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What Is Dirt Track Racing?
Often overlooked in the mainstream, dirt track racing is perhaps the most exciting form of automobile racing in North America. It’s a popular form of racing held on oval tracks with a surface of dirt or clay. Dirt track racing is done on over 1,500 tracks throughout the United States.
In the 1920s and 30s, dirt track racing became the dominant form of automobile racing in the United States due to the abundance of thoroughbred horse racing tracks.
There have been traditionally two types of racing cars that have dominated dirt track racing: open-wheel cars—including sprint cars and modifieds, which are primarily run in the Northeast and Midwest—and stock cars, which are raced in the South.
Generally speaking, most dirt tracks are ovals of less than one mile in length with the majority being ½ miles. Other tracks range from 3/8th, 1/3rd, 1/4th, and 1/8th of a mile in length. Longer length tracks tend to be more dangerous due to higher speeds, which increase the chance for injury to drivers and damage to race cars. This is why dirt tracks of one mile or more in length are extremely rare. The most common dirt track surface is clay because it retains moisture more readily, which results in more tacky conditions, allowing the cars to grip the track better and reduce dust.
Each race track and sanctioning body maintains specific rules outlining each class of race car, including dimensions, engine size, equipment requirements, and prohibitions. For the most part, tracks usually coordinate with various other tracks to allow for the widest venue for each type of car. This coordination allows the drivers to compete at many different racetracks, increase competitors' chances of winning, and lets racing associations develop a series of race events that promote fan interest.
There are several forms of dirt track oval race cars, and in this article, we will go over each type. The main types of race vehicles that race on dirt are open-wheel cars, modified cars, stock cars, and motorcycles.
Open Wheel Race Cars
An open-wheel car is a type of car with its wheels on the outside of the body and usually consisting of a single seat. Open-wheel cars differ from their production-based brethren in that their wheels are usually covered by fenders. Open-wheel race cars also tend to have a higher level of technical sophistication, with a Formula One race car being at the pinnacle of technological development and refinement.
Famous racecar driver and constructor Ray Harroun was an early proponent of lightweight, single seat, open wheel monocoque race cars and began racing them competitively in 1906 after a stint working as a mechanic in the automotive industry. He won the then prestigious AAA National Championship in 1910 and was later hired by the Mormon Motor Car Company as chief engineer. Harroun was then tasked with building a race car to compete in the inaugural Indianapolis 500 then known as the International Sweepstakes which he would go on to win. His revolutionary design dubbed the Marmon Wasp would become the blueprint and forefather of all single-seat racecar designs.
The standard open-wheel race car is simple in basic design with a small cockpit sufficient only to enclose the driver's body, with the head exposed to the air. The exception to this is modified stock cars in which the driver's head and body is contained in the car similar to that of a conventional passenger car. In modern open-wheel racecars, the engine is typically located directly behind the driver such as in Indy Car and Formula One racing; however, modifieds and sprint cars retain the standard setup where the engine is in front of the driver. Both types of cars are rear-wheel drive and depending on class rules many types are allowed to have wings at the front and rear of the vehicle, as well as a very low and virtually flat undertray that helps achieve additional aerodynamic downforce pushing the car onto the racing surface. As opposed to off-road racing, an open-wheel race car races on dedicated purpose-built road courses or temporary street circuits, however, these types of races and tracks are beyond the scope of this discussion and we will be focusing on dirt track oval racing from here on out.
Types of Dirt Track Open Wheel Cars
Walking into the gates of your local dirt track for the first time can be both exciting and a bit overwhelming with the plethora of different cars in the garage area and on the track. How do you make sense of it all? Like what is that funny-looking car with the big wings on it, or is that really a go-kart zipping around the track, and what is that behemoth rumbling around the track shaking the grandstands as it speeds by?
As any fan will tell you it all begins to make sense after you attend a few races and get to know what the different classes or divisions are and what types of cars compete in each. First and foremost one must understand that dirt track racing is a very regionalized sport and the types of cars, classes, and race procedures differ from region to region and track to track. Although dirt tracks are sprinkled throughout the United States and Canada the types of cars competing will vary from place to place. For example, in the South and Southeast, stock cars dominate the scene. You will be hard-pressed to find any tracks there running sprint cars on a weekly basis. In contrast throughout the Midwest and oddly enough Pennsylvania sprint cars are the most popular form of dirt track racing, although you will find a few stock cars here or there. In the Northeast, modifieds are king with the big block Super DIRT Modifieds always being crowd favorites. On the West Coast, you will find the highest concentration of non-wing sprint cars which always put on death-defying if not sometimes dangerous shows. We will explain what each type and most common types of open-wheel dirt track race cars are and where you can see them race.
