The Lowdown on "B20 Modifications"

How to modify and upgrade the Honda B20

"Comprehensive guide to performance parts and tuning the Honda B20 engine!"

TorqueCars are regularly getting posts asking about how to improve the B20 from people inquiring about getting more power from the B20 and wanting to know what are the optimum B20 modifications. So let us look into Honda B20 upgrades and outline the best upgrades on this great engine and point out some common pitfalls along the way.

Our aim here is to provide a guide to B20 tuning and provide tips on the optimum modifications. Honda B20 are awesome to work on and with carefully picked performance modifications like remapping, turbo upgrades and camshafts you will certainly maximize your driving experience.

When talking about the ultimate parts for your B20 engine, we are going to concentrate on the mods that give the best power gain for you money.

Improving air intake on the B20

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 losing power which risks damage to the B20. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So Getting fuel and air into each cylinder is the aim to any tuning job.

It is not unusual that there is a limit in the air flow sensor AFM/MAP on the B20 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 sapped bhp and torque at a much lower level.

Headers take the air from the air filter and allow it to be sucked into the engine cylinders with fuel for the squish phase.

The size of bore and shape and flow rate of the Intake headers can make a noticeable change to fuel atomisation on the B20.

We often see intake headers are begging for aftermarket parts, although some OEM provide decently flowing intake headers.

Adding a B20 larger valve kit, getting port work and head flowing will also raise power, this will permit raising the power increase on other parts.

B20 performance cam tips.

Each engine responds better to more or less aggressive camshaft durations check your engine on a rolling road.

The ECU mapping and injectors and fuel pump also will say much on the power gains you'll hit.

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.

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

NB: Fast road cams tend to increase the bhp over the rev range, you may sacrifice a little bottom end torque but the top end will be higher.

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

In a typical daily driver you should ideally to match your bhp range to your driving style.

I'd be gobsmaked if you have ever thought a B20 Race camshaft is a pleasure to live with when on the daily commute.

Stage 1, 2 and 3 mods for the B20

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 B20 parts:

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

Stage 2 B20 parts:

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

Stage 3 B20 parts:

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

ECU mapping helps release the full potential of all the mods you've done to your B20.

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 often rely on the mods you've done and the condition of your engine.

Turbo modifications on the B20

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 B20.

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 your car is turbo charged parts are going to net you a larger power gain and we find turbocharged engines already contain strengthened components.

However engines will have power limits

Research these limitations and upgrade to higher quality crank and pistons to survive the power.

We've seen people spending a loads on turbocharger upgrades on the B20 only to watch the motor literally blow up just after it's completed.

Larger upgraded turbochargers often suffer no power at low rpm, and low capacity turbochargers spool up quickly but won't have the high rpm engines power gains.

We are pleased that the range of turbo chargers is always increasing and we now see variable vane turbo chargers, where the vane profile is altered according to speed to lower lag and increase top end bhp.

Twin scroll turbo chargers divert the exhaust flow into two channels and push these at differently angled vanes in the turbo. 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 bhp and torque gains, although harder to install. We have this guide to twinchargers if you want to read more.

Tips about fuel supply on the B20

When you increase the bhp you will need to ramp up to the fuel delivery.

More bhp needs more fuel. Most tuners we speak with say to be generous with your injectors flow rate.

The rule of thumb is to add another 15% when buying an injector, this accounts for injector deterioration and gives a bit of 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 B20 performance exhaust upgrades

You should look to increase your exhaust system with an upgraded one is if your exhaust is creating a restriction.

On most factory exhausts you'll see the exhaust 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 usually air flow out of the engine but avoid an exhaust that is too large or you may end up will reduce the flow rate. Stick to one and a half to two and half inches for best results.

The usual suspects causing problems in your exhaust flow rate are in the catalysts installed, so adding a freer 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 B20

Like most engines an B20, 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 B20, failure to do this will exacerbate engine wear, on a tuned B20 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 B20 why not pop over to the forums at TorqueCars where you can chat about B20 tuning options and read about others projects who may be planning to do similar modifications on their B20.

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This entry was posted under Makes and Models. Tags: engine, honda
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