Unlike the previous 6.5-liter V-12 car we tested, the S65 AMG, the Black Series' transmission will remain faithfully in whatever gear you select, so we were able to measure its output from just over idle all the way to redline. We did the test in fourth gear, and the resulting increase in the length of the dyno test meant the turbos had a bit longer to spool up. That resulted in 715 lb-ft @ 3400 rpm, but any benefit was eliminated at the top of the rev range, when the additional friction of the rear wheels-spinning at 190 mph-caused a slight drop in wheel horsepower.
Last year's S65 AMG, which is rated at 612 hp and the same 738 lb-ft of torque, put down 36 fewer horsepower and 61 less lb-ft of torque. [Click here for that story.]While it seems that the peak numbers aren't much higher-especially on a percentage basis-the Black Series' bigger turbos make an enormous difference at the top of the rev range. Indeed this is where output matters most-flat out, low-end torque is irrelevant once you're moving along in first gear.
The comparison chart (below) clearly shows massive gains at high rpms. Nearing 5500 rpm, where the S65's turbos were all out of steam and the transmission forced a shift, the Black Series engine puts out more than 100 hp and 100 lb-ft more than the S65's did.
So no matter what the 0-60 numbers look like for the SL65 AMG Black Series, remember that they're more a function of grip than power. The dyno doesn't lie-the lucky few who can afford a Black Series are getting a V-12 with a much broader power band than those who settle for the regular 604-hp SL65 AMG. Those poor souls.
Click the link below for video of the SL65 AMG Black Series' gauges during the run.