The Imp Site



EVAD Developments (Racing)


Holcombe Rogus
Somerset. Phone Greenham 457

Designers and Manufacturers
of the "EVAD 4" Formula IV
racing car.




250 c.c. CLASS 1.

  1. Single seater cars only.

  2. The body must allow the easy entrance and exit of the driver without necessitating the removal of the steering wheel.

  3. Minimum wheelbase 63 inches.
    Minimum track of front and rear wheels 41 inches.
    The exhaust system to project no more than 10 inches behind the rearmost edge of the rear tyres and the outlet pipe must be horizontal or inclined downwards.

  4. The car must be raced in a form which, including any accessories or alternative parts, would retail at a total price of not more than £500 excluding engine.

  5. A roll bar is compulsory. It must be an integral part of the frame and of sufficient strength to protect the driver should the car be inverted. The height must be greater than the top of the driver's helmet when he is normally seated.

  6. The fuel tank must be separated from the driver by a fireproof bulkhead.

  7. The engine must have a maximum capacity of 250 c.c.

  8. Be designed for normal retail sale to the public.

  9. Be air-cooled.

  10. Have not more than two cylinders.

  11. Retail in running order at a price not exceeding £150.
    The definition of running order is that the engine, clutch and gearbox coupled together in such a manner that this assembly is ready to race with only the attachment of a fuel supply and the addition of an exhaust system, mount, output coupling or chain ,

The minimum total weight of driver 7 car and any fuel left at the end of every race must be 500 lb.

650 c.c. CLASS 2

  1. Engine unit must be from a Standard Series Production, Touring Motor Cycle or Sports machine derived therefrom of nhich at least 1000 have been produced.

  2. The number of gears must be unaltered.

  3. Must not be supercharged.

  4. Only pump fuel.

  5. Carburettors may be altered to another type or size. Phillips system may be used, but not fuel injection.

  6. Valve ports may be altered in size and shape. Larger valves and springs may be used, but the method of valve operation may not be changed, and cylinder heads must be of a type supplied as standard.

  7. The use of titanium or similar metals is prohibited.

  8. All other specifications as present Formula IV 250 c.c. except the maximum price of the car without engine to be £700., and wheel size to be restricted to 10".

875 c.c. CLASS 3.

  1. 875 c.c. Engine gearbox units of Car origin from series production vehicles of which at least 5,000 units have been made.

  2. All original basic component parts of the engine must be used i.e. Head, con rods, block, crank shaft, pistons and standard valves.

  3. A modified cam shaft and different springs may be fitted.

  4. Rotating parts may be lightened and polished.

  5. Cylinder heads may be modified with the exception of valves.

  6. Close ratio gears and alternative axle ratios may be fitted if available from Manufacturers.

  7. Two single choke or one double choke carburettors may be fitted. No fuel injection.

  8. Only pump fuel

  9. All other specifications as present Formula IV 250 c.c. except the maximum price of the car without engine to be £800., and wheel size to be restricted to 12" maximum.

In addition to the above, all classes of cars must comply with the R.A.C. Vehicle Regulations.







The Imp Site
   Imp Specials
      Evad 4, Formula 4 Racing Car
         Evad 4, Formula 4 Racing Car - the folder
         Evad 4, Formula 4 Racing Car - press release
         Evad, RAC Regulations F4 (this file)


© Franka


Folder supplied by Robin Human, National Weekend 2011 (Bangor)