3/14/2011-A closer look at the hp king

New handling, electronic throttle and engine upgrades highlight industry’s highest horsepower PWC
Kawasaki unveiled its much-hyped Ultra 300 series to the press in February, and the boats shown were far more than existing Ultras with a small horsepower upgrade.
Certainly that power is evident; Ultras jumped out of the hole with authority, showcasing the craft’s acceleration, and hooked up even better in rough ocean conditions.
Journalists on hand at the company’s Bahamas-based intro also noted the craft’s new electronic throttle additions, including cruise control and no-wake mode. The surprising twist, however, was the Ultra series’ newfound handling ability in calm conditions.
Horsepower King … Again
Often touted as one of, if not the best high-performance machine in rough water conditions, Kawasaki’s goal with the retooled Ultra 300 series was to deliver the quickest and fastest PWC in all water conditions.
It’s a formula that starts with power. The new Ultra delivers 40 more horsepower than the previous 260X, increases torque from 177.2 ft-lbs to 201, and ups max thrust from 1,585 pounds to 1,829 pounds. At the same time the craft has dropped weight, slimming about 44 pounds off its curb weight.
The big-ticket item is a new Eaton TVS supercharger design with 17 pounds of boost. According to Kawasaki engineers, the previous design delivered power in waves, whereas the new supercharger’s twin, four-lobe rotors provide a more constant flow of air. Performance is boosted, and throttle response is smoother. Kawi says the new supercharger is 28 percent more efficient than the previous design. Boost pressure is now 17.3 psi, compared to the former model’s 11 psi.
Meanwhile, weight has stayed virtually the same. The rotor case is actually manufactured by Eaton; Kawasaki manufactures the intake/outlet manifolds, transmission and pulley. The gear set increases the supercharger’s speed by a ratio of 2.1:1. New additions that will ease maintenance include a fogging port, automatic belt tensioner and dedicated cooling lines. A dedicated intercooler discharge offers improved flushing to maintain peak performance.
Additional new performance-oriented enhancements include a O-ring sealed, nylon intake manifold, top-end engine components, exhaust system components, electronic throttle valve, and crankshaft and engine cases. Doing the math, the overall result is about 200 hp per liter at 7,750 rpm, more than an Audi S4.
Newfound Agility
Power, however, is not this boat’s entire story. “Racing to win is in Kawasaki’s DNA,” said Product Manager Croft Long, but he quickly added, “our target with the Ultra was to be the king of watercraft, and also provide the rider confident control of the most powerful PWC in the world.”
That control, as always, starts with the Ultra’s familiar 22.5-degree deadrise hull. Hull thickness has been revised to lower the craft’s weight, but the bow area has been further reinforced to increase rigidity as well as handle the added power. The most notable change, however, likely comes from a combination of upgraded driveline components. Pump diameter has been increased from 155mm to 160; the steering nozzle is both 20mm shorter than the previous design as well as features a slightly reduced outlet nozzle diameter; and a new impeller features a revised leading edge to increase hook-up and reduce cavitation. That impeller also puts more blade surface area in contact with the water. A more pronounced top-loader intake grate also promises to more effectively load the pump.
How does all that shake out on the water? In calm conditions, the Ultra no longer displays the sweeping, slightly drifting turning style of old. Instead, it hooks up like a much smaller, nimbler feeling boat. Drop the bow thanks to the craft’s new electronic trim, and the effect is even more dramatic.
Additional Features
The addition of electronic throttle also has opened the door to features like cruise control and no-wake mode. Each is activated through buttons on the right-side handgrip. A new ECO mode also promises to reduce fuel consumption, while retaining a “sporty” performance. Kawi notes a 15 percent fuel savings at 37.5 mph. I noted the boat still felt very strong, rather than tamed.
Ergonomic changes also are found on the new Ultra 300. Handlebars are now 40mm wider than the 260 models to give a rider more leverage. Seat width also is narrower by about 16mm, with a slimmer front for an improved feel when seated. A new reverse lever also features a larger, more ergonomic design to fit the hand and offers a new pivot point that seems more natural in use. Other additions include new overall lines, new windscreen and sliding-style latch on the front storage lid and easier access flush ports for both the engine and intercooler now located on the transom. The display also has been reworked and now features larger mode buttons that are easy to access.
As in the past, an Ultra 300 LX model complements the 300X. Its most unique feature is a handlebar pad that can accept popular RAM mounts for many handheld GPS models. A two-tone, bolstered seat also is more comfortable and luxurious for extended rides. The LX also ushers in Kawasaki’s first full metallic paint job.
Retail price for the 300X is $14,499; $14,999 for the LX model. PSB