In the mechanical side, the main difference from Golf is the engine: the American Jetta employs a larger, 2.5-litre inline-5 engine. It is not the previous V5 (the costly engine died together with W8), but a new engine said to be loosely based on Lamborghini Gallardo's V10. Pardon? the V10 produces 500 horsepower, but the inline-5 only 150 hp. Can you believe? not me. Some said they share the same cylinder head (well, maybe before machined, i.e., that piece of aluminum alloy). Some said they share the same 82.5mm bore and 92.8mm stroke (well, this only implies they are built with the same tooling). The point is, the Lamborghini V10 has an aluminum block with dry sump lubrication, VVT in all camshafts, 2-stage variable intake system, lightweight pistons and con-rods, forged crankshaft… in contrast, the Volkswagen inline-5 has a cast-iron block, wet sump, no VVT, fixed intake manifolds… marketing people, stop telling me rubbish !
Even if you disregard the relationship with the Lamborghini V10, you will be disappointed by its output. A specific output of only 60 horsepower per litre looks more like a 2-valve-per-cylinder engine, but in fact this engine has twin-cam and 20 valves in total. If you remember, the outgoing 2.3 V5 produces 170 horsepower. And the latest BMW 2.5-litre six can produce 218 horsepower. With only 150 horsepower and 170 lbft of torque, accompany with a lazy manner (it won't rev beyond 5800 rpm) and a hefty 1.5 ton weight, the new Jetta is disappointingly slow. Car And Driver found a 6-speed Tiptronic-equipped car taking 9.2 seconds to 60 mph. No wonder they ran out of patience to measure 0-100 mph.