BMW B58 Six Cylinder Turbocharged Engines

BMW B58 engine in an F30 340i

B58 in an F30 340i.

Chronology

The B58 is part of BMW's modular engine series of three, four and six cylinder units with common technologies and production tooling. This six cylinder version was launched in autumn 2015 on the F30 340i. It also powers the new G11 740i. I'm sure it'll make it's way onto the X5/X6 and five series in 2016.

BMW B58 three litre turbo engine

B58 three litre turbo.

Design

The modular engine series use the technologies you'd imagine in this generation, but it also has a few radical tricks up it's sleeves.

As expected it has all alloy construction, four valves per cylinder, one coil per cylinder, Valvetronic (new generation), direct fuel injection and dual VANOS.

Unlike the smaller versions the six has no need for balancer shafts. There are two water pumps, one mechanical and one electric.

The B58 has an 11.0:1 compression ratio and runs a fairly high 1.8 bar of boost (around 26psi). The intake manifold also serves as a large water / air intercooler, this shorter intake tract should improve throttle response.

The single turbo is a twin scroll unit with it's own dedicated coolant pump. Three cylinders feed each scroll, one set to get it up to speed quickly and reduce lag, the other set to provide torque and give a good boost pressure. Its wastegate is electronically activated and its dedicated water pump can run after the engine is turned off to cool it slowly. A built in turbo timer, nice.

As seem common practice with modern BMW engines the single row timing chain is at the back of the engine, this makes access very difficult in the unlikely event it becomes a problem. The oil pump is chain driven (as usual) and also at the back of the engine. It has it's own chain tensioner and guides and also incorporates a vacuum pump! This is needed as Valvetronic engines don't generate a vacuum in the intake manifold, previous Valvetronic engines had a dedicated vacuum pump. The oil filter is much larger than the older engines but is harder to access. The high pressure fuel pump is now driven from the camshaft and not by the timing chain.

There are three acoustic covers in addition to the top cover, these also provide thermal insulation which helps the engine warm up faster and retain heat once turned off.

BMW B58 engine showing split timing chain with idler

B58 showing unusual split timing chain with idler.

Variants

Code Size Power
bhp@rpm
Torque
lb/ft@rpm
BHP/
litre
Torque/
litre
Made Bore x
Stroke
Timing Weight
(kg)
VANOS Used in
B58 3.0 322 @ 5500-6500 330 @ 1380-5000 107 110 2015 on 82x94.6 Chain ? Dual +
Valvetronic
F30 340i
G11 740i

 

BMW B58 engine in an F30 340i

B58 in an F30 340i.

Problems

As they're direct injection they may build up deposits on the intake valves which must be manually cleaned. Most modern engines suffer from this problem, not just BMWs. The head on this engine has been designed with the goal of reducing the problem compared to the previous model.

Many owners will have these engines remapped for more power. That's OK so long as it's done properly on a rolling road and not taken too far. Avoid any cheap and nasty modifications.

Clean oil is vital to the life of a turbo engine. As these engines have extended oil change intervals it's vital the correct long life oil is used. It's expensive so beware of cheap substitutes. Now more than ever the service history matters when buying used cars. Personally I'd change the oil before the recommended interval as I think it's too long.