Modding tuning and best performance upgrades on the Nissan QG18DEN engine!

Car tuning tips:QG18DEN Modifications"

QG18DEN Modifications Guide

How to modify and upgrade the Nissan QG18DEN

"Comprehensive guide to tuning the Nissan QG18DEN engine!"

Forums like the one at TorqueCars often are getting posts requesting information on how to improve the QG18DEN from people inquiring about getting more power from the QG18DEN and wanting to know what are the ultimate QG18DEN upgrades. So let us look into Nissan QG18DEN parts and outline the best upgrades on this great engine and point out some problems along the way.

The Nissan QG18DEN make a good tuning project and with the optimum sports parts like a remap, turbo upgrades and camshafts you will substantially maximize your driving enjoyment.

Car Tuning Tips will review and look at QG18DEN tuning and summarise the greatest modifications.

The greatest QG18DEN tuning mods on an engine are sensibly the ones that give the best gains for your money.

We won't be swayed by popular QG18DEN tuning mods, they need to be cost effective.

QG18DEN induction kits

Improving air intake on the QG18DEN

You need fuel and air for an engine to work. If there is a lack of fuel then it will run lean, if there is not enough air it runs rich losing power . We'll pick up on fuelling later in this article but for now we shall look at air supply.

So Pulling more air and fuel into each cylinder is the aim to any engine performance tuning project.

It is not unusual that there is a limit in the air flow sensor (AFM/MAF/MAP) on the QG18DEN when a lot more air is being drawn 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 power at a much lower level.

The intake plenum transmit the air from the intake filter and allow it to be fed into the engine and mixed with fuel.

The shape and rate of flow of the air Intake manifold can make a substantial change to fuel engine efficiency on the QG18DEN.

On popular production engines air intake manifolds are needing motorsport parts, although a few OEM provide reasonably well designed air intake manifolds.

Big valve conversions on the QG18DEN, doing a bit of port work and head flowing will also improve performance, and importantly will allow you to get increasing the performance increase on other upgrades.

QG18DEN performance cam tips.

Different QG18DEN engines respond better to more or less aggressive cam durations so view each engine as unique.

The map and fuelling also have a large bearing on the torque gains you'll hit.

Altering 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 QG18DEN camshaft will make a dramatic difference to the engine bhp. Choosing a higher performance camshaft profile raises the bhp accordingly.

NB: Fast road camshafts commonly push up the power over the rev band, you could drop a little low down bhp but top end will improve.

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

A Motorsport and race camshaft makes it harder when driving in heavy traffic.

You should ideally match your bhp range to your cars usage so for a car used daily stick with a fast road QG18DEN camshaft

Stage 1, 2 and 3 mods for the QG18DEN

Stage 1 QG18DEN parts:

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

Stage 2 QG18DEN parts:

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

Stage 3 QG18DEN parts:

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

The QG18DEN engine blocks are great to work on and we're pleased to see that there is an increase of parts and performance parts about.

Remaps allows a tuner to fully realize the full potential of all the tuning mods you've done to your QG18DEN.

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 end result usually vary depending on the tuning mods you've fitted and the condition of your engine.

Turbo modifications on the QG18DEN

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

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 QG18DEN.

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.

When the engine is turbo charged parts are simpler to install and we find turbo engines already contain many forged and stronger components.

There are common areas of failure for every engine, with some being incredibly solid and some just sufficiently able to handle stock power

See where you'll find these limitations and upgrade to better quality crank and pistons to handle the power.

We see many drivers spending a a stack of money on turbo charger upgrades on the QG18DEN only to suffer the humiliation of seeing the engine block catastrophically fail on it's first outing after it's first rolling road session.

Bigger capacity turbo chargers tend to suffer no power at low rpm, and low capacity turbo chargers spool up quickly but won't have the high rpm bhp gains.

In the last 10 years the range of turbo units is always evolving and we are seeing variable vane turbo units, permitting the vane profile is altered according to speed to lower lag and increase top end torque.

Twin scroll turbo units divert the exhaust flow into two channels and flow these at differently profiled vanes in the turbo. 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 performance gains, although more challenging to install. We have this article on twincharging if you want to read more.

Tips about fuel supply on the QG18DEN

You will need to ensure that the engine is not starved of fuel so should ramp up the fuelling when you start exceeding 20% of a performance hike. Experienced mechanics will tell you to be generous with your injectors flow rate.

As a rule of thumb add 20% capacity when fitting an injector, this allows for injector deterioration and allows 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 QG18DEN performance exhaust upgrades

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

On most factory exhausts you'll find the 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.

Do not go with the widest exhaust you can buy this will reduce 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.

Usual exhaust restrictions are traced to the catalyst and filters installed, so adding a freer flowing sports alternative will help avoid this restriction.

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

Faults issues and things to look out for on the QG18DEN

Like most engines an QG18DEN, 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 QG18DEN, failure to do this will exacerbate engine wear, on a tuned QG18DEN 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 QG18DEN why not pop over to the forums at TorqueCars where you can chat about QG18DEN tuning options and read about others projects who may be planning to do similar modifications on their QG18DEN.

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