While the 6.4L Power Stroke was virtually a home run for the Ford camp compared to its 6.0L Power Stroke predecessor, it still had its fair share of shortcomings. The addition of more emissions equipment and the Diesel Particulate Filter really hurt overall fuel economy, and design flaws in the engine have caused some issues with high-mileage durability. But when it comes to power and performance, not much comes close to the 6.4L with simple bolt-ons like intake, exhaust and tuner (550+ rear wheel horsepower capable).
While these trucks can get just about any job done without breaking a sweat, the lack of factory VVT turbo braking and manual control over the automatic transmission can really become apparent when towing heavy or sled pulling. To overcome these issues, BD Diesel of Abbottsford, British Columbia, developed a Tap shifter and VVT Exhaust Brake designed to improve the towing efficiency and overall driving experience of 2008-2010 6.4L Power Strokes.
“Along with the ability to control the shift pattern manually, the Tap Shifter kit has six preset shift patterns that can fine-tune the automatic’s shift schedule based on driving habits and modifications.”
In 2006 GM introduced an all-new transmission feature for the Duramax/Allison combination. The “Tap Shifter” allowed full manual control of the shift patterns in the automatic transmission, basically allowing the driver to override the automatic shift schedule and restrict the transmission from upshifting or downshifting by control of a +/- button located on the shift lever. This quickly became a must-have feature for diesel owners and is now a standard option in both Ram and Ford trucks.
Unfortunately, Ford didn’t start offering this until the release of the 2011 6.7L Power Stroke, leaving the 2008-2010 6.4L Power Stroke owners with the sturdy 5R110 automatic in the stone age. Watching and feeling a transmission continually hunt for gears while towing over long grades and being able to maintain a safe speed and gear while descending steep passes can get quite frustrating.
After some extensive research and testing, a new Tap Shifter for the 6.4L Power Stroke models is now in full production. The kit includes an OE 2011 Ford shift selector with built-in +/- button, professional grade wiring harness with OE pigtail connections and a LED gear select display for the dash. Using the new 6.4L Tap Shifter, owners can now control upshifts 1-5 and downshifts 5-1 at their fingertips, offering better control while towing heavy or trying to keep within their max power band on the sled pull track.
Along with the ability to control the shift pattern manually, the Tap Shifter kit has six preset shift patterns that can fine-tune the automatic’s shift schedule based on driving habits and modifications. The transmission’s normal shift points can be lowered 10 percent or raised as much as 30 percent depending on the setting you select, it also offers Semi/Manual and Race/Manual modes.
When running in Semi manual, transmission will not kick down to a lower gear until the vehicle starts to slow. The Race mode allows control of upshifts and torque converter lock-up via the tow/haul button in either fourth or fifth gear. The Tap Shifter kit will also improve the truck’s overall towing performance and engine braking when running an exhaust brake or the BD Diesel Variable Vane Turbo Brake Kit.
Variable Vane Exhaust Brake
Like the factory-equipped Tap Shifters available in the newer Ford, GM and Ram trucks, variable vane turbo braking is also standard issue these days. The VVT turbo’s adjustable vanes give quick spool-up with a broad mid-range and strong top end, for great performance throughout the rpm range. Since these vanes can be closed on command electronically, they can help in restricting exhaust output on deceleration for additional engine retarding and exhaust braking.
Ford has been using Variable Geometry turbos since the introduction of the 6.0L Power Stroke in 2003, but didn’t start offering turbo braking until the latest 2015 6.7L Power Stroke models. Since the required mechanical pieces for turbo braking are already there in the 6.4L platform, BD engineers just had to develop the electronics to control it from inside the cab.
The VVT Exhaust Brake system controls the factory high-pressure turbocharger exhaust vanes on command with two performance settings, one with vane braking only and one with vane braking and a more aggressive transmission downshift strategy. Since closing the vanes will increase back pressure within the engine, by downshifting and raising engine rpm you’ll be able to maximize the back pressure (upwards of 70 psi) and gain an additional 130-retarding horsepower for slowing your load or maintaining safer speeds on long downhill grades. The system is completely plug and play with just one wire needing to be tapped in the brake pedal harness. The professional-grade wiring harness allows for easy install (less than one hour in most cases).
The truck used in this article is a 2008 crew cab short bed with more than 170,000 miles and running a host of aftermarket parts that include a Spartan DashDaq tuner, cold air intake, 4-inch exhaust, upgraded turbochargers and a built transmission. As a laborer in the oilfields of North Dakota, the owner definitely knows how to put his truck through its paces and gave excellent feedback on the addition of the BD Diesel Tap Shifter and Exhaust Brake kit.
Towing a 27-foot 9,500-lb travel trailer, the new BD VVT Brake was tested on a two-mile-long 6-percent grade located just outside of Ogden, Utah. In stock form, starting off the grade at the posted 50-mph speed limit, the truck began to gain speed less than a half-mile down the hill. While the factory Tow/Haul mode helps in these situations (thanks to a good torque converter and shift control), the truck gained momentum up to 58 mph when the driver had to start riding the brakes to keep the vehicle within the safe speed limit down the rest of the hill.
Once at the bottom, we returned back up the grade to test out the factory upshift pattern to see how it handled the weight and allowed the engine to work and gain speed over the hill. While it felt as if the truck could’ve ran cooler EGT and worked better holding third gear, the truck did shift into fourth and lugged its way to the top, hazing smoke out the tailpipe with EGT getting ever so close to the unsafe 1,350+ range.
Turning around once again, we could make a final run back down the mountainside, this time running the BD VVT Brake in position two, which gave us both turbo vane control and a more aggressive downshift pattern. Again starting off the hill at the posted 50-mph speed limit, the truck maintained 50 mph for around three-tenths of a mile (stock had gained speed to 53 mph at this point) and then started to actually slow the truck and trailer. At the half-mile point of the 6-percent grade, the truck had downshifted and slowed to 43 mph.
Impressed with its performance, the driver opted to continue letting the truck do its thing and see what it was capable of. Within another half-mile it had slowed to just 35 mph. With almost a mile left in the downhill stretch, the exhaust brake had been so effective that it was turned off so the truck could get back up to the posted speed limit. On the return back up the hill, running the Tap Shifter in manual mode, the driver could command 1-3 gears only so a higher rpm range could be run over the grade. This kept boost up and EGT down to just 1,050 degrees over the top at the same speed as it did when running stock gear patterns.
If you own a 6.4L Power Stroke and do a lot of towing, the VVT Exhaust Brake kit will definitely aid overall control and towing performance. With first-hand testing experience showing such promising results, it can turn a treacherous downhill descent into just another Sunday drive, all while taking some of the abuse off your brake pads and rotors. As for the all-new Tap Shifter kit, whether you’re daily driving and towing or using your truck as a competition hot rod running a big single turbocharger, the control it gives you over the transmission and rpm range can really take the 6.4L’s potential to an all-new level. DW