B58 Gen 1 vs Gen 2 — What's the Difference?

If you own a B58-powered BMW, one of the first things you need to know is which generation engine you have. Gen 1 and Gen 2 B58s share the same basic architecture but have key differences that affect which parts and tunes you need.

Which One Do I Have?

B58 Gen 1 (2016–2018)

F30/F31 340i / 340i xDrive
F32/F33 440i / 440i xDrive
F36 440i Gran Coupe
G30 540i (early production, 2017–2018)
F07 640i GT

B58 Gen 2 (2019+)

G20/G21 M340i / M340i xDrive
G22/G23/G26 440i
G30 540i (2019+ production)
A90/A91 Toyota Supra 3.0
G29 Z4 M40i

The Key Differences

1. PCV System

The biggest maintenance difference. Gen 1's PCV diaphragm is a known failure point — when it goes, you'll see oil consumption, rough idle, and check engine lights. Our B58 PCV Diaphragm Replacement is our single best-selling part for a reason. Gen 2 has a more robust PCV design.

2. Cylinder Head

Gen 2 got a revised cylinder head with improved port design. Better efficiency and slightly more flow. For tuning, both respond incredibly well.

3. Intake

Different intake designs mean different aftermarket intakes. Our F-Series B58 Front Mount Intake fits Gen 1, while the G-Series B58 Front Mount Intake fits Gen 2. They're not interchangeable.

4. Spark Plugs

Both use NGK plugs. Replace every 15–20K miles if tuned, 30K if stock.

5. Turbocharger

Same basic single twin-scroll design, but Gen 2 has revised wastegate actuation. Both make 400–440 WHP reliably with bolt-ons and a tune.

Build Path — Both Gens

Stage 1 (~400 WHP)

MHD Flash Tune (requires MHD Wireless Adapter)
Upgraded spark plugs
That's it. Seriously.

Stage 2 (~440 WHP)

Everything above
RKTunes Front Mount Intake (Gen 1 or Gen 2)
Catless/high-flow downpipe
Charge pipe upgrade (Gen 1 especially — stock is known to crack)

Stage 2+ (~500+ WHP)

Everything above
Fuel pump upgrade
E85 or flex fuel
Upgraded intercooler
Custom tune from RKTunes

Bottom Line

Both gens of the B58 are incredible platforms for modification. Gen 1 needs a little more attention (PCV, charge pipe) but both make insane power for the money. Not sure which gen you have? Email us with your VIN and we'll tell you exactly what you need.