Race Converter Technology with Neal Chance

If you’ve spent any time around the sport of drag racing whatsoever, you’ve more than likely heard the name Neal Chance Racing Converters, seen the decal on the side of a car, or even had the pleasure of running one of their torque converters. Neal Chance has been a part of the high performance drag racing drivetrain landscape for more than 20 years.  Through continual advancements in technology and research, as well as development, torque converter-equipped vehicles are squarely on the map these days with record-setting performances all across the globe. They are virtually bulletproof converters come at a relatively affordable price with simplicity of maintenance and unequaled durability.

In the early 1980’s at the ripe age of 12, Marty Chance began working for his father Neal at his shop pulling transmissions out of cars and performing rebuilds. By 13, he was disassembling transmissions, and a year later, full-on builds. Once in high school, Marty began to tinker with torque converters, and following their father’s purchase of a lathe at the convincing of brother Mitch, began dissecting and learning the in’s and out’s of converters in the backroom of his father’s shop. And thus, Neal Chance Racing Converters, one of the most well respected converter manufacturers in the world, was born.

“My dad and brother were playing with torque converters and we all got to toying around with them and so I guess you could say they got the whole thing started, but I took off with it and that’s how it ended up. I was a one-man show in the back of my dads shop, and it just grew from there. I was doing this full-time by the time I was a senior in high school,” explained Marty Chance.

A torque converter turbine is loaded into a CNC machine.

A Look Inside Design and Manufacturing

Like anything, the design of a racing converter begins with a theory based from experience. That concept can then be transferred to 3D modeling software and from there it’s on its way to becoming a reality. Neal Chance engineers – who design everything in-house – utilize many of the most sophisticated CAD/CAM programs on the market, and through the use of software, can fully test and determine the functionality of a converter design before a prototype is even conceived. “It’s through this sort of engineering and testing that we’ve been able to take converter technology to the next level,” said Chance.

When a steel converter is built, it begins with the use of a donor turbine and pump impeller. The fin angles are set on the various sizes of pump impellers to a specific degree and then tack welded in place and put through the process of furnace brazing – a process where a filler metal is heated above and distributed between two or more close-fitting parts. Once complete, all of the pressure points on the pump impeller and turbine impeller are hand heli-arc welded. Each of the 28 blades – or “vanes” – are hand-welded in six different places. It is this process that makes the fins virtually indestructible.

Neal Chance engineers design everything in-house using sophisticated CAD/CAM software. Once a concept has been designed and throughly tested, it is plugged into a five-axis CNC machine, where the components that make up a racing converter are finely carved into the desired result.

After all of the welding is done on the pump impeller, the center is then cut out of it for what is known as the hub insert. The entire center of the converter is cut out so that the bearing pedestal on the inside and balloon plate on the outside are one solid piece. This design eliminates the air gap that exists on a normal balloon-plated converter.

Likewise, the turbine impeller, following the welding and brazing process, has a custom turbine hub installed that’s made from a heat-treated chromoly material and heli-arc welded on the inside and mig-welded on the outside. The impeller is then pre-machined to ensure that the body of the turbine is running true. The turbine is then face-cut so that the edge of the fins are parallel with the bearing surfaces on the turbine hub to make everything run true. Once the turbine has been machined, it is then balanced much as are the rest of the components in the converter are before completion. “We balance all of the internal components separately because they rotate independently of the exterior shell. Balanced components take less power to turn, and in taking less power to turn, that means more horsepower to the rear tires.”

On the pump side of a converter, after the installation of the hub insert, it also goes through a pre-machining process in which the exterior of the case is checked, the hub insert trued, and the inside bearing surfaces and fins are machined until they are in parallel. The pump is then a finished product, ready for assembly.

The stator, a component that it is interposed between the pump and turbine to alter flow of oil returning from the turbine to the pump, is offered in both billet and fabricated varieties depending on the size of the converter. The billet stator is fully designed on the computer and created by a five-axis CNC machine.

