Overview
Stock power
S55 stock: 425 hp (regular), 444 hp (competition). S58 stock: 473 hp (regular), 503 hp (competition). The S58 has the headline power bump out of the crate.
Turbo design
Both engines use twin turbochargers. The S55 uses two small turbos for faster spool; the S58 uses one twin-scroll turbo per bank (two turbos total but each is a twin-scroll). The S58’s design supports higher boost and more airflow.
Block architecture
Both engines are closed-deck. The S58 added more material in the cylinder bores and a stronger lower-end design for higher cylinder pressures. The S58 is built to handle more power at the block level.
Cylinder head
S58 uses a new cylinder head with revised intake and exhaust ports, higher-flow injectors, and a redesigned valvetrain. The S55’s head was the first iteration of the B-family head adapted for high-output use; the S58’s head is the next iteration.
Common faults compared
S55: rod-bearing failure (the F80/F82 M3/M4 rod-bearing recall affected a meaningful fraction of production; the bearings could spin on early production), VANOS solenoid clogging, charge-pipe blow-off. S58: VANOS solenoid clogging (same fix as S55), no rod-bearing issues, no charge-pipe issues (metal pipe from the factory). The S58 is meaningfully more reliable.
Aftermarket
Both engines have strong aftermarket. Stage 1 tunes: S55 makes ~520 hp; S58 makes ~560 hp. Stage 2: S55 makes 600+ hp; S58 makes 650+ hp. Stage 3+: both can support 800+ hp with built internals. The S58 is the newer platform so aftermarket is still developing.
FAQ
Which is faster, S55 or S58?
S58, meaningfully. 473 hp stock vs 425 hp; 503 hp in competition vs 444 hp. The S58 also has faster turbo spool from the twin-scroll design.
Did the S55 have rod-bearing issues?
Yes. The F80 M3 and F82 M4 had a rod-bearing recall affecting certain production dates. The bearings could spin under high load. Most affected cars were repaired under warranty. The S58 doesn’t have this issue.
Is the S58 the same as the B58?
No. The S58 is a different engine with stronger internals, a different head, and higher-output turbos. The B58 is the road-car version; the S58 is the M-car version.
Which should I buy, an F80 M3 or a G80 M3?
If you can afford the G80, buy it. The S58 is the better engine: more power, more reliable, better sound, better thermal management. The F80 is the better value and the tuning community is more developed.