Undoubtedly, many of you saw the viral video swirling around social media feeds a year ago of an all-black GP-class Yamaha FZR with a turbocharged SVHO engine and open exhaust claiming to be a Suzuki Hayabusa motorcycle engine swap (which it clearly wasn’t). Unlike the fake video, we’ve seen our fair share of unusual engine swaps, from turbocharged Spark motors wedged into lightweight Krash Industries’ freeride skis to supercharged Yamaha SVHO powerplants shoehorned into turn-of-the-21st-century GPR hulls. But, the four-stroke powering this mid-2000’s Sea-Doo GTX has got to be the most unusual yet.
What you’re looking at is a Malaysian-built ’03 Sea-Doo GTX that has lost its 185-horsepower 4-tec 3-cylinder Rotax outfitted with a Toyota 4A-GE “Blacktop” 20V 4-cylinder. The engine is well-known among engine tuners as being groundbreaking in several aspects: first produced in 1995 (through 1998), the 4A-GE 20V was one of the first production 5-valve engines in history, as well as featuring four 45mm throttle bodies. Recognized by its black top, the 4A-GE employed Toyota’s Variable Valve Timing (VVT) system worth an advertised 160–165 horsepower at 7,800 rpm and 120 ft·lbs at 5,600 rpm.
Although rated at 165hp, the 1.6L, many believed the fifth-generation 4A-GE engine produced closer to 200 horsepower (naturally aspirated) due to its high compression ratio (11:1). Now the engine that has become the darling for the drift scene really doesn’t make sense in a Sea-Doo when it makes arguably the same power at the stock 4-tec, and tuned supercharged Rotax plants can crank out three or four times that kind of power, but hey, it’s Monday, so we don’t care.