Opel Kadett D 400 – Group B Prototype

Published on: Mar 3, 2017 @ 19:43
(C) Jay Auger - website owner & author
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Opel Kadett D 400 Prototype


Around the same time that the Manta B 400 was being finalised as the Group B replacement for the Ascona B 400, Opel Motorsport manager Tony Fall considered an alternative for the future: use the proven chassis and mechanical components of the B 400 and install them under a much more compact and lighter chassis – the Kadett D. The project is said to have been outsourced to German specialist, Matter.



1983 Kadett D GTE.JPG
1983 Opel Kadett 1.8 GTE

Starting life as a normal Kadett D in GTE trim, the car was then carved about considerably and was “grafted” onto a Manta B 400 floorpan. This effectively turned the little Kadett from an unassuming front-wheel drive hatchback to a bold rear-wheel drive rally weapon. This “silhouette” procedure was completely allowed under the Group B regulations.


Compared to the Ascona platform, the B 400 engine in the Kadett was able to be positioned about 50 mm (2 inches) further to the rear of the front axle to slightly improve weight bias and rear traction potential. The normally aspirated, 2.4L “phase 2”, Cosworth engine was upgraded to produce around 220 horsepower.


The exterior of the Kadett D 400 featured a wide arch kit made out of composite panels and polycarbonate windows. The resulting car was said to weigh about a metric tonne but further development and/or replacement of other steel parts with aluminium or composites would most likely drop the weight even more.

The conversion process for the Kadett D 400 turned out to be very time consuming so only a total of three cars are rumoured to have been built before Tony Fall’s deadline; two complete cars and a spare body shell. All prototypes sported slight differences in their specifications and exterior panels.

At the time, not many countries and events allowed for such prototypes to compete and roam around freely. The cars were thus sent to South Africa, where the Kadett model was coincidentally very popular, for extensive testing. One of the two complete cars is said to having caught fire during testing and was unfortunately destroyed. The other car was entered in the country’s 1984 Nissan Int’l Rally and driven by Tony Pond. The Kadett D 400 showed promise, running in second place with three best stage times out of nine, until Pond was forced to retire due to an oil pump failure.


By this time, the face of the World Rally Championship (WRC) was quickly evolving with fierce four-wheel drive machinery.  The Manta B 400 was outclassed by its bespoke competition – leading Opel to “decommission” it out of the international rally scene. The Manta 4WD prototype‘s development had also been cancelled, lacking refinement and potential without a turbocharged engine, thus leaving Opel in a difficult position for their rallying future.

Team manager Tony Fall knew all too well that something even more extreme than the Kadett D 400 was needed to win in the WRC. Not to mention that the Kadett was also soon to be replaced by a new “E” generation. Hence the D 400 project in itself turned into a stepping-stone to the next phase of Fall’s master plan – ultimately giving one last pitch to the GM executives: the Kadett E 4S.


In 1986, the two Kadett D 400s that remained were purchased by Malcolm Wilson to be entered in the British Rally Championship. However, the aluminium roll cage that the cars were equipped with was no longer being accepted. Wilson had them replaced to steel and sold the cars off.

NOTE: The 1986 timing for the return of these cars to Europe sometimes makes them be incorrectly labelled as being Group S prototypes, of which they are clearly not.

Murray Grierson

One buyer, Murray Grierson, would campaign his Kadett D 400 from 1986 to 1989 in both the UK and Scotland Rally Championships to good effect – clinching regular podiums. Co-driven by Roger Anderson, Murray Grierson won the 1987 Scottish title outright and came in as a runner-up in the 1988 British National series. After finishing a disappointing third in 1989, Grierson would then swap his Kadett D 400 for a MG Metro 6R4 “Clubman 300”.

Opel Kadett D 400 Thundersaloon

The other car was turned into a Thundersaloon circuit racer at some point after changing hands and countries multiple times in the 90’s, In the end it returned to Ireland where it was re-converted into a rally car. The 400 engine somehow went missing in all of this action hence prompting then owner, Roy Haslett, to installing a 2-litres Ford Pinto engine. Haslett would use the car in the McGrady’s Insurance Down Rally in 2005, finishing 18th.

The little Kadett would reside in Haslett’s workshop for a while when Davy McLaughlin took interest in its quite unique history and purchased it. Since then, Davy and son Paul thoroughly enjoy putting the car through its paces at occasional clubman events.


Opel Kadett D 400 replica

Henk van der Linde has always been a fan of Opel’s “400” products. He learned of the Kadett D 400’s existence in the early 2000’s. In 2011, not being able to find one of the two prototypes that still existed, Henk begun building his own tribute replica out of four photographs. After its completion, the replica was shown at the 2014 Eifel Rallye Festival in Germany. Henk later sold the car to the Kaiser family in 2018.


Group/Class PROTOTYPE # built: 3
Conception / Production 1983~1984
Type 4S unit with Cosworth “crossflow” cylinder head, I-4, DOHC 16v, gas located front longitudinal
Displacement 2410 cc WRC: 2410 cc
Compression ratio 11.2:1 (presumed)
Output power – torque 220 HP @ 7000 rpm – lb-ft (- Nm) @ – rpm
Materials block: cast iron cylinder head: aluminium
  • natural / normal
  • 2 x Weber carburettors
Ignition electronic, firing order 1-3-4-2
Cooling system water-cooled
Lubrication system dry sump with oil cooler
Type rear wheel drive Getrag 5-speed gearbox
Gearbox ratios (presumed) constant input: 1.652
1st: 3.717
2nd: 2.403
3rd: 1.766
4th: 1.263
5th: 1.000
R: 4.230
constant input: 1.038
1st: 2.337
2nd: 1.671
3rd: 1.355
4th: 1.163
5th: 1.000
R: 2.650
Differential ratio 4.55 ZF hypoid bevel gears, 75% limited slip rear differential
Clutch dry – double disc
Type Kadett D steel monocoque chassis paired with Manta B floorpan. 3 door hatchback.
Front suspension (presumed) McPherson type, independent, telescopic gas shock absorbers and anti-roll bar
Rear suspension (presumed) live axle with 4 longitudinal links, panhard rod, coil springs and telescopic gas shock absorbers
Steering system rack and pinion N/A
Brakes Front and Rear Discs Dual circuit with servo, adjustable ratio split front to rear
length: 3898 mm (157.4 in) width: – mm (- in) height: 1380 mm (54.3 in)
wheelbase: 2520 mm (99.2 in) front track: – mm (- in) rear track: – mm (- in)
Rims – tires N/A N/A
Dry/Unladen Weight 1000 kg (2200 lb)* approx
Weight/power 4.5 kg/HP (10 lb/HP)
Fuel tank N/A



(C) Article by Jay Auger – website owner & author