Thin-Data Summary
The E28 M5's engine range is defined by one legendary powerplant — the M88/3 — and its North American sibling. The M88/3 3.5-litre straight-six (Europe and UK, 1984–1988) is the engine that started it all — 286 bhp, 340 Nm of torque, and a 7,000 rpm redline derived directly from the M1 supercar. It features individual throttle bodies, four valves per cylinder, and a 10.5:1 compression ratio — a genuine motorsport engine in a four-door saloon. The S38B35 (North America, 1987–1988) is essentially the same engine but with a lower 9.8:1 compression ratio and a catalytic converter, producing 256 bhp. Both engines are robust when maintained, but the M88/3 is the one that commands the highest prices and the most respect. If you're buying an E28 M5, the M88/3 is the definitive choice; the S38 is still a brilliant engine but with less power and a different character.
