Tuning Feature: Nissan VQ35HR Modified

"Comprehensive guide to tuning the Nissan VQ35HR engine!"

We are frequently getting messages about the best tips on VQ35HR mods that work. So let us look into Nissan VQ35HR parts and outline the best modifications on this great engine and point out some potential pitfalls along the way.

This Nissan V6 boasted many versions over it's production run and cylinder capacity ranged from two to four litres. Nissan produced a motorsport version badged as the VQ30DETT showing what this platform is capable of. Some of the 3.5 liter engines have pretty strong internals and can withstand up to 1000hp in ideal conditions, and parts from these high spec engines are often sourced and fitted into others accross the range.

Our aim here is to detail the best approach to VQ35HR tuning and point out the premier upgrades. Nissan VQ35HR are popular tuning projects and with the best tuning enhancements like a remap, turbo kits and camshafts you will positively enhance the drivers fun of your car.

When talking about the ultimate parts for your VQ35HR engine, we are going to concentrate on the parts that give the best value for money.

Significant power increases can be made on engines, and the VQ35HR is no exception, from camshaft upgrades. Altering the camshaft profile alters the intake and exhaust durations on the engine and can dramatically change the power band and power output.

NB: Fast road cams usually boost the torque across the rev range, you may lose a little low down power but your top end will improve.

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

A Motorsport cam is not great driving around busy urban areas.

You should ideally match your engines power to your preferences so for a car driven daily stick with a mild fast road VQ35HR cam

Some VQ35HR engines respond better to extreme camshaft durations check your engine on a rolling road.

The ECU mapping and injectors and fuel pump also have a large bearing on the torque gains you'll hit.

A longer valve duration 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.

VQ35HR Tuning Stages

Stage 1 VQ35HR modifications: Fast road camshaft, Remaps/piggy back ECU, Drilled & smoothed airbox, Panel air filters, Intake headers, Sports exhaust manifold.

Stage 2 VQ35HR modifications: Fast road cam, induction kit, Sports catalyst & performance exhaust, fuel pump upgrades, high flow fuel injectors, Ported and polished head.

Stage 3 VQ35HR modifications: Internal engine upgrades (head flowing porting/bigger valves), Competition cam, Crank and Piston upgrades to alter compression, Twin charging conversions, Engine balancing & blueprinting, Adding or Upgrading forced induction (turbo/supercharger).

ECU flashing helps to establish the full potential of all the mods you've done to your VQ35HR.

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

It is the whole point to any performance tuning task to get air and fuel into your VQ35HR

Headers take the air during the suck phase from the filter and allow it to be pulled into the engine cylinders with fuel for the squish phase.

The size of bore and shape and flow characteristics of the Headers can make a substantial difference to to fuel atomisation and engine efficiency on the VQ35HR.

Most intake headers are begging for motorsport parts, although some car makers provide fairly well optimized intake headers.

Increasing the VQ35HR valve size, doing a bit of port work and head flowing will also boost power, and as an added benefit will raise potential for a greater power increase on other parts.

Turbo upgrades for the VQ35HR

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 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 major power gains.

If the engine has a turbo already fitted upgrades are going to net you a larger power gain and you'll see that turbo charged engines already contain strengthened components.

There are weak spots for every engine, with some being incredibly solid and some only just able to handle stock power

See where you'll find these limits and install higher quality components to cope with the power.

There are many guys spending a lot of money on turbo upgrades on the VQ35HR only to suffer the indignity of watching the whole thing throw a rod soon after it's been enthusiastically driven.

Larger upgraded turbo units will usually suffer low end lag, and little turbo units spool up quickly but won't have the peak end torque gains.

Thanks to progress the choice of turbo units is always developing and we are seeing variable vane turbo units, allowing the vane profile is altered according to speed to lower lag and increase top end bhp.

Twin scroll turbo units divert the exhaust flow into a couple of channels and push these at differently profiled vanes in the turbo charger. They also help the scavenging effect of the engine.

It is common that there's a limitation in the air flow sensor (AFM/MAF/MAP) on the VQ35HR when a lot more air is being fed into the engine.

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

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

Uprating VQ35HR fuel injectors

Don't overlook the need to increase the fuel system when you are increasing the torque - it makes the car more thirsty. Don't forget to over specify your injector capacity.

The accepted safe increase is to add 20% capacity 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 VQ35HR performance exhausts

You may need to replace your exhaust if the existing exhaust is actually causing a restriction in flow.

On most factory exhausts you should find that the flow rate is still good 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 generally help improve air flow out of the engine but avoid an exhaust that is too big or you may end up reduce the flow rate. Stick to 1.5 to 2.5 inches as a rule of thumb.

Usual exhaust restrictions can be located in the emissions filters installed, so adding a freer flowing performance alternative will help avoid this restriction.

Problems and issues to look out for on the VQ35HR

The VQ35HR 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 VQ35HR, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your VQ35HR engine please join us in our friendly forum where you can discuss tuning options in more detail with our VQ35HR 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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We really like hearing from our readers, and hearing about which tuning mods were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our VQ35HR guides and tips are kept up to date.

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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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