The Twin-Turbo Tuesday McLaren V8 Special
Though it doesn’t boast the kind of brand recognition of, say, Porsche or Ferrari, the McLaren supercar is an illusive cut above virtually all the other automobiles on the market. Sensual, aggressive, and unattainable to most, these British dream machines parade around Dubai and Las Vegas like turbocharged unicorns on steroids, which is exactly why they are under our microscope today.
Most people may not know it, but the 3.8-liter, twin-turbo V8 that resides in the typical McLaren wasn’t designed by the automaker but was actually outsourced to British-based engineering firm Ricardo, which did the majority of the R&D work. Ricardo got the specs they needed from McLaren, and then over the next few months developed a custom motor that matched the automaker’s requested weight, dimensions, power levels, and mounting locales in order to accommodate various vehicle sizes and performance demands. By using a flat-plane crank, Ricardo was able to outfit these “M838T” motors with a dry-sump lubrication system and get the most out of the unit.
As with most V8 motors, the M838T sports a 90-degree bend between its two rows of cylinders, but only has a 3.8-liter displacement rating. With the assistance of a custom tuned turbo on each side, in a car like the 12C it cranks out around 616 horsepower and 443 pound-feet of torque. Even in the refined 570GT “slow-poke” it returns around 562 horsepower and equals the 12C in torque numbers, so don’t expect this monster of an engine to back down in any trim level.
But there’s more to this story than a shitload of stampeding ponies and a large lump of twisting torque. Even though these cars are equal parts expensive, obscure, and extreme, there’s a lot more to them that deserves exploration. In fact, they have been outfitted with outdated technology in order to go faster.
The Kiwi on the carbon fiber engine cover seen here is a sly nod to New Zealand, the birth place of McLaren’s founder, Bruce McLaren. So technically, much like the 3.8-liter V8 in all of its cars, the brand itself has roots elsewhere. Back under the rear hatch, this potent V8 gets filled with dual-overhead camshafts, four valves per cylinder, and variable cam timing adjustment capabilities. Redlining somewhere around 8,500 RPM, the engine’s compression ratio is quite low at 8.7:1, because force-fed motors tend to suffer at higher compression rates.
Sitting as low and as far away from the rear bumper as possible, the M838T rocks an air intake system that is extremely lightweight, and more directly aligned which reportedly makes it quite a bit easier to tune. Engineers also opted to make its fuel system port injected instead of direct injected, which to some sounds much like a step backward in regards to engine evolution; but port injection is a whole lot easier to tune and still offers outstanding power gains.
Other unique touches include an amplifier on the intake manifold, which makes the motor more aggressive sounding, and the way in which all of the engine’s belt-driven accessories have been rerouted. This means that everything from the air-conditioning compressor and water and oil pumps to the alternator have been bumped down beneath the turbos on both sides in order to meet space and weight constraints.
Built to be as bulletproof and compact as possible, the twin-turbo McLaren motor is without question an interesting take on modern force-fed nobility, and the best part is that it works extremely well. According to McLaren, “80% of torque is available at below 2,000rpm, ensuring great driveability and no need to floor the throttle to deliver performance.” That’s a massive amount of grunt right off the line, but with even more power waiting on the upper end of the powerband, chances are that drivers won’t be letting off the gas anytime soon in these brilliantly crafted British supercars.