Banks Powers the JLTV

Gale Banks and the JLTV: How a small engineering firm beat billion-dollar competitors to win the most important engine contract of the century.

It’s not often that the U.S. military goes looking for a replacement for its most widely used vehicle platform, but that’s what it did when it put out the call for a new Joint Light Tactical Vehicle. Many of the biggest defense contractors submitted designs, including A.M. General, which was the company behind the long-lived and nearly ubiquitous HMMWV. In the end, it was Oshkosh Defense that submitted the winning design and it had a Banks turbodiesel engine powering it – the D866T, beating out multi-billion-dollar companies like Cummins and Caterpillar.

The JLTV is an incredible machine with a design focused on crew survivability, particularly in cases of improvised explosive devices (IEDs) that were such a problem for the HMMWV. While many of its features and capabilities remain classified, it has some tricks it has up its sleeve that we do know about. For example, the massive JLTV can squat down on its air suspension so it can be air- or sea-portable and this highly advanced suspension also gives the JLTV an unbelievably smooth ride compared to the old coil-sprung HMMWVs.

In the years that followed the awarding of the JLTV contract, Banks Tech (a subsidiary of Gale Banks Engineering) has delivered over 25,000 of the 6.6-liter turbodiesel engines, which is impressive on its own, but not nearly as impressive as what it took for a little company in Southern California to clinch the biggest military engine contract in decades.

“This vehicle is the result of a years long design and test competition involving the biggest names in the defense and diesel engine industry,” said Gale Banks, Chief Engineer at Banks Power.

The Oshkosh JLTV has destroyed the competition. – Gale Banks

Ultimately, the government’s selection of Banks came down to the brand’s unshakeable reliability, proven through the grueling 400-hour NATO endurance test. This test sees an engine tested to its absolute limits.

The test involves running an engine for two hours at a time moving between peak horsepower and peak torque at wide-open-throttle and 100 percent load for 10 hours at 125 degrees ambient temperature. No more than two 10 hour cycles can be run in a day without an eight-hour cool-down period mandated after each pair of cycles. The cool down adds difficulty to the test because more wear and tear occurs as an engine comes up to operating temperature, thus introducing more opportunities for failure. Any dip below 95 percent rated power that can’t be fixed in the standard allowable maintenance between each 100-hour block is considered a failure. Any failure requires a complete retest.

The D866T was able to withstand this torture test thanks to Gale Banks’ decades of experience in winning endurance-focused races on both land and sea and it remains one of our proudest achievements.
D866T.

Of course, a lot of design and engineering work went into the design of the D866T engine – five years worth. The standard 6.6-liter Duramax engine is a potent powerplant right from the factory but any engine that will see service with the military is going to be met with a series of special requirements that would challenge any engineer and which are unique to a military vehicle.

In the five year development cycle for the D866T, Banks went on to replace over 300 stock GM parts. Among the components that were beefed up were the crank pulley, which was replaced by a Banks viscous damper and a custom front accessory drive to cope with the heavy strain placed on it by the JLTV’s massive electrical and hydraulic loads.

The factory GM ECM was binned in favor of Banks’ AutoMind engine management, developed in concert with Bosch, allowing for 100 percent custom engine calibration. When we say “custom calibration,” we mean it. The Banks calibration for the JLTV features over 30,000 individual parameters, each of which has been fine-tuned for optimal performance and reliability.

Part of the need for all that calibration control comes from the military’s mandate that the JLTV be able to run on a fuel called JP-8, which the military uses as a sort of “universal fuel”. This integration was challenging because the kerosene-based JP-8 lacks a great deal of diesel fuel’s inherent lubricity – which the whole fuel system counts on for survival – which can cause excess wear in common rail diesel engines, like the D866T. JP-8 is also known for making cold starts more difficult. Figuring out how to tune around these difficulties and how to prevent wear to critical components was one of Banks’ biggest wins in the JLTV process as a whole.

In the course of the development of the D866T platform, Banks secured several patents, including two for the engine’s lubrication system. One of those was for a design that cured a known issue with oil collecting in the engine’s cylinder heads and not draining back down to the oil pan quickly enough. Needless to say, this was a huge win for long-term durability and was key in securing the JLTV contract.

Finally, before delivering our engines to Oshkosh or A.M. General, we do a hot test of each engine where we run it on our engine dynos to ensure that there are no issues and that break-in is handled appropriately. This is not a routine process for the vast majority of passenger vehicles, where the engines will be cold tested at best, aka not actually started, merely spun to verify compression.
Banks Military History

Of course, the D866T isn’t the only engine that Banks has designed for the military. Back in the early 2000’s, the military was finding its HMMWVs severely underpowered in high altitude areas of operation, like Afghanistan. Banks stepped in and developed a turbocharging kit for that model’s 6.5-liter diesel to bring back the power that altitude had sapped, and ultimately making for a safer, more robust vehicle.

It doesn’t stop there, either. In an effort to investigate fuel saving measures for the existing HMMWV fleet, the U.S. Army put out a request for hybrid diesel engine designs. Banks developed a V6 P2 parallel hybrid diesel with an 800-volt electrical architecture (which has only recently become common in electrified vehicles) , based around Stellantis’ VM Motori-based EcoDiesel platform. The result when placed in a HMMWV was a highly fuel efficient vehicle that offered excellent performance and the ability to both run silently in EV mode, but also to power entire remote work sites thanks to its battery system.

Banks’ work with the military continues with the JLTV as production is taken over from Oshkosh by A.M. General, with the venerable Banks D866T under its armored hood. This partnership will continue to offer our soldiers a quick, reliable vehicle that can handle the toughest terrain in any combat zone.