Modding and performance tuning parts for the Honda L series engine!

Tuning guide "L series Modifications"

How to modify and upgrade the Honda L series

"Comprehensive guide to tuning the Honda L series engine!"

Popular tuning sites like TorqueCars are always getting posts about how to improve the L series from people wanting to know what are the best tips for L series mods that work. So let us look into Honda L series upgrades and outline the best upgrades on this great engine and point out some potential pitfalls along the way.

Therefore we look into L series tuning and point out the greatest mods that work. Honda L series great bases for a tuning project and with carefully chosen motorsport modifications like remaps, turbo upgrades and camshafts you will definitely enhance your driving pleasure.

The top L series parts on an engine are typically the ones that give the biggest return for your money.

We won't be swayed by popular L series parts, they need to be cost effective.

L series induction kits

Improving air intake on the L series

You need air and fuel for an engine to work. If there is little supply of fuel then it will run lean, if there is a lack of 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 it's important to any tuning job to feed air into your L series but this has a knock on effect with the air flow sensor.

It is common that there is a limit in the air flow sensor MAF/MAP on the L series when loads more air is being drawn into the engine.

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

Intake manifolds carry the during the engines suck phase from the intake filter and allow it to be drawn into the engine cylinders.

Shape and flow characteristics of the air Intake manifold can make a noticeable difference to to fuel atomisation and engine efficiency on the L series.

On popular production engines headers are in desperate need of aftermarket tuning parts, although a few car makers provide fairly well optimized headers.

Big valve conversions on the L series, getting port matching and head flowing will also lift bhp, the fantastic side effect is it will permit a greater bhp increase on other mods.

L series performance cam tips.

Each engine responds better to different camshaft durations so set your engine up on a rolling road.

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

Longer valve durations can alter the torque 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 L series camshaft will make a dramatic difference to the engine engines power. Choosing a higher performance camshaft profile raises the engines power accordingly.

NB: Fast road cams commonly increase the bhp through the rpm band, you could sacrifice a little low end power but your top end will improve.

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

A Motorsport camshaft is not great in heavy traffic.

You should ideally optimize your bhp range to your cars usage so for a typical daily driver stick with a shorter duration L series camshaft

Stage 1, 2 and 3 mods for the L series

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 L series parts:

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

Stage 2 L series parts:

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

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

Stage 3 L series parts:

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

Carefully think through your options and then buy your tuning parts and set yourself a power target to avoid costly mistakes.

Remapping helps unlock the full potential of all the modifications you've done to your L series.

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 power output usually depend much on the modifications you've carried out and the condition of your engine.

Turbo modifications on the L series

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 L 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 major power gains.

When an engine is turbocharged, modifications are more reliable and most turbo engines are made using stronger components.

However most engines have weakspots

We recommend you find these limits and upgrade to more solid crank and pistons to utilize the power.

There are many people spending a lot of money on turbo charger upgrades on the L series only to suffer the indignity of watching the engine block explode when it's used in anger.

Bigger upgraded turbos tend to suffer low end lag, and little turbos spool up more quickly but do not have the high rpm bhp gains.

Thanks to new tech the choice of turbos is always improving and we commonly find variable vane turbos, allowing the vane profile is altered according to speed to lower lag and increase top end bhp.

Twin scroll turbos divert the exhaust flow into a couple of channels and flow these at differently profiled vanes in the turbocharger. They also increase the scavenging effect of the engine.

Beefing up the air intake by adding a supercharger or additional turbo will help you achieve very large bhp and torque gains, although more challenging to configure. We have this in depth look at twinchargers if you want to read more.

Tips about fuel supply on the L series

Don't omit to boost the fuel system when you are increasing the power - it makes the car more thirsty. We would recommend you to over specify your flow rate on the injectors.

As a rule of thumb add 15% capacity when fitting an injector, this takes into account injector deterioration and provides 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 L series performance exhaust upgrades

You should look to improve your exhaust system with an upgraded one is if your current exhaust is creating a flow problem.

On most factory exhausts you'll see the exhaust 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.

Do not go with the largest exhaust you can buy this will slow up the exhaust flow rate - the best exhausts 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.

Typically exhaust restrictions can be traced to the emissions filters installed, so adding a higher flowing 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 L series

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

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