IMSA

The series debuted in 1971. It was originally aimed at two of FIA's stock car categories running at two different classes, the GT (Group 3 and 4) and Touring (Group 1 and 2) cars. The first race was held at Virginia International Raceway; it was an unexpected hit with both the drivers and a handful of spectators who attended. For the following year, IMSA founder John Bishop brought in sponsor R. J. Reynolds and in 1975, introduced a new category called All American Grand Touring (AAGT). In 1977, the series would go through a series of major changes. IMSA permitted turbocharged cars for the first time as well as introducing a new category called GTX for cars based on the Group 5 rules. In 1981, after Bishop decided to not follow FIA's newly introduced Group C rules, so he introduced the GTP class for sports prototypes. In 1989, Bishop sold off his organization. After a period of decline in the early 1990s, the Worlds Sports car category was introduced in 1993 to replace the GTP category in 1994. After a period of multiple ownerships, the organization was eventually renamed Professional Sports Car Racing (PSCR). In 1999, PSCR decided to drop their own championship in order to sanction a new American Le Mans Series. Despite various names, the GT series was known commonly as the IMSA series as it had been the organization's dominant series. [edit] Initial divisions The 1971 season was the first racing season, and featured six races. GT cars, similar to the European classes Group 2 and Group 4, were competing in the early seasons. They were divided into four groups. GTO cars were Grand Touring type cars with an engine of 2.5 L displacement or more. This category was dominated by the Corvettes, then by the Shelby Mustangs and then the various factory teams consisting of Cougars, RX-7s, Celicas and finally, the 300ZX. GTU cars were Grand Touring type cars with engines of 2.5 L displacement or less. This series was dominated by the Porsche 914-6, then the Datsun 280ZX and finally by the Mazda RX-7s through the end of the 80's. TO were a touring-type car such as Camaro, Javelin or Mustang with an engine of 2.5 L or more displacement. TU were a touring-type car such as Alfa Romeo GTV, Datsun 510 or BMW 2002 with an engine of 2.5 L or less displacement.

The Camel GT era The first champions were Peter Gregg and Hurley Haywood, in a Porsche 914-6 GTU. Common winners in these early years of IMSA were the Porsche 911 Carrera RSR and Chevrolet Corvette. Camel became the title sponsor during the 1972 season, and the series became known as "Camel GT Challenge Series". The sponsor's corporate decal had to be displayed in a visible manner on the left and right side of the car, and its patch on the Nomex driver's uniform's breast area, featuring Joe Camel. Initially, cars were marked visibly with its category tag, stating which category they belong, but onward from the middle of the 1975 season, all cars within the series had to bear a rectangular IMSA GT decal, which incorporated its logo on the left followed by a large GT tag as well as Joe Camel decal. Starting fields of 30 or more competitors were not unusual during this era. One of the premiere race events was the "Paul Revere 250" which started at the stroke of midnight of the 4th of July. The race was conducted entirely during the night from start to finish. In 1974 a new category called All American Grand Touring (AAGT) was introduced to counteract the Porsche dominance in GTO. Cars such as Chevrolet Monzas or Camaros were typical. This category did not run without controversy. In 1981, Bob Sharp Racing team used a loophole in the rules to build a Datsun 280ZX inside the U.S. with a V8 engine from a Nissan President. This car was not a success and became obsolete when the new GTP category was created. The TU would be phased out in 1974 along with the TO for the following year. Turbochargers were not permitted until the mid-1977 season. They became permitted after protests by Porsche's motorsport department after inspecting Al Holbert's AAGT winning Chevrolet Monza, which had won two titles. Prior to 1977, Porsche privateers struggled with obsolete 911 Carrera RSRs against the AAGT cars. Engine sizes were determined by IMSA officials, who had devised a set of rules to determine fair competition, using a displacement versus minimum weight formula. Turbochargers were taken into account as well as rotary power, fuel injection, and many other engine features. As a result, the new premier class known as GTX (Grand Touring Experimental, which was based on FIA's Group 5), brought on the absolute dominance of the Porsche 935. The 935 became the most successful car in the series.[citation needed] The most successful driver of the seventies was Peter Gregg, who won championships in 1971, 1973, 1974, 1975, 1978, and 1979. Twin turbos were eliminated at the end of the 1982 season after John Paul, Sr. and John Paul, Jr. dominated in a modified 935.

