Tuning the Hyundai Smartstream

"Building the best modified Hyundai Smartstream engine!"

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

We shall examine the options for your Smartstream tuning and outline the best mods that work.

A Hyundai Smartstream  engine provides a fun base for your project and with carefully chosen performance parts like a remap, turbo improvements and camshafts you will dramatically maximize 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 Smartstream was released in 2018 and comes as a straight 4/6 and V6 configuration and turbocharged versions were also produced, thanks to a lower compression ratio, and updating fuelling and mapping.

  • Smartstream G1.6 121 hp
    Hyundai Venue (2019–present)
  • Smartstream G1.6T 178 hp
    Hyundai Sonata (2019–present)
    Kia Optima/Kia K5 (DL3) (2019–present)
  • Smartstream G2.0 158 hp *(hybrid = 192hp)
    Hyundai Sonata (2019–present)
    Kia Optima/Kia K5 (DL3) (2019–present)
  • Smartstream G2.5 177hp
    Hyundai Azera (2019-present)
    Hyundai Sonata (2019–present)
    Kia Optima/Kia K5 (DL3) (2019–present)
  • Smartstream G2.5T 300hp
    Genesis GV80 (2020–present)
  • Smartstream G3.5T 375hp
    Genesis GV80 (2020–present)
  • Smartstream D3.0 274hp
    Genesis GV80 (2020–present)

What are the most effective Smartstream tuning mods

When talking about the best best for your Smartstream engine, we are going to focus on the tuning parts that give the best power gain for you spend.

Significant gains on the Smartstream can be made from camshaft upgrades. Altering the camshaft profile alters the intake and exhaust durations on the engine and can dramatically change the engines power and power output.

Fast road camshafts tend to raise the bhp across the rev band, you could sacrifice a little low down bhp but the top end will be lifted.

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.

A Motorsport and race cam won't do well if on the daily commute.

You should ideally match your engines power to your usage of the car so for a road car stick with a fast road Smartstream cam

Different Smartstream engines respond better to more aggressive camshaft durations so view each engine as unique.

The map and fuelling also have a large bearing on the power gains you'll make.

Longer valve 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.

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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:

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

Modifying to Stage 2:

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

Modifying to Stage 3:

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

Careful think through then find your modifications and set yourself a power target to avoid disappointment.

ECU flashing should help to release the full potential of all the parts you've done to your Smartstream.

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 vary depending on the parts you've fitted and the condition of your engine.

It is vital to any engine performance tuning job to shove more air and fuel into each cylinder

Intake manifold flow the air during the suck phase from the air cleaner and allow it to be sucked into the engine cylinders with fuel for the squish phase.

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

Commonly we find the intake headers are ripe for a performance upgrade, although a few makers provide well optimised intake headers.

Fitting big valve kits, getting port matching and head flowing will also increase performance, this will allow you to get raising the performance increase on other modifications.

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 Smartstream

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

When an engine is fitted with a turbocharger parts are going to make more power and turbo charged engines are built with strengthened components.

There are practical limits for every engine, with some being very over engineered and some just sufficiently able to handle stock power

Research these limits and fit stronger pistons, crank and engine components to survive the power.

There are many car owners spending a lot of money on turbocharger upgrades on the Smartstream only to see the engine block throw a rod when it's been finished.

Big turbo units often suffer no power at low rpm, and low capacity turbo units spool up really quickly but won't have the top end bhp gains.

We are pleased that the market of turbo units is always evolving and we commonly find variable vane turbo units, where the vane profile is altered according to speed to lower lag and increase top end torque.

Twin scroll turbo units divert the exhaust flow into two channels and direct these at differently angled vanes in the turbo charger. They also increase the scavenging effect of the engine.

You'll commonly see there is a restriction in the air flow sensor (AFM/MAF/MAP) on these engines when loads 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 power at a much lower level.

Adding a supercharger or additional turbo will make large performance gains, although more challenging to configure. We have a twincharger performance adding guide if you want to read more.

Fuelling

Don't dismiss the need increase the fuel delivery when you are increasing the torque - it makes the car more thirsty. It is important to over specify your flow rate on the injectors.

The rule of thumb is to add another 20% when buying an injector, this 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.

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

We'll illustrate on the 4 cylinder engines how you need to match flow with power. The 6 cylinders will need less cc as each injector is only providing 1/6th of the fuel.

4 Cylinder turbocharged engines

  • 58 PSI 340cc/min 200hp
  • 58 PSI 511cc/min 300hp
  • 58 PSI 682cc/min 400hp

4 Cylinder NASP engines

  • 58 PSI 285cc/min 200hp
  • 58 PSI 426cc/min 300hp

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 upgrade your exhaust if the current exhaust is actually creating a restriction in flow.

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 can usually air flow through the engine but avoid an exhaust that is too big or you may end up will reduce the flow rate. Stick to 1.5 to 2.5 inches as a rule of thumb.

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

Weak spots Issues & problem areas on the

The engines are generally reliable and solid as long as they are regularly serviced and maintained.

Regular oil changes are vital on the , especially when tuned and will help extend the life and reliability of the engine.

For more information on Tuning your engine please join us in our friendly forum where you can discuss tuning options in more detail with our 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 articles which are continually updated.

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