The BMW M3 E92 holds a special place in M’s lanes. It’s the only 3-er to get a V8, and with a red line well north of 8,000 rpm, it’s a humdinger to wring out. When everything is perfect, the naturally aspirated mill generates 414 horsepower (309 kilowatts) in the original version. The 2010 M3 shown here is indeed original, but at 152,000 miles it’s not exactly new.
How will this mileage affect the V8 power strip? Things like this always depend on maintenance, and judging by what we see in this torque video from Evolve Automotive, it looks well maintained. However, the group has considerable experience with the M3 V8, and it felt a bit flat on a test drive. A few passes on the bench confirmed that the BMW was a little out of power. Not bad, but with a healthy engine making 414 ponies at the crankshaft, the crankshaft only succeeds 398 once the calculations are done.
But wait, there is more.
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This time around, we’re not just witnessing a high-performance, high-mileage car that gets tested on a test bench. Evolve Automotive delves into engine parameters, showing just how smart modern systems and diagnostic equipment can be. For all intents and purposes, the engine was running fine. But data from those tests showed that the M3’s computer was pulling the ignition timing to the upper end of the rev range. Delaying the ignition timing causes the spark plugs to ignite later, which may be safer for the engine but also reduces horsepower.
Apparently, on the M3 V8, frequent spark plug changes are required to keep the car at peak power. The spark plugs in this engine only had about 30,000 miles of use according to the video, but of course after changing them the missing power came back. A series of dynamometer shots with new spark plugs showed the ignition timing had almost returned to factory specifications at high revs, and power increased to 411 hp (306 kW) at the crankshaft. It’s close enough to call this high mileage motor like New.
Changing the spark plugs every 30,000 miles can be a pain, but on high performance engines, such maintenance can indeed make a big difference.