare capacity should the engine need 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.

D Series Performance Exhausts

You may need to replace your exhaust if the current exhaust is actually creating a restriction.

On most factory exhausts you'll see your flow rate is ok 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 generally help improve air flow from the engine but avoid an exhaust that is too big or you could stuff up the flow rate. Generally speaking you should stick to around 1.5 to 2.5 inches for best results.

Typically exhaust restrictions can be located in the catalyst installed, so adding a faster flowing performance aftermarket version removes the restriction, and rather than doing an illegal catalyst removal, will keep the car road legal.

We note that performance catalysts perform a similar power improvement to test pipe mod and have the added benefit of keeping your car street legal, as decat or catalyst removal is not a legal mod.

Weak spots, Issues & problem areas on the D Series

The D Series 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 cause flat spots and loss of power, this is a larger issue on direct injection engines but should be looked out for on all engines. We have tips on removing carbon Avoid short journeys and use a good quality fuel.

Frequent oil changes are highly recommended on the D Series, and more importantly so when the car is tuned and will help prolong the life of the engine.

If you want to know more, or just get tips on Tuning your D Series engine please join us in our friendly forum where you can discuss D Series tuning options in more detail with our D Series owners. It would also be worth reading our unbiased Honda 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 appreciate people taking the time to tell us what our members have got up to and which tuning parts work best for them on each model of car. We use your comments and feedback to improve the accuracy of these D Series tuning guides which get regular updates and revisions.

This article is flagged for an update, so please pass on specific tips below that I can include. All articles, and content was written by me, Waynne Smith TorqueCars founder. Some outlines are just too general so I appreciate your feedback and suggestions. This entry was filed under Honda. You can leave a response below or join our forum to discuss this article and car modification in detail with our members.

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