Pro Modified, also known as Pro Mod, is a class or division in the sport of

drag racing Drag racing is a type of motor racing in which automobiles or motorcycles compete, usually two at a time, to be first to cross a set finish line. The race follows a short, straight course from a standing start over a measured distance, mos ...

used in the

NHRA The National Hot Rod Association (NHRA) is a governing body which sets rules in drag racing and hosts events all over the United States and Canada. With over 40,000 drivers in its rosters, the NHRA claims to be the largest motorsport sanction ...

and FIA (quarter-mile) and the Professional Drag Racers Association (PDRA) (eighth-mile). It is similar to the Top Doorslammer class as defined by the ANDRA.

Overview

NHRA Pro-Mod - Driver Stevie Fast - Bahrain 1 Racing

This division has specific rules about

engines An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gen ...

, components, bodies, etc. Pro Modifieds can either be raced on 1/4 mile or 1/8 mile tracks. Usually, the NHRA races Pro Mod cars on the 1/4 mile, resulting in high 5 to low 6 second passes, while the PDRA races strictly on 1/8 mile track setups, allowing for high 3 second-to low 4 second passes. Despite Pro Modified cars being slower than the

Top Fuel Top Fuel is a type of drag racing whose dragsters are the quickest accelerating racing cars in the world and the fastest sanctioned category of drag racing, with the fastest competitors reaching speeds of and finishing the runs in 3.641 second ...

or Funny Car classes, it has become one of the most popular divisions of the sport because of being full-bodied cars resembling Pro Stock cars with a hood scoop or superchargers being permitted. The Professional Drag Racers Association's Pro Modified classes are based on which type of power adder is used (turbochargers or superchargers in Boost, while nitrous oxide is in Nitrous). Due to the near-limitless engine/

drivetrain A drivetrain (also frequently spelled as drive train or sometimes drive-train) or transmission system, is the group of components that deliver mechanical power from the prime mover to the driven components. In automotive engineering, the driv ...

combinations and incredibly lenient rule system used by most Pro Modified racing organizations (for example, no manufacturers matching engine and body requirement), competing teams in this series of drag racing have virtually every freedom to make their car as fast and competitive as it can possibly be. The Pro Modified class originated in the UK in 1988, and was followed in the USA by the IHRA a year later. In Europe, Pro Modified moved from the NDRS to become an FIA class in 2006. The off season between the 2009 and 2010 seasons was the most controversial in years. The IHRA, the first sanctioning body to run the class in the USA, dropped the class in a move to focus more on

nitromethane Nitromethane, sometimes shortened to simply "nitro", is an organic compound with the chemical formula . It is the simplest organic nitro compound. It is a polar liquid commonly used as a solvent in a variety of industrial applications such as in ...

powered vehicles. Picking up where the IHRA left off, the NHRA announced that through a partnership with Get Screened America, Pro Mod would become a full-fledged professional class, running a limited schedule but still competing for national event trophies and a world champion. The winningest drivers in US Pro Modified history are Scotty Cannon, Mike Janis and Shannon Jenkins.

Engines

Starting in the 2020 season there are 4 different engine combinations available for the Pro Modified category. Cars utilizing forced induction via either a

turbocharger In an internal combustion engine, a turbocharger (also known as a turbo or a turbosupercharger) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake air, forcing more air into th ...

roots-type supercharger The Roots blower is a Pump#Positive-displacement pumps, positive displacement lobe pump which operates by pumping a fluid with a pair of meshing lobes resembling a set of stretched gears. Fluid is trapped in pockets surrounding the lobes and ca ...

or Centrifugal-type supercharger are limited to 526 cubic inches with the turbos having a maximum inlet size of 88 millimeters. Both types of forced-induction cars must adhere to a 2,650 lb minimum weight with driver. Normally aspirated vehicles using nitrous oxide are limited to 960ci and 2,425 lbs (1,100 kg) with the driver. Nitrous cars use high octane racing gasoline as fuel while supercharged and turbo cars use methanol as fuel. These engines put out an extremely large amount of horsepower, some at approximately 2500 to upwards of 4000 H.P. The engines propel the cars down the track at speeds of over 250 mph.The

exhaust system An exhaust system is used to guide reaction exhaust gases away from a controlled combustion inside an engine or stove. The entire system conveys burnt gases from the engine and includes one or more exhaust pipes. Depending on the overall syste ...

is similar to that of a Funny Car. Simple short header pipes bolted onto the

engine block In an internal combustion engine, the engine block is the structure that contains the cylinders and other components. The engine block in an early automotive engine consisted of just the cylinder block, to which a separate crankcase was attach ...

