Hyundai/Mitsubishi Omega / 8A8 / G8AA Tuning

"All you need to know about tuning and performance parts on the Hyundai Omega engine!"

We detail the best approach to Omega tuning and outline the optimum modifications. Hyundai Omega great bases for a tuning project and with carefully chosen upgrades like a remap, turbo upgrades and camshafts you will positively enhance your driving enjoyment.

History, Power & Specs of the Engine

The Hyundai Omega engine or G8AA (aka the 4.5D or Mitsubishi 8A8)

The engine block was cast by Hyundai and the head was produced by Mitsubishi. We love to see collaboration between car makers and have seen some impressive engines born from these partnerships.

  • 4498cc has a 10.7:1 compression ratio
  • DOHC with multiport fuel injection
  • Power output is 256 hp 260 PS @5,500 rpm  275 lbft @2,500 rpm

This engine was replaced with the Tau engine in 2008

Best Omega parts

The top tuning mods on an engine are in our opinion the ones that give the best power gain for you spend.

We won't be swayed by popular Omega tuning mods, they need to be cost effective.

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

Fast road camshafts normally bump the bhp throughout the rpm range, you might lose a little bottom end torque but the high end rpm power will be lifted.

Motorsport camshafts, bump the high end rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

On a typical daily driver you need to optimize your engines power to your preferences.

I'd be surprised if you have found a Motorsport cam is a pleasure to live with when on the daily commute, because the lumpy idle will make the car prone to stall and smooth driving at low rpm becomes impossible. If you are developing a track car this doesn't matter as you are in the high end of your RPM range anyway and that is where you want the power to be.

Some Omega engines respond better to different cam durations so set your engine up on a rolling road.

The map and fuel pump and injectors also will make differences on the torque gains you'll get.

Extending exhaust or intake durations 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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Best Engine Mods for your car

  1. Mapping - remapping provides the most advantage in terms of cost savings,  aftermarket ECUs, and piggyback ECUs are all alternatives.
  2. Fast road cams are one of the most significant mechanical changes, but they must be installed by someone who knows what they're doing and they are not always easy to source but you might find a local firm to regrind a stock camshaft.
  3. Intake and Exhaust - Note that on their own these mods will NOT ADD POWER in most cases, but they can help enhance power after other mods by removing the restriction.
  4. Upgrades to turbochargers and superchargers - forced induction is the most efficient approach to increase air supply, allowing you to burn more fuel and make more power. It is one of the most costly upgrades but provides the best gains.
  5. Head work - The goals of porting and flowing the head are to get air flowing into the engine while removing flow restrictions and turbulence.

Typical stage 1 mods often include: Sports exhaust header/manifold, Fast road camshaft, drilled & smoothed airbox, Remaps/piggy back ECU, Intake manifolds, Panel air filters.

Typical stage 2 mods often include: fuel pump upgrades, Sports catalyst & performance exhaust, induction kit, Fast road cam, Ported and polished head, high flow fuel injectors.

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

The Omega engines make great tuning projects and we see that there are increasing numbers of modifications and performance parts about.

ECU mapping should help to unlock the full potential of all the upgrades you've fitted to your Omega.

(In some cases, as the factory ECU is locked flashing is not an option, so an aftermarket ECU is the route to take, and many of these will outperform factory ECU's but make sure it has knock protection and that you get it setup properly.)

It will usually give you around 30% more power on turbocharged vehicles and 15% on NA (naturally aspirated) engines, but you mileage will vary depending on the upgrades you've done and the condition of your engine.

Forcing fuel and air into the Omega engine is the whole point to any car tuning project.

Intake manifold carry the air from the filter and allow it to be sucked into the engine and mixed with fuel.

The bore size, shape and rate of flow of the Intake manifold can make a big change to fuel atomisation and engine efficiency on the Omega.

Most intake are improved through performance upgrades, although some makers provide reasonably well designed intake.

Larger Omega valves, doing some port work and head flowing will also raise bhp and torque, the fantastic side effect is it will permit raising the bhp and torque increase on other parts.

Turbo upgrades

NA (naturally aspirated) 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 Omega

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

When an engine is fitted with a turbo mods are going to make more power and we find turbo charged engines are built with more solid components.

There are common areas of failure for every engine, with some being incredibly solid and some only able to handle stock power

Research these limitations and install stronger pistons, crank and engine components to cope with the power.

We see many car owners spending a lots of money on turbo upgrades on the Omega only to watch the Omega throw a rod on it's first outing after it's used on the roads.

Bigger turbos tend to suffer a bottom end lag, and smaller turbos spool up really quickly but won't have the peak rpm bhp gains.

In the last 10 years the range of turbo units is always developing and we commonly find variable vane turbo units, allowing the vane angle 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 profiled vanes in the turbo charger. They also increase the scavenging effect of the engine.

It is not unusual that there is a limit in the air flow sensor MAP/MAF/AFM on these engines 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 limited torque at a much lower level.

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

Fuelling

Don't miss you'll need to ramp up the fuelling when you are increasing the bhp and torque - it makes the car more thirsty. We would recommend you to over specify your flow rate on the injectors.

The accepted safe increase is to add 20% capacity when fitting an injector, this allows for injector deterioration and affords 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 58 psi of fuel pressure at idle.

These V8's do not need very big injectors, and the following chart shows how much power you can extract from each injector, although the block will need major work to get near these figures it does show that fuel delivery is not an issue and you should focus on getting more air into the engine, and improving the flow through each cylinder/exhaust.

8 Cylinder turbocharged engines

  • 58 PSI 340cc/min 400hp
  • 58 PSI 511cc/min 600hp
  • 58 PSI 682cc/min 800hp

8 Cylinder NA (naturally aspirated) engines

  • 58 PSI 285cc/min 400hp
  • 58 PSI 426cc/min 600hp
  • 58 PSI 568cc/min 800hp

Exhaust

You may need to uprate your exhaust if the existing exhaust is creating a flow problem.

On most factory exhausts you'll see the 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.

Note that with the largest exhaust you can find 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.

Typically exhaust restrictions are traced to the emissions filters installed, so adding a freer flowing race alternative such as a sports catalyst pretty much removes this restriction, thanks to it's larger size and surface area, and will effectively raise the performance to levels you would expect without having a catalyst installed, but keeps the car road legal.

Weak spots Issues & problem areas on the Omega

The Omega engines are generally reliable and solid units, as long as you follow the manufacturers service schedules, and use a good quality oil to ensure longevity. Few problems should happen as long as they are regularly serviced and maintained.

Carbon build up in the head, particularly around the valves which will sap power or create flat spots, this is a larger issue on direct injection engines but should be looked out for on all engines. We have tips on removing carbon build up.

Some of our members have had issues with flat spots or glitches after applying mods and upgrades or tuning, this is not usually related to this engines design, so instead see our article on diagnosing flat spots and problems after tuning which should help you get the bottom of this issue.

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

If you would like to know more, or just get some friendly advice 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.

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