Modding and performance tuning parts for the Nissan VH41DE engine!

Tuning guide "VH41DE Modifications"

VH41DE Modifications Guide

How to modify and upgrade the Nissan VH41DE

"Comprehensive guide to tuning the Nissan VH41DE engine!"

Sites like TorqueCars are regularly getting posts requesting information on how to improve the VH41DE from people wanting to know what are the things tuners are recommending when it comes to VH41DE modifications. So let us look into Nissan VH41DE parts and outline the best mods that work on this great engine and point out some frequent tuning mistakes along the way.

The Nissan VH41DE offer good returns when tuned and with the optimum tuning parts like ECU maps, turbo upgrades and camshafts you will dramatically maximize your driving experience.

Our aim here is to review and look at VH41DE tuning and summarise the optimum upgrades.

When talking about the best parts for your VH41DE engine, we are going to focus on the tuning mods that give the best power gain for you spend.

VH41DE induction kits

Improving air intake on the VH41DE

You need air and fuel for an engine to work. If there is not enough fuel then it will run lean, if there is not enough 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 whole point to any engine upgrade job to get air into the VH41DE engine but this has a knock on effect with the air flow sensor.

You'll commonly see there is a limitation in the air flow sensor (AFM/MAF/MAP) on the VH41DE when loads more air is being sucked 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 was restricting power at a much lower level.

Engines intake headers transmit the during the engines suck phase from the filter and allow it to be pulled into the engine cylinders.

The bore size, shape and flow rate of the Air Intake manifolds can make a substantial change to fuel engine efficiency on the VH41DE.

Many mass produced engine plenum chambers are in desperate need of aftermarket parts, although a few OEM provide reasonably well designed plenum chambers.

Adding a VH41DE larger valve kit, carrying out VH41DE port enlargement and head flowing will also improve performance, and as an added benefit will allow you to get increasing the performance increase on other upgrades.

VH41DE performance cam tips.

Some VH41DE engines respond better to different camshaft durations than others.

The ecu map and fuel pump and injectors also have a large bearing on the power gains you'll make.

Altering 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 VH41DE can be made from cam upgrades. Changing the cam profile alters the intake and exhaust durations on the engine and can dramatically change the bhp and power output.

NB: Fast road cams normally push up the bhp over the rev range, you might lose a little low down power but your higher rpm power will be lifted.

Motorsport and race cams, push up the higher rpm power 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 optimize your torque band to your usage of the car so for a typical daily driver stick with a mild fast road VH41DE camshaft

Stage 1, 2 and 3 mods for the VH41DE

Stage 1 VH41DE parts:

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

Stage 2 VH41DE parts:

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

Stage 3 VH41DE parts:

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

The VH41DE engine blocks are great to work on and thanks to their popularity there are plenty of mods and performance parts around.

Mapping allows a tuner to release the full potential of all the upgrades you've done to your VH41DE.

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 usually differs on the upgrades you've carried out and the condition of your engine.

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

Turbo modifications on the VH41DE

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 VH41DE.

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 an engine has a turbo already fitted upgrades are simpler to install and we find turbo charged engines are made with many forged and stronger components.

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

Research these limitations and upgrade to forged components to survive the power.

It's not unheard of drivers spending a a stack of money on turbo upgrades on the VH41DE only to suffer the indignity of watching the engine catastrophically fail just after it's used on the roads.

Larger capacity turbo units will usually experience low end lag, and little turbo units spool up more quickly but don't have the peak rpm power band gains.

Thanks to new tech the world of turbo units is always moving on and we are seeing variable vane turbo units, where the vane profile is altered according to speed to lower lag and increase top end performance.

Twin scroll turbo units divert the exhaust flow into 2 channels and feed these at differently profiled 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 challenging to get working. We have this article on twincharging if you want to read more.

Tips about fuel supply on the VH41DE

Don't overlook the need to look at the fuel delivery when you are increasing the bhp - it makes the car more thirsty. We would recommend you to be generous with your injector capacity.

The rule of thumb is to add 15% capacity when buying an injector, which takes into account injector deterioration and provides you 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 VH41DE performance exhaust upgrades

Only look to uprate your exhaust system with an upgraded one is if the existing exhaust is actually creating a restriction.

On most factory exhausts you'll see your 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.

Sports exhausts generally help improve air flow out of the engine but avoid an exhaust that is too wide or you could 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 filters installed, so adding a freer flowing race 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 VH41DE

Like most engines an VH41DE, 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 VH41DE, failure to do this will exacerbate engine wear, on a tuned VH41DE 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 VH41DE why not pop over to the forums at TorqueCars where you can chat about VH41DE tuning options and read about others projects who may be planning to do similar modifications on their VH41DE.

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