Tuning the Toyota SZ

"All you need to know about performance parts and tuning the Toyota SZ engine!"

Carref prides itself on providing the latest tips and guides to your modification project.

Now we'll review SZ tuning and highlight the optimum mods that work. Toyota SZ are popular engines and with carefully picked motorsport mods like a remap, turbo kits and camshafts you will noticeably increase your driving experience.

We rely on our visitors to pass on tips and tell us about their projects and what worked on their car, and this article is the culmination of the feedback we have received. First let us look at the history and specs of this engine and then consider which tuning modifications work best on it.

History of the Engine

The SZ family was a joint project between Daihatsu and Toyota, and the aim was to create a compact engine that had good economy, reliability and reasonable power levels, it came in 3 generations with revised capacity each time.

1SZ-FE

1.0 L (997 cc). 16 valve straight 4 69.1 hp 70 lbft

  • Toyota Yaris
  • Toyota Echo
  • Toyota Vitz

2SZ-FE

1.3 L (1,297 cc 86 hp 90 lbft There was also a turbocharged version K3-VET

  • Toyota Yaris
  • Toyota Echo
  • Toyota Vitz
  • Toyota Belta
  • Toyota Ractis (XP100)

3SZ-VE

1.5 L 107 hp 104 lbft

  • Daihatsu Terios
  • Daihatsu Gran Max
  • Daihatsu Luxio
  • Daihatsu Sirion
  • Daihatsu Materia / Daihatsu Coo
  • Toyota bB
  • Toyota Passo Sette
  • Toyota Avanza
  • Toyota Rush
  • Perodua Alza
  • Perodua Myvi SE / Perodua Myvi Advance

Tuning the Toyota SZ and best SZ performance parts.

What are the most effective 1SZ-FE 2SZ-FE and 3SZ-FE tuning parts

The best 1SZ-FE 2SZ-FE and 3SZ-FE tuning parts on an engine are obviously the ones that give the best value for money.

We won't be swayed by popular 1SZ-FE 2SZ-FE and 3SZ-FE tuning parts, they need to be cost effective.

Significant gains on the 1SZ-FE 2SZ-FE and 3SZ-FE can be made from cam upgrades. Altering the cam profile alters the intake and exhaust durations on the engine and can dramatically change the engines power and power output.

Fast road camshafts usually raise the performance throughout the rev range, you may lose a little low down torque but the top end will be higher.

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

For a typical daily driver should ideally to match your power band to your cars usage.

I would be surprised if you find a 1SZ-FE 2SZ-FE and 3SZ-FE Race camshaft is a pleasure to live with when on the daily commute.

Some 1SZ-FE 2SZ-FE and 3SZ-FE engines respond better to mild camshaft durations than others.

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

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.

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How to tune your car

  1. Improve the handling

    Focus on Suspension improvements, such as coilovers and make sure the bushings are in good order and that the alignment is correct. Then focus on improving the brakes, with a big disk brake conversion kit and fast road brake pads.

  2. Remove restrictions

    Focus on the intake and exhaust with filters being the common point of restriction in a tuned car. Intercoolers may also become restrictive on turbo engines so this may also need to be uprated.

  3. Burn more fuel & air

    Increase the fuelling so it matches the air coming into the engine. The ratio is important so you need to improve the fuel pump and injectors, so the head mods, big valve conversions, fast road camshafts and forced induction upgrades extra supply of air is adequately met.

  4. Test and replace any weak parts

    Weak areas are commonly the clutch, the turbocharger and pistons and crankshaft in a highly tuned engine. Makes sure these components will cope with your power aspirations.

  5. The Tune or Remap

    A cars ECU controls the fuel, timing, spark and even the turbo in some cases, so to fully extract your gains you should remap the car last and this will fully release the power. Some cars are easy to map, and others require piggyback ECU's or aftermarket ECU's but this is the most vital step of your tuning project.

Modifying to Stage 1:

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

Modifying to Stage 2:

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

Modifying to Stage 3:

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

Plan your options and then acquire your parts and set yourself a power target to save yourself from expensive mistakes.

