Modding uprating the Nissan VQ35HR engine!

Tuning guide "VQ35HR Modifications"

VQ35HR Modifications Guide

How to modify and upgrade the Nissan VQ35HR

"Comprehensive guide to tuning the Nissan VQ35HR engine!"

Forums like the one at TorqueCars are always getting posts requesting information on how to improve the VQ35HR from people wanting to know what are the best tips on VQ35HR modifications. So let us look into Nissan VQ35HR upgrades and outline the best upgrades on this great engine and point out some problems along the way.

Car Tuning Tips will review and look at VQ35HR tuning and outline the ultimate upgrades. Nissan VQ35HR are popular engines and with the best uprated upgrades like remaps, turbo kits and camshafts you will certainly enhance your driving pleasure.

The optimum VQ35HR tuning parts on an engine are sensibly the ones that give the best power gain for your hard earned cash.

We won't be swayed by popular VQ35HR tuning parts, they need to be cost effective.

VQ35HR induction kits

Improving air intake on the VQ35HR

You need air and fuel for an engine to work. If there is a lack of fuel then it will run lean, if there is not enough air it runs rich losing power which risks damage to the VQ35HR. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So Forcing air and fuel into your VQ35HR is vital to any engine modification job.

It is not unusual that there is a restriction in the air flow sensor AFM/MAP on the VQ35HR when considerably 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 flow the on the suck phase from the filter and allow it to be drawn into the engine and mixed with fuel.

Shape and rate of flow of the Intake headers can make a noticeable effect on to fuel delivery on the VQ35HR.

I usually find intake headers are improved through a performance upgrade, although some car makers provide decently flowing intake headers.

Fitting big valve kits, doing some port matching and head flowing will also improve bhp and torque, this will afford you an improved bhp and torque increase on other modifications.

VQ35HR performance cam tips.

Different VQ35HR engines respond better to more aggressive camshaft durations so view each engine as unique.

The engine timing and fuel pump and injectors also have a large bearing on the torque gains you'll get.

Longer valve durations 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.

Significant air intake, and exhaust improvements on the VQ35HR can be made from camshaft upgrades. Changing the camshaft profile alters the intake and exhaust durations on the engine and can dramatically change the bhp and power output.

NB: Fast road cams usually bump the torque throughout the rpm band, you may sacrifice a little low down bhp but your higher rpm power will be better.

Competition cams, bump the higher rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

On a car driven daily you must carefully try to match your power band to your preferences.

I'd be shocked if you find a VQ35HR Competition camshaft is a pleasure to live with when in heavy traffic.

Stage 1, 2 and 3 mods for the VQ35HR

Stage 1 VQ35HR parts:

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

Stage 2 VQ35HR parts:

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

Stage 3 VQ35HR parts:

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

The VQ35HR power plant respond well to mods and we note that there are increasing numbers of parts and tuning parts around.

Remapping should help to unlock the full potential of all the modifications you've done to your VQ35HR.

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 the outcome may vary depending on the modifications 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 VQ35HR

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 VQ35HR.

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 the engine has forced induction tuning mods are more reliable and most turbocharged engines are built with better components.

However you'll find engines have weakspots

Research these restrictions and fit better quality crank and pistons to cope with the power.

There are many people spending a lot of money on turbo upgrades on the VQ35HR only to experience the car literally blow up on it's first outing after it's used in anger.

Bigger turbo chargers commonly suffer no power at low rpm, and little turbo chargers spool up really quickly but do not have the peak rpm power band gains.

In recent times the choice of turbo chargers is always developing and we now see variable vane turbo chargers, permitting the vane profile is altered according to speed to lower lag and increase top end bhp.

Twin scroll turbo chargers divert the exhaust gases into a couple of channels and flow these at differently designed vanes in the turbo charger. They also improve 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 complex to setup. We have this article on twincharging if you want to read more.

Tips about fuel supply on the VQ35HR

You will need to ensure that the engine is not starved of fuel so will need to ramp up the fuelling when you start exceeding 20% of a bhp hike. Most tuners we speak with say to be generous with your injector capacity.

As a rule of thumb add 20% when fitting an injector, this accounts for 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 VQ35HR performance exhaust upgrades

The only time you should look to uprate your exhaust system with an upgraded one is if the current exhaust is actually causing a restriction.

On most factory exhausts you'll see the exhaust flow rate is 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 will certainly help air flow from the engine but avoid an exhaust that is too large 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.

Typically exhaust restrictions come around the catalyst and filters installed, so adding a faster flowing performance alternative will help avoid this restriction.

Decat pipes (NB:catalysts reduce harmful engine emissions) is illegal in most countries and regions.

Faults issues and things to look out for on the VQ35HR

Like most engines an VQ35HR, 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 VQ35HR, failure to do this will exacerbate engine wear, on a tuned VQ35HR 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 VQ35HR why not pop over to the forums at TorqueCars where you can chat about VQ35HR tuning options and read about others projects who may be planning to do similar modifications on their VQ35HR.

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