Tuning Feature: Nissan VH45DE Modified

"Comprehensive guide to tuning the Nissan VH45DE engine!"

We often are getting posts requesting info on the best VH45DE upgrades. So let us look into Nissan VH45DE mods and outline the best mods that work on this great engine and point out some common pitfalls along the way.

Our aim here is to examine the options for your VH45DE tuning and outline the best modifications for your car. Nissan VH45DE are good project engines and with the optimum tuning upgrades like a remap, turbo improvements and camshafts you will noticeably improve the drivers experience of your car.

The greatest VH45DE upgrades on an engine are in our opinion the ones that give the best power gain for you spend.

We won't be swayed by popular VH45DE upgrades, they need to be cost effective.

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

NB: Fast road camshafts usually boost the power across the rev range, you may lose a little bottom end torque but top end will be lifted.

Competition camshafts, boost 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 will just annoy you whilst in heavy traffic.

You should ideally match your engines power to your cars usage so for a typical daily driver stick with a mild fast road VH45DE camshaft

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 will say much on the bhp gains you'll hit.

Extending exhaust or intake 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.

VH45DE Tuning Stages

Stage 1 VH45DE modifications: Intake headers, Panel air filters, Sports exhaust manifold, Remaps/piggy back ECU, Drilled & smoothed airbox, Fast road camshaft.

Stage 2 VH45DE modifications: Fast road cam, fuel pump upgrades, induction kit, Sports catalyst & performance exhaust, high flow fuel injectors, Ported and polished head.

Stage 3 VH45DE modifications: Crank and Piston upgrades to alter compression, Competition cam, Internal engine upgrades (head flowing porting/bigger valves), Adding or Upgrading forced induction (turbo/supercharger), Twin charging conversions, Engine balancing & blueprinting.

Remaps helps unlock the full potential of all the parts you've done to your VH45DE.

It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but the end result may differs on the parts you've applied and the condition of your engine.

Pushing air into your VH45DE is the aim to any tuning task.

Intake headers flow the air during the suck phase from the air filter and allow it to be drawn into the engine cylinders with fuel for the squish phase.

Shape and rate of flow of the Intake headers can make a substantial effect on to fuel delivery on the VH45DE.

I usually find intake headers are in desperate need of an upgrade, although some makers provide reasonably well designed intake headers.

Increasing the VH45DE valve size, carrying out 3 or 5 angle valve jobs and porting and head flowing will also increase torque, and importantly will afford you increasing the torque increase on other upgrades.

Turbo upgrades for the VH45DE

NASP engines need quite a lot of work when you add a turbo, so we have a separate guide to help you take into account the pros and cons of going this route on your VH45DE

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

When your car has a turbo already fitted tuning parts are more reliable and you'll see that turbo charged engines will have stronger components.

However you will find an engines have limits

See where you'll find these restrictions and upgrade to better pistons and crank to utilize the power.

We see many drivers spending a lots of money on turbocharger upgrades on the VH45DE only to see the car catastrophically fail on it's first outing after it's used on the roads.

Large capacity turbos often suffer a bottom end lag, and smaller turbos spool up more quickly but don't have the peak end power band gains.

Thanks to progress the selection of turbo units is always moving on and we commonly find variable vane turbo units, allowing the vane angle is altered according to speed to lower lag and increase top end bhp.

Twin scroll turbo units divert the exhaust gases into two channels and flow these at differently designed vanes in the turbo. They also increase the scavenging effect of the engine.

You'll commonly see there's a limit in the air flow sensor MAF/MAP on the VH45DE when considerably more air is being drawn into the engine.

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

Adding a supercharger or additional turbo will make large bhp and torque gains, although more complex to get working. We have this article covering twinchargers if you want to read more.

Uprating VH45DE fuel injectors

You will need to ensure that the engine is not starved of fuel so need to increase the fuelling when you start exceeding 20% of a bhp and torque increase.We strongly recommend you to over specify your injectors flow rate.

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.

We think this one is common sense, but you'll need to match your fuel injector to the type of fuel your car uses as well.

Best VH45DE performance exhausts

You may need to improve your exhaust 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 when you start pushing up the power levels you will need to get a better flowing exhaust.

Please dont run with the largest exhaust you can source you'll reduce the exhaust flow rate - the best exhausts for power gains are usually between 1.5 to 2.5 inches. It is the shape and material more than the bore size.

Usual exhaust restrictions are in the catalyst installed, so adding a better flowing high performance alternative will help avoid this restriction.

Problems and issues to look out for on the VH45DE

The VH45DE engines, if regularly serviced and maintained, are generally very reliable and have few issues. {But if neglected they can cost a small fortune|When neglected they get very expensive to run|They can however be quite expensive if neglected| }

Regular oil changes are vital on the VH45DE, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your VH45DE engine please join us in our friendly forum where you can discuss tuning options in more detail with our VH45DE owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.

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This article is flagged for an update, so please pass on specific tips below that I can include. All articles, and content was written by me, Waynne Smith TorqueCars founder. Some outlines are just too general so I appreciate your feedback and suggestions. This entry was filed under Nissan. You can leave a response below or join our forum to discuss this article and car modification in detail with our members.

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