A Stator comes to life on the five axis CNC machine.

The final component is the drive cover, which is the component that bolts to the flexplate. All of the drive covers at Neal Chance are made in-house from billet material. A drive cover begins life as a 100-pound chunk of billet steel material that goes through a lathe and five CNC processes to create the final product. A Neal chance drive cover uniquely features two extra holes on the converter pad so that if a mid-plate is ever added, you can simply add a bolt-on pad extension the same thickness as the mid-plate, bolted on using countersunk screws. Thus, you can swap the converter between vehicle makes, making it a very versatile unit. “Between all of our innovations, we’ve strived to bring the racers a converter that is less dependent on the converter manufacturer. In other words, I’ve taken myself out of the equation,” said Chance.

From 400 to 4,000 Horsepower Applications

Neal Chance offers four basic levels of torque converters that are differentiated by their intended use, design, materials, and price. These range from units designed for use in street and strip applications, all the way up to those used in 4000+ horsepower Pro Modified vehicles.

The Street Performance Converter is designed for for use in high performance muscle cars and trucks that are intended for street driving use, and feature cast aluminum stators, billet steel front covers, and other durable components. The Weld Up Racing Converter, found in more record-setting cars over the years than any other model, sports the fully heli-arc welded fin, options for billet steel and aluminum stators, and custom fin angles. From there, you get into the bolt together converters: the more basic steel model that is a refinement of the original bolt together, and then the full-on, lightweight, billet aluminum racing converter that is six pounds lighter than the steel bolt together and as much as 17 pounds lighter than others on the market.

Billet Racing Converter


  • 5 Axis CNC Machined Body and Fins
  • NCRC Extreme Duty Monster Mechanical Diode
  • Stators available in Fabricated Steel, CNC Billet Steel or CNC Billet Aluminum
  • Custom 5 Axis CNC Machined Fins increase efficiency.
  • Heavy Duty Thrust Bearings
  • Hardened and Ground Pump Hub
  • Dynamic Hi-Speed Neutral Balanced
  • Optional CNC Machined Billet Titanium Drive Cover
  • Available in 8″, 9″, and 10″ models

Bolt Together Racing Converter

  • 100% Furnace Brazed
  • 100% Completely Heli-Arc Welded Fins
  • Anti-Balloning Cover
  • NCRC Extreme Duty Mechanical Diode
  • Stators available in Fabricated Steel, CNC Billet Steel or CNC Billet Aluminum
  • Custom Fin Angles
  • Heavy Duty Thrust Bearings
  • Hardened and Ground Pump Hub
  • Billet Steel Front Cover
  • Dynamic Hi-Speed Neutral Balanced
  • Optional CNC Machined Billet Aluminum Drive Cover for reduced rotating weight
  • Available in 8″, 9″ and 10″ models

Weld Up Racing Converter

  • 100% Furnace Brazed
  • 100% Completely Heli-Arc Welded Fins
  • Anti-Balloning Cover
  • NCRC Mechanical Diode
  • Stators available in Fabricated Steel, CNC Billet Steel or CNC Billet Aluminum
  • Custom Fin Angles
  • Heavy Duty Thrust Bearings
  • Hardened and Ground Pump Hub
  • Billet Steel Front Cover
  • Dynamic Hi-Speed Neutral Balanced
  • Available in 8″, 9″, and 10″ models

Street Performance Converter

  • Intended primarily for street use in high performance muscle cars and trucks
  • Furnace Brazed and Heli-Arc Welded Fins
  • Cast Aluminum Stator
  • Anti Balloning Plate Available
  • Torrington Roller Thrust Bearings
  • Hardened and Ground Pump Hub
  • Billet Steel / Fabricated Front Cover
  • Conventional Spring and Roller Sprag
  • Dynamic Hi-Speed Neutral Balanced
  • Custom Fin Angle for your application

Design Differences

While the price and performance between the models vary greatly, the strength, durability, and internal design are the same throughout. The billet aluminum racing converter and the steel weld together unit sport the very same components and will take the same level of horsepower and punishment, with the only difference being the lightweight materials used in their construction and one being accessible and the other not.

