Tuning the Vauxhall X20SED

"Comprehensive guide to tuning and performance parts on the Vauxhall X20SED engine!"

We are frequently seeing threads about the best X20SED mods that work. So let us look into Vauxhall X20SED modifications and outline the best modifications on this great engine and point out some potential pitfalls along the way.

In this article we examine X20SED tuning and point out the greatest modifications. Vauxhall X20SED are popular tuning projects and with the optimum sports modifications like remaps, turbo kits and camshafts you will greatly increase your driving enjoyment.

When talking about the ultimate parts for your X20SED engine, we are going to concentrate on the upgrades that give the biggest return for your cash.

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 bhp gains are on offer for cam upgrades.

NB: Fast road camshafts commonly raise the performance throughout the rpm band, you might lose a little bottom end bhp but your higher rpm power will be lifted.

Motorsport camshafts, raise the higher 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 torque band to your cars usage.

You will never find a X20SED Motorsport cam is a pleasure to live with when driving around busy urban areas.

Some X20SED engines respond better to less aggressive cam durations so set your engine up on a rolling road.

The ECU mapping and fuelling also will make differences on the power gains you'll achieve.

A longer valve duration can alter the power 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.

X20SED Tuning Stages

Stage 1 X20SED modifications: Remaps/piggy back ECU, Intake headers, Sports exhaust manifold, Fast road camshaft, Panel air filters, Drilled & smoothed airbox.

Stage 2 X20SED modifications: Ported and polished head, Sports catalyst & performance exhaust, high flow fuel injectors, fuel pump upgrades, Fast road cam, induction kit.

Stage 3 X20SED modifications: Internal engine upgrades (head flowing porting/bigger valves), Crank and Piston upgrades to alter compression, Adding or Upgrading forced induction (turbo/supercharger), Engine balancing & blueprinting, Competition cam, Twin charging conversions.

Remaps should help to to establish the full potential of all the upgrades you've done to your X20SED.

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

Forcing air and fuel into each cylinder is the main goal to any tuning job.

Headers carry the air from the filter and allow it to be fed into the engine cylinders.

The bore size, shape and rate of flow of the Plenum can make a substantial improvement to fuel atomisation and engine efficiency on the X20SED.

We often see intake are in desperate need of an upgrade, although some manufacturers provide fairly well optimized intake.

Larger X20SED valves, doing some X20SED port enlargement and head flowing will also lift power, the fantastic side effect is it will allow you to get a better power increase on other tuning parts.

Turbo upgrades for the X20SED

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 X20SED

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

When the engine is turbo charged tuning parts are relatively easy and you'll see that turbo charged engines are built using better components.

There are practical limits for every engine, with some being over specified and some only able to handle stock power

Research these restrictions and fit forged components to cope with the power.

We see many guys spending a lots of money on turbo upgrades on the X20SED only to have the engine catastrophically fail when it's first rolling road session.

Large upgraded turbochargers will usually suffer low end lag, and low capacity turbochargers spool up much more quickly but won't have the top end bhp gains.

Thanks to progress the world of turbo units is always developing and we now see variable vane turbo units, allowing the vane angle is altered according to speed to lower lag and increase top end performance.

Twin scroll turbo units divert the exhaust flow into 2 channels and direct these at differently designed vanes in the turbocharger. They also help the scavenging effect of the engine.

It is not unusual that there is a restriction in the air flow sensor AFM/MAP on the X20SED when a lot more air is being pulled into the engine.

We note 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor was restricting performance at a much lower level.

Adding a supercharger or additional turbo will make large bhp and torque gains, although more challenging to install. We have this article on twincharging if you want to read more.

Uprating X20SED fuel injectors

When you boost the bhp you will need to ramp up to the fuelling.

More bhp needs more fuel. It makes sense to over specify your injectors flow rate.

The accepted safe increase is to add 20% to the flow rate when specifying an injector, this accounts for injector deterioration and allows a bit of 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 X20SED performance exhausts

You may need to upgrade your exhaust if the existing exhaust is actually causing a flow problem.

On most factory exhausts you'll see your flow rate is still 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 equal out the flow of air through the engine.

But if the exhaust pipe is too big, ie: over 2.5 inches bore, you will lose a lot of the exhaust flow rate and end up losing power and torque.

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

Problems and issues to look out for on the X20SED

The X20SED engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the X20SED, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your X20SED engine please join us in our friendly forum where you can discuss tuning options in more detail with our X20SED 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 upgrades were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our X20SED 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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