Probably the most exciting model was the Turbo Manta, which appeared in October 1974. It was the result of a joint venture between Opel, D.O.T. (Dealer Opel Team) and Tony Fall Ltd. (Broadspeed) and was only available in the U.K.
Based on the Manta Berlinetta but re-assembled in the UK to install the Holset turbo unit, the result was a car with a 75% increase in power and a 52% increase in torque over the standard 1900cc engine.
28 cars were built; they were only available in black, with a distinctive large GT/E type front air dam and silver coachlines with small "turbo" lettering on the rear quarters.
They all had maroon cloth interiors and a steel factory fitted sunroof.
A turbo boost gauge replaced the clock in a set of pod mounted SR type gauges.
Sadly reliability suffered (especially when second or third owners tried to run these cars 'on the cheap') and very few working examples remain.
The turbo unit is shown to the left of the photo with the carburettor and plenum chamber in the centre, to the right is the air filter.
Would you like to build a turbo replica? Click here to find out more
- Only available in Black
- Front spoiler
- 1900cc engine with low compression pistons, heavy duty valve springs and special head gasket
- Holset turbocharger and special manifolds
- Modified Solex carburettor in special plenum chamber
- Boost gauge in place of pod mounted clock
- Modified exhaust system
- Heavy duty clutch
- Burgundy colour coded velour interior with imitation wood cappings on the door and rear quarters
- Burgundy colour coded headlining
- Burgundy colour coded carpet
- Burgundy boot carpet
- Black vinyl roof
- Full-width rubber inserts on front and rear bumpers
- Sports steering wheel
- Dashboard tachometer (rev counter)
- Pod above centre console with oil pressure, boost pressure and ammeter gauges
- H1 Halogen headlamps
- Headlamp washers and wipers
- 13 x 6J Aluminium alloy sports wheels
- 185/70HR 13 tyres
- "Berlinetta" script badge on front wings
- "1900" badge on front wings
- "Turbo" decals on rear wings
- 3.44 - 1.00 rear axle
The Story of the Manta A Turbo by Steve Godfrey
Consider the performance figures:
- 0-60 in 7.6 seconds
- 15.7 second standing quarter mile
- Top speed 125mph
- Power output of 156 bhp
- Torque of 174 lb/ft at 4000rpm
These might be considered normal for a '90s hot hatch, but considering that they came from Motor magazine in 1974 is stunning.
The car in question was the Broadspeed turbo conversion of the Manta A series. In late 1973 Opel had five turbo Mantas prepared by European specialists Turbo-May. A year later GM decided to develop the conversion for the British market. For this purpose, they chose tuning experts Tony Fall and Ralph Broad.
The cars were not produced at the factory but were effectively a bolt on conversion (a similar arrangement to the Irmscher GT/E Exclusives or Lotus Carlton/Omega). It was only available through DOT (Dealer Opel Team) member garages and could be had in any colour so long as it was black.
The basis of the car was the Berlinetta model with Burgundy trim. Many extras were included: larger front brake discs, headlamp wash/wipers, inertia reel seatbelts, tinted windows, headrests and sunroof. To this, Broadspeed would add silver coachlines, 6Jx13 light alloy wheels, a front spoiler and auxiliary gauges (ammeter, clock and boost gauge).
The engine was stripped to allow the fitment of low compression pistons (7.6:1) as used for the American market. A special head gasket was installed along with heavy-duty valve springs, which allowed the engine to rev to 7000rpm. An oil cooler was also added.
The clutch pressure plate was replaced with a heavy-duty version and automatic variants benefited from uprated torque converters.
The standard carburettor was retained, but jetting was altered and the secondary choke modified to manual operation. This was enclosed in a pressure box and supplied with fuel from an electric fuel pump through a pressure regulator.
A Holset 3LDG turbocharger, fitted to a specially cast manifold, provided the boost, assisted by an unusual recycling valve to reduce turbo lag.
A special exhaust front pipe was used, mated to the standard exhaust with the main silencer's baffling removed.
The distributor's advance curve was modified to suit the installation and, to prevent damage; a rev limiter was included.
No modifications were deemed necessary to the suspension or brakes.
The Selling Price
The completed car cost £3,493. The original plan called for a production of 100 cars, however a poor exchange rate, escalating fuel prices and the introduction of the Manta B series limited production.
The Surviving Cars
From an ex-Broadspeed employee, we have learned that they produced one prototype, five demonstrators / press cars and 21 customer cars.
The register holds information on the following vehicles:
- VMT 409M: The prototype Manta A turbo. Unusually it was based on a SR, not Berlinetta, shell. It was originally painted bright yellow.
- XGH 386N: The first press / demonstrator and Paris Show car. Where is it now?
- XGH387N: Another press car originally from St. Leonard's on Sea, East Sussex. It is currently in poor condition and stored awaiting restoration.
- XGH 393N: The last known press car. Unusually it was fitted with an automatic transmission. Sadly, it was stolen by joy riders in January '92 and destroyed.
- JCV 222N: Little history available. Unusually a factory roll cage, trimmed to match the car, and boot firewall were fitted from new. This car is in excellent condition and, although stored for the winter months, runs well.
- GAR 951N: The car's first owners were Trebor-Sharp Ltd. Currently it is stored, could use repanelling, but still runs.
- KJA 170P: No history available, stripped and undergoing restoration work.
- KNO 1N: No history available, in storage, partially stripped and awaiting restoration.
- OUH 16N: Accident damaged in 1984 and has remained in storage ever since.
- JBV 187N: No history available, current owner unknown.
- OLA 1P: Believed to have belonged to the same owners from new. Although written off in a motorway crash in '88, it was comprehensively rebuilt and has been spotted regularly since. It is fitted with an automatic transmission.
- GUR 83N: No information available.
- JOJ 742N: Currently owned by a scrap car dealer. It is very derelict and has been painted blue.
Current prices are hard to estimate due to these cars' rarity and desirability. Estimates range from around £3000 for a very poor condition car to over £15,000 for one in top condition.
Copies of the front spoiler can be found occasionally, but genuine ones are very rare.
Photo shows the unusual "turbo" badge added to the rear quarters of these cars