Modding uprating the Vauxhall C16NZ engine!

Tuners tips on "C16NZ Modifications"

C16NZ Modifications Guide

How to modify and upgrade the Vauxhall C16NZ

"Comprehensive guide to tuning the Vauxhall C16NZ engine!"

Our friends at TorqueCars are regularly seeing threads requesting info on how to improve the C16NZ from people wanting to know what are the things tuners recommend when it comes to C16NZ mods that work. So let us look into Vauxhall C16NZ mods and outline the best modifications on this great engine and point out some common pitfalls along the way.

Now we shall review C16NZ tuning and point out the greatest upgrades. Vauxhall C16NZ make a good tuning project and with the ultimate upgrades like a remap, turbo kits and camshafts you will maximize your driving enjoyment.

Just because particular parts are appear in lots of C16NZ projects it doesn't mean it is good, we shall focus on the optimum parts that will give your C16NZ the best power gain for you money.

Without us subscribing to the misaprehension of 'if it's shiny and makes more noise it must be good' you seem to get in many tuning magazines and on car forums'.

C16NZ induction kits

Improving air intake on the C16NZ

You need air and fuel for an engine to work. If there is insufficient fuel then it will run lean, if there is insufficient air it runs rich resulting in lost power . We'll pick up on fuelling later in this article but for now we shall look at air supply.

So Forcing air into each cylinder is the whole point to any car tuning task.

You'll commonly see there is a limitation in the air flow sensor AFM/MAF on the C16NZ when a lot 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 limited torque at a much lower level.

Intake manifolds transmit the on the suck phase from the intake filter and allow it to be fed into the engine and mixed with fuel.

The bore size, shape and flow rate of the Intake headers can make a substantial improvement to fuel atomisation on the C16NZ.

On popular production engines plenum chambers are needing aftermarket parts, although a few OEM provide reasonably well designed plenum chambers.

Fitting big valve kits, doing some port matching and head flowing will also improve bhp, and as an added benefit will allow you to get a greater bhp increase on other tuning mods.

C16NZ performance cam tips.

Different C16NZ engines respond better to different cam durations so set your engine up on a rolling road.

The ecu map and fuel pump and injectors also have an effect on the torque gains you'll hit.

Extending exhaust or intake 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.

Altering your C16NZ camshaft will make a dramatic difference to the engine engines power. Choosing a higher performance camshaft profile raises the engines power accordingly.

NB: Fast road cams normally bump the bhp over the rpm band, you may lose a little bottom end power but the high end rpm power will be better.

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

On a typical daily driver you need to optimize your power band to your preferences.

You'll never have found a C16NZ Competition cam is a pleasure to live with when driving in heavy traffic.

Stage 1, 2 and 3 mods for the C16NZ

Stage 1 C16NZ parts:

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

Stage 2 C16NZ parts:

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

Stage 3 C16NZ parts:

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

Review your options and then acquire your tuning mods and set yourself a power target to avoid wasting your time and money.

ECU mapping should help to to establish the full potential of all the mods you've done to your C16NZ.

Tuning tips and articles Engine tuning Transmission tuning Care care Intake & exhaust mods Improve handling Forums

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 your results will differs on the mods you've applied and the condition of your engine.

Turbo modifications on the C16NZ

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 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.

When your car has forced induction mods are more reliable and turbo engines will have uprated components.

However most engines have limits

Discover these restrictions and fit better quality crank and pistons to handle the power.

It's not unheard of people spending a lots of money on turbocharger upgrades on the C16NZ only to suffer the humiliation of seeing the C16NZ catastrophically fail soon after it's first rolling road session.

Large upgraded turbo units tend to suffer low end lag, and smaller turbo units spool up quickly but do not have the peak end power band gains.

Thankfully the choice of turbos is always moving on and we now see variable vane turbos, where the vane profile is altered according to speed to lower lag and increase top end performance.

Twin scroll turbos divert the exhaust flow into a couple of channels and push these at differently angled vanes in the turbo. 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 torque gains, although harder to setup. We have this article on twincharging if you want to read more.

Tips about fuel supply on the C16NZ

You will need to ensure that the engine is not starved of fuel so need to uprate the fuelling when you start going beyond 20% of a bhp hike. Don't forget to be generous with your flow rate on the injectors.

The accepted safe increase is to add 20% capacity when fitting an injector, which takes into account injector deterioration and provides a little spare capacity should the engine require 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 C16NZ performance exhaust upgrades

You may need to increase your exhaust system with an upgraded one is if the current exhaust is actually causing a restriction.

On most factory exhausts you should find that the exhaust flow rate is good 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 equal out the flow of air through the engine.

But if the exhaust pipe is too large, ie: over two and a half inches diameter, you will lose a lot of the exhaust flow rate and end up losing power and torque.

Typically exhaust restrictions are in the filters installed, so adding a faster flowing sports alternative will help avoid this restriction.

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

Faults issues and things to look out for on the C16NZ

Like most engines an C16NZ, 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 C16NZ, failure to do this will exacerbate engine wear, on a tuned C16NZ 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 C16NZ why not pop over to the forums at TorqueCars where you can chat about C16NZ tuning options and read about others projects who may be planning to do similar modifications on their C16NZ.

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