(thnx Ringo)3.8.4 Any vertical cross section of bodywork normal to the car centre line situated in the volumes defined below must form one tangent continuous curve on its external surface. This tangent continuous curve may not contain any radius less than 75mm :
a) the volume between 50mm forward of the rear wheel centre line and 300mm rearward of the rear face of the cockpit entry template, which is more than 25mm from the car centre line and more than 100mm above the reference plane ;
b) the volume between 300mm rearward of the rear face of the cockpit entry template and the rear face of the cockpit entry template, which is more than 125mm from the car centre line and more than 100mm above the reference plane ;
c) the volume between the rear face of the cockpit entry template and 450mm forward of the rear face of the cockpit entry template, which is more than 350mm from the car centre line and more than 100mm above the reference plane.
d) the volume between the rear face of the cockpit entry template and 450mm forward of the rear face of the cockpit entry template, which is more than 125mm from the car centre line and more than 675mm above the reference plane.
The surfaces lying within these volumes, which are situated more than 55mm forward of the rear wheel centre line, must not contain any apertures (other than those permitted by Article 3.8.5) or contain any vertical surfaces which lie normal to the car centre line.
3.8.5 Once the relevant bodywork surfaces are defined in accordance with Article 3.8.4, apertures, any of which may adjoin or overlap each other, may be added for the following purposes only :
- single apertures either side of the car centre line for the purpose of exhaust exits. These apertures may have a combined area of no more than 50,000mmP2 when projected onto the surface itself. No point on an aperture may be more than 350mm from any other point on the aperture.
- apertures either side of the car centre line for the purpose of allowing suspension members and driveshafts to protrude through the bodywork. No such aperture may have an area greater than 12,000 mmP2P when projected onto the surface itself. No point on an aperture may be more than 200mm from any other point on the aperture.
I don't see any mention of the outlet having to start as soon as the exhaust outlet starts. You may be privy to information I am not, but on the basis of 3.8.5 I see no problem with their gills as is.