1977 BMW Motorsport 320i Group 5 ‘HAT’ – Ex Ronnie Peterson

One of 31 E21 320i Group 5 cars constructed by BMW Motorsport GmbH for competition in Group 5 ‘Division two up to 2000cc class’ for the 1977 season, originally constructed for the Hohmann Auto Technik (HAT) team for their use in the 1977 Deutsche Rennsport Meisterchaft (DRM) driven by Formula One ace Ronnie Peterson and Mario Ketterers

Group 5 ’Special Production’ was introduced by the FIA in 1976 to reinvigorate motor racing with two aims in mind: attract manufacturers to the sport and fill circuits with spectators at a time when interest in prototype sports racing cars was waning. The scant rules demanded that the original shape of the bodywork be retained: bonnet, roof and boot had to be identical in size to their road going counterparts.

Beyond those requirements and retaining overall dimensions and engine capacity, whether turbocharged or not, pretty much anything went! It was always the FIA’s intention for Group 5 to become a class in which engineers could use their imagination and in doing so some of the most outlandish machines emerged. Group 5 cars had three things in common: they were unbelievably fast, innovative from an engineering perspective and very exciting to watch.

In 1976 series production of the CSL and 2002 was discontinued and it was the last year that BMW Motorsport ran factory CSL’s, with Porsche’s introduction of the 934 it was evident BMW needed a new car to remain competitive within the new regulations of Group 5. BMW engineers Rainer Bratenstein and Martin Braungart received the challenging task of creating a fresh Group 5 racer. Enter the E21, BMW’s foundational 3 series that first saw production in road form in 1975.

The E21 was known for its compact dimensions, shark nose, driver orientated cockpit and light/nimble driver characteristics meant BMW’s decision to base the Group 5 racer on the new 3 series was no surprise. It was important that the track racer bore a passing resemblance to the car parked in front of your house and the development of this model set the precedent for 50 years of driver focused BMW road cars.

Unlike other Group 5 racers that relied heavily on a spaceframe tubular construction, the E21 retained a lot of its original production body with only the rear wheel arches being cut out to accommodate the huge rear tyres. The roll cage was used to stiffen the body as much as possible and weight savings were made with the aerodynamic package, flared wings, bonnet, doors, side-skirts produced in fibreglass. Side and rear windows were in constructed from perspex with just the front screen made in glass and dry weight came in at 830kg of a permissible 790 kg minimum.

With just 3 months of development available to them the BMW engineers cleverly utilised some of the tried and tested mechanical components from the CSL such as steering knuckles, wheel carriers and braking system. BMW Motorsport utilised their  M12/7 Formula 2 engine that featured dry sump lubrication and Kugelfischer mechanical fuel injection, putting out a reliable 300-430 hp at a heady 11,200 rpm. BMW Motorsport also ran the 320 with a 1.4L Turbo engine which helped develop the units later used in their Formula One efforts

Initial testing was completed by Brian Redman driving the first Group 5 320 in race conditions, completing 207 laps of Zeltweg on September 28th 1976 and further development aided by Eddie Cheever, who completed another successful 118 laps of the Salzburgring in October of that year before the three ‘BMW Juniors’, Manfred Winkelhock, Eddie Cheever and Mark Surer continued testing duties alongside Formula One veterans Ronnie Peterson and Gunnar Nilsson at Paul Ricard before Christmas. Just over thirty examples were constructed by BMW Motorsport and they remain one of the most iconic BMW competition cars of all time

HOHMANN-AUTO-TECHNIK – ‘HAT’

Amateur racing driver Reinhold Hohmann acquired two of these cars for his Leonberg based team working alongside technical ace Dieter Basche, a BMW Team GS engineer and former racing driver. During its first season in 1977 E21-R1-07 was driven by F1 ace Ronnie Peterson and Mario Ketterer amongst others and it competed in 8 races throughout the DRM Championship in Europe:

13/03/77 Bergisher Lowe Zolder – Pieter Bienefeld 8th

27/03/77 Goodyear 300km Rennen Nurburgring – Ronnie Peterson 3rd (Division 2)

01/05/77 ADAC Eifelrennen Nurburgring – Ronnie Peterson – Did Not Finish

08/07/77 ADAC Super Sport Rennen Kassel – Caiden Airfield – Mario Ketterer 9th

22/05/77 Flugplatzrennen Mainz-Finten – Jochen Dauer – 11th

03/07/77 Norisring Nürnberg – Rudolf Doetsch 3rd

24/07/77 ADAC Flugplatzrennen Diepholz – Mario Ketterer – 7th

30/07/77 Grosser Preis von Deutschland Hockenheim – Mario Ketterer – 6th

AUTOSPORT 31ST MARCH 1977 – REPORT

‘Despite poor weather, a crowd of 70,000 turned out at the Nurburgring last Sunday to watch the non championship Goodyear 300 Group 4/5 race’.

‘The Group 5 entry was one of which a World Championship promoter would be proud, the quality of the cars themselves and the £ 30.000 prize fund attracting several top-line drivers. The closeness of the leading 2-litre times promised much for the 99.32 mile race, and the promise was fulfilled.’

‘Fastest in the 2-litre division was Ronnie Peterson, having a drive for Dieter Basche’s Hohmann Auto Technik team in their BMW 320i (8: 11.1).’

‘Peterson and Cheever had a real no-holds-barred dice in their 2-litre BMW’s which prompted the Elf Team Tyrell F1 man jokingly to ask that “SENIOR team” be prominently stencilled on his car before the afternoon race, so that the young American could make no mistake about the status quo. However, on the third lap Ronnie’s electrics failed and he retired.

‘In the (second) race: ‘This time, Ronnie Peterson found himself up against Stuck, the German led the division at first, with Peterson crawling all over him, but then the Swede dived inside the Faltz car at the end of the pits straight, and it was Stuck’s turn to fight. After many close shaves, the inevitable finally happened and the two BMW’s touched, Stuck retiring to the pits. The 2-litre dice had taken the pair ahead of all but the Bramring Porsche, but Ronnie’s efforts to retain second overall were thwarted by his damaged bodywork, and he soon lost the place to the hard charging Hezemans. Schurti also passed the stricken Hohmann car to take third overall, and almost on the line Cheever came up to demote Ronnie to fifth place overall.’

In 1978 Helmut Bross acquired the car and various drivers competed with chassis E21-R1-07 under the HAT banner. A year later Tom Walkinshaw arranged its sale to Gerry Tyack of Cewfew Garage who competed with it in hillclimbs in the UK. Later the car competed throughout the UK at the hands of Brian Chatfield. In 1993 it was in the hands of Tom Walkinshaw before the current owner acquired R1-07 in 2007

Restoration work started in 2011 with the challenge of returning the car back to its original 1977 specifications, carried out to an exceptionally high standard by Melbourne Performance Centre in Australia and completed in 2017. Since its restoration E21-R1-07 has seen sparing use, successfully participating in 2023 Le Mans Classic and ready for the 2026 season ahead, hugely eligible and offered with extensive spares package in race ready condition

With their outlandish bodywork, fat, sticky rubber and high revving Formula 2 engines they are demanding yet rewarding to pilot and a favourite with crowds wherever they are raced or demonstrated today. Fresh from its restoration and with little use since, E21-R1-07 is ready to be enjoyed by its lucky new owner in the 50^th anniversary year of the conception of the model