B Stead

There's a new racing class or specifications for a track car.

It's a "Scratch". Then a Scratch is a roll cage on an aftermarket C3 frame where the roll cage replaces the "birdcage" subframe. The aftermarket C3 frame and the roll cage must be mild steel.

Of course the roll cage must mount a fabricated floorpan, a fabricated firewall, a windshield, and have brackets for bodywork, steering column, pedals, and so on.

The windshield must be in the correct location otherwise one car could have aerodynamic advantage over another. The front and rear windshields may be plexiglass or Lexan.

The best way to fabricate the roll cage is to get a junk "birdcage" and use that as a guide.

The Scratch doesn't have swinging doors but just outer door panels attached to the roll cage. And the Scratch could be a convertible or a coupe. The most likely bodywork is the C3 bodywork but any bodywork not longer or wider than the C3 could be used. Carbon fiber bodywork is not allowed.

The Scratch uses the same size tires and wheels front and rear.

Here are the wheel and tire sizes:

255/40-18, 18 x 9
255/35-19, 19 x 9
265/40-18, 18 x 9.5
265/35-19, 19 x 9.5
275/40-18, 18 x 9.5
275/35-19, 19 x 9.5

Wheel offsets are -14mm to 0mm.

And then the Scratch will most likely use the C3 suspension geometry because of the wheel offsets. The C3 frame makers offer various developments of C3, C4, and C5 suspensions. Adjustable coilovers may be used with the suspension geometry.

Next, the Scratch uses a 16-valve pushrod V8 crate engine that is designed for a carburetor and rated at 360 HP or less. That's a crate engine offered by any major auto maker.

The Scratch uses a four-speed manual transmission where fourth gear is 1.00 . The rear axle ratios are 3.08, 3.55, or 4.11 . The differential is an OEM type.

The minimum weight of the Scratch is 2600 pounds and the minimum ground clearance is 3.0". The roll cage build-out is unlimited including frame and suspension bracing but controlled by the minimum weight. Front airdam and sideskirts are not allowed but controlled by the minimum ground clearance. A rear deck spoiler is allowed. The minimum roll cage is an eight-point sports car type with three door bars on the driver's side and two door bars on the passenger side.

The fuel tank must be a fuel cell designed for race cars. The oil pan may be changed or baffled.

Basically, this Scratch racing class is designed to be affordable but to not require the gutting of an OEM car. Also, the 98" wheelbase is not too short. Finally, the Scratch has a frame geometry to attach a roll cage to and is therefor a fundamentally sound race car.

Legal points are that the C3 frame design is in the public domain by patent law. And the C3 bodywork is offered to the public as replacement parts by replacement parts makers
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spazegun2213

where are these specs coming from? which body is hosting this?

B Stead

The Scratch racing class is my own promotion and trademark claims. And then I am a central source as an authority on the rules.

http://www.kbhscape.com/racing.htm

The hope for the class is that racing organizations will license use of the class. Or if enough track day cars are built then interest in the class can develop
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Supercharged111

Have you already built one?

B Stead

You're posting from Colorado Springs ?

I might build one with a 620 HP LSX454 crate engine for Pikes Peak
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Supercharged111

That I am. I don't see a location for you, are you close? Or plan to be close in August?

Reason I ask if you've built one yet is it will be worth its weight in gold to promote a new series.

B Stead

Yeah, my bodywork should arrive from Turin, Italy within a few weeks.

At this point I'm looking for club classing but club classing worldwide. Or maybe a feature series in a small country. Of course anyone can build the fames and make their own motorsports cottage industry.