Remaps allows a tuner to release the full potential of all the upgrades you've done to your 1SZ-FE 2SZ-FE and 3SZ-FE.

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

It is the aim to any tuning task to feed more air into each cylinder

Air Intake manifolds transmit the air from the intake filter and allow it to be fed into the engine cylinders with fuel for the squish phase.

Design and flow characteristics of the Headers can make a large effect on to fuel engine efficiency on the 1SZ-FE 2SZ-FE and 3SZ-FE.

I usually find plenum chambers are needing aftermarket parts, although a few car makers provide decently flowing plenum chambers.

Increasing the 1SZ-FE 2SZ-FE and 3SZ-FE valve size, doing a bit of port work and head flowing will also boost bhp, and as an added benefit will raise potential for increasing the bhp increase on other mods.

Which turbo upgrades are best?

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 1SZ-FE 2SZ-FE and 3SZ-FE

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 your motor is turbo charged mods are more reliable and you will discover turbo charged engines are made with uprated components.

However engines will have power limits

See where you'll find these restrictions and upgrade to higher quality components to utilize the power.

We've seen guys spending a a stack of money on turbo charger upgrades on the 1SZ-FE 2SZ-FE and 3SZ-FE only to see the engine block throw a rod on it's first outing after it's been enthusiastically driven.

Larger upgraded turbos tend to experience no power at low rpm, and smaller turbos spool up quickly but don't have the peak rpm bhp gains.

In the last 10 years the range of turbochargers is always evolving and we now see variable vane turbochargers, permitting the vane profile is altered according to speed to lower lag and increase top end bhp and torque.

Twin scroll turbochargers divert the exhaust gases into 2 channels and feed these at differently designed vanes in the turbocharger. They also increase the scavenging effect of the engine.

It is common that there's a limit in the air flow sensor (AFM/MAF/MAP) on the 1SZ-FE 2SZ-FE and 3SZ-FE when considerably 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 sapped bhp at a much lower level.

Adding a supercharger or additional turbo will make large bhp and torque gains, although more challenging to get working. We have this feature on twinchargers if you want to read more.

Fuelling

Don't dismiss the need raise the fuelling when you are increasing the bhp - it makes the car more thirsty. When it comes to your injectors capacity and flow rate you need some spare capacity, so don't calculate which injector and fuel pump setup will match your needs exactly or you'll have flat spots and fuelling issues and problems.

The rule of thumb is to add 20% when fitting an injector, this allows for injector deterioration and gives a bit of 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.

All the following flywheel power targets will assume an injector duty cycle of 80% and a base of 58psi of fuel pressure at idle.

4 Cylinder turbocharged engines

  • 58 PSI 340cc/min 200hp

4 Cylinder NASP engines

  • 58 PSI 285cc/min 200hp

Choosing the right performance exhaust

One of the most common mistakes and problems we see in tuning projects is usually down to the exhaust, or rather a poorly chosen exhaust for your engine.

You may need to improve your exhaust if the current exhaust is actually creating a flow problem.

On most factory exhausts you'll see your flow rate is still ok even on modest power gains, but when you start pushing up the power levels you will need to get a better flowing exhaust.

Note that with the widest exhaust you can source you'll slow up 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 traced to the emissions filters installed, so adding a higher flowing sports alternative will help avoid this restriction.

Weak spots, Issues & problem areas on the 1SZ-FE 2SZ-FE and 3SZ-FE

The 1SZ-FE 2SZ-FE and 3SZ-FE engines are generally reliable and solid as long as they are regularly serviced and maintained.

Regular oil changes are vital on the 1SZ-FE 2SZ-FE and 3SZ-FE, especially when tuned and will help extend the life and reliability of the engine.

For more information on Tuning your 1SZ-FE 2SZ-FE and 3SZ-FE engine please join us in our friendly forum where you can discuss tuning options in more detail with our 1SZ-FE 2SZ-FE and 3SZ-FE owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.

Please help us improve these tips by sending us your feedback in the comments box below.

We love to hear what our visitors have got up to and which parts work best for them on each model of car. Comments are used to improve the accuracy of these

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