heads extend down from the motor and curve upward just before reaching the ground. The exhaust pipes are visible just behind the front wheels of the vehicle. Most of the time, each exhaust port on the heads has its own individual pipe, but in the case of turbocharged engines the four pipes on each side of the

converge into one single pipe which then leads into one of the two

s, as Pro Mod engines are almost exclusively charged by one turbocharger on each side of the motor (one turbocharger for each four cylinders), resulting in two exhaust pipes instead of eight. On November 4, 2019, the

announced the inclusion of the 526ci

Centrifugal supercharger A centrifugal supercharger is a specialized type of supercharger that makes use of centrifugal force in order to increase intake pressures and power. An increase in combustion intake air pressure allows the engine to burn more fuel, which results i ...

as well as the 960ci nitrous injected combinations. Those will be legal for competition as of the first race of the 2020 season. In 2021 and 2022, racer with centrifugal supercharged powertrains took home the NHRA Pro Mod world championship. As of 2023, NHRA announced a rules change to reduce the minimum weight of screw supercharged entries from 2,740 pounds to 2,700 pounds. This change is expected to bring more balance to the competitive field and ensure a level playing field for all teams.

Bodies

The body of a Pro Modified car is somewhat similar to a Pro Stock race car. Pro Mod race cars have either a forward-facing (with the opening in front)

hood scoop A hood scoop (North American English) or bonnet scoop (Commonwealth English), sometimes called bonnet airdam and air dam, is an upraised component on the hood of a motor vehicle that either allows air to directly enter the engine compartment ...

for nitrous injected cars, or the hood may be cut to allow a supercharger to be fitted through onto a blown motor. Also, a Pro Modified car is usually fitted with a long, flat wing extending from the base of the rear

windshield The windshield (American English and Canadian English) or windscreen (Commonwealth English) of an aircraft, car, bus, motorbike, truck, train, boat or streetcar is the front window, which provides visibility while protecting occupants from t ...

and past where the lip of the trunk lid would be on a normal car. This wing aids in

downforce Downforce is a downwards lift force created by the aerodynamic features of a vehicle. If the vehicle is a car, the purpose of downforce is to allow the car to travel faster by increasing the vertical force on the tires, thus creating more gri ...

and

stability Stability may refer to: Mathematics *Stability theory, the study of the stability of solutions to differential equations and dynamical systems ** Asymptotic stability ** Exponential stability ** Linear stability **Lyapunov stability ** Marginal s ...

, and helps keep the car on the ground. Many body styles are represented in the Pro Mod class. Everything from a

Plymouth Superbird The Plymouth Superbird is a highly modified, short-lived version of the Plymouth Road Runner with applied graphic images as well as a distinctive horn sound, both referencing the popular ''Looney Tunes'' cartoon character Road Runner. It was th ...

to a

Volkswagen Beetle The Volkswagen Beetle, officially the Volkswagen Type 1, is a small family car produced by the German company Volkswagen from 1938 to 2003. One of the most iconic cars in automotive history, the Beetle is noted for its distinctive shape. Its pr ...

has been seen at the dragstrip in Pro Mod fitting. Some of the more common body styles include the

Chevrolet Corvette The Chevrolet Corvette is a line of American two-door, two-seater sports cars manufactured and marketed by General Motors under the Chevrolet marque since 1953. Throughout eight generations, indicated sequentially as C1 to C8, the Corvette is not ...

and Camaro, the

Ford Mustang The Ford Mustang is a series of American Car, automobiles manufactured by Ford Motor Company, Ford. In continuous production since 1964, the Mustang is currently the longest-produced Ford car nameplate. Currently in its Ford Mustang (seventh ...

, and

Studebaker Studebaker was an American wagon and automobile manufacturer based in South Bend, Indiana, with a building at 1600 Broadway, Times Square, Midtown Manhattan, New York City. Founded in 1852 and incorporated in 1868 as the Studebaker Brothers Man ...

vehicles. Small pick-up trucks, like the Chevrolet S-10 also make for popular Pro Mod vehicle choices. The material with which the body of a Pro Modified race car is constructed out of is a Carbon Fiber or similar composites, similar to the material used in the bodies of most race cars. In 2008, the IHRA banned any body style of a current legal Pro Stock car ( Chevrolet Cobalt, Dodge Stratus, or

Holden Commodore The Holden Commodore is a series of automobiles that were sold by now-defunct Australian manufacturer Holden from 1978 until 2020. They were manufactured from 1978 to 2017 in Australia and from 1979 to 1990 in New Zealand, with production of ...

, or the former Pontiac G6 GXP) from being used in Pro Modified, but that rule disappeared when the IHRA ceased sanction of the class. Any legal body style is permitted in NHRA or PDRA sanctioned races, with former NHRA

Pro Stock Motorcycle Pro Stock Motorcycle, formerly known as Pro Stock Bike, is a motorcycle drag racing class that is the two-wheeled equivalent of Pro Stock. It has been a feature of NHRA drag racing since the 1980s when it was added to the professional class s ...

champion Matt Smith racing his father's (Trickie Rickie Smith's) 2010-style Chevrolet Camaro at the 2011 U. S. Nationals.

References

{{Class of Auto racing Drag racing classes

Overview

Engines

Bodies

See also

References