Opel Manta A
series Turbo by
Steve Godfrey & Mark Kinnon
Overview
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 availble 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 distinstive 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
Identifying
Features
- Only available in Black
- Front spoiler
- 1900cc engine with low
compression pistons, heavy duty valve springs and
special head gasket
- Holset turbo charger 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 immitation wood capings 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 Alluminium 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.
History
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.
Modifications
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.
Prices
Current prices are hard to estimate due to these cars'
rarity and desirability. A handful have been sold, mostly
in very poor condition, for around the £500 mark. Those
in top condition would be valued around £5,000.
Turbo Spoiler
Copies of the front spoiler are
available from RMJ mouldings (01743 350881) or are made
by Trevor Lewis (01253 851680).
Photo shows the unusual
"turbo" badge added to the rear quarters of
these cars
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