The trick to getting 375 horsepower from only 3.5 liters is efficient breathing combined with a light, fast-revving reciprocating assembly. But the key to the F355's incredible sound lies in its 180-degree "flat" crankshaft, which is common in racing and produces equal firing impulses between each cylinder bank. Therefore, to optimize both intake and exhaust tuning, each bank can be treated as if it were its own four-cylinder engine. However, unlike a conventional 90-degree crankshaft, the flat crank engine isn't inherently balanced and will shake. Ferrari has compensated for this with a set of high-tech engine mounts that damp most of the vibration before it hits the passenger cell. From 6000 rpm up to its 8500-rpm redline, it sounds like an Indy car (minus the turbo whine). There's a radio of some sort in the car, but it would be a sin to turn it on.
The temptation for Ferrari's engineers to use an electronic valve-control system like Honda's Variable Valve Timing and Lift Electronic Control (VTEC) must have been intense, but the three intake and two exhaust valves sitting atop each combustion chamber have advantages of their own. The intake valves sit together in a crescent with the center one opening and closing 10 degrees later in the crankshaft rotation than the other two. Theoretically, that laggard valve should increase turbulence in the combustion chamber and promote more-efficient combustion.
Air enters the engine through twin air boxes via ducting at each rear wheel, and then through large air trumpets for a straight shot into each combustion chamber. Somehow, Ferrari has snuck in an exhaust system that seems unmuffled yet incorporates a variable exhaust backpressure control to maintain the ideal volume no matter what the engine speed.
Combine the F355's exotic induction and exhaust systems with an 11.0:1 compression ratio and an ultralight reciprocating assembly featuring titanium connecting rods, and the result is a high-revving engine that's among the world's most efficient air pumps. That respiratory efficiency translates into 375 horsepower at a way-up-there 8250 rpm (just 250 rpm short of the breathtaking redline). Do the math, and that works out to an output of 107.3 horsepower/liter-the highest of any naturally aspirated production car engine ever sold in the United States. To put this in perspective, if they had the same specific output of the Ferrari, the Chevrolet Corvette's 5.7-liter LT1 V-8 would produce 611 horsepower (instead of 300) and the Dodge Viper's 8.0-liter V-10 would make 858 (instead of 400).
Behind the longitudinally positioned engine is a transverse six-speed manual transaxle. Once the expeditionary force has returned with news of first gear's location, it takes a firm hand to maneuver the alloy shifter through the traditional Ferrari external metal gate and into position. With a horsepower peak higher than the parking-lot crowd at an Allman Brothers concert, there isn't a lot of low-end torque. Still, 268 pound-feet of peak torque at 6000 rpm is deceptive; the engine builds revs so quickly that it's always only micro-moments away from dipping into its twist stockpile. Even loafing at freeway speeds in sixth, the car will pull hard from 3000 rpm onward.
Getting the best off-the-line acceleration time is a tricky balance between wheelspin, clutch slippage, and engine bogging. It ultimately took 5000-rpm launches followed by billows of tire smoke to produce a 0-60-mph time of 4.7-seconds, and to rocket through the quarter mile in 12.8 seconds at a 110.2-mph terminal velocity. Currently, the only quicker car on sale in the U.S. is the Porsche 911 Turbo; the F355 shreds both the Corvette ZR-1 and Dodge Viper in quarter-mile contests.
...
>>next page