BMW B58 3.0 Turbo I6

Старый двигатель N55 I6:

Displacement: 2979cc
Bore x Stroke: 84mm x 89.6mm
Compression Ratio: 10.2:1
Horsepower: 302-335
Torque: 332 lb-ft
Redline: 7000 rpm

Новый двигатель B58 I6:

Displacement: 2998cc
Bore x Stroke: 82mm x 94.6mm
Compression Ratio: 11.1:1
Horsepower: 320
Torque: 330 lb-ft
Redline: 7000 rpm

The difference in architecture between the B48 and N55 is greater than the N54 and N55. It has a new cylinder head design to lower carbon buildup, new intercooler, new thermostat, lighter Valvetronic, and new pumps.

While the N55 did go to a single turbo instead of the twins the N54 had it maintained the same basic geometry sharing the same bore and stroke as well as the same compression ratio. The N55 could be essentially boiled down to an N54 with one turbo and Valvetronic added in.

The B58 changes the architecture a bit going to an even more undersquare design. Less bore, more stroke. They also raised the compression ratio. 11.1:1 is definitely getting up there for a modern turbo motor even one that is direct injected. The B58 is slightly larger although this is a minor point. BMW seems to want more stroke and higher compression for low end performance and spool. The N55 is not a high revver by any means but the B58 is geared even more toward low end torque and spool. The higher compression will help with fuel efficiency as well.

 

The B-Series is going to make nice gains in the aftermarket as all the BMW factory turbo inline-6 motors do. BMS (Burger Tuning) is already at work at this. Let's take a look at their stock and Alpha Stage I tuned figures:



The stock motor through the automatic transmission puts down 331 horsepower to the wheels and 339 lb-ft of torque to the wheels. As is the BMW trend now with the turbo powerplants their crank output ratings tend to be closer to wheel output ratings. 331 to the wheels exceeds the 320 crank rating meaning this motor is closer to 400 horsepower than 320.

This is not all that different from the N54 and N55 era although the N54 started in the 275 wheel horsepower range with a crank rating of 302. BMW actually is moving more towards being conservative in their ratings.

 

Comparing the B58 F30 340i automatic to the N55 F30 335i automatic at the wheels shows a definite factory advantage for the B58:



298 wheel horsepower and 306 lb-ft of torque for the stock N55 automatic. It is underrated as well just not quite to the same degree as the B58 F30 340i.

Comparing the tuned numbers is tricky. For one, the above graph shows a flash tune. The B58 tuned numbers are from a BMS JB4 piggyback. You will see B58 tuning evolve just like the N55 and N54. Piggybacks will dominate early on and flash tuning will be more prevalent over time. Eventually, both approaches will likely be used as history shows us.

For now, the B58 is at 379 wheel horsepower and 378 lb-ft of torque on the early BMS JB4 Alpha Stage I setup. The horsepower numbers stands out in particular. BMS believes the B58 turbocharger is larger and therefore it holds its torque better toward redline which results in the better horsepower curve toward redline. It comfortably exceeds a flash tuned N55 which drops off much harder toward redline. However, the N55 shows much more peak torque down low. It is almost a 100 lb-ft of torque advantage.

The N55 should not have that large of a torque advantage down low but this is early B58 tuning once again. Look at the BMS N55 JB4 figures:

 

2016 BMW F30 340i B58 with JB4 and Methanol hits 450whp on the dyno

http://boostaddict.com/content.php?6931-JB4-B58-Methanol-Dyno-Testing-450whp

The current setup is 100% stock except for a B58 JB4 BETA, BMS intake, and a BMS B58 water/meth kit. Exhaust is fully stock. Fuel was ~93 octane and meth mixture ~80%.

 

Еще одна BMW 340 F30 (B58) и замеры на различных модификациях

Baseline Stock: 314 whp 339wtq
BMS Intake: 324 whp 335wtq
BMS Intake + VM 4" Downpipe: 344 whp 354wtq
BMS Intake + VM 4" Downpipe + Jb4 Map1: 370whp 400wtq





Хороший мотор получился

 

BMW F22 M240i automatic faster than BMW F87 M2 DCT

 

Audi RS3 2.5 TFSI vs. BMW F22 M240i B58 acceleration comparison 0-250 kph (155 mph)

 

Кстати, в Мск на стенде Dynojet полностью стоковый BMW 340 с B58 показал 327 WHP.

 

Она со старта проиграла и не успела догнать, не такая уж и большая разница в мощности, даже с учетом того, что в БМВ в стоке как раз 370 примерно. Ходом думаю бмв чуть быстрее будет.