A few years ago, we tested all the basic bolt-ons in this E39 BMW M5, which included Evosport pulleys, a full engine-back Supersprint exhaust system and Powerchip/Evosport software. Because there wasn't a good intake system available at the time, we swapped a pair of performance drop-in filters. The car turned into a rocket and registered over 377 wheel-hp on a Dynojet 248C dyno.
Advanced Flow Engineering has recently released its intake system for the M5. Since it's been a while and we'd be testing on a different dyno at Tuning Technologies, we established a new baseline. Additionally, in order to find the intake's true gains, we reinstalled stock filter elements, ordered from Bavarian Autosport-a great source for factory BMW maintenance and aftermarket performance parts, including this AFE intake system.
Peak wheel-hp: 358.5 @ 6500 rpm
Peak wheel-trq: 330 lb-ft @ 4650 rpm
Transmission: Six-speed manual
Testing octane: 91
Supersprint 100-cell metallic catalysts
Supersprint crossover pipe
Supersprint cat-back exhaust
Dyno Type: Dynojet 424x
Temperature: 60 degrees F
Location: Tuning Technologies, Colton, California
Transmission Test Gear: Fourth
On its initial pull, the ABS system sent out a failure warning, limiting runs to 5000 rpm before the rev limiter kicked in. Prior experience of this vehicle reminded us to pull the two ABS fuses (#17 and #30), which did the trick. Throughout this dyno session, oil and water temperatures were kept to 200 and 190 degrees F respectively, and the air intake temperature to 90 degrees.