Modding uprating the BMW B58 engine!

Tuning guide "B58 Modifications"

B58 Modifications Guide

How to modify and upgrade the BMW B58

"Comprehensive guide to performance parts and tuning the BMW B58 engine!"

Popular tuning sites like TorqueCars are regularly seeing threads asking about how to improve the B58 from people wanting to know what are the premier B58 modifications. So let us look into BMW B58 mods and outline the best modifications on this great engine and point out some common pitfalls along the way.

The BMW B58 are popular engines and with carefully picked motorsport parts like ECU maps, turbo upgrades and camshafts you will certainly maximise your driving fun.

We shall outline options for your B58 tuning and report on the premier modifications.

Just because particular modifications are popular with B58 owners it doesn't mean it is good, we shall focus on the greatest modifications that will give your B58 the best power gain for you spend.

Without us subscribing to the popular mentality of 'if it's shiny and makes more noise it must be good' you seem to get in many tuning magazines and on car forums'.

B58 induction kits

Improving air intake on the B58

You need air matched to fuel for an engine to work. If there is too little fuel then it will run lean, if there is not enough air it runs rich losing power which risks damage to the B58. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So Pulling more fuel and air into your B58 is vital to any engine tuning project.

You'll commonly see there is a limit in the air flow sensor (AFM/MAF/MAP) on the B58 when loads more air is being sucked into the engine.

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

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

The size of bore and shape and rate of flow of the air Intake manifold can make a substantial difference to to fuel mixing and power on the B58.

It's not uncommon that plenum chambers are in desperate need of a performance upgrade, although a few manufacturers provide reasonably well designed plenum chambers.

Increasing the B58 valve size, carrying out port matching and head flowing will also improve performance, this will make space for a greater performance increase on other upgrades.

B58 performance cam tips.

Some B58 engines respond better to different camshaft durations check your engine on a rolling road.

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

Extending exhaust or intake 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.

Altering your B58 cam will make a dramatic difference to the engine torque. Choosing a higher performance cam profile raises the torque accordingly.

NB: Fast road camshafts normally push up the torque over the rpm band, you may lose a little bottom end power but higher rpm power will be better.

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

On a daily driver you should ideally to match your bhp range to your driving style.

I'd be surprised if you find a B58 Motorsport and race camshaft is a pleasure to live with when on the daily commute.

Stage 1, 2 and 3 mods for the B58

Stage 1 B58 parts:

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

Stage 2 B58 parts:

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

Stage 3 B58 parts:

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

The B58 engine blocks are fantastic to work on and we're happy to report there are increasing numbers of modifications and performance parts around.

ECU flashing should help to fully realize the full potential of all the tuning mods you've done to your B58.

Tuning tips and articles Engine tuning Transmission tuning Care care Intake & exhaust mods Improve handling Forums

You will typically expect to see gains of approximately 20-30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but the outcome may depend much on the tuning mods you've fitted and the condition of your engine.

Turbo modifications on the B58

To get a turbo working on a NASP engine there is a lot involved, from lowering compression ratio to improved fuel supply and mapping, so we have found a great guide to helpavoid the common pitfalls or end up with an unfinished project because you were not told what you were getting into by doing this on the B58.

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

When your car is turbocharged, upgrades are simpler to install and we find turbocharged engines will have uprated components.

However you'll find engines will need better parts at higher power limits

Research these limits and fit higher quality components to survive the power.

We see many car owners spending a lots of money on turbo upgrades on the B58 only to see the motor go up in smoke just after it's finished.

Large capacity turbochargers tend to experience no power at low rpm, and small turbochargers spool up more quickly but won't have the peak rpm engines power gains.

In recent times the selection of turbo chargers is always developing and we commonly find variable vane turbo chargers, permitting the vane profile is altered according to speed to lower lag and increase top end torque.

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

Beefing up the air intake by adding a supercharger or additional turbo will help you achieve very large torque gains, although more difficult to install. We have this guide to twinchargers if you want to read more.

Tips about fuel supply on the B58

You will need to ensure that the engine is not starved of fuel so need to increase the fuelling when you start exceeding 20% of a bhp and torque hike. It makes sense to over specify your flow rate on the injectors.

The accepted safe increase is to add 15% capacity when fitting an injector, this allows for injector deterioration and provides a bit of spare capacity should the engine require more fuel.

Don't forget that different fuel grades will usually require different settings, a high octane fuel will burn more efficiently than lower octane fuel for example. A car will trim fuel supply to keep within the ideal air fuel mix but at the extreme ends you may need to adjust your injector capacity, or the mapping or you'll get flat spots and potential lean or rich fuel issues..

Recommended B58 performance exhaust upgrades

You may need to upgrade your exhaust system with an upgraded one is if the current exhaust is creating a restriction.

On most factory exhausts you should find that the flow rate is still good even on modest power gains, but on a serious tuning project with a big boost in power you will certainly need to get a better flowing exhaust.

Please dont run with the biggest exhaust you can source you'll slow the exhaust rate - the best exhausts for power gains are usually between one and a half to two and half inches. Your exhaust design, the bend angles and construction are what have more effect on flow rates than your pipe width to a certain extent. So the exhaust design is a big factor.

Usual exhaust restrictions are traced to the emissions filters installed, so adding a better flowing race alternative will help avoid this restriction.

Decat pipes (NB:catalysts reduce harmful engine emissions) is illegal in most countries and regions.

Faults issues and things to look out for on the B58

Like most engines an B58, should have few issues if it gets properly serviced and looked after.

We cannot stress enough the need for oil changes with the correct grade of oil on the B58, failure to do this will exacerbate engine wear, on a tuned B58 this is more important than ever and close attention should be paid to your maintenance schedule.

If you are interested in learning more or getting impartial tuning advice for your B58 why not pop over to the forums at TorqueCars where you can chat about B58 tuning options and read about others projects who may be planning to do similar modifications on their B58.

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