Harley-Davidson Fat Boy Gets the Supercharged Steroidal Treatment
A supercharged Harley-Davidson Fat Boy produced a stratospheric 234 horsepower and 215 lb-ft of torque.
TTS Performance looks at a stock Harley-Davidson FLSTF Fat Boy and says “Well, that’s a bit anemic.” As such, the British performance parts outfitter produces an Inferno CC supercharger system for 2017 and newer Milwaukee-Eight (M8) Softails. However, the dyno sheet might blow away your expectations for forced induction on Harley-Davidson’s M8 117 twin.
It should be said that the team at TTS Performance didn’t start from stock. Instead, the black Harley-Davidson Fat Boy’s M8 117 motor had a Screamin’ Eagle SE8-515 cam already. On top of the cam work, the Fat Boy packed a set of Screamin’ Eagle cylinder heads.
However, these are mild performance upgrades compared to TTS Performance’s Inferno CC supercharger kit. The Rotrex C30-94 counterclockwise supercharger bolts onto the shifter side of the bike, and like other supercharger units, takes up a fair amount of space.
The result? TTS Performance dyno’d the supercharged Harley-Davidson FLSTF Softail at a tire-roasting 234 horsepower. Of course, it’s not just a bump in power; it’s torque, too. The supercharged Fat Boy produced 215 lb-ft of torque at 5,300 rpm. Understandably, the builders replaced the stock clutch with a centrifugal lockup unit to handle the bike’s extra grunt.
Marked Improvement Over FactorMilwaukee-Eight 117 Power
Unsurprisingly, the supercharged M8 117 V-Twin has much more ferocity than the stock mill. In dyno testing, the factory-spec engine produced 94.2 horsepower and 118 lb-ft of torque. While that’s a hefty improvement over the twin-cam 103 engines of yesteryear, it’s a far cry from the supercharged M8.
Of course, there are concessions. A glance at the supercharger kit reveals a custom bracket to make the shifter accessible. Yes, it really is that wide. However, the Fat Boy’s thick posture isn’t exactly a corner carver. It is, however, a drag-strip-ready Softail.
Photos: TTS Performance