Find out about "GA Modifications"

How to modify and upgrade the Nissan GA

"Comprehensive guide to tuning the Nissan GA engine!"

Our friends at TorqueCars are regularly getting emails about how to improve the GA from people inquiring about getting more power from the GA and wanting to know what are the things tuners recommend when it comes to GA modifications. So let us look into Nissan GA tuning mods and outline the best mods that work on this great engine and point out some frequent tuning mistakes along the way.

The Nissan GA great bases for a tuning project and with the best upgrades like a remap, turbo upgrades and camshafts you will certainly maximise your driving opportunities.

In this article we look at GA tuning and outline the greatest upgrades.

The top GA upgrades on an engine are sensibly the ones that give the best power gain for your hard earned cash.

We won't be swayed by popular GA upgrades, they need to be cost effective.

Improving air intake on the GA

You need air and fuel for an engine to work. If there is insufficient fuel then it will run lean, if there is too little air it runs rich losing power which risks damage to the GA. 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 the main goal to any car tuning project.

It is not unusual that there's a limit in the air flow sensor AFM/MAP on the GA when considerably 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 torque at a much lower level.

Engine intake manifolds transmit the air from the filter and allow it to be sucked into the engine and mixed with fuel.

Shape and rate of flow of the Plenum can make a substantial difference to to fuel delivery on the GA.

It's not uncommon that air intake manifolds are crying out for motorsport parts, although a few manufacturers provide reasonably well designed air intake manifolds.

Fitting big valve kits, carrying out GA port enlargement and head flowing will also improve torque, and as an added benefit will afford you a better torque increase on other mods.

GA performance cam tips.

Different GA engines respond better to more or less aggressive cam durations so view each engine as unique.

The map and fuel pump and injectors also have a large bearing on the bhp gains you'll achieve.

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

NB: Fast road camshafts commonly bump the performance across the rpm range, you could sacrifice a little low end torque but the top end will be lifted.

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

On a car driven daily you should ideally to optimize your bhp range to your preferences.

I'd be amazed if you find a GA Motorsport camshaft is a pleasure to live with when on the daily commute.

Stage 1, 2 and 3 mods for the GA

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 GA parts:

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

Stage 2 GA parts:

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

Stage 3 GA parts:

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

Remapping allows a tuner to to establish the full potential of all the tuning parts you've done to your GA.

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 will vary depending on the tuning parts you've fitted and the condition of your engine.

Turbo modifications on the GA

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 GA.

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

If the engine is fitted with a turbocharger parts are going to net you a larger power gain and turbo engines will have better components.

However most engines will need better parts at higher power limits

Discover these limitations and fit stronger pistons, crank and engine components to handle the power.

There are many guys spending a a stack of money on turbo upgrades on the GA only to watch the car explode soon after it's been completed.

Large capacity turbochargers often suffer low end lag, and little turbochargers spool up much more quickly but do not have the peak rpm engines power gains.

Thankfully the world of turbo chargers is always moving on and we are seeing variable vane turbo chargers, permitting 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 gases into a couple of channels and direct these at differently angled vanes in the turbo charger. They also help 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 gains, although more complex to get working. We have this guide to twinchargers if you want to read more.

Tips about fuel supply on the GA

You will need to ensure that the engine is not starved of fuel so should ramp up the fuelling when you start going beyond 20% of a power hike. Experienced mechanics will tell you to over specify your injector capacity.

The accepted safe increase is to add another 20% when buying an injector, this allows for injector deterioration and allows a little 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 GA performance exhaust upgrades

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

On most factory exhausts you should find that your flow rate is still 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 will certainly help air flow out of the engine but avoid an exhaust that is too big or you could will reduce the flow rate. Stick to one and a half to two and half inches as a rule of thumb.

Usual exhaust restrictions can be traced to the filters installed, so adding a higher flowing sports alternative will help avoid this restriction.

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

Faults issues and things to look out for on the GA

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

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

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