Modding and performance tuning parts for the Honda D16 engine!

Discover "D16 Modifications"

How to modify and upgrade the Honda D16

"Comprehensive guide to performance parts and tuning the Honda D16 engine!"

TorqueCars are regularly getting emails asking about how to improve the D16 from people wanting to know what are the best D16 upgrades. So let us look into Honda D16 mods and outline the best upgrades on this great engine and point out some common pitfalls along the way.

Now we will examine the options for your D16 tuning and summarise the premier modifications. Honda D16 great bases for a tuning project and with a few sensible sports upgrades like remaps, turbo kits and camshafts you will definitely enhance your driving fun.

Just because particular tuning parts are appear in lots of D16 projects it doesn't mean it is good, we will focus on the greatest tuning parts that will give your D16 the best power gain for you money.

Without us subscribing to the misaprehension of 'if it's shiny and makes more noise it must be good' you seem to get in many tuning magazines and on car forums'.

D16 induction kits

Improving air intake on the D16

You need fuel and air for an engine to work. If there is too little fuel then it will run lean, if there is a lack of air it runs rich losing power and potentially damaging the engine. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So it's important to any performance tuning project to shove more air and fuel into each cylinder but this has a knock on effect with the air flow sensor.

It is common that there is a restriction in the air flow sensor AFM/MAF on the D16 when loads more air is being drawn into the engine.

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

Headers carry the during the engines suck phase from the filter and allow it to be drawn into the engine and mixed with fuel.

Design and flow rate of the Intake headers can make a large effect on to fuel atomisation on the D16.

We often see intake are begging for performance upgrades, although some OEM provide well optimised intake.

Big valve conversions on the D16, doing some D16 port enlargement and head flowing will also boost bhp, and as an added benefit will make space for increasing the bhp increase on other upgrades.

D16 performance cam tips.

Each engine responds better to extreme cam durations so set your engine up on a rolling road.

The ecu map and fuel pump and injectors also will say much on the bhp gains you'll make.

Extending exhaust or intake durations can alter the bhp 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.

Altering your D16 cam will make a dramatic difference to the engine bhp. Choosing a higher performance cam profile raises the bhp accordingly.

NB: Fast road cams tend to push up the torque through the rev range, you might lose a little bottom end power but your top end will be higher.

Competition cams, push up the top end band but as a result the car will not idle smoothly and low end power nearly always suffers.

A Motorsport and race cam makes it harder when driving in heavy traffic.

You should ideally match your power band to your cars usage so for a car driven daily stick with a mild fast road D16 cam

Stage 1, 2 and 3 mods for the D16

Stages Of Modifications For D16

Usually, modifications of the D16 engine are further sub-classified into three types which are referred to as Stage 1, 2 and 3 mods in the ascending order of performance.

Before we break the best tuning upgrades down into stages of tune, let's list the most effective tuning upgrades for you.

  1. Suspension Upgrades - always improve your cars handling
  2. Brake Upgrades - Even before adding power improve those brakes
  3. Intake - make sure the intake is not restricted, use filters and intake upgrades to improve this
  4. Exhaust - as with 3 ensure there is not restriction in the exhaust, cats are the usual bottleneck
  5. Tunes - remapping, piggyback ECU's and aftermarket ECU's can all make decent gains
  6. Fuelling - when you've increased power you'll need to match this with more fuel
  7. Turbo upgrades - Improving the intake with a large turbo and better flowing intercooler will be the biggest power gain you'll see (but one of the most complex).

This video guide to tuning cars is a great starting point to work from in your project.

Stage 1 D16 parts:

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

Stage 2 D16 parts:

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

Stage 3 D16 parts:

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

Tuning tips and articles Engine tuning Transmission tuning Care care Intake & exhaust mods Improve handling Forums

While Stage 1 modifications are usually restricted to intake headers, sports exhaust manifolds and panel air filters to name a few, the Stage 2 and 3 go over and beyond by delivering exceptional performance due to the incorporation of advanced level parts such as the fuel pump upgrades, inductions kits, high flow fuel injectors, engine balancing along with crank and piston upgrades.

It is worth noting that Stage 1 and 2 comprise of fast road cams whereas Stage 3 has competition cams for exceptional performance.

The D16 power trains respond well to mods and we're happy to report there is a lot of parts and tuning parts around.

ECU flashing will help unlock the full potential of all the upgrades you've done to your D16.

