Tuning the Toyota SZ

"Comprehensive guide to tuning the Toyota SZ engine!"

This pages aim is look into SZ tuning and outline the greatest upgrades. Toyota SZ great bases for a tuning project and with the best uprated modifications like a remap, turbo kits and camshafts you will really increase your driving enjoyment.

Just because particular upgrades are appear in lots of SZ projects it doesn't mean its worth having, instead we will highlight only those upgrades that we reckon are the best and that will give your SZ the best value for money to power increase.

Altering your SZ camshaft will make a dramatic difference to the engine engines power. Choosing a higher performance camshaft profile raises the engines power accordingly.

NB: Fast road cams usually increase the bhp through the rev range, you might lose a little low end bhp but your higher rpm power will be lifted.

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

On a car driven daily must carefully try to match your bhp range to your typical driving style.

I'd be amazed if you have found a SZ Race cam is a pleasure to live with when driving in heavy traffic.

Each engine responds better to more or less aggressive camshaft durations so set your engine up on a rolling road.

The ECU mapping and fuelling also have a large bearing on the power gains you'll hit.

Extending exhaust or intake durations 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.

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

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

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

Mapping helps release the full potential of all the parts you've fitted to your SZ.

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

It is vital to any engine tuning job to get air into the SZ engine

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

Shape and flow characteristics of the Headers can make a large effect on to fuel engine efficiency on the SZ.

Many mass produced engine intake are improved through a performance upgrade, although a few makers provide well optimised intake.

Big valve conversions on the SZ, carrying out port matching and head flowing will also boost bhp, the fantastic side effect is it will give you a greater bhp increase on other parts.

Turbo upgrades

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 SZ

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

If a car is fitted with a turbocharger tuning parts are going to net you a larger power gain and turbo engines use uprated components.

However every engines will have power limits

See where you'll find these limits and fit better pistons and crank to handle the power.

We've seen tuners spending a loads on turbo charger upgrades on the SZ only to see the motor catastrophically fail soon after it's been finished.

Bigger capacity turbochargers will usually experience no power at low rpm, and low capacity turbochargers spool up quickly but do not have the peak end torque gains.

Thanks to new tech the market of turbochargers is always improving and we now see variable vane turbochargers, where the vane profile is altered according to speed to lower lag and increase top end torque.

Twin scroll turbochargers divert the exhaust flow into a couple of channels and direct these at differently angled vanes in the turbo charger. They also boost the scavenging effect of the engine.

It is common that there's a limit in the air flow sensor AFM/MAP on the SZ when considerably more air is being pulled into the engine.

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

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

Fuelling upgrades and mods

Don't omit to raise the fuel system when you are increasing the bhp - it makes the car more thirsty. It is important to be generous with your flow rate on the injectors.

The rule of thumb is to add 20% capacity when fitting an injector, this takes into account injector deterioration and affords 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.

Exhaust upgrades and mods

You may need to boost your exhaust if the current exhaust is creating a restriction.

On most factory exhausts you should find that the exhaust 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.

Do not go with the largest exhaust you can source you'll slow up the exhaust flow rate - the best exhausts for power gains are usually between 1.5 to 2.5 inches. It is the shape and material more than the bore size.

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

Weak spots, Issues & common problem areas on the SZ

The 1SZ-FE 2SZ-FE and 3SZ-FE engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the 1SZ-FE 2SZ-FE and 3SZ-FE, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

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

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.

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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 Toyota. 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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