4-Stroke Technology is Sea-Doo’s Redesigned GTI SE
By Captain Vince Daniello
Until this year, choosing a Sea-Doo personal watercraft meant opting for a four-stroke engine on a higher-priced model with extra features, or settling with older two-stroke technology in an “entry-level” PWC. Not so anymore, as Sea-Doo’s completely redesigned GTI SE is built with the same four-stroke Rotax 4-TEC engine as the rest of the multi-passenger watercraft, and enough standard features for hours of fun on the water.
Last year’s GTI was powered with a 2-stroke, fuel injected 110 horsepower engine, which was clean and quiet as two-strokes go, but still not as advance as Sea-Doo’s 4-stroke engines. The 2006 GTI features the same basic 4-stroke power as the rest of Sea-Doo’s boats, but in a 130 horsepower configuration. This same engine is offered in 155 horsepower, 185 horsepower, and 215 horsepower on other models. Besides the cleaner, smoother, quieter operation inherent in 4-stroke engines, Sea-Doo’s 4-TEC engine also features the only closed cooling system in the industry, which circulates antifreeze through the engine to keep it cool, rather than pumping lakewater or seawater through the motor like other PWCs. The antifreeze is kept cool by a heat exchanger built into the bottom of the hull, much the same way as the antifreeze in your car’s engine is kept cool by the radiator.
Not just a re-power, the 2006 GTI is an entirely new design from the keel up. The hull is about six inches longer and two inches wider than previous GTI models, with an 18 ½ degree “V” bottom. This is somewhat less “V” than other Sea-Doo models, providing the GTI with a little more lift for better performance from its 130 horsepower. The flatter hull also gives the rider a choice of whether to make tight turns with precision, or goose the throttle at just the right moment to allow the GTI’s back end to break free – sort of the on-the-water version of high school parking lot “doughnuts” in the days of muscle cars. Years ago, most PWCs had this ability, which has gradually been engineered out in favor of tighter turns and improved tracking, but Sea-Doo brought this fun aspect of PWC riding back – with one important difference. The PWCs of the nineties required practice to keep the boat from sliding sideways in tight turns. While test riding Sea-Doo’s new GTI SE, I found it turned on a dime every time I wanted it to, but required just a little practice and finesse to get it to slip and slide, giving consistent control for safety, yet still allowing for wet and wild fun. If there is a down side to the new hull, it’s distance cruising. The 22 ½ degree “V” hull of Sea-Doo’s other boats is better suited to cut through choppy water if the wind picks up. The GTI’s somewhat flatter hull handles a chop, just not as comfortably.
While some entry-level offerings skimp on important features, the GTI SE comes with all the essential implements for fun and convenience. Sea-Doo’s completely redesigned instrument package displays tachometer, speed, fuel, and temperature simultaneously, without the scroll button needed on previous models to switch information on the display. This is a slightly watered-down version of the new gauge packs on Sea-Doo’s higher priced boats, but still provides all the basics. The GTI SE also comes with dual mirrors, a ski-tow ring, retractable boarding step, safety gear, and other important equipment.
So how did Sea-Doo offer all the technology of their more expensive models at an entry-level price? Since the 4-stroke engine is used in just about everything Sea-Doo makes, it becomes cost effective to use it the GTI as well, according to company spokesmen. Also, the 130 horsepower version offered in the GTI doesn’t have the supercharger needed for 185 horsepower or intercooler added to boost it to 215 horsepower. Sea-Doo simplified the boat as well. For example other models have a two-piece seat with storage under the aft section. The GTI has a one piece seat with no storage beneath, although there is a large removable, watertight storage bin in the bow, and an extra deep storage compartment under the handlebars. The GTI also uses applied decals to dress it up, where other Sea-Doo’s have molded plastic and chrome trim.
The GTI SE we tested is a slight upgrade to Sea-Doo’s basic GTI. The SE includes mirrors, a boarding step, and expanded gauge pack over the standard GTI, but either version comes equipped with the 130 horsepower 4-stroke engine and closed cooling. With this new power plant, our test topped out at 53.5 mph, and accelerated from 0 to 30 mph in 2.5 seconds, not as fast as some of Sea-Doo’s other boats, but still plenty of power to carry multiple passengers or pull a skier or boarder.
Both the SE model and basic GTI also include Sea-Doo’s security system, where safety lanyards are electronically coded for each individual watercraft. Also, an additional lanyard, called a learning key, limits the boats top speed to about 35 mph and correspondingly decreases acceleration.
Off-power steering is an important safety feature on personal watercraft, which are both propelled and steered by a water jet rather than a traditional propeller and rudder. This is inherently safer when operating around people in the water, as there are no appendages beneath the hull to strike or entangle a person. But since a stream of water both propels and steers the PWC, steering control is eliminated when the engine is turned off or throttle released. To counteract this, several companies keep RPM above idle for a few moments after the throttle is released. This allows the PWC to decelerate but still pumps enough water out the stern to steer. Sea-Doo took an entirely different approach, attaching small rudders on either side of the hull at the stern to add steering both while decelerating from high speed, and while maneuvering at idle. Sea-Doo’s system, called Off Power Assisted Steering or OPAS also works whether the engine is running or not.
The personal watercraft market has become specialized, offering comfortable distance cruisers, nimble sports boats, powerful muscle craft, and even ski and wakeboard models, but I suspect most PWCs are often called upon to fill most of these roles. Sea-Doo’s newly redesigned GTI SE meets the basic needs of all, engineered with the company’s newest technology for one specific purpose: having fun on the water.