The engine I have chosen to use in my replica
is the BMW V12 M70, circa 1990. This engine can be found in
the BMW 750. The only difference between the 750i and 750iL
is an extra 4 inches of leg room in the back.
You can pick these cars up very cheaply, Especially for a
car that cost at least £50,000 new. I got mine from
ebay, at a lower price than either of the UK Diablo kit manufacturers
could provide just the engine alone. It was also MOT'd until
september and had a couple of months road tax left!
My car was manufactured in 1990, this means it has the 'drive
by wire' throttle control. In this system the throttle is
controlled by two motorised butterfly valves, one per bank
of six cylinders. The accelerator pedal is read via a potentiometer
weighted to feel like a regular pedal. This means that there
is no throttle cables to run.
The BMW engine system is much more complicated than other
cars of its year. Its 'drive by wire' system necessitates
the use of a complex engine management system. Many kit-builders
have gone down the route of dispensing with it in its entirety,
and using one of the many third party engine management systems,
However these can be very expensive!. I intend to use the
original BMW engine management system, More on this can be
found in the Electrical section.
The car also provides lots of other useful parts for the build.
If you are fitting air conditioning, as I am, you will require
the compressor and condensor radiator. The radiator can be
purchased new for less than a hundred pounds, but the compressor
is very expensive, so its worth holding on to. The rest of
the car can be broken and the parts sold, who knows, you could
even make a profit on it...
Other engine options you might consider include the venerable
Rover V8, Renault V6 (Including turbo), Renault 21 Turbo and
the Chevy/Ford small or large block engine.
|Here is the rear view of the
car. I have hidden the registration as I will be recording
the car as scrap. You often see cars taken to and from
scrap auctions with the registration covered over to prevent
unscrupulous people from using the registration on a stolen
|Front view of the car shows its generally
good condition. The only external damage I could find
is on the roof above the rear window, and a small crack
in the front bumber. The badges enamel is starting to
peel, and the windscreen is starting to show 'fogging'
inbetween the laminate layers. Pictures of the engine
as its removed from the car will be available in the 'engine'
|Things you need from your Donor
Apart from the engine, you are going
to need some other bits and pieces from the car.
- Throttle potentiometer assembly, You need to cut
its wiring out, make sure you cut it beyond its connector
to make future replacement easier.
- ECU's. You need the three silver boxes closest
the bulkhead. I also removed the housing box to make
At the rear of the engine compartment at the passenger
side is the heater coolant pump. This provides hot
air to the passenger compartment before the engines
main thermostat opens. You may need this to provide
effective heater control.
- The entire engine loom and fuse boxes. You do not
need all of this, some of it goes to the ABS pump
etc... But its better to have more than you need then
find out you are missing something later on.
- Catalytic converters, oxygen sensors and relays.
Depending on year, you might not have these parts
at all. All the BMW documentation indicates that these
parts should be present on all models. This was not
the case with my model.