It’s fair to say that Harley-Davidson is pretty proud of its Milwaukee Eight V-twin engine, especially in its most potent form, the 117 cubic-inch monster reserved for only its highest echelon bikes. Indian Motorcycles just fired a shot across the bow of the Wisconsin cruiser bike juggernaut today with the official launch of the PowerPlus engine. This 108 cubic inch overhead cam watercooled heckin chonker of an engine develops a class-leading 122 horses and 128 lb-ft of torque.
The new PowerPlus is based on existing Scout architecture, cribbing the four valves per cylinder and OHC layout, but it’s obviously much larger in displacement and focused on big-piston big-torque. It develops its comparatively high in the rev range for a big twin, with power peak coming at 5500 rpm and max torque at 3800, spinning out to a 6500 rpm redline. With an 11:1 compression ratio, it’s a pretty modern engine as V-twins go.
An absolute mountain of torque isn’t a bad thing when you’re riding a bagger bike, which is where this engine will find itself soon. It was developed specifically for the new Indian Challenger fixed-fairing bagger. RideApart spied the Challenger carefully snuck into some Indian press materials last month, and it doesn’t look half bad. It’s the one in the back, behind the Scout.
“We challenge our engineers with the notion that anything less than best-in-class design and performance will simply not get it done, and it’s clear with this new engine that they have delivered on that high standard,” said Steve Menneto, Indian Motorcycle President. “Countless hours were spent in design, development and testing to ensure this is the best liquid-cooled V-twin ever developed, and I could not be prouder of our team and this incredible motor.”
“You simply cannot deliver the ultimate bagger without an engine that stands head and shoulders above anything else in its class, and that was the motivation behind the PowerPlus,” said John Callahan, Indian Motorcycle Vice President, Engineering. “We developed the most sophisticated V-twin powerplant in the industry, and then we spent month after month, hour upon hour, putting it through the most intense paces to ensure it could take whatever we threw at it. The end result is something truly special.”
According to Indian the new PowerPlus motor has already been subjected to about a million miles of simulated use dyno testing, as well as more than a quarter million miles of on-road test.
While most won’t find 122 horses from a 1.76 liter two-cylinder all that impressive [Yeah, I read the comments on my bike reviews] it’s the 128 lb-ft that really moves the needle. It’s only four more than the big Harley’s torque number, but depending on the Challenger’s final specs, it looks like it should be the right engine for the job.