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Entry-Level Open Wheel Race Cars
A go-kart is a small tubular frame open-wheel vehicle that typically uses small 2-stroke or 4-stroke gasoline-powered engines. Racing karts are single-seat vehicles that can reach speeds up to 160 mph but the typical dirt track kart usually reaches speeds ranging from 30 to 50 mph. Most karts are open and have no roll cage, but on many dirt tracks, a cage is required due to the higher speeds being reached and the increased chance of a rollover or flip usually caused by close contact racing.
Karts are usually the entry-level class at most tracks and people looking to get into the sport find this an economical way to test the waters before committing serious money on a true race car. Drivers can start racing karts as young as 7 or 8, however, there are different classes divided between different age groups. During a typical Saturday night racing program the karts are usually the first class on the track and the races tend to be very short, anything ranging from 4 laps for a trophy dash to 20 laps for a feature event. One of two types of qualifying and race formats can be used. Some tracks use a racing format of two 10-lap heats followed by a 20-lap final. Finishing positions in the two heat races are used to calculate the starting position in the feature race. The other popular format is time qualifying. Karts equipped with transponders are sent out onto the track in groups of 5 or less to try to achieve the fastest lap time. Positions for the 20-lap feature event are determined by qualifying times.
Quarter Midgets are a popular class of entry-level racing and the next step up from racing karts. A quarter midget is ¼ the size of a full midget sprint car. Drivers are usually restricted to the ages of 5 to 16 years old and there are upwards of 4,000 quarter midget racers in the United States.
Most quarter midgets can reach speeds of anywhere between 30 to 45 mph and this is considered safe due to the limited size of the tracks they compete on. Tracks are typically banked dirt ovals of 1/20th of a mile long. Although quarter midgets can run on larger tracks that run Saturday night programs this is not common and most quarter midget races are sanctioned by a local or regional sanctioning body that runs on tracks specifically built for quarter midget racing.
A micro sprint is the next class of race car found on dirt tracks after quarter midgets. They are smaller versions of full sprint cars and must run a side-mounted, chain-driven 600 cc motorcycle engine. They can either be winged or non-winged depending on the track regulations. Their chassis and body style is like that of a full-sized sprint car or midget sprint car. The minimum weight for a winged sprint is 750 lbs while non-winged must weigh 725 lbs. Generally speaking, a micro sprint is supposed to be a more cost-effective alternative to racing a mini sprint or midget but sometimes can cost just as much or more depending on the level of competition and willingness to invest in the program. The minimum age at most tracks to race micro sprints is 12 and there is no maximum age so many adults can find enjoyment racing in this class also.
Very similar in appearance to a micro sprint, a mini-sprint is a slight step up from its micro counterpart and is more comparable to a full-size sprint car in appearance and a midget sprint car in size and dimensions. In a true mini-sprint, the driver sits upright as in a sprint or midget. Mini-sprints feature an upright style chassis, and a center-mounted four-cylinder motorcycle engine and are similar in size and appearance to a modern-day midget sprint car. Engines are chain-driven and can range anywhere between 600 cc and 750 cc in size and cars can weigh anywhere between 750 to 825 lbs.
Midget Sprint Car
A midget packs a lot of power into a small package and these cars feature a very high power-to-weight ratio and typically use four-cylinder engines. Midget engines have 300 to 400 horsepower while only weighing 1,000 lbs, which makes these cars extremely fast, and very dangerous. Full safety roll cages are mandatory for this exact reason. They are designed to run relatively short sprint-style races seldom exceeding 50 laps in distance.
The United States Auto Club (USAC) is the primary sanctioning body for midget racing in the United States and the national midget championship is one of the crown jewels of their vaunted Triple Crown Championship. Few local tracks conduct a weekly midget racing program and most midget races are hosted by a regional or national touring series.
Non-Wing Sprint Car
Historically speaking all sprint cars were non-winged and it wasn’t until the 1960s that winged sprint cars began to overshadow their non-winged counterparts. However, there is still a strong following for non-winged sprint cars, especially in California where this type of racing garners the most support. Purists however respect non-wing sprint racers because this type of car is more difficult to control as traction is harder to find and the cars spend more time sideways putting a premium on driver skills and offering more side-by-side racing. This also makes them extremely dangerous and there has been an increase in serious and fatal injuries leading to non-winged sprint cars being banned on certain tracks.
