Some Pictures

Articles

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Car Specification

Class:	750 Motorclub Formula 750
Chassis:	Steel spaceframe
Layout:	» Rear wheel drive » Clubmans
Engine:	» Fiat 1108cc FIRE engine » prepared by Guy Croft Racing Engines » Modified to run longditudally » GC aluminium inlet manifold » GC designed 4:1 steel exhaust » Weber DCOE40 carburettor (one choke blanked)
Transmission:	» Reliant 4 speed gearbox » Tilton hydraulic release bearing » GC/Helix flywheel » Helix clutch plate and basket
Drivetrain:	» MG Midget live axle » 3.7:1 ratio non-locking differential
Cooling:	» Single front mounted Brise aluminuim radiator » silicon hoses » Mocal Oil/Water cooler » Alumimium swirl pot and catch tanks by GG Williams » Radiator exhausts on nose cone
Wet Weight:	350 - 450kgs TBT
Aerodynamics:	» NACA 63(²)-415 Hi-Lift, Low-Drag Rear Wing » Full length undertray inc. Venturi tunnel and rear diffuser » Full width front splitter inc. raised centre to feed undertray » Basic shape vastly simplified over original EVO
Wind Tunnel Tested:	I Wish
Max Power:	67.6bhp @ 5708rpm
Top Speed:	115mph with 3.7:1 diff
Fuel Tank Capacity:	TBA
Fuel Type:	Unleaded
Ground Clearance:	1 3/4"
Road Legal:	No Way!

In Detail

To the right is a picture of the undertray, the undertray's primary purpose is to control the air movement beneath the car.

Without the undertray the air beneath the car becomes turbulent producing lift (most road cars produce lift) and making the car unstable at speed.

But the EVO II does more than that, you may notice the large raised channel running through centre of the undertray. The purpose of this is to draw air from the centre of the car to the rear, this creates a low pressure region at the centre point of the car which in turn sucks the car to the ground (downforce).

To the left is a picture of the rear wing, you can also see the rear diffuser (rear part of the undertray) at the bottom.

The wing has been built to NACA (old name for NASA) specifications and scaled to match the car CD and estimated power output. The wing will produce 5 times more downforce than drag.

The wing has been positioned as far to the rear of the car as the rules will allow, the wing must be positioned above the road rather than above the bodywork to make it as effecient as possible.

The wing is also positioned slighly to the rear of the rear diffuser, this is intentional, the wing will aid the diffuser in drawing the air through the undertray.

To the left is a picture of the rear wing mount.

As you can see, I decided to put the pivot (to change the angle of attack of the wing) to the rear of the adjusting bolt. Most wings that I have seen have the adjusting bolt at the rear.

The rear wing of a "formula 750" car cannot exceed a height of 900mm from ground level. With the pivot at the rear, the angle of attack can be modified without an adverse affect on the height of the wing.

Just a small point, but valid none the less.

Try and ignore the fact the I have hex head bolts sticking out the side, I know this isn't going to aid airflow, I just haven't got round to changing them to dome heads yet.