Class 1 Touring Cars refers to two generations of prototype silhouette-style touring car regulations employed by the FIA.
The first generation was a production-based formula introduced in 1993 along with Class 2 Touring Cars, the latter officially becoming known as Super Touring cars from 1995. Class 1 permitted more liberal modifications to the vehicles than those allowed for Class 2 cars.[1]
These Class 1 regulations restricted engines to a maximum of six cylinders, 2.5 litres capacity and four valves per cylinder.[2] The basic unit had to be derived from a production engine made in quantity by the same manufacturer as the car, although it did not have to be from the same model as that being raced and could be extensively modified. All-wheel drive, traction control, anti-lock brakes and electronically controlled differentials were permitted. Aerodynamic aids were free below the wheel centreline and, from 1995, suspension systems could be purpose-built rather than production-based.[3]
Class 1 Touring Cars contested the Deutsche Tourenwagen Meisterschaft (DTM) series from 1993 to 1995,[4] the International Touring Car Series (ITC) in 1995[5] and for the International Touring Car Championship (ITC) in 1996.[6]
Only three manufacturers, Alfa Romeo, Mercedes-Benz and Opel, competed in Class 1 during the short history of the original category, with genuine works efforts (Audi and BMW had built cars based on the B4 80 Quattro and E36 M3 respectively for the class, but never raced them)[7] and the withdrawal of Alfa Romeo and Opel from the ITC at the end of 1996 effectively spelt the end of the class.
In early 2014, the DTM and the Japanese Super GT Series began a co-operation agreement in which the two series would begin to merge their technical regulations.[8] This led to an official tie-up in September of the same year, with plans for the DTM to move to 2.0-litre inline-4 engines by 2017.[9] Aerodynamic alterations were agreed in 2015, with the seeds sown for potential joint-races between the series.[10]
Later in the same year however, the regulation changes were postponed to 2019 given DTM manufacturers' reluctance to potentially engage in more costly development.[11] Super GT would also delay the implementation of the regulations to 2020, as the final regulations were signed off in 2018.[12]
The second generation of Class 1 Touring Car is a purpose-built racer based on a two-door road-going model. The cars feature a two-litre turbocharged inline-four engine, capped at 650 hp and mounted in the front of the car. Push-to-pass and DRS are employed on the DTM vehicles (but not in Super GT), which benefit from 3.4t of downforce. All vehicles must be front-engine, rear-wheel drive.[13] [14]
The first Class 1 cars debuted at the 2019 DTM Hockenheim round. DTM and Super GT conducted joint-races at the end of 2019, however both saw the previous generation Super GT GT500 cars enter.[15] Aston Martin, entering DTM for the first time through the new regulations, concluded their program after a single season with constructors R-Motorsport claiming the cars were too expensive.[16] Audi followed suit by announcing their departure from the series for the 2021 season in April 2020.[17] The DTM eventually abandoned the regulation set after just two seasons and switched to a GT3–based formula from 2021.[18]
| Marque | Picture | Model | Engine | First race | Last race | |
|---|---|---|---|---|---|---|
| Alfa Romeo | 155 | Alfa Romeo Busso-based 2.5L V6 60° Alfa Romeo 690[19] 2.5L V6 90° | 1993 DTM – Zolder 1 | 1996 ITC – Suzuka | ||
| Mercedes-Benz | 190E | Mercedes-Benz M102 2.5L I4 | 1993 DTM – Zolder 1 | 1993 DTM – Hockenheim 2 | ||
| C-Class | Mercedes-Benz M106[20] [21] 2.5L V6 90° | 1994 DTM – Zolder 1 | 1996 ITC – Suzuka | |||
| Opel | Calibra | General Motors C25XE 2.5L V6 54° Cosworth KF (Isuzu 6VD1 derived)[22] 2.5L V6 75° | 1993 DTM – Hockenheim 2 | 1996 ITC – Suzuka |
| Marque | Picture | Model | Engine | First race | Last race | |
|---|---|---|---|---|---|---|
| Aston Martin | Vantage | HWA AFR Turbo 2.0 I-4t | 2019 DTM – Hockenheim 1 | 2019 DTM – Hockenheim 2 | ||
| Audi | RS5 Turbo | Audi RC8 2.0 TFSI I-4t | 2019 DTM – Hockenheim 1 | 2020 DTM – Hockenheim 2 | ||
| BMW | M4 Turbo | BMW P48 Turbo 2.0 I-4t | 2019 DTM – Hockenheim 1 | 2020 DTM – Hockenheim 2 | ||
| Honda | NSX-GT | Honda HR-420E 2.0 I-4t | 2020 Super GT – Fuji 1 | 2023 Super GT – Motegi | ||
| Civic Type R-GT GT500 | ||||||
| Nissan | GT-R Nismo | Nissan NR20A 2.0 I-4t | 2020 Super GT – Fuji 1 | 2021 Super GT – Fuji 2 | ||
| Z | 2022 Super GT – Okayama | |||||
| Toyota | GR Supra | Toyota RI4AG 2.0 I-4t | 2020 Super GT – Fuji 1 |