Guide to BMW B58 performance tuning Mods

"BMW B58 Tuning"

The N55 engine was retired and replaced with the B58 in 2015.

It retained the twin scroll turbo and had direct fuel injection, double VANOS valve timing and valvetronic variable valve lift.

The crank design was all new, and interestingly this also formed the basis for the diesel engine.

The engine warms up quickly thanks to clever heat management and this also helps reduce emissions.

It also produces it's power quite low in the rev range, so doesn't have be driven as hard as on other engines.

We review and look at B58 tuning and point out the greatest modifications. BMW B58s are fantastic to work on and with the best performance parts you can positively enhance your driving enjoyment.

Please ignore the manufacturers claimed power figures, in the real world most B58 are making much more power, they also make a great basis for your tuning project.

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History, Power & Specs of the B58 Engine


The 355 bhp had the M performance power pack and sound kit as fitted in the M3 M4 series.

  • 2015–  322 hp at 5,500–6,500 rpm  (332 lbft) at 1,380–5,000 rpm
  • 2016–  335 hp at 5,500 rpm  (369 lbft) at 1,520–4,500 rpm
  • 2017–  335 hp at 5,500–6,500 rpm (332 lbft) at 1,380–5,200 rpm
  • 2016–  355 hp at 5,500–6,500 rpm  (369 lbft) at 1,520–4,800 rpm


  • 2018–  335 hp at 5,000–6,500 rpm  (369 lbft) at 1,600–4,500 rpm


  • 2018–  335 hp at 5,000–6,500 rpm (369 lbft) at 1,600–4,500 rpm
  • 2018–  382 hp at 5,000–6,500 rpm (369 lbft) at 1,600–4,500 rpm


  • 2019–  473 hp at 6,250 rpm 443 lbft at 2,600–5,950 rpm
  • 2019–   503 hp at 6,250 rpm 443 lbft at 2,600–5,950 rpm


  • 2020- Toyota Supra 337 HP 420 lbft *
    *(The claimed power was 335 & 365lbft  but engines seem to make much more than this when put on the dyno.)

Best B58 modifications

Just because a upgrades is popular with B58 owners it doesn't mean its worth having, instead we will highlight only those upgrades that we reckon are the best and that will give your B58 the biggest power gain return for your cash.

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

Fast road cams usually bump the power through the rev range, you could drop a little bottom end power but top end will be better.

Motorsport and race cams, bump the top end band but as a result the car will not idle smoothly and low end power nearly always suffers.

On a car used daily must carefully try to match your engines power to your usage of the car.

I'd be surprised if you have thought a Motorsport and race camshaft is a pleasure to live with when driving in heavy traffic. The low end idle will be very lumpy and irregular, so something you would notice on a track when you drive in the upper third of the rpm band, but on roads this is a serious issue and we've heard from lots of drivers lamenting their decision to add an extreme competition cam profile to their engine.

Some B58 engines respond better to more or less aggressive camshaft durations check your engine on a rolling road.

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

Altering 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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Best mods for your B58

  1. Air Induction kits and high flowing exhausts - Please note that on their own these mods will NOT ADD TORQUE in most applications, but they enable you to release power after other upgrades by freeing up a restriction.
  2. ECU Tunes - A Remapped B58 ECU provides the biggest gains in terms of your investment, aftermarket ECUs, and Tuning boxes are all alternatives.
  3. Internal engine mods - crank, pistons, conrods & compression ratio including balancing and blueprinting
  4. Turbo upgrades - Adding a turbocharger is the most significant way to improve intake air supply, ensuring you are able to combust more fuel and make power gains. Typically one of the most technically difficult upgrades you'll see massive gains.
  5. Lightened Flywheels - a lower weight flywheel will significantly improve the engines free revving nature. But not always recommended for all B58 engines.
  6. Fast road Camshafts are significant power adders, but should always be installed by someone who knows what they are doing and you might struggle to find one but we are sure you'l; find a local firm to regrind a stock camshaft for you.

B58 Tuning Stages

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

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

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

The B58 engine blocks make great tuning projects and thankfully there is an increase of mods and performance parts about.

ECU mapping should help to establish the full potential of all the parts you've fitted to your B58.

(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 parts you've done and the condition of your engine.

Getting air into your B58 is the whole point to any engine performance tuning task.

Your intake manifold will direct the air during the suck phase from the filter and allow it to be sucked into the engine and mixed with fuel.

The shape and rate of flow of the Intake manifold can make a big improvement to fuel mixing and power on the B58.

Commonly we find the air intake manifolds are needing a performance upgrade, although a few OEM provide fairly well optimized air intake manifolds.

Fitting big valve kits, doing a bit of 3 or 5 angle valve jobs and porting and head flowing will also increase torque, the fantastic side effect is it will permit a better torque increase on other mods.

B58 Turbo upgrades

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.

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 B58

When a car is fitted with a turbocharger tuning mods are more reliable and you'll see that turbocharged engines are made using better components.

However most engines will need better parts at higher power limits

Research these limits and fit more solid crank and pistons to cope with the power.

There are many guys spending a a stack of money on turbocharger upgrades on the B58 only to watch the engine throw a rod when it's been enthusiastically driven.

Big turbo chargers tend to suffer low end lag, and smaller turbo chargers spool up more quickly but won't have the peak rpm bhp gains.

We are pleased that the selection of turbochargers is always developing and we commonly find variable vane turbochargers, permitting the vane profile is altered according to speed to lower lag and increase top end performance.

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

You'll commonly see there's a limitation in the air flow sensor AFM/MAP on these engines when loads more air is being fed into the engine.

We see 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped performance at a much lower level.

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

B58 Fuelling Mods

When you lift the torque you will need to ramp up to the fuelling.

More torque needs more fuel.  We strongly recommend you to over specify your injector capacity.

The accepted safe increase is to add 20% capacity when fitting an injector, helps cope with injector deterioration and gives you some spare capacity should the engine require more fuel.

B58 Exhaust

You may need to boost your exhaust if your current exhaust is actually creating a restriction.

On most factory exhausts you should find that the exhaust flow rate quite well 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 help increase the flow of gases through the engine.

But if your exhaust is too big, ie: it's over 2.5 inches bore, you will lose a great deal of your flow rate and end up losing power and torque.

Remus exhausts make good power gains on the B58 engine

Usual exhaust restrictions come around the catalyst installed, so adding a faster flowing performance catalyst removes the restriction. We note that performance cats perform similarly to decats and have the added benefit of keeping your car street legal, as decats or catalyst removal is illegal in most territories for road going cars.

Weak spots Issues & problem areas on the B58

The B58 engines are extremely reliable and solid as long as they are regularly serviced and maintained.

Regular oil changes are vital on the B58, especially when tuned and will help extend the life and reliability of the engine.

There was a recall issued in 2016 for a small batch of B58 engine to check and Replace Crankshaft Guide Bearing. It is known to wear prematurely, and you'll get a warning light on rather than a catastrophic and costly engine failure.

If you would like to know more, or just get some friendly advice on Tuning your BMW engine please join us in our friendly forum where you can discuss B58 tuning options in more detail with our B58 owners. It would also be worth reading our unbiased BMW tuning articles to get a full grasp of the benefits and drawbacks of each modification.

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