Tuning the BMW S62B50

"Comprehensive guide to tuning the BMW S62B50 engine!"

Our aim here is to look into S62B50 tuning and report on the ultimate modifications for your car. BMW S62B50 make awesome project engines and with the best modified modifications like remapping, turbo kits and camshafts you will certainly enhance your driving enjoyment.

Just because particular mods are are common on S62B50 it doesn't mean its worth having, so we'll focus mods that will give your S62B50 the best power gain for you money.

The cam profile plays a big part in the engines power output so cam upgrades make quite a large difference. The intake and exhaust durations will alter depending on the chosen cam profile, so large power band gains are on offer for cam upgrades.

NB: Fast road camshafts normally increase the performance throughout the rpm range, you might lose a little low down torque but the top end will be better.

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

For a car used daily you need to optimize your engines power to your preferences.

I'd be gobsmaked if you have found a S62B50 Motorsport and race cam is a pleasure to live with when in heavy traffic.

Different S62B50 engines respond better to extreme camshaft durations check your engine on a rolling road.

The map and injectors and fuel pump also have an effect on the torque gains you'll hit.

A longer valve duration 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.

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

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

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

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

Mapping helps unlock the full potential of all the tuning mods you've fitted to your S62B50.

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 usually depend much on the tuning mods you've fitted and the condition of your engine.

Pulling more air into the S62B50 engine is vital to any engine modification project.

Air Intake manifolds flow the air during the suck phase from the filter and allow it to be drawn into the engine and mixed with fuel.

Structure and flow rate of the Intake can make a large improvement to fuel engine efficiency on the S62B50.

Many mass produced engine intake are needing motorsport parts, although a few manufacturers provide reasonably well designed intake.

Big valve conversions on the S62B50, doing some port work and head flowing will also improve power, & more importantly will make space for increasing the power increase on other upgrades.

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 S62B50

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 the engine has a turbo already fitted mods are going to make more power and turbocharged engines are built using many forged and stronger components.

However most engines have weakspots

We recommend you find these limits and fit better quality crank and pistons to utilize the power.

It's not unheard of guys spending a loads on turbo upgrades on the S62B50 only to suffer the humiliation of seeing the engine block catastrophically fail when it's first rolling road session.

Large turbochargers commonly experience no power at low rpm, and low capacity turbochargers spool up really quickly but won't have the high rpm torque gains.

Thanks to progress the range of turbos is always developing and we are seeing variable vane turbos, permitting the vane angle is altered according to speed to lower lag and increase top end bhp.

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

You'll commonly see there is a limit in the air flow sensor MAP/MAF/AFM on the S62B50 when considerably more air is being fed into the engine.

You'll see that 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor was restricting bhp at a much lower level.

Adding a supercharger or additional turbo will make large performance gains, although more complex to install. We have this in depth look at twinchargers if you want to read more.

Fuelling upgrades and mods

When you improve the performance you will need to pay attention to to the fuel delivery.

More performance needs more fuel. We would recommend you to over specify your injector capacity.

The accepted safe increase is to add 20% capacity when specifying an injector, this takes into account injector deterioration and affords you some 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

Only look to boost your exhaust if your current exhaust is actually creating a restriction.

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.

Please dont run with the largest exhaust you can source this will reduce 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 performance alternative will help avoid this restriction.

Weak spots, Issues & common problem areas on the S62B50

The S62B50 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the S62B50, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your S62B50 engine please join us in our friendly forum where you can discuss tuning options in more detail with our S62B50 owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.

History of the Engine

S62 engine is the BMW M high performance version of the M62, which was released in the E39 M5.

  • S62B50
    294 kW (394 hp)@6,600 rpm
    500 nm (369 lbft)@3,800 rpm

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