Winged Sprint Cars
Winged Sprint Cars are simply put the fastest, highest horsepower, and most dangerous race cars on dirt today. They are truly awesome machines and words cannot describe what it is like to see one in person. Although they can be seen throughout America, sprint car racing is the motorsport of the Midwest. The vast majority of sprint car racing's biggest events take place at tracks in this region.
As the fastest cars on dirt, everything about a sprint car is pure speed and anything not absolutely necessary to make the car go fast is discarded. They do not even have starters and have to be pushed to start. You may hear or see the term 360 or 410 sprints. This is referring to the engine displacement. 360 means the engine has 360 cubic inches of engine displacement and 410 means the engine has 410 cubic inches of engine displacement.
The purpose of the wings is to provide as much down-force as possible in order to keep the car glued to the track. Tracks now limit wing size to 25 square feet. While many tracks allow wings that can be adjusted by the driver in the cockpit many do not. The cars use methanol fuel and the gas tanks can carry anywhere from 25 to 35 gallons, but drivers and crews have to be mindful of fuel load because carrying too much will make the car too heavy, and not carrying enough will result in running out and that spells the end of the night because there is no time to refuel in a 50 lap sprint race.
When it comes to engines the 410 is the engine of choice for Outlaw Sprint Cars. These engines are capable of producing an amazing 850 horsepower and that is spectacular in a car only weighing 1,400 lbs. Due to high cost, most local dirt tracks only run 360 Sprints and this enables many hobby racers to compete due to lower costs and availability of engine parts. Typical 360 engines are based on production cast-iron blocks and heads, using a wet sump in place of the expensive dry-sump system, and forbidding down nozzles. These restricted engines are typically much cheaper to build at around $10,000.
Silver Crown Car
A silver crown car is a throwback of a bygone era and are the direct decedents of the old Indianapolis Roadsters that ran throughout the 1950s and early 60s. Silver Crown cars run on dirt or asphalt and look very much like a sprint car but much bigger. They run production-based V-8 engines capable of producing 700 horsepower while only weighing 1,500 making for one quick and nimble race machine.
As we leave the exciting world of the light and nimble high horsepower sprint cars and go over to the other side of dirt track racing and learn about the fender bending, beating, and banging world of stock cars we will enter a completely different racing culture. With roots dating back to the 1920s prohibition era when moonshine runners would attempt to outrun the authorities in souped-up production cars. With the repeal of prohibition in 1933, there was an abundance of fast modified cars sitting about so guys got together and started having informal races against one another. It quickly became apparent that there would need to be some standard set of rules if the races were to be fair so Bill France Sr. and other promoters from the south got together and came up with a uniform set of rules in the guise of the National Association for Stock Car Automobile Racing or NASCAR for short and the rest is history.
Street Stocks and Pure Stocks
Street Stocks are a rough and tumble class of production-based race cars. This class is the most numerous on the local dirt track due to the fact that few modifications are allowed and a car can be brought from a local junkyard and brought up to racing standards. A team has to simply strip the car of all unnecessary components and add a safety roll cage and go racing. Depending on the track they can be called street stocks, pure stocks, hobby stocks, bombers showroom stocks, or U-cars. Due to the abundance of front-wheel drive cars now available in many junkyards this type of car has become more prevalent on local dirt tracks. Street stocks are the most numerous class of stock cars on dirt because affordability and car counts continue to be high despite recent economic challenges.
Super Stocks are the next highest stock car class of racing at the local dirt track. Very similar in appearance to street stocks, super stocks allow more modifications to the engine and are capable of producing between 500 and 550 horsepower. Depending on track they can be called super stocks, sportsman, or limited late models. Super stocks have the same body rules as dirt late models and super late models with the main difference typically being maximum engine displacement size, certain required cylinder head angles, maximum compression ratios, and maximum carburetor size. Suspension rules typically forbid the use of expensive canister shocks. Tire choice is also limited to spec tires usually produced by the Hoosier Tire.
Dirt Late Model
Dirt Late Model stock cars have the same body rules as super stocks but have more stringent rules than the higher-level super late models. Many tracks require small-block V-8s that must be all steel except the intake manifold. Crate engines have also become a popular option for many local tracks. General Motors is the primary supplier of crate engines. These engines are sealed at the intake manifold, cylinder head, front cover, and oil pan with special twist-off bolts. Crate engines can’t be altered, modified, or changed in any way from factory specifications.