The GT spaceframe era In 1984, GT cars were required to bear a large square decal to determine which category each cars are represented in, GTU would therefore bare a black U on white and white O on black to represent GTO. All others only bore their standard IMSA GT decals. One big change to the rules during the 1980s was the 2.5 liter ceiling having been changed to 3.0 liters, with the maximum of 6.0 liter ceiling still in place. As for the complex set of series rules, 3.0L cars was required to weigh 1,900 lb (860 kg). whereas 6.0L weighed no less than 2,700 lb (1,200 kg). 2 valve turbocharged cars were given an extra 15% weight and 4 valve turbocharged, 20% extra. Electrical fuel injection was to become common and ground effects were prohibited. Steering, braking, transmission and suspension could be left up to the constructor. Bigger and more powerful engines were permitted under homologation rules.[10] Other items that had to be left as unchanged were the number of valves, ports and spark plugs of the original configuration. The Toyota Celica Tc, piloted by the likes of Chris Cord, Willy T. Ribbs and Dennis Aase, proved to be dominant within its class until the teams defection to GTP, utilizing the same engine, becoming dominant once again. Other teams would follow this example, notably Chevrolet Beretta (in the Trans-Am series) and Mazda MX-6 (in IMSA GTU). The Celica was one of the few example of cars that had broken away from its production GT derivatives of the earlier years as with full spaceframe chassis, they became serious race cars. By 1987, the category became dominated by factory teams, with testing sessions becoming common and rules tailored to welcome them in, rather than turn them away, other than that, cars were required to resemble their showroom counterpart with oversized fenders as they were not permitted to be over the width of 79 inches (2,000 mm). There were no restrictions to body materials as most teams favored removable fiberglass and one of the only that remains of the production counterpart is the sheet steel roof. Another car that exploited the rule system was Audi's 90, with its highly advanced four wheel drive system, the car had a potential to become a car to beat during the 1989 season, although the car was proven to be dominant, despite heavy competitions from two factory teams, Roush Racing Mercury Cougar XR7 and Clayton Cunningham Racing Nissan 300ZX, taking seven wins out of fifteen, as Audi stayed away from the early season endurance classics (Daytona and Sebring) as well as having two cars out of the race in two different rounds, therefore costing them the title for both makes and driver (Hans-Joachim Stuck). Another manufacturer to experience a run of wins was Mazda. After some success by the Mazda RX-2 and Mazda RX-3, the Mazda RX-7 won its class in the IMSA 24 Hours of Daytona race ten years in a row, starting in 1982, and won the IMSA GTU championship each year from 1980 through 1987. The car went on to win more IMSA races in its class than any other model of automobile, with its one hundredth victory on September 2, 1990. In 1981, purpose-built GTP cars (Grand Touring Prototypes) appeared in the championship, these being similar to the new FIA Group C cars which would be introduced to the World Endurance Championship from 1982. The main difference between the two categories was the former had no emphasis on fuel consumption. Brian Redman was the first champion of the GTPs, driving a Lola T600 with a Chevrolet engine. March also fielded prototypes, in which Al Holbert won the 1983 championship with a Chevrolet powered car changing to Porsche power later in the season, and Randy Lanier a year later with Chevrolet power. 1984 also saw the introduction of the Porsche 962, which dominated the series from 1985 to 1987. Nissan then took control of the series in 1988, but faced challenges from Jaguar, Porsche, and Toyota throughout the proceeding three years. Toyota was quickest in 1992 and 1993 at the end of GTP era. Along with the GTP cars, the Camel Lights cars, a smaller capacity, non-turbocharged lower powered prototype category was introduced in 1985. Argo were the first Lights champions, followed by Spice. Other well known participants were the Tiga, Royale, Alba, Fabcar, and Kudzu. Starting from the 1986 season, the GTP category had their own decal, which similar to the IMSA GT side decal, an extra P was added to denote their category, Camel Lights cars also bore the same decal. There were many other manufacturers in the GTP class, such as URD, Spice, Intrepid or Gebhardt, and in the early 1990s, Mazda.

