Modding uprating the Honda K20 engine!

Tuners tips on "K20 Modifications"

K20 Modifications Guide

How to modify and upgrade the Honda K20

"Comprehensive guide to performance tuning the Honda K20 engine!"

Forums like the one at TorqueCars are always seeing threads about how to improve the K20 from people inquiring about getting more power from the K20 and wanting to know what are the things tuners recommend when it comes to K20 upgrades. So let us look into Honda K20 parts and outline the best modifications on this great engine and point out some frequent tuning mistakes along the way.

The Honda K20 are popular tuning projects and with the optimum modified mods like ECU maps, turbo improvements and camshafts you will certainly improve your driving pleasure.

Here we review K20 tuning and summarise the best upgrades.

When talking about the top parts for your K20 engine, we are going to focus on the upgrades that give the best power gain for you money.

K20 induction kits

Improving air intake on the K20

You need air and fuel for an engine to work. If there is not enough fuel then it will run lean, if there is not enough air it runs rich resulting in lost 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 Pulling fuel and air into your K20 is the aim to any engine performance tuning project.

It is not unusual that there's a limitation in the air flow sensor MAP/MAF/AFM on the K20 when a lot more air is being pulled into the engine.

When tuning you may well find you need to get an air sensor or flow meter capable of upto 4 bars to cope with quite large power gains, whereas the OEM air sensor limited performance at a much lower level.

Engine intake manifolds flow the air from the filter and allow it to be drawn into the engine cylinders.

The bore size, shape and flow rate of the Plenum can make a large effect on to fuel atomisation and engine efficiency on the K20.

Commonly we find the plenum chambers are needing a performance upgrade, although some car makers provide fairly well optimized plenum chambers.

Increasing the K20 valve size, doing some port matching and head flowing will also boost performance, and as an added benefit will permit increasing the performance increase on other modifications.

K20 performance cam tips.

Some K20 engines respond better to more or less aggressive cam durations than others.

The map and fuel pump and injectors also have an effect on the power gains you'll achieve.

Longer 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.

Significant air intake, and exhaust improvements on the K20 can be made from cam upgrades. Changing the cam profile alters the intake and exhaust durations on the engine and can dramatically change the bhp and power output.

NB: Fast road camshafts usually bump the bhp throughout the rev range, you could sacrifice a little low down bhp but the top end will be better.

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

A Competition cam is not great in heavy traffic.

You should ideally match your engines power to your cars usage so for a road car stick with a shorter duration K20 cam

Stage 1, 2 and 3 mods for the K20

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 K20 parts:

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

Stage 2 K20 parts:

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

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

Stage 3 K20 parts:

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

Review your options and then buy your modifications and set yourself a power target to avoid costly mistakes.

A remap helps fully realize the full potential of all the tuning parts you've done to your K20.

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 figures achieved may depend much on the tuning parts you've fitted and the condition of your engine.

Turbo modifications on the K20

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 K20.

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.

When an engine has forced induction parts are simpler to install and we find turbo charged engines are built using strengthened components.

There are weak spots for every engine, with some being extremely strong and some just sufficiently able to handle stock power

We recommend you find these limitations and upgrade to higher quality crank and pistons to utilize the power.

There are many people spending a loads of money on turbocharger upgrades on the K20 only to watch the engine literally blow up when it's been finished.

Big capacity turbochargers often experience a bottom end lag, and little turbochargers spool up really quickly but won't have the top end bhp gains.

We are pleased that the range of turbo units is always moving on and we commonly find variable vane turbo units, allowing the vane profile is altered according to speed to lower lag and increase top end bhp and torque.

Twin scroll turbo units divert the exhaust flow into a couple of channels and flow these at differently designed vanes in the turbo charger. They also boost the scavenging effect of the engine.

Beefing up the air intake by adding a supercharger or additional turbo will help you achieve very large power gains, although more complex to install. We have this feature on twinchargers if you want to read more.

Tips about fuel supply on the K20

When you lift the bhp you will need to increase to the fuelling.

More bhp needs more fuel. It makes sense to over specify your injectors flow rate.

The accepted safe increase is to add 15% when fitting an injector, this takes into account injector deterioration and affords some spare capacity should the engine need 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 K20 performance exhaust upgrades

We'd only recommend you look to increase your exhaust system with an upgraded one is if your current exhaust is actually creating a restriction in flow.

On most factory exhausts you'll find the flow rate is good 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.

Don't go with the biggest exhaust you can buy this will slow up the exhaust flow rate - the best for power gains are usually between one and a half to two and half inches. Your exhaust design, the bend angles and construction are what have more effect on flow rates than your pipe width to a certain extent. So the exhaust design is a big factor.

Usual exhaust restrictions are traced to the emissions filters installed, so adding a faster flowing 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 K20

Like most engines an K20, 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 K20, failure to do this will exacerbate engine wear, on a tuned K20 this is more important than ever and close attention should be paid to your maintenance schedule.

If you are interested in learning more or getting impartial tuning advice for your K20 why not pop over to the forums at TorqueCars where you can chat about K20 tuning options and read about others projects who may be planning to do similar modifications on their K20.

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