Tuning the Vauxhall C16NZ

"Comprehensive guide to performance parts and tuning the Vauxhall C16NZ engine!"

We are regularly getting posts asking how to improve the C16NZ from people wanting to know what are the best tips on C16NZ modifications. So let us look into Vauxhall C16NZ parts and outline the best upgrades on this great engine and point out some problems along the way.

The Vauxhall C16NZ are fantastic to work on and with the best motorsport upgrades like ECU maps, turbo improvements and camshafts you will positively improve your driving enjoyment.

Let us look into C16NZ tuning and show the optimum modifications.

Just because particular parts are are common on C16NZ it doesn't mean you should fit it, we shall optimum parts that will give your C16NZ the biggest power gain return for your cash.

Significant gains on the C16NZ can be made 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 normally increase the bhp through the rpm band, you might lose a little low down torque but the high end rpm power will be lifted.

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

For a typical daily driver must carefully try to match your engines power to your cars usage.

I'd never have ever thought a C16NZ Race camshaft is a pleasure to live with when in heavy traffic.

Some C16NZ engines respond better to more aggressive cam durations check your engine on a rolling road.

The ecu map and fuel pump and injectors also will make differences on the torque gains you'll make.

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.

C16NZ Tuning Stages

Stage 1 C16NZ modifications: Intake headers, Panel air filters, Fast road camshaft, Drilled & smoothed airbox, Sports exhaust manifold, Remaps/piggy back ECU.

Stage 2 C16NZ modifications: induction kit, fuel pump upgrades, Sports catalyst & performance exhaust, Ported and polished head, Fast road cam, high flow fuel injectors.

Stage 3 C16NZ modifications: Adding or Upgrading forced induction (turbo/supercharger), Competition cam, Engine balancing & blueprinting, Crank and Piston upgrades to alter compression, Twin charging conversions, Internal engine upgrades (head flowing porting/bigger valves).

Plan your options and then source your tuning parts and set yourself a power target to save yourself from expensive mistakes.

A remap will help to establish the full potential of all the upgrades you've done to your C16NZ.

It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but figures achieved usually rely on the upgrades you've done and the condition of your engine.

Pulling more air into the C16NZ engine is vital to any tuning job.

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

The size of bore and shape and flow characteristics of the Intake headers can make a noticeable effect on to fuel engine efficiency on the C16NZ.

We often see intake manifold are needing an upgrade, although some car makers provide reasonably good intake manifold.

Larger C16NZ valves, doing a bit of port work and head flowing will also raise bhp and torque, and as an added benefit will make space for raising the bhp and torque increase on other upgrades.

Turbo upgrades for the C16NZ

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 C16NZ

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

If your car has forced induction modifications are going to net you a larger power gain and turbo engines are built with stronger components.

There are tuning limits for every engine, with some being extremely strong and some only just able to handle stock power

We recommend you find these restrictions and install better pistons and crank to utilize the power.

We see many people spending a lots of money on turbo upgrades on the C16NZ only to watch the motor literally blow up when it's completed.

Large upgraded turbos will usually suffer a bottom end lag, and low capacity turbos spool up much more quickly but don't have the peak rpm engines power gains.

In recent times the range of turbos is always evolving and we are seeing variable vane turbos, permitting the vane profile is altered according to speed to lower lag and increase top end performance.

Twin scroll turbos divert the exhaust gases into 2 channels and feed these at differently profiled vanes in the turbo charger. They also help the scavenging effect of the engine.

It is not unusual that there is a limitation in the air flow sensor MAP/MAF/AFM on the C16NZ when loads more air is being fed into the engine.

Going up you'll find 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor limited performance at a much lower level.

Adding a supercharger or additional turbo will make large performance gains, although more difficult to get working. We have this guide to twinchargers if you want to read more.

Uprating C16NZ fuel injectors

Don't forget to increase the fuel system when you are increasing the performance - it makes the car more thirsty. Most tuners we speak with say to over specify your flow rate on the injectors.

The accepted safe increase is to add another 20% when specifying an injector, which takes into account injector deterioration and affords you some 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 C16NZ performance exhausts

You only need to to uprate your exhaust if your current exhaust is creating a flow problem.

On most factory exhausts you'll find your 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 from the engine but do not go too wide or you may end up will reduce the flow rate. Stick to 1.5 to 2.5 inches for best results.

Usual exhaust restrictions can be located the filters installed, so adding a higher flowing sports alternative will help avoid this restriction.

Problems and issues to look out for on the C16NZ

The C16NZ engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the C16NZ, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your C16NZ engine please join us in our friendly forum where you can discuss tuning options in more detail with our C16NZ owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.

We need your help to complete and improve this page, so do give us your feedback in the comments box below.

We really like hearing from our readers, and hearing about which modifications were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our C16NZ guides and tips are kept up to date.

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