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So, it’s fitting that Gale Banks Engineering, which is responsible for its share of the aftermarket diesel power out there on the road, developed a special high-performance billet torque converter that can handle the newfound power.
We tested the Banks Billet Torque Converter in a Ford F-250 Super Duty with a 7.3-liter Power Stroke that has been upped in power output. Along with the new torque converter, we installed a Banks TransCommand unit to beef up clutch-line pressures.
The Banks torque converter features a billet cover manufactured to maintain its structural integrity under extreme heat and mechanical stress. On most pickups, the portion of the stock torque converter that is bolted to the engine flex plate is a stamped-steel housing with welded-on tabs, which can deflect or distort the housing under sustained high loads such as those induced by engines with boosted power output or overweight trailers. This distortion usually causes high spots on the machined metal surface that is engaged by the lockup clutch. With less metal surface contacting the clutch surface, clutch slippage, dust and heat multiply in a vicious cycle.
Banks addresses these issues by using a one-piece billet cover that is precision-machined. This billet construction reduces flex, thereby retaining clutch contact surface even under heavy loads. This means quicker, surer lock-up and less slippage which, in turn, helps prevent heat, wear and fluid contamination.
Other features of the Banks converter that make it tougher also improve performance. For example, stock inverter and turbine blades are held in place by small tabs that protrude through a slot. The tabs are bent over to hold them in place. These fins can become loose and diminish in efficiency when subjected to high loads.
The fins in a Banks torque converter are furnace-brazed in place to prevent loosening caused by high power and weight loads. Furnace brazing creates a much stronger bond to withstand the rigors of heat and fluid pressure; a similar process is used on jet engine parts.
The Banks dual-disc clutch maximizes surface area to reduce slippage under the combination of high torque and heavy load. Carbon-ceramic clutch materials improve on the stock cellulose-based paper material, meaning less clutch material is being ground off of the plates and into the automatic-transmission fluid (ATF).
We started by installing a transmission-oil-temperature gauge because fluid temperatures are one of the best indicators of what is going on with the torque converter. In fact, a transmission-oil-temperature gauge is a good idea for anyone who pulls heavy loads and/or has significantly increased the power output of their tow vehicle.
We installed the sensor for the temperature gauge in the line near where the fluid leaves the transmission before going to the cooler. This location gives a better read on torque-converter activity instead of just how well your transmission cooler is working. Trailer Life advises putting the sensor in the pan for a number of reasons (most gauges are calibrated for pan temperatures, and pan temperatures are what the transmission gets), but as important as the location of the gauge is that you have one, and a good baseline for keeping an eye on ATF temperature.
We monitored transmission temperatures under several conditions including town driving, highway cruising, and acceleration runs. As expected, transmission temperatures went up when the torque converter was working the hardest in stop-and-go traffic and under heavy acceleration.
Torque converters are happiest when locked-up and cruising. In fact, the experts we talked to said the hottest conditions for your torque converter are at low speeds with a load – like backing up into a camping spot or pulling a steep incline from a stop – and those conditions where a manual transmission would need to slip the clutch to get going or change gears.
Our tests showed slightly lower transmission temperatures with the Banks setup. On average, the temperatures were 5°F lower under a variety of conditions with the Banks equipment installed.
We ran a series of tests while towing a 7,000-pound trailer, first with the stock torque converter, and then with the Banks TransCommand and billet torque converter installed.
Our initial fuel-consumption tests saw no measurable changes between the two setups. This is not surprising because we towed a 7,000-pound trailer at a highway cruising speed of 65 MPH. Both the stock and the Banks torque converters would have been in lock-up mode in these conditions, which means the clutches were producing a good non-slip connection between the engine and the transmission.
With a longer-duration fuel-economy test we would expect to see fuel-economy improvements in stop-and-go conditions with the Banks converter because with a lower stall speed and quicker shifts, it should take less fuel to get things moving. This is based on our personal experience because dynos programmed for stop-and-go driving tend to reside at the Environmental Protection Agency, and a trailer makes no difference unless the dyno is programmed for the additional loads.
Also, under a heavier load, when you are really pouring some diesel to it (like on a steep grade), you should also see some fuel improvements and slightly lower temperatures as slippage in the torque converter is reduced with the Banks upgrade.
ACCELERATION WITH ATTITUDE
Our muscled-up F-250, towing the trailer while using the stock torque converter, averaged a 0-60 MPH acceleration time of 15.4 seconds. During the tests we noticed a considerable amount of shudder, which we attributed to slippage in the torque-converter clutches, although shudder under load can also come from other sources.
With the new Banks torque converter installed, the average 0-60 MPH acceleration time was 14.7 – a 0.7-second improvement. While clutch shudder was nearly eliminated, another problem arose: With the new torque converter, there was a significant increase in wheel spin, even with the heavy trailer-tongue weight. That shows how much more power the billet converter is putting to the rear wheels compared to the stock unit. Most of the advantage in acceleration will occur once the vehicle’s rolling and tire slip is minimized; if you tow a heavy fifth-wheel this should not be an issue.
During our acceleration tests we also recorded 40-60 MPH times. The average 40-60 MPH time with the stock torque converter was 8.5 seconds. The average 40-60 MPH time with the Banks Billet Torque Converter and TransCommand combination was 7.6 seconds. This represents an improvement of nearly a full second in those on-ramp spurts.
We found that the lower stall speed of the new torque converter was noticeable in normal driving conditions. Or, in layman’s terms, it takes less throttle input to get things moving. We also noticed the F-250 shifts quicker and firmer under hard acceleration.
Because the new converter was installed to improve durability and protect the transmission, we were pleasantly surprised by the improvement in acceleration and driving fun. Any improvements in fuel economy will likely be negated by the urge to stand on the throttle more often.
The torque converter could be installed by a skilled backyard mechanic in about a day. The instruction manual that comes with it is quite detailed, but the recommended tools list has some specialized items, like transmission hoists, a flywheel rotating tool and a torque-converter holding tool.
The Banks Billet Torque Converter and TransCommand is an effective combination for those who are hauling heavy loads and/or have increased the power of their trucks with performance upgrades.
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