Fall of GTP Following a successful heart surgery in 1987, Bishop began to rethink his priorities. He was approached by Mike Cone and Jeff Parker, owner of Tampa Race Circuit. In January 1989 Bishop and France sold the series to Cone and Parker. The new owners relocated the IMSA headquarters from Connecticut to Tampa Bay. Bishop would stand down as president in favor of Mark Raffauf, who was his deputy and its representative on the ACCUS board. Cone and Parker sold it to businessman Charles Slater. Both lost millions attempting to revive the sagging TV ratings. By 1992, there were a number of factors that led to the decline of the GTP category. Porsche concentrated on its IndyCar program when critics stated that the Zuffenhausen marque should have built a followup of its 962. Back in 1988, Al Holbert realized that the 962 was beginning to feel dated. For some, much of the blame was on organization to allow the Japanese works teams to dominate the series. Under Bishop's original vision, privateers and works were able to race equally. Privateer teams to walked away, and the Japanese economy started to go downhill. These factors led Nissan and Mazda to walk away from the series. Critics say that the diminished variety of cars that would disappoint race fans which would finally kill the series in 1993. GTP cars ran their last race on October 2, 1993 at Phoenix International Raceway. The GTP category was credited for many innovations in the U.S. including antilock brakes, traction control, and active suspension. Dave Cowart and Kemper Miller's Red Lobster sponsored team of the early 1980s would innovate racing team hospitalities which became adopted by virtually every other teams in the future. But for those who competed, it was credited for its camaraderie within drivers, especially rivals. Hans Stuck, commenting in the foreword of the book Prototypes: The History of the IMSA GTP Series, sarcastically compared the series' camaraderie to Formula One's lack of such.

World Sports Cars With rising costs and factory teams walking away from the series which meant diminishing entries, IMSA introduced a new prototype category for in 1993 called World Sport Car (WSC). The WSC replaced the GTP and Lights closed-top cars for the following year. The WSC cars were open-top, flat-bottomed sports-prototypes with production engine as opposed to racing versions of production engines from GTP cars. The WSC cars made their debut at the Miami Grand Prix with a sole entry of Brent O'Neill. The car finished last among the cars that were still running. After skipping the 12 Hours of Sebring, the category would compete for the remainder of the season as non-championship rounds, with no more than four cars entering. In 1994 Camel would be replaced by Exxon as the title sponsor.

Trans Am

The Trans-Am Series is an automobile racing series which was created in 1966 by Sports Car Club of America (SCCA) President John Bishop. Originally known as the Trans-American Sedan Championship it has evolved over time from its original format as a manufacturers championship for modified racing sedans to its current form as a drivers championship open to GT style cars. The series was formed at the dawn of the pony car era and was derived from the SCCA's A & B Sedan amateur Club Racing classes, based upon commercially produced cars which had been modified for racing competition. Originally the series was open to FIA Group 2 Touring Cars and it featured two classes, Over 2.0 Liter (O-2) and Under 2.0 Liter (U-2), with both classes running together. The series was best known for competition among American V8 sedans such as the Ford Mustang, Chevrolet Camaro, Plymouth Barracuda, Mercury Cougar, AMC Javelin, Pontiac Firebird, & Dodge Challenger in the 1960s and early 1970s. Marques such as Porsche, Alfa Romeo, Datsun, Mini-Cooper, Saab, and Volkswagen competed in the series Under 2.0 Liter category. The Sports Car Club of America is the sanctioning body for the series and holds the rights to the "Trans-Am" name (Note: trademark ownership is limited to the "Trans-Am" logo, and does not currently extend to the text "Trans-Am" when not used in the context of SCCA-sanctioned events, subject to trademark owner's dispute). The series has also been licensed by the Champ Car World Series and ran the majority of its races in support of the parent open-wheel championship. Beginning in the seventies, Trans Am cars would also be seen competing in the IMSA GT Series. Peter Gregg won the 1973 and 1974, both times driving a Porsche Carrera RSR. He would dominate GT racing for a decade. John Greenwood won the 1975 title in a pair of Chevrolet Corvettes. The fields were made of A and B production cars, for what appears as one of the less exciting seasons ever. Bob Sharp ended up 3rd in a Datsun 260Z.

