Update #1 September-1-2010 02:49 PM PDT:
Our friends at Diesel Power are also testing a 6.7L Power Stroke V-8 this week. Check out the results of their pre-flash dyno run. You can see significant differences in measured output due to the different dyno hardware.
It will be interesting to see if both 6.7L PSDs show the same relative performance change after the flash upgrade later this week.
This week, Ford is expected to release a free power upgrade for the all-new 6.7-liter Power Stroke V-8 diesel that’s available in the 2011 F-Series Super Duty. The boost will come through an update to the engine's software, raising power levels to a best-in-class 400 horsepower and 800 pounds-feet of torque.
That’s an increase of 10 hp and 65 pounds-feet and over the initial "Job 1" 390-hp (@ 2,800-rpm), 735 pounds-feet version (@ 1,600-rpm) of the engine that was announced in February.
"Job 2" trucks are already leaving the factory in Kentucky with the new power settings, Ford spokeswoman Anne Marie Gattari said Tuesday.
We’re testing a 2011 Ford F-350 King Ranch with the 6.7 that was built before the upgrade was available on the assembly line. Later this week, we plan to visit a Ford dealer to have the pickup’s engine control unit flashed with the new software. It should be available at Ford dealers nationwide by Friday.
Before then, we paid a visit to our friends at Gale Banks Engineering in Azusa, Calif., to borrow time on their chassis dynamometer to empirically measure the horsepower and torque curves of the 6.7.
Instead of measuring output using a standard sweep acceleration test -- like you might on a Dynojet dyno -- Banks tested using a steady state step test on a Mustang dyno.
We started at high rpm with the diesel powertrain at full operating temperature, loaded the engine for a minute, then dropped it in 200-rpm increments, where we measured performance again and repeated, to as low as it would go – approximately 2,000 rpm, when the torque converter would no longer stay locked.
With the transmission in fourth gear (1.15 transmission gear ratio), maximum torque was measured at 598.2 pounds-feet, and horsepower peaked at 305.4 hp. Both measurements were made at the rear wheels instead of at the crank, which is about 20 percent below Ford’s official figures.
Banks’ staff adjusted the results according to SAE weather correction factors for horsepower and torque measurements for the tested environmental conditions: 77 degrees, 29.5 inches barometric pressure and 52 percent humidity.
A 15 to 20 percent power loss from the crank to the rear wheels due to friction and rotational parasitic forces is a fair number to use, gauging the relative difference between claimed and dynoed numbers.
Overall, our dyno numbers also track very closely with the power curves that Ford provided to us earlier this year. It should be noted that we saw a slight but consistent drop in engine output between 2,400-rpm and 2,800 rpm during three separate dyno runs. We’re not sure of the cause. It could be from the exhaust gas recirculation system, which is used to help reduce nitrogen oxide emissions by cooling combustion temperatures.
We also used the dyno to measure zero to 60 mph time, which came in at 9.05 seconds.
Stay tuned later this week for a second run on the dyno, after updating the engine’s software.