Super Dirt Late Model
A dirt super late model is the top class found at the local level and is the primary car type used in the regional and national tour series throughout the United States and Canada. These cars feature steel constructed tube frame chassis with aluminum bodies that give them the sleek aerodynamic appearance of a stock race car but there is nothing stock about these 2,300-pound machines. The cars are powered by an 850 horsepower engine that can turn in excess of 9,000 RPM. The engines are based on V-8 Chevy, Ford, and MOPAR power plants. These cars are considered to be the most sophisticated cars in dirt racing. They hit speeds well over 100 mph and slide around the corners of the track. They are raced on dirt tracks throughout the country anywhere from 1/4 to 1/2 mile in length.
Racing these types of cars can be extremely expensive with a single car costing upwards of $70,000 dollars. Used parts and components can be purchased, but in order to be competitive, only the top of the line equipment is required. Winning engines must be capable of producing upwards can cost $40,000 dollars or more. Unlike in NASCAR racing, many super late model teams and drivers travel to major events forgoing competing in a single touring series because they can make more money racing in major events. Most touring series and special events offer different motor options with the use of different total vehicle weights to create an even playing field.
Dwarf Cars are scale replicas of vintage modified race cars. They are true open modified style cars without fenders and run 1,250 cc engines which are limited in size. They are 5/8th scale vintage 1928-48 American-made automobiles and feature full steel roll cages. They also have sheet metal bodies and have full racing suspension and are capable of speeds over 100 mph on the straight-away. This is an affordable class and a cost-effective alternative to full-sized race cars. A brand-new roller car is $7,000. Most engines are supplied through the salvage pool and typically cost between $1,500 and $2,500. Sometimes one can find a used dwarf car ready to race for under $3500.
Legends Cars are an economical form of racing very similar to dwarf cars but with stricter rules and regulations and have fiberglass bodies. The bodies are 5/8-scale replicas of American automobiles from the 1930s and 40s and are powered by Yamaha motorcycle engines. The sanctioning body for Legends car racing is called INEX. INEX stands for inexpensive racing. Legends are an offshoot of dwarf cars and are styled after vintage modified race cars that competed in the 1950s and 60s. They are common on both dirt and asphalt race tracks.
Dirt modifieds are the most popular and common type of race car racing on dirt tracks throughout the United States. They are the oldest type of race car currently racing today with a history dating all the way back to the days of the post–World War 1940s. The term for modified comes from the fact that they are not stock but, rather, modified passenger cars differentiating them from production-based cars. Early modifieds began with drivers modifying their production-based cars to give them a competitive edge. Over time, cars in this class have morphed into something that no longer represents any current production-based vehicles. Today, modifieds are a hybrid between a traditional stock car and an open-wheel race car.
IMCA style modifieds are the most common type of modified raced throughout the United States and Canada, but originally started out as dirt modifieds but are also raced on asphalt. In this style of modified the driver sits on the left side of the car and lack the down-force components of other types of dirt modifieds. IMCA modifieds use stock production frame components as part of the racing chassis and are popular because of their simple design, light-weight, high power, and ability to easily adapt to varying track conditions.
Super DIRT Modifieds
Super DIRT Modifieds are one of the premier types of modifieds racing in North America and are unique in the fact that they are the only major race car type that still runs big-block engines. They run engines of up to 467 cubic inches engine displacement and can range from 650 to 800 horsepower and can reach speeds upwards of 160 mph. The minimum weight for these cars is 2,500 lbs.
Motorcycle Flat Track Racing is an obscure and often overlooked form of dirt track racing that has a history dating back to the 1930s. They run either two-stroke or four-stroke engines in amateur competition while four-strokes dominate professional competitions. Flat track bikes have front and rear suspension, and rear brakes. Successful riders will often move to road racing, which is considerably more lucrative. Many top American riders in Grand Prix motorcycle racing began their careers as flat track racers.
The American Motorcyclist Association (AMA) is the primary sanctioning body for this type of racing and its premier division is the AMA Grand National Championship. During its golden age of the 1950s through the late 1970s, this was the most popular form of motorcycle racing in the United States. Flat Track motorcycles can reach speeds of 130 mph with an engine displacement of 550 cc to 1250 cc but are restricted to 750 cc in race conditions. Major manufacturers include Honda, Kawasaki, KTM, Suzuki, and Yamaha. Mile race tracks are the most common and are run at venues that also conduct thoroughbred horse racing; however, half-mile tracks are also common and are held at tracks that also hold automobile races.
