BMW’s Iconic E39 M5 Almost Had The Unlikeliest Engine

Date:2025-08-04 00:40:44 Category:tech Views:2 Comment:0

BMW’s Iconic E39 M5 Almost Had The Unlikeliest Engine originally appeared on Autoblog.

Transitioning to V8 power for the M5 was far from a simple decision for BMW

If asked to name the most outstanding quality of BMW’s E39 M5, most fans would point to its legendary V8 engine, a high-revving beast of a power plant that cemented this M5 as one of the best sports sedans ever made.

But the E39 M5 almost never had a V8 at all. BMW North America is currently celebrating its 50th anniversary with several intriguing stories related to the company’s history, and one of these involves the two engine types considered before the E39 M5 actually got a V8.

I6 And V6 Turbos Were Considered For E39 M5

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The last M5 before the E39, the E34, used a 3.8-liter six-cylinder engine with 340 horsepower. However, it had reached its development limit, so BMW began exploring other options for use in the E34’s successor.

“We had two opportunities: a V8 or a turbocharged six-cylinder,” said the E39 M5 Project Leader, Alex Hildebrandt. At the time, the M division was led by Karlheinz Kalbfell. “We were at the end of the energy crisis in Europe, and there was some doubt about whether this kind of car would find further demand on the market,” Hildebrandt said. “Kalbfell was eager to play this card of fuel efficiency, which didn’t mean we wouldn’t have powerful engines but that the efficiency of the engines should be outstanding in comparison to the power. There was no way to come to that with a V8, because in the end, eight cylinders have to be fed. We had a lot of discussions about turbocharging, but at the time turbocharging mainly added fuel consumption and power at the upper end of the rev range, rather than torque in the middle.”

At the time, BMW was intrinsically linked to naturally-aspirated engines, so turbocharging would have been a significant step away from that. It wasn’t until 2006 that the N54 arrived, the first mass-produced turbocharged gas engine from BMW.

A turbo V6 was also proposed, which would have been even more shocking, given BMW’s preference for inline six-cylinder engines.

In the end, the V8 was decided to be the “best technical solution” for the E39 M5. The 394-horsepower S62 ended up being a masterstroke, especially paired with the involving manual gearbox.

E39 Was Perfectly Balanced, But An Even More Vicious M5 Was Coming

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Going with the V8 proved to be a great choice for the E39 M5. It could hit 60 mph in just 4.8 seconds, but this car wasn’t only superb in a straight line.

“It’s one thing to throw a V8 into a four-door sedan and make it go fast in a straight line,” said Scott Doniger, who became BMW North America’s M Brand Manager. “A heavy front end typically unbalances a sedan, but the M5 didn’t feel like a heavy sedan. The package just worked holistically, with phenomenal handling balance under acceleration or braking, and especially in cornering.”

By the time production ended in 2003, a total of 9,198 E39 M5s were sold in the USA, proving that the M5’s move away from six-cylinder power was a good one.

It was followed by the insane E60 M5, a more flawed car but one with a sensational engine. This one had a 5.0-liter V10 known as the S85, and it was inspired by BMW’s Formula 1 experience. Producing 500 hp and revving to 8,250 rpm, it again threw out the M5 rulebook. However, the E60 was let down by complex technologies and a poor reliability reputation.

Had BMW not taken the technical leap that it did with the E39 M5, it may not have been as willing to take the V10 risk with the E60.