Mitsubishi 6B31 Tuning

"All you need to know about performance parts and tuning the Mitsubishi 6B3 engine!"

The Mitsubishi 6B3 make awesome project engines and with the best modifications like remaps, turbo kits and camshafts you will noticeably maximize your driving enjoyment.

Here we look at 6B3 tuning and highlight the premier modifications for your car.

History, Power & Specs of the 6B3 Engine

Naturally aspirated 60° V6 3.0 L (2,998 cc)

6B31

  • 220 PS (162 kW; 217 hp) at 6250 rpm, 276 Nm (204lbft) at 4000 rpm
  • 230 PS (169 kW; 227 hp 276 Nm (204lbft) at 4000 rpm, 291 Nm (215lbft) from 2010

Tuning the Mitsubishi 6B3 and best 6B3 performance parts.

Best 6B3 mods

The ultimate 6B3 tuning mods on an engine are as we have found the ones that give the biggest return for your cash.

We won't be swayed by popular 6B3 tuning mods, they need to be cost effective.

Altering your 6B3 camshaft will make a dramatic difference to the engine power band. Choosing a higher performance camshaft profile raises the power band accordingly.

Fast road camshafts tend to bump the torque across the rev range, you may lose a little bottom end power but the higher rpm power will be lifted.

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

In a daily driver you need to match your power band to your preferences.

I'd never have found a 6B3 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.

Different 6B3 engines respond better to less aggressive cam durations so view each engine as unique.

The map and injectors and fuel pump also have a large bearing on the bhp gains you'll get.

A longer valve duration can alter the bhp 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.

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

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

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

The 6B3 engines make great tuning projects and thanks to their popularity there are increasing numbers of mods and performance parts out there.

ECU flashing will help unlock the full potential of all the modifications you've done to your 6B3.

(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 you can expect to see around 15% on NASP engines, but figures achieved usually differs on the modifications you've carried out and the condition of your engine.

Pulling air into each cylinder is the whole point to any engine upgrade project.

Intake transmit the air from the filter and allow it to be drawn into the engine cylinders.

Shape and flow rate of the Air Intake manifolds can make a noticeable difference to to fuel delivery on the 6B3.

It's not uncommon that intake are improved through performance upgrades, although some car makers provide reasonably well designed intake.

Larger 6B3 valves, getting port work and head flowing will also raise bhp and torque, and more importantly will allow you to get increasing the bhp and torque increase on other parts.

6B3 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 6B3

The more air you can 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 turbocharged, tuning parts are going to net you a larger power gain and turbocharged engines use better components.

However engines have limits.Discover these limitations and install better quality components to handle the power.

It's not unheard of car owners spending a fortune on turbo charger upgrades on the 6B3 only to see the motor throw a rod when it's been finished.

Large turbochargers will usually experience no power at low rpm, and smaller turbochargers spool up much more quickly but do not have the peak end bhp gains.

Over the last 20 years the choice of turbos is always improving and we now see variable vane turbos, where the vane profile is altered according to speed to lower lag and increase top end torque.

Twin scroll turbos divert the exhaust flow into 2 channels and feed these at differently designed vanes in the turbo charger. They also increase the scavenging effect of the engine.

It is common that there's a limitation in the air flow sensor MAF/MAP on the 6B3 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 was restricting power at a much lower level.

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

Fuelling

Don't forget to ramp up the fuel delivery when you are increasing the performance - it makes the car more thirsty. We would recommend you to be generous with your injectors flow rate.

The accepted safe increase is to add 20% when fitting an injector, this accounts for injector deterioration and gives a little 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.

6B3 Performance Exhausts

You only need to to replace your exhaust if the existing exhaust is 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.

Sports exhausts generally help improve air flow out of the engine but do not go too big or you might just stuff your flow rate and make things worse. So generally speaking, keep to a size of 1.5 to 2.5 inches for best results.

Common exhaust restrictions come around the emissions filters installed, so adding a higher 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 6B3

The 6B3 engines are generally reliable and solid 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 6B3, 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 6B3 engine please join us in our friendly forum where you can discuss 6B3 tuning options in more detail with our 6B3 owners. It would also be worth reading our unbiased Mitsubishi tuning articles to get insights into each modification and how effective they will be for your car.

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 mods work best for them on each model of car. Comments are used to improve the accuracy of these 6B3 articles which are continually updated.

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