“We actually put a weld together 10-inch converter in Gil Mobley and Chuck Ulsch’s Extreme 10.5 Camaro that just set the record at 206 MPH, ” said Chance.” He runs the all billet aluminum converter, but we’ve also had an all-steel weld together in there. Our reasoning was that we wanted to see what the difference was in performance with the lighter converter, and the aluminum version was significantly quicker. But it will still handle the horsepower.”

The front covers of a Neal Chance converter begin life as a 100 pound chunk of billet aluminum.

The primary difference that exists between the basic converter from Neal Chance or other manufacturers is the two vastly differing and opposing goals for their use. For any heads up vehicle, the goal is always to gain every possible thousandth of a second on the track. For a bracket racing application, however, consistency is much more the name of the game than elapsed time. As such, bracket racers commonly use the weld together converter because they don’t have the necessity of being inside of the converter, nor are they trying different setups and components.

Every Neal Chance Racing Converter is custom built per the customers’ application and needs, from the size of the converter, to the materials and the attributes of the internal components. Along with the basic models mentioned above, a steel and billet converter option is available that can then be upgraded over time with interchangeable parts into a full billet aluminum racing setup.

“We don’t keep anything on the shelf,” joked Chance. “In fact, we don’t even have a shelf. When a guy calls me to order a torque converter, he needs to be ready to spend 20-30 minutes telling me about his vehicle, the type of racing he does, and that sort of thing.”

While drag racing has been and continues to be the main stage for Neal Chance products, many other applications benefit from the use of high performance torque converters. Marty and his team recently built a custom piece for an off-road racing team that found much success with its use, and boat drivetrain prototypes also exist. Their products have been utilized in sand hill climb competitions overseas, and monster trucks have been running converters such as Neal Chance’s since the very beginnings of the sport.

Innovation

By far, the biggest contribution that Neal Chance Racing Converters has brought to the racing industry and that for which they are most known is the the two-piece, bolt together converter. “After we were wiped out by a tornado in 1999, I still found my SEMA award that I won in 1987 for best engineered new racing product of the year for the bolt-together torque converter,” explained Chance. “And it’s kind of crazy that 20 years later, in 2007, TCI won the same award for a similar product. This is something we’d been all over the globe with for 20 years.”

The bolt-together converter made Neal Chance a household name the world over because of it’s simple yet genius design that gave racers access to the internals of the converter in a way that had never been offered prior. Until the bolt together hit the market, the torque converter was essentially a black mystery box that racers commonly made the scapegoat any time something was amiss with their car due to being the one and only component on ones race car that there was virtually zero access to. If the car wasn’t running right, racers just formed the conclusion that it was the fault of the torque converter. “With the innovation of the bolt together converter, the customer then had access to open the thing up to determine if there was a problem with it,” explained Chance. “If a racer smoked his transmission and there was a converter full of trash, he didn’t have to send it halfway across the country and have it cleaned out. He unbolted it, cleaned it out himself, and within a half hour had a fresh, clean torque converter ready to go.”  Another of the great benefits of the bolt together converter was the ability to essentially tune the converter in a similar fashion to a clutch, in that you’re basically setting an efficiency ratio for the power curve of the vehicle.

Neal Chance has taken a lot of heat over the years from some of the sanctioning bodies within the sport due to the cost of the bolt together converter and it’s relative cost to a weld together unit. One such organization even went so far as to outlaw it’s use in their class due to the dominance of the design. “If you were to look at anyone else in the country in a heads-up class that’s competitive running weld together converters, you couldn’t find one that had less than six of them in their trailer. But if you looked at a racer that used a bolt together, you wouldn’t find anyone carrying more than one.”

Much of the increase in performance as well as the cost-savings in heads-up naturally aspirated classes such as NMRA’s Hot Street and NMCA Pro Stock can be directly attributed to the use of bolt together converters. These competitors, who in the past would regularly carry upwards of 15 different converters with them to the racetrack now have just one.

