Dyno Test: Ford 6.7-liter Power Stroke V-8 Diesel After Factory Power Update

Update #1 September-10-2010 02:41 PDT:
With apologies to Ford and our readers, we could have tested lower into the RPM range (below 2,000 rpm) on the 2011 Super Duty.

Ford's all-new 6R140 six-speed automatic transmission includes a new manual mode feature that would have let us select and hold the gear we wanted all the way down to about 900 rpm, when line pressure would be too low for the torque converter to stay locked.

We dynoed the truck using range-select, setting fourth gear as the uppermost gear. In that mode, the transmission held fourth until about 1,950 rpm, at which point it wanted to downshift to third — hence the 2,000 rpm floor found below in our results.

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We've retested a 2011 Ford F-Series Super Duty after updating its diesel powertrain with new software calibrations from Ford that the automaker says gives it class-leading power ratings among heavy-duty pickup trucks.

Last week, Ford released the free power upgrade as part of a customer satisfaction program. For the next 12 months, early buyers of the 2011 Super Duty with the all-new 6.7-liter Power Stroke diesel V-8 can have their engine control unit and transmission control unit software updated for free at their local Ford dealer.

The upgrade process is similar to a firmware update in a smart phone or PC and is expected to take about 30 minutes. Afterward, the 6.7 diesel is rated at 400 horsepower and 800 pounds-feet of torque – an increase of 10 hp and 65 pounds-feet 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 leaving the Super Duty factory in Kentucky are being shipped with the new power settings, and dealers are updating unsold trucks on their lots.

Before we updated the ECU and TCU in a 2011 Ford F-350 King Ranch Super Duty, we tested it Aug. 31 on the chassis dynamometer at Gale Banks Engineering to measure power output from the 6.7 at the rear wheels.

Graphed results of the best of three dyno runs at Banks with the Job 1 calibrations.

Banks Engineering is a well-known technical leader in the diesel- and gas-engine tuning aftermarket. The company offers software and hardware performance enhancements for diesel engines and has set the world land-speed record for the fastest diesel-powered vehicles.

Overall, the Job 1 6.7 dyno numbers we gathered at Banks tracked closely with the power curves that Ford provided to us earlier this year, though we noted a slight but consistent drop in engine output between 2,400 and 2,800 rpm during three separate dyno runs. We’re not sure of the cause. It could have been 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 times, which came in at a best time of 9.05 seconds and an average of 9.12 seconds after three runs.

To obtain the Job 2 software update, we visited Colley Ford in Glendora, Calif., just like any other new Super Duty owner. Working with the excellent service team at Colley, we had the truck flashed and ready to roll about 30 minutes after our appointment started.

We wondered if we’d be able to tell using our butt dyno if the truck had more power after the Job 2 update. While it was difficult to say that the truck had extra oomph, it was apparent to us that the software upgrade gave the 6.7 Super Duty powertrain a new sense of refinement and confidence. Gear shifts were smoother and less noticeable after the update than before getting on the freeway and driving on surface streets. The truck didn’t feel as jumpy as it had running the Job 1 calibrations.

6.7-liter Ford Power Stroke V-8 crate engine on the shop floor at Gale Banks Engineering. Two 6.6-liter Duramax V-8s were sitting next to it.

We also liked that the gearshift indicator — engaged with a tap of the +/- select shift button on the gearshift stalk when the truck is in full automatic mode — remained visible in the Super Duty’s new 4.2-inch LCD trip computer after we started the truck, shut it off and restarted it. Before the update, the gearshift indicator had to be manually requested with a button push after the start of each new key cycle. However, we wondered most if Ford could deliver on its promise of extra power? Back to Banks Engineering we went.

Instead of measuring power output using a standard sweep acceleration test — like you might on a Dynojet chassis 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, and then dropped it in 200-rpm increments. We measured performance again and repeated the process to as low as it would go – approximately 2,000 rpm, when the torque converter would no longer stay locked.

The Job 2 results presented below (versus Job 1) are the average horsepower and torque from three dyno runs.

With the transmission in 4th gear (1.15 transmission gear ratio), maximum torque was measured at an average of 643.9 pounds-feet at 2,000 rpm, and horsepower peaked at 306.8 hp at 2,800 rpm. Both measurements were made at the rear wheels instead of at the crank, which is about 20 percent below Ford’s official figures.

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.

Compared to the results of our Job 1 dyno, Ford has definitely delivered on its promise.

Graphed results of Job 1 vs. Job 2 average horsepower and torque measurements (after three runs with each calibration) on the dyno. Note the increase in power lower in the rev range after the ECU and TCU flashes.

We saw a max torque gain of 45 pounds-feet at 2,000 rpm, or 7.5 percent higher than the average torque measured during our earlier dyno session. We suspect we would have seen an even greater increase in torque had we been able to measure below 2,000 rpm, closer to the 6.7’s max torque peak around 1,600 rpm.

The biggest horsepower gain we measured was 21.4 hp higher at 2,600 rpm than the average hp measured last week.

We did notice power drop-offs after the Job 2 flash at the very high end of the power band, between 3,200 and 3,600 rpm, compared to Job 1.

Overall, it seems that Ford has shifted and increased power to lower in the engine’s rev range. We’re doubtful that we could tell there’s less power high in the rpm band because above 3,200 rpm the engine is getting ready to upshift to the next gear to regain its power sweet spot. Ford also appears to have corrected whatever factor might have been responsible for the slight power drop we saw during the Job 1 test between 2,600 and 2,800 rpm. The Job 2 power curves have smoother arcs.

Perhaps the best indicator of improved powertrain performance was a solid drop in measured zero to 60 mph times on the dyno. Before the flash, the average zero to 60 time we measured was 9.12 seconds. Afterward, the average was 8.82 seconds, or a net decrease of .3 seconds.