Taming High Performance Diesel Torque

  Mike Purugganan   May 03, 2018   Blog   0 Comment

The diesel engine has become a solid fixture of the light truck market for several decades, and have become a target of a slice of the high performance aftermarket.  For a variety of reasons, the desire to extract more horsepower and torque from these basically utilitarian powerplants have captured a sizeable segment of light truck enthusiasts that helped me on moving with the help also of http://montrealmovers.com/ .

A leader in the light truck diesel market has been the Dodge, now RAM, brand of Fiat-Chrysler America (FCA).

Beginning in 1989, Dodge began to install the B-series Cummins 5.9-liter inline, turbocharged 6-cylinder engine with a modest (by today’s standards) 160 horsepower in the brand’s 2500- and 3500-series pickups.  The target audience were buyers in the agricultural, construction and other industries where the diesel’s low end torque (400 ft-lb) matched well with the heavy loads encountered. The trucks were equipped with manual transmissions or the rugged A-727 Chrysler automatic transmission.

Ford and General Motors quickly responded by offering their V-8 diesel engines, designed for their medium-duty commercial trucks into the Chevrolet/GMC and Ford pickup lineups following the Dodge/Cummins introduction.  The awareness of the advantages of the diesel powerplants soon attracted the recreational vehicle market – particularly the owners of large, bumper hitch and fifth-wheel travel trailers.  It also began to create interest in the truck enthusiast marketplace.

However, it was Dodge’s Cummins power plant which seemed to attract the most interest.  The excellent torque of the inline-6 seemed to fill the needs of the various markets which were attracted to the diesels, and a solid marketplace was born.

As years passed, the 5.9-liter Cummins engine became intercooled, and an inline injector pump replaced the initial rotary pump, and 4-valve heads replaced the original 2-valve heads as the marketplace was asking for more power and torque.  These changes pushed the power to 350 horsepower, and the torque to 650 ft-lb.

In model year 2008, the engine was expanded to the current 6.7-liters, but the power and torque remained the same as the 5.9 of the previous year – 350 horsepower and 650 ft-lb of torque.  For several years, the horsepower remained constant at 350 HP, but the torque began to climb in 2011 when it reached the 800 ft-lb mark. For model year 2018, the RAM 2500 Cummins diesel package is rated at 370 HP and 800 ft-lb of torque, while the RAM 3500 offers a class-leading 930 ft-lb of torque, and 370 HP.

All of the improvements from the Cummins factory engine package over the years saw the Dodge and RAM models set the standard in diesel performance, and the diesel light truck market has responded – with 2 million-plus Cummins-powered Dodge and RAM trucks sold since 1989.

Power and torque enhancing products from the performance aftermarket have blossomed over the years, and the diesels have taken to the track.  Diesel drag racing has seen significant growth, as well as classes for diesel-powered 4-wheel drive truck pulling.  This also includes street performance enthusiasts, plus those wanting added towing and hauling capabilities for commercial or recreational use.

A problem…

However, there is a weak spot in the chain.  It is between the crankshaft and the transmission, particularly true with automatic transmission-equipped trucks.  As with gasoline engines, diesel engines which get the performance boosted significantly above the stock factory ratings, the strain placed on the drivetrain can potentially cause significant damage.  This is particularly true in competition environments, but can also be a problem in heavy duty use.

As power and torque of the Cummins engine increased, FCA recently turned to heavy-duty Aisin 6-speed automatic transmission to handle the ultra-high torque loads north of 900 ft-lb found in the 2017 and 2018 3500-series, but the factory flexplates are approaching their limits.

When racers and enthusiasts “turn up the wick” on the Cummins B-series engines, they are exposing themselves to the risk of flexplate failures, and the possibility of vehicle damage, and personal injury to themselves and/or bystanders.

