New Sea-Doo engine reaches 300 hp o’fun

Rotax 1630 ACE debuts in two performance PWC

When BRP’s Rotax engineers in Austria set out to develop a 300 horsepower engine, they didn’t simply start with a previously produced engine and update it. Instead, they started from scratch, building the new Rotax 1630 ACE engine from the ground up.

Every component went through careful consideration, making many features unique to this power plant. In fact, Martin Lachance, director of product development for Sea-Doo, said the list of new features is so long that he spent half an hour describing them to the Sea-Doo marketing team. 

Rotax 1630 ACE

The Rotax 1630 ACE, which powers the 2016 RXT-X 300, RXP-X 300 and GTX Limited 300, has new cylinder heads, new intake and new exhaust. The compression chamber was changed to improve efficiency. The new pistons were reinforced to handle the additional horsepower, and a new crankshaft was needed to handle the additional strokes.

“The first thing you’ll notice starting the engine is how smooth it is. There’s no vibration. It’s much better than the 1.5-liter that we had in the past, so it’s efficiency, but also, the results — you can feel it on the water on the machines just by starting the engine itself,” Lachance said during a walkaround of the engine at a mid-September media launch in Nashville.

In addition, the supercharger is all-new with 32 blades — twice as many as are featured in the Rotax 1503 — and a wheel that spins 8 percent faster.

“The shape of the blades and the channel around it have been optimized by computer design to offer 30 percent more boost,” Lachance explained.

Rotax also developed new ignition curves to efficiently match the increased air boost with the output of the larger fuel injectors, which drove the 15 percent increase in horsepower.

“It has almost twice the ignition discharge, better spark to the compression chamber,” Lachance said.

Of course, those weren’t the only improvements. Rotax also developed new plasma coating technology for the aluminum block engine, which is a thermal spraying process that creates a metallic layer that provides a hard and durable surface to withstand piston friction. And a much larger cooler offers 30 percent more cooling capacity.

“That’s a bunch of improvement all around to make sure that we have, again, reached the next level for Sea-Doo,” Lachance said.

Taking it for a spin

While a look at the RXP-X 300 on shore and the engine walkaround piqued the interest of the media at the Sea-Doo event, all were excited to hop aboard the craft.

As one consumer boating journalist said to me, with the RXP-X 300, you can already be going 55 mph, hit the throttle and take off like a rocket. The speed and acceleration impressed even seasoned PWC riders.

On top of the performance aspect, many also complemented the Sea-Doo staff on the ergonomics of the new units. The Ergolock seat that’s available on all 2016 RXT models allows riders to hold on to the machine better with their legs. The full Ergolock system, which includes the seat, an Adjustable Ergonomic Steering (A.E.S.) handlebar and angled footwell wedges all add to the comfort of the RXT-X 300. This system, in conjunction with the new handlebar grips with palm rest, made the 300-hp RXT-X manageable for even my almost-5-foot-2 frame.

And compliments were given on the second-generation iBR, which provides more responsive activation, reducing the stopping distance by nearly 160 feet sooner than deceleration without braking. Not that any of us wanted to stop.

Sea-Doo’s media ride included a journey through a lock on the Cumberland River as well as a stop to peek at RIVA Racing’s special edition 2016 RXP-X 350, which increases the horsepower using a redesigned aluminum RIVA/Wilson Billet Intake Manifold, a RIVA Power Filter Kit, a RIVA Cold Air Upgrade Kit and a RIVA Catch Can/Engine Breather Kit, along with a RIVA “GEN-4” Power Cooler that’s 25 percent larger than the stock intercooler. The only time journalists pouted was when they were told we could only look at the RIVA Racing RXP-X 350 and couldn’t ride it.

However, overall reaction for the new Sea-Doos was positive, as PWC journalists got amped up for the 300 horses driving the machines. Sea-Doo produced a video of media reaction and another of dealer reaction on the dealer demo days, and both can be viewed at youtube.com/seadootv. You can also catch video of me aboard the RXT-X 300 on Nashville’s Cumberland River at youtube.com/powersportsbusiness1.