Ford tells us how it developed a relatively small V6 to achieve GT-grade power and performance
Supercar currency places a premium on cubic capacity. Big cubes understandably yield big dividends in power and torque. That’s old-school thinking.
The V6 destined to power the new Ford GT displaces only 3.5 litres. About the decision to develop a 3.5-litre V6 instead of a V8, Ford says that more is less. Meaning, with less weight, the new GT doesn’t need more cubic capacity.
This new-school thinking and technology is also influencing Honda in support of its twin turbocharged V6 in the new NSX. The NSX’s acceleration performance is boosted by three electric motors and a compact battery pack.
Ford decided early during the philosophical design of the GT to reduce weight as the primary strategy to enhance straight-line acceleration and cornering agility.
Produce as much power from the light and small 3.5-litre V6 and maximise the impact of every kiloWatt by shaving every kilogram. A hybrid drivetrain with a heavy battery pack and electric motors did not fit the GT’s power-to-weight design brief.
There are other reasons for choosing a V6, says Jamal Hameedi, Chief Engineer at Ford Performance. Lighter and shorter than a V8, it allowed better packaging behind the co*ckpit of the unique aerodynamically contoured body shell.
And efficient aerodynamics is equally as important to the GT as achieving an excellent power-to-weight ratio. The alloy V6 with twin turbochargers ticked both boxes.
Visually, the new GT obviously shares familial DNA with previous generations, but the use of a V6 instead of a V8 makes the new GT unique. Its predecessor swung for the fences with a 5.4-litre supercharged V8 creating a hefty 410 kW and 678 Nm and a glorious V8 roar.
Producing a beautiful deep and raspy exhaust note from the turbocharged V6 may be Hameedi’s greatest challenge. He and Steve Russ, Technical Leader for Internal Combustion Engines, say the V6 develops more than 450kW but if you want an exact number you’ll have to wait.
The twin-turbocharged 3.5-litre V6 is loosely based on the Ecoboost V6 in F-150. About all that carries over to the GT is the crankshaft and general engine block.
Dual overhead camshafts, four-valve per cylinder makes for a rather exotic truck engine. Still, pushing it to supercar performance has been an ordeal with significant Ford-supported development work done by Roush Yates.
Development moved from dyno to race track in 2014 when Ford agreed to supply Chip Ganassi Racing and driver Scott Pruett for the United SportsCar Championship (USCC) Series. A few months ago, the team using a variation of this Ford 3.5-litre V6 won the Rolex 24 at Daytona.
In USCC race-spec, peak output from the twin turbocharged V6 is restrained (coincidentally) to 450kW by limiting turbo boost pressure and restricting air intake and enforcing a rev ceiling of 7300rpm.
The GT V6 will be liberated from those restrictions, so we can expect the turbocharged V6 to rev higher and boost harder, and peak power will be limited only by pump fuel and a warranty.
Don’t be surprised if Ford in late 2016 unleashes the GT with peak power closer to 475kW or more.
“We looked at the limiting factors to be able to get more airflow through the engine and to get more horsepower,” says Russ.
“We tested 63 different camshaft configurations and eight different turbos from several different suppliers to find the optimal combination to deliver the power needed for the GT. The engine has to have unique pistons, connecting rods and other components to deal with the higher speeds and pressures of the GT. All of this was virtually modelled and tested.”
The driver can select from four performance modes: Normal, Sport, Track and Wet. You get the idea, and each mode elicits a unique engine performance, throttle input and suspension set-up — all controlled through one of Ford’s off-the-shelf PCM (power control module).
The core software if very tuneable, Russ says, to achieve the four distinct drive modes in the GT.
“There are some unique things that get calibrated like we have a mode that is able to spool the turbos up very fast – anti-lag logic. We call it Transient Performance Mode which enables the VCTs (variable camshaft phasing) to be controlled to quickly spool the turbos up so the engine’s throttle response feels like a large naturally aspirated engine and not a turbocharged engine of the past.”
Ford certainly talks a good game about the 2016 GT.
