Modding uprating the Nissan VQ37VHR engine!

Everything You Need To Know About "VQ37VHR Modifications"

How to modify and upgrade the Nissan VQ37VHR

"Comprehensive guide to tuning and performance parts on the Nissan VQ37VHR engine!"

Sites like TorqueCars are regularly getting messages asking about how to improve the VQ37VHR from people wanting to know what are the best tips for VQ37VHR mods that work. So let us look into Nissan VQ37VHR modifications and outline the best modifications on this great engine and point out some frequent tuning mistakes along the way.

The Nissan VQ37VHR provide a fun base for your project and with the optimum uprated tuning mods like a remap, turbo kits and camshafts you will noticeably maximize your driving fun.

In this article we examine the options for your VQ37VHR tuning and provide tips on the ultimate modifications.

Just because particular mods are are common on VQ37VHR it doesn't mean its worth having, so we'll concentrate on the best mods that will give your VQ37VHR the best value for money to power increase.

Without us subscribing to the popular 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'.

VQ37VHR induction kits

Improving air intake on the VQ37VHR

You need fuel and air for an engine to work. If there is not enough fuel then it will run lean, if there is too little 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 primary aim to any engine modification job to push fuel and air into your VQ37VHR but this has a knock on effect with the air flow sensor.

It is common that there is a restriction in the air flow sensor (AFM/MAF/MAP) on the VQ37VHR when loads more air is being fed 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.

Air Intake manifolds take the during the engines suck phase from the intake filter and allow it to be fed into the engine cylinders.

The bore size, shape and flow rate of the Plenum can make a large effect on to fuel atomisation and engine efficiency on the VQ37VHR.

Commonly we find the intake manifold are needing aftermarket parts, although some car makers provide well optimised intake manifold.

Increasing the VQ37VHR valve size, carrying out port matching and head flowing will also raise performance, & more importantly will raise potential for a greater performance increase on other upgrades.

VQ37VHR performance cam tips.

Some VQ37VHR engines respond better to mild cam durations so set your engine up on a rolling road.

The ECU mapping and fuelling also have an effect on the power gains you'll make.

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.

Significant air intake, and exhaust improvements on the VQ37VHR can be made from cam upgrades. Changing the cam profile alters the intake and exhaust durations on the engine and can dramatically change the torque and power output.

NB: Fast road cams usually increase the performance across the rev range, you might lose a little low end bhp but your top end will be better.

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

A Competition cam is not great driving in heavy traffic.

You should ideally match your torque band to your cars usage so for a car driven daily stick with a shorter duration VQ37VHR cam

Stage 1, 2 and 3 mods for the VQ37VHR

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 VQ37VHR parts:

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

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

Stage 2 VQ37VHR parts:

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

Stage 3 VQ37VHR parts:

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

The VQ37VHR power trains respond well to upgrades and we're happy to report there is an increase of modifications and tuning parts about.

ECU mapping helps release the full potential of all the upgrades you've done to your VQ37VHR.

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 rely on the upgrades you've fitted and the condition of your engine.

Turbo modifications on the VQ37VHR

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 VQ37VHR.

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 your motor has forced induction upgrades are going to make more power and you will discover turbo charged engines will have strengthened components.

There are tuning limits for every engine, with some being very over engineered and some just sufficiently able to handle stock power

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

There are many guys spending a loads on turbo charger upgrades on the VQ37VHR only to suffer the humiliation of seeing the whole thing literally blow up on it's first outing after it's used on the roads.

Big capacity turbo chargers will usually suffer no power at low rpm, and low capacity turbo chargers spool up quickly but don't have the peak end torque gains.

Over the last 20 years the selection of turbos is always evolving and we now see variable vane turbos, allowing the vane angle is altered according to speed to lower lag and increase top end performance.

Twin scroll turbos divert the exhaust gases into a couple of channels and feed these at differently angled vanes in the turbo charger. 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 torque gains, although more difficult to setup. We have this guide to twinchargers if you want to read more.

Tips about fuel supply on the VQ37VHR

When you raise the bhp you will need to pay attention to to the fuelling.

More bhp needs more fuel. Care modifiers usually say to over specify your injector capacity.

As a rule of thumb add 20% to the flow rate when fitting an injector, which takes into account injector deterioration and provides a bit of 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 VQ37VHR performance exhaust upgrades

You only need to to replace your exhaust system with an upgraded one is if the existing exhaust is creating a restriction.

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.

Sports exhausts can usually air flow through the engine but do not go too wide or you may end up 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 located the emissions filters installed, so adding a faster 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 VQ37VHR

Like most engines an VQ37VHR, 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 VQ37VHR, failure to do this will exacerbate engine wear, on a tuned VQ37VHR 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 VQ37VHR why not pop over to the forums at TorqueCars where you can chat about VQ37VHR tuning options and read about others projects who may be planning to do similar modifications on their VQ37VHR.

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

We want to know your experiences with modifications on your VQ37VHR, it helps us improve our tips and keeps us current so please use the comments box to drop a tip.

If you liked this page please share it with your friends, drop a link to it in your favourite forum or use the bookmarking options to save it to your social media profile.

Check out TorqueCars new YouTube channel, and see their awesome new content...


Please use our forums if you wish to ask a tuning question, and please note we do not sell parts or services, we are just an online magazine.

Help us improve, leave a suggestion or tip

Your Constructive comments on this article