Tuning the Vauxhall C20NE

"Comprehensive guide to performance tuning the Vauxhall C20NE engine!"

We are always seeing threads asking how to improve the C20NE from people wanting to know what are the things we are recommending when it comes to C20NE modifications. So let us look into Vauxhall C20NE upgrades and outline the best mods that work on this great engine and point out some frequent tuning mistakes along the way.

Now we will examine the options for your C20NE tuning and summarise the optimum modifications for your car. Vauxhall C20NE are popular engines and with a few sensible modified modifications like a remap, turbo upgrades and camshafts you will definitely maximize your driving enjoyment.

Just because particular parts are appear in lots of C20NE projects it doesn't mean you should fit it, we will recommend only what we regard as the greatest parts that will give your C20NE the best value for money to power increase.

Significant gains on the C20NE 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 push up the bhp and torque throughout the rpm band, you might lose a little bottom end power but the high end rpm power will be higher.

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

A Race camshaft won't do well if driving around busy urban areas.

You should ideally optimize your power band to your driving style so for a car driven daily stick with a fast road C20NE camshaft

Some C20NE engines respond better to more or less aggressive cam durations than others.

The ECU mapping and fuel pump and injectors also have an effect on the bhp gains you'll achieve.

A longer valve duration 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.

C20NE Tuning Stages

Stage 1 C20NE modifications: Remaps/piggy back ECU, Intake headers, Sports exhaust manifold, Panel air filters, Fast road camshaft, Drilled & smoothed airbox.

Stage 2 C20NE modifications: induction kit, high flow fuel injectors, Ported and polished head, Sports catalyst & performance exhaust, fuel pump upgrades, Fast road cam.

Stage 3 C20NE modifications: Internal engine upgrades (head flowing porting/bigger valves), Engine balancing & blueprinting, Twin charging conversions, Crank and Piston upgrades to alter compression, Adding or Upgrading forced induction (turbo/supercharger), Competition cam.

Remaps allows a tuner to to establish the full potential of all the upgrades you've done to your C20NE.

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

It is vital to any engine upgrade job to force air into the C20NE engine

The intake plenum take the air during the suck phase from the air cleaner and allow it to be pulled into the engine and mixed with fuel.

Design and flow characteristics of the Intake manifold can make a large improvement to fuel atomisation and engine efficiency on the C20NE.

We often see intake headers are in dire need of aftermarket tuning parts, although some makers provide fairly well optimized intake headers.

Fitting big valve kits, doing some port matching and head flowing will also raise bhp and torque, and as an added benefit will give you a greater bhp and torque increase on other parts.

Turbo upgrades for the C20NE

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 C20NE

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

If the engine is turbocharged, tuning mods are giving better power gains and you will discover turbo engines are made with stronger components.

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

It is important to find these limitations and upgrade to forged components to survive the power.

There are many people spending a a stack of money on turbocharger upgrades on the C20NE only to experience the engine throw a rod just after it's completed.

Bigger turbo units often experience low end lag, and low capacity turbo units spool up quickly but won't have the top end engines power gains.

We are pleased that the choice of turbo units is always developing and we commonly find variable vane turbo units, allowing the vane angle is altered according to speed to lower lag and increase top end bhp.

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

You'll commonly see there's a restriction in the air flow sensor AFM/MAP on the C20NE when considerably more air is being sucked into the engine.

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

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

Uprating C20NE fuel injectors

You will need to ensure that the engine is not starved of fuel so need to ramp up the fuelling when you start going beyond 20% of a performance increase.Most tuners we speak with say to over specify your flow rate on the injectors.

The rule of thumb is to add 20% when specifying an injector, which takes into account injector deterioration and provides 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 C20NE performance exhausts

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

On most factory exhausts you'll see the flow rate is 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 will certainly help air flow from the engine but avoid an exhaust that is too wide or you may end up will reduce the flow rate. Stick to 1.5 to 2.5 inches for best results.

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

Problems and issues to look out for on the C20NE

The C20NE engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the C20NE, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your C20NE engine please join us in our friendly forum where you can discuss tuning options in more detail with our C20NE 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 parts were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our C20NE 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 Vauxhall. 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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