You will typically expect to see gains of approximately 20-30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but your mileage usually rely on the upgrades you've applied and the condition of your engine.

Turbo modifications on the D16

To get a turbo working on a NASP engine there is a lot involved, from lowering compression ratio to improved fuel supply and mapping, so we have found a great guide to helpavoid the common pitfalls or end up with an unfinished project because you were not told what you were getting into by doing this on the D16.

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

If an engine has forced induction parts are simpler to install and most turbo charged engines are built using harder and stronger components.

However most engines have weakspots

See where you'll find these limits and fit better quality components to survive the power.

We see many people spending a lots of money on turbo upgrades on the D16 only to have the whole thing catastrophically fail when it's been enthusiastically driven.

Larger turbochargers tend to suffer no power at low rpm, and smaller turbochargers spool up more quickly but don't have the high rpm torque gains.

In recent times the market of turbochargers is always improving and we are seeing variable vane turbochargers, permitting the vane angle is altered according to speed to lower lag and increase top end torque.

Twin scroll turbochargers divert the exhaust flow into 2 channels and flow these at differently designed vanes in the turbo. They also improve the scavenging effect of the engine.

Beefing up the air intake by adding a supercharger or additional turbo will help you achieve very large performance gains, although more challenging to configure. We have this guide to twinchargers if you want to read more.

Tips about fuel supply on the D16

When you lift the bhp you will need to increase to the fuel delivery.

More bhp needs more fuel. Experienced tuners recommend to over specify your injectors flow rate.

The rule of thumb is to add 20% capacity when specifying an injector, which takes into account injector deterioration and affords some spare capacity should the engine require more fuel.

Don't forget that different fuel grades will usually require different settings, a high octane fuel will burn more efficiently than lower octane fuel for example. A car will trim fuel supply to keep within the ideal air fuel mix but at the extreme ends you may need to adjust your injector capacity, or the mapping or you'll get flat spots and potential lean or rich fuel issues..

Recommended D16 performance exhaust upgrades

You only need to to upgrade your exhaust system with an upgraded one is if the current exhaust is actually creating a restriction in flow.

On most factory exhausts you'll find the flow rate is still ok even on modest power gains, but on a serious tuning project with a big boost in power you will certainly need to get a better flowing exhaust.

Sports exhausts can help balance the flow of gases through the engine.

But if the exhaust pipe is too big, ie: it's over two and a half inches diameter, you will lose a great deal of your flow rate and end up losing power and torque.

The usual suspects causing problems in your exhaust flow rate are traced to the catalyst and filters installed, so adding a faster flowing high performance alternative will help avoid this restriction.

Catalyst removal (NB:catalysts reduce harmful engine emissions) is illegal in most countries and regions.

Faults issues and things to look out for on the D16

Like most engines an D16, should have few issues if it gets properly serviced and looked after.

We cannot stress enough the need for oil changes with the correct grade of oil on the D16, failure to do this will exacerbate engine wear, on a tuned D16 this is more important than ever and close attention should be paid to your maintenance schedule.

The Honda D16 is a very reliable engine so the issues are not that common.

Distributors require replacement every few years and they can cause issues as they wear out manifest as tracking marks inside and engine misfiring.

The Crankshaft pulley is somewhat prone to failure requiring replacement, check for cracks, noise and vibrations which can be an early warning sign.

Engine idle issues are commonly down to throttle issues and cleaning usually resolves this, in some cases the Lambda (O2) sensor can be the culprit.

However, like all other engines, ensure to change the oil on time and always use high-quality fuel.

Some instances have occurred in the past in which carbon built-ups in the head have been reported which is not something too concerning as it can be cleaned easily.

If you are interested in learning more or getting impartial tuning advice for your D16 why not pop over to the forums at TorqueCars where you can chat about the best D16 tuning mods and read about others projects who may be planning to do similar modifications on their D16.

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

We want to know your experiences with tuning parts on your D16, it helps us improve our tips and keeps us current so please use the comments box to drop a tip.

If you liked this page please share it with your friends, drop a link to it in your favourite forum or use the bookmarking options to save it to your social media profile.

Check out TorqueCars new YouTube channel, and see their awesome new content...


Please use our forums if you wish to ask a tuning question, and please note we do not sell parts or services, we are just an online magazine.

Help us improve, leave a suggestion or tip

Your Constructive comments on this article