There are several dozen sanctioning bodies that conduct dirt track racing throughout the United States and Canada. Below is a listing of the largest and most popular. In addition to sanctioned races, there are hundreds of regional and national special events run throughout the year.
The World of Outlaws (WoO)
The World of Outlaws is the top sanctioning body for winged Sprint Cars in the United States and Canada. They sanction two major national touring series including the World of Outlaws Sprint Car Series and the World of Outlaws Late Model Series. The series is owned by World Racing Group, which also owns the Super Dirt Car Series.
World of Outlaws runs a national tour of high power to weight, custom fabricated sprint cars called the World of Outlaws Sprint Cars. The cars feature large adjustable wings on top and large rear tires that transfer their power to the dirt surfaces they race on. The series travels primarily the United States, but it also has sanctioned races in Canada, Mexico, and Australia. They hold approximately 92 races per year at 52 different tracks across 24 states and three Canadian provinces
A World of Outlaws Sprint Car is a purpose-built open-wheel race car that must weigh at least 1,400 pounds with the driver in the car. The 410-cubic inch engine is fueled by methanol. They produce approximately 850 horsepower and transfer it to the ground through specially built racing tires. The series cars have a large top wing with sideboards that face opposite directions to help produce a great amount of down-force to plant the car on the track and help the car turn and maximize grip, both in the corners and on the straightaways. They also run with smaller nose wings.
The World of Outlaws Dirt Late Model Series runs a similar tour that features dirt late models and its national tour runs many of the same venues as the Sprint Cars. The series runs over 50 events at more than 30 tracks in 20 states and Canada.
Lucas Oil Late Model Dirt Series
The Lucas Oil Late Model Dirt Series is a dirt late model national touring series that runs nearly 50 events in 19 different states. They are one of the top-level dirt late model racing series in the United States. The cars are capable of producing over 800 horsepower. Chevrolet, Ford, and Mopar are all represented in this series. Fields are healthy with an average of 44 cars attempting to qualify for each event. Marque events include the Winter Nationals at East Bay Raceway Park, the Show-Me 100 at Lucas Oil Speedway, and the Lucas Oil Late Model Knoxville Nationals at Knoxville Raceway.
International Motor Contest Association (IMCA)
IMCA is the oldest active sanctioning body in the United States with a history dating all the way back to 1915. It’s currently based out of Vinton, Iowa, and features several classes and divisions of weekly racing in six geographical regions of the United States. The series holds races in eight classes including modifieds, dirt late models, non-wing and winged sprint cars, stock cars, hobby stocks, Sportmods, and Sport Compacts. The IMCA championships are held annually at the IMCA Super Nationals at Boone Speedway in Boone, Iowa.
United Midwestern Promoters (UMP)
UMP is a short-track racing sanctioning body in the United States that is owned and operated by Dirt Motorsports a division of the World Racing Group. UMP sanctions short-track racing on dirt tracks from 1/5 mile in length to 1-mile in length. They currently sanction eight different racing divisions on over 100 tracks in 19 states and one province in Canada. Classes include: Super Late Models, Modifieds, Pro (Crate) Late Models, Limited Modifieds, Sportsman, Street Stocks, Factory Stocks, and 4 Cylinders.
Super DIRT car Series
The Super DIRT car Series is a dirt-modified touring series based in the Northeastern United States. They sanction races in four classes including the Big Block Modifieds, 358 Modifieds, Sportsman, and the Pro Stock Series. Up until the close of the 2015 racing season, the series premiere event was the Super Dirt Week held at the New York State Fairgrounds in Syracuse, NY. Future plans for the event are in the works for the race to be held at a new, state-of-the-art facility that is currently under construction about 20 minutes north of Syracuse.
United States Auto Club (USAC)
USAC is a major automobile sanctioning body and is the successor of the American Automobile Association (AAA). It currently sanctions races in the Silver Crown Series, National Sprint Car Series, National Midget Series, HDP Midget Series, Quarter Midget Series, and the Traxxas TORC Series.
One of the most famous series in all of motorsports is the USAC Triple Crown. The Triple Crown is earned if any single driver succeeds in winning all three of the USAC National Championships in a single season. Currently, USAC sponsors a National Championship where driver's finishes in their 25 best races are counted toward the championship and the winner will receive a high dollar cash award. Points are accumulated in the three national series: sprints, midgets, and Silver Crown.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.