Evolution Rules evolved over the years, incorporating FIA touring and grand-touring classes as well as SCCA Club Racing classes. The different classes had restrictions placed on the allowed modifications in an effort to equalize competition between the different cars. In 1976, Trans-Am returned to the two category format, classifying FIA Group 4 and 5 cars as "Category II". George Follmer took the 1976 title in a Porsche 934 entered by Vasek Polak. Those cars had been banished by IMSA, and found a new home for the 1976 season. They would be allowed to run by the end of the same season. In 1977, Peter Gregg took another title in a Porsche 934, while Bob Tullius won Category I in his Jaguar XJS. Greg Pickett campaigned a Greenwood Chevrolet Corvette and dominated the series. Bob Tullius again took the Category I crown. John Paul Sr had a trouble free 1979 season and earned the last Category II title in another Greenwood tubeframe Chevrolet Corvette. Gene Bothello won Category I in a Chevrolet Corvette. The GT Era, Big Money, Turbos & Cost Escalation (1980-1988) In 1980, the SCCA developed a weight-to-displacement ratio for handicapping cars. Five-liter, 2600 pound vehicles dominated the field. Soon, tube-frame cars, often based upon commercially available and relatively inexpensive short-track stock car chassis, would begin to appear, eventually becoming the standard for Trans-Am competitors. Turbocharged, small-displacement engined cars would also appear and proliferate as the decade wore on. John Bauer won the title in his Porsche 911SC, defeating the likes of Greg Pickett and Phil Currin, both driving Chevrolet Corvettes and Gene Bothello's Chevrolet Camaro. In 1981, the series gained momentum and saw many teams and drivers came back to the Trans Am. Different makes earned victories. Eppie Wietzes took the title in his Chevrolet Corvette, beating Bob Tullius in his Group 44 Jaguar XJS. Elliot Forbes Robinson won the 1982 crown with a Huffaker prepared Pontiac Firebird. Tom Gloy had a late victory at Sears Point, driving a Ford Mustang. Willy T. Ribbs in a DeAtley Motorsports Camaro in 1983. 1983 marked the emergence of DeAtley Competition, a wealthy contractor who was assembling a two-car team of racing Camaros for the Trans-Am series. DeAtley's major sponsor was Budweiser. Ribbs came to the team as the number two driver, with English Formula One driver David Hobbs driving the teams primary car. They dominated the 1983 season, with Ribbs winning five races and Hobbs winning four. The smooth driving veteran Hobbs took the Trans-Am championship with his more consistent finishes, while the more brilliant, yet aggressive Ribbs was named Trans-Am Rookie of the Year. During practice for the first round of the 1984 Trans Am season, Ribbs fought with fellow competitor, Bob Lobenberg, over an on track incident incident and was summarily fired from the team. Out of a ride for the first four events, Ribbs joined Roush Racing, who had entered into Trans-Am competition that season, driving Mercury Capris. With the help of Ribbs's 3 wins, Mercury took the manufacturers' title from DeAtley's Chevrolet. For the next six years Roush entries would dominate the series, winning 46 of the 83 races. Back with Roush again for the 1985 season, Ribbs scored seven victories and became the leading money winner in Trans-Am series history, yet finished second in points, as teammate Wally Dallenbach, Jr. used his consistently higher finishes to take the championship . 1986 was wildly competitive as the aforementioned Turbocharged, small-displacement engined cars would become more powerful and go from field fillers to race winners. The Roush Racing Mercury Capri V8s and Merkur XR4Ti turbo 4s were head to head against Camaro V8s, and the turbocharged Buick Somerset, when actor/race driver Paul Newman shocked everyone and took round 8 in his Nissan 300ZX Turbo. Dallenbach would again take the championship, this time in a Protofab Camaro. The Roush Merkurs won of Scott Pruett and Pete Halsmer dominated the 1987 season, winning all but one race, with Elliott Forbes-Robinson taking that win in his Porsche 944 Turbo. Pruett would take home the championship. In 1988, after years of rallying, Audi would enter the series with the 200 turbo quattro via the services of Bob Tullius's Group 44 Racing. As usual the car ran their trademark Quattro system. However this did not run without controversy as the car, piloted by Haywood and with both Walter Röhrl and Hans Joachim Stuck sharing duties, steamrollered the opposition taking eight out of thirteen wins. As Audi would defect to IMSA by the end of the season, the SCCA would change the regulation to a two wheel drive only and banning cars with non American engines from taking part. It appeared to be a shame, as it became some kind of a road racing NASCAR show.

The Modern Era (1989-2006) Dorsey Schroeder won the 1989 Championship, driving a Ford Mustang. He wore #25, which celebrated the 25 years birthday for this legendary car. Tommy Kendall won his first Trans Am title in a Chevrolet Beretta. It was the first time this model would ever win a major title. Scott Sharp, son of Bob Sharp, won his first title in 1991, driving a Chevrolet Camaro. Jack Baldwin won the next year, While Scott Sharp took his second crown again in 1993. In the nineties Tommy Kendall, in a Ford, was the driver to beat- he would take four driver's championships in this decade. Chevrolet was also prominent in this time period, with 6 drivers' champions in their cars.