Using a diesel truck as a tow rig is one of the reasons you bought it in the first place. Those towing duties include work and play.
A case in point is Jereme Miltier, at RPM Offroad, in Bristol, Tennessee. He frequently uses his ’07.5 GMC Sierra 2500 HD to tow trail rigs or even one of the shop’s many championship-winning desert race trucks or buggies. The truck has a factory-installed electronic brake controller, but additional help is always welcome in the braking department—especially when towing 15,000-plus pounds of race truck and trailer up and back down steep mountain grades.
To enhance the towing capability and safety of his LMM Duramax-powered GMC, Miltier opted to install the Banks SpeedBrake and iQ interface. He invited us up to the shop, just a few miles down the road from the famous Bristol Motor Speedway, to follow along with the installation and testing of the system.
The SpeedBrake from Banks is considered one of the best exhaust brakes on the market for newer Ford and GM diesel trucks with variable geometry turbos. When paired with the Banks iQ interface, the iQ not only controls the functions and settings of the SpeedBrake, it also has five virtual gauge fields that can be displayed in digital or analog formats to monitor vital engine and truck stats.
On the ’07.5 LMM Duramax engine, the display can show boost, SpeedBrake application percentage, engine load, fuel level, intake pressure, intake temperature, rpm, speed, throttle percentage, gear, grade, fuel pressure, elevation, DPF regeneration status, direction, barometric pressure, ambient temperature, instant economy, soot, time, transmission temp and engine temp.
The iQ can also function as an OBD-II scan tool that will allow you to read and reset trouble codes from your truck. On top of that, Banks has included an economy display that helps you keep track of your fuel expenses and efficiency, as well as trip calculations. It is also battery powered and can be used outside the truck to play games, listen to music, view pictures, watch movies or even view Office documents with its Windows CE-based software.
With multiple operation modes and settings, the driver can tailor the SpeedBrake engine braking to suit his driving style and vehicle load. In Manual mode, the system can be set for low, medium or high braking force that can be activated whenever the driver is off the throttle or when the vehicle brakes are applied. When the system is put in the Auto mode, the driver can set the desired descent speed in 1- or 5-mph increments—much like a cruise control for downhill use. The Auto mode can also be set to activate when off throttle or when the brakes are applied.
Conventional exhaust brake systems rely on a butterfly valve or similar restriction in the exhaust system to create backpressure on the engine and provide additional engine braking. The engineers at Banks Power used comparable methods with the SpeedBrake but took it a very big step further.
It uses a harness that integrates with the factory ECU to control the variable geometry turbocharger to act as an exhaust brake. But beyond that, it also controls the torque converter and transmission. By locking the torque converter and downshifting the transmission, the SpeedBrake delivers improved braking performance, as compared to a traditional exhaust brake.
The SpeedBrake is available for ’04.5-’10 GM Duramax 6.6L diesel trucks, ’03-’07 6.0L Ford Power Stroke diesel trucks and ’08-’10 6.4L Power Stroke diesel trucks. To take full advantage of the SpeedBrake capabilities, you’ll want to spring for the optional 5-inch touch screen iQ interface controller, but the system can also be installed with a rotary switch control that offers the low-, medium- and high-strength braking options, as well as foot brake operation; but it does not offer the Auto mode speed setting capability.
Operating the SpeedBrake system is very simple, and while the iQ has an astounding amount of capabilities, it is still easy to use. The Low setting is best used for an unloaded truck or when hauling light loads, while the Medium setting is good for moderately loaded trucks. The High setting works best when the truck is heavily loaded. Of course, the Auto mode and speed setting for downhill operate just like a cruise control and will probably be the most-used mode when towing heavy loads.
The SpeedBrake system comes with everything needed to install it in your truck and could easily be installed by most DIYers in probably under two hours. RPM Off-road installation technician Michael Powell installed the system on Miltier’s GMC in an hour and 15 minutes (this included the typical photography slow-downs involved with documenting the installation for an article).
It is much easier to install than a standard exhaust brake. It offers plug-and-play installation using connectors that mate to the factory connectors in your truck with no modifications to your exhaust system or splicing into your truck’s wiring harness.
If you own a late-model diesel with a VVT computer-controlled turbo and are looking for a little more “Whoa!” power heading downhill with a load, the Banks SpeedBrake is worth checking out.
Miltier loaded the Cummins-powered Dodge 2500 HD that the RPM Offroad team built and won a SCORE Stock-Full Class Championship with a flatbed gooseneck trailer and took us out for a ride through the hills and valleys surrounding Bristol, Tennessee. With a tuned Duramax under the hood of his GMC, he had no problems pulling up the grades; and thanks to the SpeedBrake, going down was a stress-free ride, too.
He made multiple trips down a 6.9 percent grade, trying the system out on different settings. With the SpeedBrake set to the High setting, the truck and the 15,000-plus-pound trailer gently eased down the grade, reaching the 15mph low speed limit before the bottom of the hill—without touching the brakes on the truck or trailer.
The Medium setting was similarly under control with a little more speed, as expected, while the Low setting was a little too light for such a heavy load on a steep grade. It would be perfect for towing with lighter loads. When Miltier used the Auto mode on the SpeedBrake and dialed the desired speed to 40 mph, the system took over as soon as he let off the throttle and slowed the truck to 40 mph. He then maintained that speed the rest of the way down the grade.
Speaking about the SpeedBrake operation, Miltier said, “The touch screen is easy to read and easy to use, thanks to the large screen size. It makes towing much easier on the truck’s brakes with the SpeedBrake, since I was able to keep the truck safely under control on steep grades without even touching the brakes—even with the race truck on the trailer. For the money, the SpeedBrake is worth it, versus other exhaust brakes, because you get so much more with it, and it works so well.”
The GMC 2500 HD has big brakes, but with the SpeedBrake activated, you can keep them cool and ready for action while letting the engine and transmission provide the braking.
The 5-inch touch screen is easy to read and use. It can be configured to match your truck’s gauges while displaying up to five parameters.
546 Duggan Avenue
Azusa, CA 91702
1804 Volunteer Parkway
Bristol, TN 37620
By Chris Tobin
Photography: Chris Tobin