Modding upgrading and tuning the Vauxhall Z20LEL engine!

Tuning guide "Z20LEL Modifications"

Z20LEL Modifications Guide

How to modify and upgrade the Vauxhall Z20LEL

"Comprehensive guide to tuning and performance parts on the Vauxhall Z20LEL engine!"

TorqueCars are regularly getting messages requesting information on how to improve the Z20LEL from people inquiring about getting more power from the Z20LEL and wanting to know what are the greatest Z20LEL modifications. So let us look into Vauxhall Z20LEL parts and outline the best mods that work on this great engine and point out some problems along the way.

This pages aim is examine the options for your Z20LEL tuning and outline the greatest modifications for your car. Vauxhall Z20LEL really good project engines and with a few sensible sports upgrades like remapping, turbo improvements and camshafts you will positively improve your driving enjoyment.

When talking about the best parts for your Z20LEL engine, we are going to concentrate on the upgrades that give the best power gain for you money.

Z20LEL induction kits

Improving air intake on the Z20LEL

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

So Forcing air and fuel into your Z20LEL is vital to any engine modification task.

It is not unusual that there is a limit in the air flow sensor MAF/MAP on the Z20LEL when considerably 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 sapped bhp at a much lower level.

Headers transmit the air from the intake filter and allow it to be fed into the engine and mixed with fuel.

Structure and flow rate of the Air Intake manifolds can make a large effect on to fuel delivery on the Z20LEL.

I usually find intake headers are ripe for an upgrade, although some manufacturers provide decently flowing intake headers.

Increasing the Z20LEL valve size, doing some 3 or 5 angle valve jobs and porting and head flowing will also boost power, the fantastic side effect is it will permit an improved power increase on other tuning mods.

Z20LEL performance cam tips.

Each engine responds better to different cam durations so view each engine as unique.

The map and fuel pump and injectors also have a large bearing on the torque gains you'll make.

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.

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

NB: Fast road camshafts tend to boost the bhp and torque across the rev band, you may lose a little low down bhp but top end will be better.

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

For a car used daily you must carefully try to optimize your torque band to your preferences.

I'd be surprised if you have found a Z20LEL Competition camshaft is a pleasure to live with when driving in heavy traffic.

Stage 1, 2 and 3 mods for the Z20LEL

Stage 1 Z20LEL parts:

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

Stage 2 Z20LEL parts:

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

Stage 3 Z20LEL parts:

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

The Z20LEL engines are great to work on and we're finding that there is a growing number of mods and performance parts around.

Remaps helps to establish the full potential of all the modifications you've done to your Z20LEL.

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 power output often depend much on the modifications you've carried out and the condition of your engine.

Turbo modifications on the Z20LEL

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 Z20LEL.

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 an engine is fitted with a turbocharger mods are relatively easy and we find turbocharged engines use more solid components.

However most engines will need better parts at higher power limits

It is important to find these restrictions and install stronger pistons, crank and engine components to survive the power.

There are many tuners spending a loads on turbocharger upgrades on the Z20LEL only to watch the motor catastrophically fail on it's first outing after it's used on the roads.

Bigger turbo units commonly suffer a bottom end lag, and low capacity turbo units spool up quickly but won't have the peak rpm torque gains.

We are pleased that the selection of turbos is always increasing 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 gases into two channels and direct these at differently designed vanes in the turbo charger. 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 more challenging to get working. We have this feature on twinchargers if you want to read more.

Tips about fuel supply on the Z20LEL

When you boost the bhp and torque you will need to ramp up to the fuel system.

More bhp and torque needs more fuel. Don't forget to over specify your injector capacity.

The rule of thumb is to add another 20% when buying an injector, this allows for injector deterioration and provides you some spare capacity should the engine need 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 Z20LEL performance exhaust upgrades

You only need to to improve your exhaust system with an upgraded one is if the existing exhaust is actually creating a restriction in flow.

On most factory exhausts you'll see the flow rate is still fine 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 will certainly help air flow from the engine but avoid an exhaust that is too large or you may end up will reduce the flow rate. Stick to one and a half to two and half inches for best results.

Typically exhaust restrictions are in the emissions filters installed, so adding a freer flowing race 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 Z20LEL

Like most engines an Z20LEL, 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 Z20LEL, failure to do this will exacerbate engine wear, on a tuned Z20LEL 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 Z20LEL why not pop over to the forums at TorqueCars where you can chat about Z20LEL tuning options and read about others projects who may be planning to do similar modifications on their Z20LEL.

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