Fun at the Dynamometer

Last Saturday I took the car west to Kausala, about 110 km away, where the M-B club held a dyno event. Here's a video of the numerous dyno pulls we took with my car.

The car put out 213 hp at the rear wheels at 4800 rpm and 370 Nm of torque at 3000 rpm. If you're wondering about the low amount of horsepower, note that there are numerous factors you must consider:

• Dynamometers do not put out comparable horsepower readings, each dyno will be biased one way or the other.
• Dynos do not measure horsepower, they measure among other things speed and torque. Horsepower is always calculated which means dynos will use differing formulas for getting a horsepower reading.
• Dynoing cars with wet automatic gearboxes will always result in a false reading because the torque converter distorts the torque reading.
• Performance measured at the rear wheels cannot ever be reliably compared to performance measured at the flywheel due to drivetrain loss.

This is not to say my car is "actually as good as new although the dyno says otherwise". It is old and probably tired. But a 560 SEC ECE, with 300 hp from the factory, was measured at 182 hp in the same dyno, so there you go!

You can see big clouds of blue smoke exiting the tailpipe after each pull. It sure looks scary but note that no blue smoke exits the exhaust during the power band, only on overrun. We speculated that this is typical for old M-B engines and the M117 in particular; when the engine is at the top of the revband, there is a hard vacuum inside the engine. Then you let go of the throttle and the air intake closes. The vacuum state causes some of the oil in the head to enter the combustion chamber past the valve stems. I measured the oil level when I got back home and there was no visible difference. Also my car loses no oil between oil changes.