In recent years, the introduction of the lightweight billet aluminum and titanium converters has further solidified Neal Chances’ place on the racing industry map. Simple logic tells us that by removing reciprocating weight from the end of the crankshaft, the crankshaft accelerates faster and in turn, the car is faster. As such, converter-equipped cars have seen significant performance gains in recent years in due part to the rear wheel horsepower gained from the lightweight design. “We borrowed a lot of technology from the aerospace industry, as well as some other sources that we can’t actually name. But we’re confident that our designs will never be fully copied because of the engineering thats behind it,” said Chance.

Neal Chance's engineers - who design everything in-house - utilize many of the most sophisticated CAD/CAM programs on the market, and through the use of software, can fully test and determine the functionality of a converter design before a prototype is even conceived.

Marty and his staff of engineers have continual, full-time research and development projects on the drawing board and beyond, with large amounts of time, money, and resources invested in the technological evolution of torque converter design. As well, they serve as a subcontractor for the aerospace industry from within their 36,000 square foot facility. As a company known for being at the forefront of innovation, they’re obviously very tight-lipped about future technologies, but indicated that some projects they are very excited about are in the works and will change the face of racing converters once again. Chance questioned, “We rely on continually developing new products. What are the best and fastest components out there and asking what does it take to be better?…what does it take to get to the next level?”

Success in Racing

In recent years, Pro Modified, Outlaw 10.5, Drag Radial, and other high horsepower drag racing applications have ditched their clutch combinations in favor of automatic transmissions and torque converters in rapidly growing numbers, and the records and championships have spoken volumes.

Marty attributes two factors to the rise of popularity and performance with torque converters: technology and the shift in the sport toward more 1/8 mile racing by venues such as the ADRL and heads-up, small tire events. “When you’re racing eighth mile versus quarter mile, it’s nothing new for the converter to be faster than the clutch. The only thing new is the distance to the finish line.”

The shorter racing distance plays into the hand of the torque converter-equipped cars through what is known as torque multiplication. This attribute accelerates the car quicker and faster through the front half of the race track. It’s only the back half where the clutch notoriously holds an advantage over the torque converter. Advancements in technology have helped the converter to gain some ground on clutch-equipped cars in the quarter mile over the years, but it’s nothing new for a clutch car to be chasing down the converter car from the 1/8 mile on. “Technology with torque converters is increasing at a rapid pace, whereas the gains in clutch technology are at a much slower pace,” said Chance.  “I don’t want to say that clutch technology played out, but they’ve gotten all they can and now the gains are much smaller than what the converter is making. We had more ground to gain.”

To accomplish the task of building converters for such cars, years of engineering has gone into increasing structural rigidity to create something that can handle the heat, hydraulic pressures, radial forces, and tire shake exerted on them. “The amount of stress inside of a converter during tire shake is almost unthinkable,” said Chance. “Take a C-rotor screw blower car that makes 3,700 horsepower and put that thing into tire shake, well the converter is what’s between the rear tires and the crankshaft. That converter experiences hydraulic forces and heat that are practically unfathomable. It’s like taking 3,700 horsepower and turning it on and off, on and off, load and unload as fast as a paint shaker.”

Advancements in torque converter technology have grown by leaps and bound in the last decade, due in parts to the effort of dedicated manufacturers in the market such as Neal Chance. And today, the torque converter has taken a stronghold in the sport of drag racing and beyond as not only a viable alternative to the clutch in high horsepower, demanding vehicles, but in many cases, a superior combination. And if the present is any indication, the sky is the limit for the torque converter.

Article Sources

About the author

Andrew Wolf

Andrew has been involved in motorsports from a very young age. Over the years, he has photographed several major auto racing events, sports, news journalism, portraiture, and everything in between. After working with the Power Automedia staff for some time on a freelance basis, Andrew joined the team in 2010.
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