Modding and performance tuning parts for the Nissan VQ40DE engine!

All you need to know about "VQ40DE Modifications"

VQ40DE Modifications Guide

How to modify and upgrade the Nissan VQ40DE

"Comprehensive guide to tuning the Nissan VQ40DE engine!"

Our friends at TorqueCars are always seeing threads requesting info on how to improve the VQ40DE from people inquiring about getting more power from the VQ40DE and wanting to know what are the best VQ40DE mods that work. So let us look into Nissan VQ40DE modifications and outline the best modifications on this great engine and point out some problems along the way.

Therefore we review VQ40DE tuning and highlight the best mods that work. Nissan VQ40DE have loads of potential and with a few sensible upgrades like a remap, turbo improvements and camshafts you will greatly increase your driving fun.

Just because particular parts are appear in lots of VQ40DE projects it doesn't mean it is good, instead we'll focus on the ultimate parts that will give your VQ40DE the biggest power gain return for your cash.

Without us subscribing to the mentality of 'if it's shiny and makes more noise it must be good' you seem to get in many tuning magazines and on car forums'.

VQ40DE induction kits

Improving air intake on the VQ40DE

You need fuel and air for an engine to work. If there is too little fuel then it will run lean, if there is insufficient 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 the goal to any engine tuning job to get air and fuel into the VQ40DE engine but this has a knock on effect with the air flow sensor.

You'll commonly see there is a limit in the air flow sensor AFM/MAF on the VQ40DE when loads more air is being fed into the engine.

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

Intake headers take the air from the air cleaner and allow it to be sucked into the engine cylinders with fuel for the squish phase.

Design and rate of flow of the Headers can make a big difference to to fuel atomisation and engine efficiency on the VQ40DE.

I usually find intake manifold are needing aftermarket tuning parts, although a few OEM provide well optimised intake manifold.

Fitting big valve kits, getting VQ40DE port enlargement and head flowing will also increase power, and significantly will make space for raising the power increase on other parts.

VQ40DE performance cam tips.

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

The ECU mapping and injectors and fuel pump also have a large bearing on the torque gains you'll achieve.

A longer valve duration 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.

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 bhp gains are on offer for cam upgrades.

NB: Fast road camshafts usually increase the performance across the rpm range, you may lose a little low down power but the top end will improve.

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

For a car driven daily you should ideally to match your torque band to your preferences.

I'd be gobsmaked if you have found a VQ40DE Motorsport cam is a pleasure to live with when driving in heavy traffic.

Stage 1, 2 and 3 mods for the VQ40DE

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 VQ40DE parts:

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

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

Stage 2 VQ40DE parts:

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

Stage 3 VQ40DE parts:

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

Carefully think through your options and then find your upgrades and set yourself a power target to save yourself from expensive mistakes.

A remap should help to to establish the full potential of all the upgrades you've done to your VQ40DE.

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 your mileage often vary depending on the upgrades you've fitted and the condition of your engine.

Turbo modifications on the VQ40DE

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 VQ40DE.

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

If an engine is fitted with a turbocharger upgrades are going to make more power and most turbocharged engines are made with many forged and stronger components.

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

It is important to find these restrictions and fit forged components to survive the power.

We see many guys spending a loads of money on turbo upgrades on the VQ40DE only to have the motor throw a rod just after it's been enthusiastically driven.

Larger turbo chargers often suffer a bottom end lag, and small turbo chargers spool up more quickly but do not have the high rpm torque gains.

Thanks to new tech the range of turbochargers is always increasing and we commonly find variable vane turbochargers, permitting the vane angle is altered according to speed to lower lag and increase top end bhp.

Twin scroll turbochargers divert the exhaust flow into a couple of channels and feed these at differently angled vanes in the turbo. 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 and torque gains, although more complex to get working. We have this in depth look at twinchargers if you want to read more.

Tips about fuel supply on the VQ40DE

When you increase the bhp you will need to uprate to the fuel system.

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

As a rule of thumb add another 20% when fitting an injector, this allows for injector deterioration and gives a little 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 VQ40DE performance exhaust upgrades

We'd only recommend you look to improve your exhaust system with an upgraded one is if the existing exhaust is actually causing a flow problem.

On most factory exhausts you'll find the flow rate is still ok 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.

Please dont run with the widest exhaust you can buy you'll slow the exhaust rate - the best 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 are traced to the catalyst installed, so adding a faster flowing race 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 VQ40DE

Like most engines an VQ40DE, 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 VQ40DE, failure to do this will exacerbate engine wear, on a tuned VQ40DE 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 VQ40DE why not pop over to the forums at TorqueCars where you can chat about VQ40DE tuning options and read about others projects who may be planning to do similar modifications on their VQ40DE.

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