The 6.7L Ford Power Stroke Has Arrived - Inside Perspective
It was released four years ago, but the wheels have finally been greased for making considerable horsepower with your 6.7L Power Stroke. Thanks to the aftermarket, companies are ruling out weak links, adding durability, and unleashing more get up for 2011 to 2014 Fords.
Riding the coattails of the 6.4L Power Stroke -- an engine that (when tuned) could make an 2008 to 2010 Ford Super Duty send 550 to 590 hp to the pavement -- Blue Oval fans were very optimistic to see what the all-new, all-Ford V-8 could do. But once aftermarket tuners finally cracked the ECM’s code, some key weaknesses began to surface. 1) The Bosch CP4 injection pump couldn’t supply enough fuel volume to make 500 hp, and 2) the small, variable-geometry, single-sequential turbocharger was out of steam at 2,800 rpm, making for a flat horsepower curve past 2,500 rpm. It’s been our experience that the 6.7L’s dual- compressor-wheeled turbo is the reason why 2011 to 2014 trucks dyno low. We had to get to the dragstrip to find out that our Spartan-tuned 2011 Ford F-350 crew cab was getting between 440 and 460 hp to the wheels (it made just 397 hp on the SuperFlow dyno at Randall’s Performance, which we consider to be very accurate).
"If you’re a diesel enthusiast, the last thing you want to be told is that a $3,500 set of rods is necessary if you want to make 500 hp."
Once long-awaited aftermarket tuning was released for the 6.7L Power Stroke, it spread like wildfire -- and the aforementioned factory turbo began to show its mechanical weakness. Units that regularly saw elevated boost levels (30 psi or more), high drive pressure (55 psi or more), and shaft speeds exceeding 160,000 rpm could quickly bite the dust, and tuned 6.7Ls have become almost synonymous with turbo failure. If you haven’t experienced it, chances are you know someone who has.
Even more serious (and after a handful of downed engines), there were legitimate concerns that connecting rod failure would be common on tuned 6.7Ls. If you’re a diesel enthusiast, the last thing you want to be told is that a $3,500 set of rods is necessary if you want to make 500 hp. A combination of aggressive fueling at low rpm (big torque, high cylinder pressure) and the stock turbo (in several cases, coupled with a large atmospheric turbo) creating excessive drive pressure proved too much for connecting rods that are much smaller in size than what you’d find inside a 6.4L (or even a 6.0L) Ford Power Stroke.
The aftermarket has a way of using proven, old-school tech to solve new-age problems -- and the stuff it’s come up with so far for the 6.7L is a perfect example of that. Fixed-geometry turbo kits are now on the market, and we showcased Maryland Performance Diesel’s 6.7L Non-VGT kit last month (“Feed the Beast,” May ’14). MPD’s system does away with the troublesome factory unit and bolts a higher-flowing, more reliable, T4-flanged BorgWarner S300 in its place. To solve the CP4’s fuel volume issue, H&S Motorsports stepped up to the plate with its dual high-pressure fuel kit. By adding a beltdriven CP3 to the 6.7L, it works in conjunction with the factory CP4 and provides enough fuel volume for 900 hp. Tying it all together for the new Fords is H&S Performance’s Maxx Calibration Control (MCC) software, which allows tuning gurus to write custom ECM files that limit timing advance down low (saving rods) and maximize horsepower up top.
Thanks to the increased airflow, adequate fuel volume, and custom tuning, the aftermarket has been able to maximize the potential of the 6.7L’s stock piezo electronic injectors. Several trucks with the setup listed above have cleared 600 rwhp on chassis dynos, and they’ve accomplished this without the factory lift pump and TorqShift transmission ever breaking a sweat!