Tuning the Daewoo S-Tec

"Comprehensive guide to performance tuning the Daewoo S-TEC engine!"

In this article we look into S-TEC tuning and show the best modifications. Daewoo S-TEC great bases for a tuning project and with a few sensible upgrades like ECU maps, turbo kits and camshafts you will certainly maximise your driving pleasure.

Just because particular mods are popular with S-TEC owners it doesn't mean you should fit it, so we'll greatest mods that will give your S-TEC the best value for money to power increase.

Altering your S-TEC cam will make a dramatic difference to the engine torque. Choosing a higher performance cam profile raises the torque accordingly.

NB: Fast road cams tend to raise the bhp and torque across the rev band, you could sacrifice a little bottom end torque but your higher rpm power will be better.

Motorsport cams, 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 car driven daily one should, ideally, try to match your power band to your driving style.

I would be surprised if you find a S-TEC Motorsport and race cam is a pleasure to live with when in heavy traffic.

Some S-TEC engines respond better to less aggressive cam durations than others.

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

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, Remaps/piggy back ECU, Fast road camshaft, Sports exhaust manifold, Panel air filters.

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

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

Carefully think through your options and then acquire your mods and set yourself a power target to save yourself from expensive mistakes.

Remaps helps unlock the full potential of all the tuning mods you've fitted to your S-TEC.

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

Feeding more air into your S-TEC is the whole point to any engine performance tuning task.

Headers flow the air from the air cleaner and allow it to be drawn into the engine and mixed with fuel.

The size of bore and shape and rate of flow of the Headers can make a big change to fuel atomisation and engine efficiency on the S-TEC.

I usually find headers are in dire need of aftermarket tuning parts, although some manufacturers provide decently flowing headers.

Fitting big valve kits, carrying out 3 or 5 angle valve jobs and porting and head flowing will also boost torque, and importantly will raise potential for increasing the torque increase on other tuning 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 S-TEC

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.

When your car is turbo charged tuning mods are simpler to install and you'll see that turbo engines already contain many forged and stronger components.

However engines have weakspots

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

It's not unheard of people spending a fortune on turbo upgrades on the S-TEC only to suffer the humiliation of seeing the motor literally blow up when it's first rolling road session.

Larger turbo units often suffer no power at low rpm, and small turbo units spool up quickly but do not have the high rpm power band gains.

Thankfully the world of turbos is always moving on and we are seeing variable vane turbos, permitting the vane profile is altered according to speed to lower lag and increase top end bhp and torque.

Twin scroll turbos divert the exhaust flow into a couple of channels and flow these at differently angled vanes in the turbocharger. They also help the scavenging effect of the engine.

You'll commonly see there is a restriction in the air flow sensor (AFM/MAF/MAP) on the S-TEC when loads more air is being drawn into the engine.

You'll see that 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 torque gains, although more difficult to configure. We have this article covering twinchargers if you want to read more.

Fuelling upgrades and mods

Don't dismiss the need improve the fuel system when you are increasing the power - it makes the car more thirsty. Most tuners we speak with say to over specify your injector capacity.

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

Exhaust upgrades and mods

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

On most factory exhausts you'll find your flow rate is still 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 widest exhaust you can buy this will 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 traced to the filters installed, so adding a faster flowing performance alternative will help avoid this restriction.

Weak spots, Issues & common problem areas on the S-TEC

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

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

History of the Engine

The S-Tec is a collaborative engine from Suzuki and Daewoo (now part of GM) and was fitted to the Tico, Fino Matiz Kalos and Kwid.


0.8 L

(796 cc) 36 kW (49 PS 48hp @6000 rpm 71.5Nm 52.7 lbft @4000 rpm

1.0 L

(995 cc) 48.5 kW (66 PS 65hp @5400 rpm 91Nm 67 lbft @4200 rpm

1.2 L

(1,150 cc) 53 kW (72 PS 71hp @5400 rpm 104Nm 77 lbft @4400 rpm


Used in the Aveo Sail and Beat or Spark models

1.0 L

(995 cc) 50 kW (68 PS 67hp @6400 rpm 93Nm 69 lbft @4800 rpm


62 kW (84 PS; 83hp @6000 rpm 114Nm 84 lbft @3800-4400 rpm


60 kW (82 PS; 80hp @6400 rpm 111Nm 82 lbft @4800 rpm

80.5 PS 59.2 kW 79.4hp @6200 rpm 108Nm 80 lbft @4400 rpm (Gasoline)

80.04 PS 58.87 kW; 78.95hp @6400 rpm (LPG) 104 Nm (77 lbft)
@4400 rpm (LPG)


62.66 kW (85 PS; 84hp @6400 rpm 112.05Nm (82.64 lbft @6400 rpm



1.4 L (1,399 cc) 76 kW (103 PS; 102hp @6000 rpm 131Nm (97 lbft @4200 rpm


1.5 L (1,485 cc) 85 kW (116 PS; 114hp @6000 rpm 144Nm (106 lbft @3800 rpm


1.5 L (1,451 cc) T 110 kW (150 PS; 148hp @5500 rpm 230Nm (170 lbft
@2000-3800 rpm

Use in the second generation Chevrolet Sail

For more information on Tuning your S-Tec engine please join us in our friendly forum where you can discuss tuning options in more detail with our S-Tec 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 improving this article, so please send us your feedback in the comments box below and pass on any tips, points or facts we have wrong or have not covered.

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 S-Tec guides and tips are kept up to date.

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