Sea-Doo's GTX 4-TEC Supercharged Shows Off Her Raw Power

Tested by Capt. Vince Daniello

The basic principle behind a turbocharger or a supercharger is the same: force as much air into the cylinders as possible. Just like fanning a fire in a fireplace, the more air, the hotter the fire for more efficient fuel burn and greater power. In general terms, a turbocharger uses a fan mounted in the exhaust to turn another fan that forces air into the cylinders, with no direct connection between the engine and the turbo. Turbos are typically lighter than superchargers, and don’t require any of the engine’s horsepower to turn the fans. (A turbocharger effectively captures the energy of the exhaust gas, which would otherwise be wasted out the tail pipe.)

While turbos are great for producing mid and high-end power, they require the engine to produce sufficient exhaust pressure before working effectively. (You have to put wood in the fireplace and wait for it to catch on fire before getting any heat.) The fuel goes into the engine, produces exhaust, then the turbo provides the air required to burn the fuel most effectively. This split-second delay is called turbo lag, and is the reason some turbocharged engines give a puff of smoke when accelerating. A supercharger, on the other hand, is connected directly to the engine, typically off the camshaft. While this steals a bit of horsepower at top end, the supercharger’s effect is immediate, providing enough air to burn all the fuel the moment the throttle is opened. For this reason, superchargers are preferred for immediate, push-you-back-in-the-seat acceleration, particularly when starting from slow speed.

With a 1494 cc, 185 horsepower 4-stroke engine, Sea-Doo’s Supercharged GTX 4-TEC is, according to the manufacturer, the most powerful personal watercraft on the market.

Performance

With the lesson in basic engine design over, let me explain what this means to Sea-Doo’s new supercharged personal watercraft: quick response and raw power. While this is not the fastest PWC in Sea-Doo’s lineup, she's a big, powerful boat that jumps every time you kick the throttle, like the muscle cars of the seventies.

Features

The supercharged model includes the features of her sister, the GTX 4-TEC, such as a four-cycle engine with closed cooling system, multi-function LCD display, and Sea- Doo’s learning key which limits acceleration and top end speed for less experienced riders. O.P.A.S. (Off Power Assisted Steering), a clever system that deploys small rudders on the sides of the stern, adds some directional control at very slow speeds. (Directional control is a relative thing; the system works well but was never actually intended to provide “steering”. It simply adds some control to what would otherwise be an uncontrolled slow spin.) At high speed, water pressure lifts the O.P.A.S. rudders up and out of the way.

I really enjoyed testing this boat. With her huge, supercharged engine, I had a lot of fun accelerating out of tight turns and making quick hole-shots. Sea-Doo’s Supercharged GTX 4-TEC is sure to please even the most power-hungry personal watercraft rider.

• Top speed for the Sea-Doo GTX 4-TEC Supercharged is 60.0 mph (N/A kph), burning gallons per hour (gph) or N/A liters per hour (lph).


• Time to plane for the Sea-Doo GTX 4-TEC Supercharged is ~ seconds.


• Time from 0 to 30 of the Sea-Doo GTX 4-TEC Supercharged is 3.3 sec. seconds.