Tuning the Vauxhall Z20LER

"Comprehensive guide to tuning the Vauxhall Z20LER engine!"

We are frequently getting emails requesting information on the best Z20LER power upgrades. So let us look into Vauxhall Z20LER mods and outline the best upgrades on this great engine and point out some common pitfalls along the way.

This pages aim is outline options for your Z20LER tuning and highlight the best modifications. Vauxhall Z20LER are awesome to work on and with the right uprated tuning mods like ECU maps, turbo upgrades and camshafts you will certainly enhance your driving pleasure.

The best Z20LER tuning mods on an engine are obviously the ones that give the biggest return for your cash.

We won't be swayed by popular Z20LER tuning mods, they need to be cost effective.

The cam profile plays a big part in the engines power output so cam upgrades make quite a large difference. The intake and exhaust durations will alter depending on the chosen cam profile, so large engines power gains are on offer for cam upgrades.

NB: Fast road cams normally boost the bhp across the rev band, you might lose a little bottom end torque but high end rpm power will be higher.

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

A Competition cam makes it harder when in heavy traffic.

You should ideally match your engines power to your cars usage so for a car driven daily stick with a fast road Z20LER cam

Each engine responds better to more aggressive cam durations check your engine on a rolling road.

The engine timing and fuel pump and injectors also will say much on the torque gains you'll make.

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.

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Z20LER Tuning Stages

Stage 1 Z20LER modifications: Fast road camshaft, Panel air filters, Remaps/piggy back ECU, Intake headers, Sports exhaust manifold, Drilled & smoothed airbox.

Stage 2 Z20LER modifications: Sports catalyst & performance exhaust, fuel pump upgrades, induction kit, Ported and polished head, high flow fuel injectors, Fast road cam.

Stage 3 Z20LER modifications: Adding or Upgrading forced induction (turbo/supercharger), Competition cam, Internal engine upgrades (head flowing porting/bigger valves), Engine balancing & blueprinting, Twin charging conversions, Crank and Piston upgrades to alter compression.

A remap will help fully realize the full potential of all the modifications you've done to your Z20LER.

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 may vary depending on the modifications you've done and the condition of your engine.

It is vital to any performance tuning task to pull air into each cylinder

Intake take the air from the filter and allow it to be sucked into the engine cylinders.

Structure and flow characteristics of the Plenum can make a big effect on to fuel delivery on the Z20LER.

Commonly we find the air intake manifolds are crying out for a performance upgrade, although a few manufacturers provide reasonably good air intake manifolds.

Big valve conversions on the Z20LER, getting Z20LER port enlargement and head flowing will also boost torque, and more importantly will make space for a better torque increase on other parts.

Turbo upgrades for the Z20LER

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 Z20LER

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 an engine has a turbocharger tuning mods are relatively easy and you will discover turbo charged engines use better components.

However engines have limits

Research these restrictions and fit higher quality crank and pistons to survive the power.

We've seen people spending a loads of money on turbo charger upgrades on the Z20LER only to have the car literally blow up just after it's used in anger.

Large capacity turbochargers often suffer low end lag, and smaller turbochargers spool up quickly but don't have the peak rpm power band gains.

Over the last 20 years the market of turbo chargers is always improving and we commonly find 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 two channels and feed these at differently angled vanes in the turbo. They also boost the scavenging effect of the engine.

It is common that there is a limitation in the air flow sensor MAP/MAF/AFM on the Z20LER when a lot more air is being drawn into the engine.

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

Adding a supercharger or additional turbo will make large power gains, although harder to install. We have this in depth look at twinchargers if you want to read more.

Uprating Z20LER fuel injectors

When you improve the bhp you will need to increase to the fuel system.

More bhp needs more fuel. We strongly recommend you to be generous with your flow rate on the injectors.

The rule of thumb is to add 20% to the flow rate when fitting an injector, which takes into account injector deterioration and gives a little spare capacity should the engine need 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 Z20LER performance exhausts

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

On most factory exhausts you'll find the 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.

Do not go with the biggest exhaust you can source this will reduce the exhaust flow rate - the best for power gains are usually between 1.5 to 2.5 inches. It is the shape and material more than the bore size.

Usual exhaust restrictions are in the catalyst installed, so adding a faster flowing race alternative will help avoid this restriction.

Problems and issues to look out for on the Z20LER

The Z20LER engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the Z20LER, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your Z20LER engine please join us in our friendly forum where you can discuss tuning options in more detail with our Z20LER 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 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 Z20LER 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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