Guide to BMW B58 performance tuning Mods

"BMW B58 Tuning"

The N55 engine was retired and replaced with the B58 in 2015. Toyota used this engine in the Supra and it is a firm favourite among tuners and enthusiasts alike, and the range of parts and upgrades just keeps on expanding.

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 to release the torque.

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

B58B30M0

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

B58B30M1

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

B58C30O1

• 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

S58B30T0

• 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
• The S58 used two turbos instead of the twinpower twinscroll unit of the B58 and was optimized to deliver power at the upper end of the RPM range.

B58B30C

• 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.

B58 Camshaft Upgrades

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.

Kelford offer a nice 270°/268° camshaft upgrades on the B58 which can help the engines breathing.

Fast road cams (a mild profile suitable for the street) usually bump the power through the rev range, you could drop a little bottom end power but top end will be much better and the power will essentially be where you need it the most.

Motorsport and race cams 288°/292°, bump the top end band but as a result the car will not idle smoothly and low end power nearly always suffers.

When fitting cams always check the valve clearance, if you are adding lift (which is the whole point) you don't want the valves colliding with the pistons.

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/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.

The map and fuel pump and injectors also will make differences on the power gains you'll get and should be setup to suit the new valve durations.

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" or mild profile 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'll 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).

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, but your end results 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.

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. As this engine was used in the Supra, there is a lot of interest in performance upgrades and mods, and the aftermarket has not disappointed.

However most engines will need better parts at higher power limits so research these limits and fit more solid crank and pistons to cope with the power on those extremely high power builds.

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 which is why BMW opted for this as it delivers power in a similar way to large NA 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're aiming to boost torque in your engine, you'll also need to adjust the fueling to achieve those higher power levels.

One effective strategy is to consider switching to a different type of fuel, such as race-spec fuels or utilizing Ethanol or even Water Methanol injection systems. These fuel choices can help you reach those elevated power figures you desire without risking ignition problems.

In the world of tuning, it's worth noting that introducing up to 10% Ethanol into your fuel mix can often help in clearing most of the timing corrections that might occur.

If you're willing to go further, pushing the Ethanol content to up to 30% can allow for a higher level of tuning, optimizing your engine's performance.

However, it's essential to acknowledge that in the UK, fuel choices can be somewhat limited, and the cost of specialized fuels can be prohibitive.

This limitation can impact your options for optimizing fuel for increased torque and power.

Increasing torque requires a straightforward equation: more torque needs more fuel.

Assuming you've managed to increase the volume of air going into your B58 engine, the next critical step is to ensure that the fuel delivery matches this demand.

In this context, the capacity of your injectors and the pattern in which they spray the fuel become equally vital factors to consider. Properly matched fuel delivery is crucial for achieving the desired power and torque gains in your engine.

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

If your current exhaust system is causing a bottleneck, it might be time to consider an upgrade.

Most stock exhaust systems manage the flow of exhaust gases reasonably well, especially when dealing with moderate power increases.

However, when you're aiming for more significant power gains, upgrading to a more efficient exhaust system becomes essential.

The concept behind performance or sports exhaust systems is to facilitate the smoother movement of exhaust gases through the engine.

In this scenario, back pressure becomes your adversary. To maximize performance, you want to maintain high exhaust gas velocity.

Interestingly, larger exhaust bore sizes can sometimes hinder this flow, creating a delicate balancing act.

In the context of BMW's B58 engine, Remus exhaust systems have gained a reputation for delivering notable power enhancements and we have had good feedback, let us know what your experiences have been with exhaust upgrades on your B58.

Their design and engineering aim to optimize exhaust flow, making them a popular choice among enthusiasts looking to boost performance.

Typically, the primary bottleneck in exhaust systems arises from the catalytic converter.

Upgrading to a high-performance catalyst that allows for faster gas flow can effectively eliminate this restriction.

It's worth noting that performance catalytic converters offer advantages similar to decatalyzers (decats), but with an important added benefit: they keep your vehicle compliant with street legal requirements.

In many regions, the removal of catalytic converters, or decatalyzing, is illegal for cars intended for road use, making performance catalytic converters a more viable and legal option.

Sadly though in some areas replacement of a working catalyst is also outlawed! Check your local regs before proceeding with this one.

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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