The guilty party is high levels of torque, which can lead to the stock flexplate beginning to show hairline cracks, which can lead to serious cracking or distortion.  Cracks and/or distortion seriously weakens the structure, which can shear at the flexplate’s mount to the crankshaft output flange, causing loss of power to the transmission, and the engine to freewheel to high RPM levels.  It may also cause shearing at the flexplate mounts to the torque converter.  Additionally, excessive twisting may cause failure of the welds on starter ring gear.  The failure of the flexplate has caused failed parts to break through the transmission’s converter housing, and send parts into the truck body or out of the truck itself.

Racing sanctioning bodies, recognizing the dangers, are specifying the flexplates used in diesel competition be certified to meet the tough, competition diesel-specific SFI 29.3 specification.  For lower horsepower/torque engines used in competition (street stock or mildly modified) or heavy hauling or towing, the standard SFI 29.1 is recommended.

A solution

One of the leading suppliers of diesel performance flexplates is PRW Industries (Perris, Calif.).   Recognizing the need for a performance flexplate solution, the company has engineered a Cummins flexplate from the ground up, using computer-aided design (CAD) to assure the highest design tolerances.  The PQX® Signature Series flexplates are made from a single piece of high-strength billet steel.  The design include the starter gear machined into the billet flywheel, which eliminates the potential for a starter gear weld failure.

Each raw steel billet plate is placed into a computer-controlled machining center, and using the CAD created program, is manufactured to precise tolerances.  Each flexplate is then precision balanced, and given a black oxide coating.  These flexplates are available for the 1994-2007 5.9 liter engine, and the 2008-current 6.7 liter engine.  (See specifications below)

Following the initial SFI certification, to assure the racing community of a manufacturer’s continuing compliance, the SFI periodically purchases a flexplate at random, and retest to the tough certification process to assure the flexplate meets or exceeds the minimum standards.

PRW also offers diesel flexplates in the company’s PQX® Platinum Series line that meet the SFI 29.1 specification, which are a significant improvement over the OEM flexplates.  They are available for both Cummins engines.  Additionally, they are available for Ford Powerstroke engines – the 1989 – 2006 7.3 liter engine with the E4OD or 4R100 transmissions, and the 2003 – 2007 6.0 and 6.4 liter engines equipped with the 5R110 transmission, On other advertisements, if you’re looking for reputable online casino gaming, check this out!
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The PRW PQX® Platium Series flexplates have a very durable 4 mm steel centerplate which provides a solid foundation for these new designs. The starter ring gears are precision welded to meet SFI specifications, using a robotic, cold-welding process.  (See specifications below)

 

PQX® SFI-Rated Signature Series Steel Diesel Flexplates (Competition) for Cummins B-series engines

Application Balance Teeth Weight Part Number
DODGE 5.9L Cummins 1994-07, One Piece Billet Steel, Meets SFI Diesel Spec 29.3, Black Oxide Internal 152 11.50 lb 1835921
DODGE/RAM 6.7L Cummins 2007-Up, One Piece Billet Steel, Meets SFI Diesel Spec 29.3, Black Oxide Internal 152 12.25 lb 1840821

PQX® SFI-Rated Platinum Series Diesel Steel Flexplates for B-series Cummins, Ford Powerstroke

 

Application Balance Teeth Weight Part Number
DODGE 5.9L Cummins 1994-07 (Prior years may require aftermarket transmission spacer) Meets SFI Spec 29.1 Internal 152 9.75 lb 1835910
DODGE/RAM 6.7L Cummins 2007-Up, Meets SFI Spec 29.1 Internal 152 9.70 lb 1840810
FORD 6.0L/6.4L Powerstroke Diesel, 2003-2007 363ci for 5R110 Transmission, Meets SFI Spec 29.1 External 141 9.39 lb 1836311
FORD 7.3L Powerstroke Diesel, 1989-2006 445ci for E4OD or 4R100 Transmissions, Meets SFI Spec 29.1 External 155 9.53 lb 1844511

 

PRW feels the line of SFI 29.1 and 29.3 spec flexplates for high performance/competition diesels fills a very much needed safety niche in the high performance diesel market.  These flexplates, properly used and installed, will protect personal safety and property.

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