Nissan VH45DE Tuning

"All you need to know about tuning the Nissan VH45DE engine!"

We were asked for more information on tuning and building a modified VH45DE and particularly which turbo upgrades work best, so we've created this article which covers our go to tuning modifications for this engine and what we feel are the optimum value tuning modifications you can do.

This pages aim is examine VH45DE tuning and point out the ultimate mods that work. Nissan VH45DE make awesome project engines and with the best modifications like ECU maps, turbo improvements and camshafts you will substantially improve your driving enjoyment.

History, Power & Specs of the VH45DE Engine

This is a large NASP V8 block which sounds fantastic and offers planet shifting levels of torque

  • 1990-1996 Infiniti Q45
    278 hp (207 kW; 282 PS), 294 lbft (399 Nm)
    With VTC the engine made around 310 bhp (231 kW; 314 PS) and 330 lbft (450 Nm)
  • 1990-2002 Nissan President
    278 hp (207 kW; 282 PS), 294 lbft (399 Nm)

The large capacity and good design is often swapped into other models, there is no replacement for displacement as they say.

Tuning the Nissan VH45DE and best VH45DE performance parts.

Best VH45DE tuning mods

The top VH45DE modifications on an engine are obviously the ones that give the best power gain for you spend.

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

Significant gains on the VH45DE can be made from cam upgrades. Altering the cam profile alters the intake and exhaust durations on the engine and can dramatically change the torque and power output.

Fast road camshafts normally raise the power across the rpm range, you might lose a little low down bhp but top end will be better.

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

A Race cam is not great in heavy traffic.

You should ideally optimize your engines power to your usage of the car so for a typical daily driver stick with a fast road VH45DE cam

Different VH45DE engines respond better to less aggressive camshaft durations than others.

The engine timing and fuelling also will make differences on the bhp gains you'll make.

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.

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Best Engine Mods for your car

  1. Engine Tunes - engine tuning/remapping provides the most advantage in terms of cost savings,  aftermarket ECUs, and piggyback ECUs are all alternatives.
  2. Fast road cams are one of the most significant mechanical changes, but they must be installed by someone who knows what they're doing and they are not always easy to source but you might find a local firm to regrind a stock camshaft.
  3. Intake and Exhaust - Note that on their own these mods will NOT ADD POWER in most cases, but they can help enhance power after other mods by removing the restriction.
  4. Upgrades to turbochargers and superchargers - forced induction is the most efficient approach to increase air supply, allowing you to burn more fuel and make more power. It is one of the most costly upgrades but provides the best gains.
  5. Head work - The goals of porting and flowing the head are to get air flowing into the engine while removing flow restrictions and turbulence.
  6. Typical stage 1 mods often include:
    Remaps/piggy back ECU, Panel air filters, Sports exhaust header/manifold, Fast road camshaft, drilled & smoothed airbox, Intake manifolds.

    Typical stage 2 mods often include:
    fuel pump upgrades, induction kit, Ported and polished head, high flow fuel injectors, Fast road cam, Sports catalyst & performance exhaust.

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

    The VH45DE power trains are fantastic to work on and we're pleased to see that there are quite a few choices of upgrades and performance parts about.

    ECU mapping allows a tuner to release the full potential of all the modifications you've done to your VH45DE.

    (In some cases, as the factory ECU is locked flashing is not an option, so an aftermarket ECU is the route to take, and many of these will outperform factory ECU's but make sure it has knock protection and that you get it setup properly.)

    It will usually give you around 30% more power on turbocharged vehicles and you can expect to see around 15% on NA (naturally aspirated) engines, but the end result usually rely on the modifications you've done and the condition of your engine.

    Getting fuel and air into each cylinder is the main goal to any car tuning task.

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

    Structure and rate of flow of the Intake can make a substantial change to fuel atomisation on the VH45DE.

    I usually find manifolds are in desperate need of performance upgrades, although some OEM provide well optimised headers.

    Increasing the VH45DE valve size, doing a bit of port work and head flowing will also boost torque, & importantly will make space for increasing the torque increase on other tuning parts.

    VH45DE Turbo upgrades

    NA (naturally aspirated) 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 superb power gains.

    When your motor is turbocharged, mods are going to net you a larger power gain and you'll see that turbo engines already contain strengthened components.

    However every engines will need better parts at higher power limits.Research these limits and install forged components to handle the power.

    We see many drivers spending a loads on turbocharger upgrades on the VH45DE only to see the whole thing explode soon after it's used in anger.

    Large capacity turbochargers commonly suffer a bottom end lag, and low capacity turbochargers spool up quickly but do not have the high rpm torque gains.

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

    Twin scroll turbo units divert the exhaust flow into 2 channels and feed these at differently designed vanes in the turbocharger. They also improve the scavenging effect of the engine.

    It is not unusual that there's a limitation in the air flow sensor AFM/MAP on the VH45DE when loads 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 power at a much lower level.

    Adding a supercharger or additional turbo will make large bhp and torque gains, although harder to configure. We have this feature on twinchargers if you want to read more.

    Fuelling

    Don't miss you'll need to uprate the fuel delivery when you are increasing the torque - it makes the car more thirsty. Most tuners we speak with say to over specify your flow rate on the injectors.

    As a rule of thumb add 20% when specifying an injector, which takes into account injector deterioration and allows a bit of 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.

    VH45DE Performance Exhausts

    You should look to improve your exhaust if your current exhaust is actually causing a restriction in flow.

    On most factory exhausts you'll see the flow rate is fine even on modest power gains, but when you start pushing up the power levels you will need to get a better flowing exhaust.

    Sports exhausts will certainly help air flow through the engine but do not go too big or you might just stuff your flow rate and make things worse. So generally speaking, keep to a size of 1.5 to 2.5 inches for best results.

    Typically exhaust restrictions can be traced to the catalyst and filters installed, so adding a freer flowing performance catalyst removes the restriction. We note that performance cats perform similarly to decats and have the added benefit of keeping your car street legal, as decats or catalyst removal is illegal in most territories for road going cars.

    Weak spots, Issues & problem areas on the VH45DE

    The VH45DE engines are generally reliable and solid units, as long as you follow the manufacturers service schedules, and use a good quality oil to ensure longevity. Few problems should happen as long as they are regularly serviced and maintained.

    Carbon build up in the head, particularly around the valves which will sap power or create flat spots, this is a larger issue on direct injection engines but should be looked out for on all engines. We have tips on removing carbon build up.

    Some of our members have had issues with flat spots or glitches after applying mods and upgrades or tuning, this is not usually related to this engines design, so instead see our article on diagnosing flat spots and problems after tuning which should help you get the bottom of this issue.

    Pre 94 models had a plastic timing chain guides, which have been known to fail and cause damage to other engine components, if replaced with the newer metal version there should be no issues.

    Regular oil changes are vital on the VH45DE, especially when tuned and will help extend the life and reliability of the engine.

    If you would like to know more, or just get some friendly advice on Tuning your VH45DE engine please join us in our car forums where you can discuss with our VH45DE owners. It would also be worth reading our unbiased articles to get a full grasp of the benefits and drawbacks of each modification.

    Please help us improve these tips by sending us your feedback in the comments box below.

    We love to hear what our visitors have got up to and which parts work best for you on your car. Which helps us keep our guides and tips up to date helping others with their modified car projects. Your feedback and comments are used to keep this page up to date, and help improve the accuracy of these VH45DE tuning guides which get regular updates and revisions.

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