Modding tuning and best performance upgrades on the Honda L13 engine!

Discover "L13 Modifications"

How to modify and upgrade the Honda L13

"Comprehensive guide to tuning the Honda L13 engine!"

Our friends at TorqueCars are frequently getting messages requesting information on how to improve the L13 from people wanting to know what are the best L13 mods that work. So let us look into Honda L13 tuning mods and outline the best modifications on this great engine and point out some problems along the way.

This pages aim is provide a guide to L13 tuning and show the ultimate modifications. Honda L13 make a good tuning project and with carefully chosen tuning upgrades like ECU maps, turbo kits and camshafts you will certainly maximise your driving experience.

When talking about the greatest parts for your L13 engine, we are going to focus on the tuning mods that give the best value for money.

L13 induction kits

Improving air intake on the L13

You need air matched to fuel for an engine to work. If there is insufficient fuel then it will run lean, if there is little flow of air it runs rich sapping power which risks damage to the L13. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So Feeding fuel and air into each cylinder is vital to any engine upgrade job.

It is common that there is a limit in the air flow sensor AFM/MAF on the L13 when loads more air is being sucked into the engine.

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

Engines intake headers take the during the engines suck phase from the air filter and allow it to be pulled into the engine cylinders with fuel for the squish phase.

Structure and flow characteristics of the Headers can make a big change to fuel atomisation and engine efficiency on the L13.

Many mass produced engine plenum chambers are ripe for aftermarket tuning parts, although some car makers provide reasonably good plenum chambers.

Fitting big valve kits, doing a bit of L13 port enlargement and head flowing will also increase bhp, this will make space for raising the bhp increase on other tuning mods.

L13 performance cam tips.

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

The engine timing and fuelling also have an effect on the bhp gains you'll achieve.

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.

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

NB: Fast road camshafts normally boost the power over the rpm range, you may lose a little low down power but your top end will be higher.

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

A Competition cam won't do well if on the daily commute.

You should ideally match your bhp range to your cars usage so for a car used daily stick with a shorter duration L13 cam

Stage 1, 2 and 3 mods for the L13

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 L13 parts:

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

Stage 2 L13 parts:

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

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

Stage 3 L13 parts:

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

Review your options and then find your mods and set yourself a power target to avoid disappointment.

Remapping will help fully realize the full potential of all the parts you've done to your L13.

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 the outcome may depend much on the parts you've applied and the condition of your engine.

Turbo modifications on the L13

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 L13.

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.

If your car is turbo charged tuning mods are relatively easy and you'll see that turbo engines already contain harder and stronger components.

There are practical limits for every engine, with some being incredibly solid and some only just able to handle stock power

Discover these limits and fit better quality components to cope with the power.

It's not unheard of people spending a lot of money on turbocharger upgrades on the L13 only to have the engine catastrophically fail soon after it's been finished.

Large upgraded turbochargers often experience low end lag, and small turbochargers spool up really quickly but do not have the top end bhp gains.

Thankfully the market of turbo chargers is always improving and we commonly find variable vane turbo chargers, allowing the vane angle is altered according to speed to lower lag and increase top end bhp and torque.

Twin scroll turbo chargers divert the exhaust flow into two channels and flow these at differently profiled vanes in the turbocharger. 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 power gains, although harder to configure. We have this article on twincharging if you want to read more.

Tips about fuel supply on the L13

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

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

The rule of thumb is to add 20% when buying an injector, which takes into account injector deterioration and affords you 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 L13 performance exhaust upgrades

Only look to boost your exhaust system with an upgraded one is if your exhaust is actually causing a flow problem.

On most factory exhausts you should find that your flow rate is fine 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 equal out the flow of air through the engine.

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

Usual exhaust restrictions can be traced to the catalysts installed, so adding a faster flowing high performance alternative will help avoid this restriction.

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

Faults issues and things to look out for on the L13

Like most engines an L13, 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 L13, failure to do this will exacerbate engine wear, on a tuned L13 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 L13 why not pop over to the forums at TorqueCars where you can chat about L13 tuning options and read about others projects who may be planning to do similar modifications on their L13.

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