This Lamborghini V-12 is a consumer version of the racing engine that is so dominant in European offshore racing. Actually, it is nearly the same engine. As a result, many components are far tougher than need be for consumer use. This may change as Lamborghini and DDC (the U.S. distributor) discover modifications that will better adapt the engines to nonracing applications without hurting their superior performance. For example, the electric fuel pumps are loud: at idle you can hear them over the exhaust - and the boat doesn't have mufflers! Smaller pumps might provide adequate fuel with less disturbance.

But then, the exhaust note is an indication of just how smoothly this engine performs. From idle to WOT, it evolves from a gentle purr to a rich, throaty throb, but never to an uncivilized roar.

The L900i has an excellent weight-to-horsepower ratio (1.35:1) thanks to its aluminum block and heads. The crank is a special steel alloy with seven main bearing journals. The engine is fuel injected, and though the intake system employs thermatically-controlled gate valves, timing is straightforward with two valves per cylinder (24 valves).

With a bore of 4.15 inches and a 3.50 inch stroke, the L900i displaces 570 cubic inches. It develops 650 bhp at 5200 rpm with maximum torque (730 lb-ft) at 4000 rpm. The compression ratio is 8.4:1. 

This review/article originally appeared in Power & Motoryacht Magazine, July 1994 and is written by Capt. Bob Armstrong. For more great powerboat reviews, visit their website and subscribe at: https://www.powerandmotoryacht.com/uncategorized/subscribe-power-motoryacht