Rules Question - Brake Ducts

[tmitbyh]

7.10 Body

a) Vehicle bodywork must remain stock except for the following:

11) Two (2) openings may be cut in the front valence to allow up to a three (3) inch diameter duct leading to the front brakes only. Factory fog lights may be removed and holes used for brake ducts or left open.

 

For the three inch diameter is that the whole system or just the opening? Here is why I ask. I am looking to eventually run my EJ1 in H4. I have the foglights removed and was going to run ducting from the opening in the fog light covers. If I recall correctly it is a two and a half inch or three inch opening. I was going to fabricate a coupling to the back of the fog light cover and the material I have sitting around my garage is a three inch opening but is three and a half inches from outer edge to outer edge. So the ducting would have to be three and a half inches. So to recap I would have a two and a half or three inch opening in the bumper cover to a three inch coupling opening to a three and a half inch ducting.

 

Would that be legal or should I just get my hands on some three inch coupling to be on the safe side and just run three inches all the way through?

[wm577]

To be safe I would use 3" or less ducting. It's going to be hard to keep anything over 3" from rubbing on the wheel, ground, axle, or something else anyway. However, I doubt anyone would ever protest brake duct size. IMO that would be a real lame protest.

[0x1]

Agreed. You should really look at whether you can even fit the 3.5" ducting in there anyway as most of us can't even use 3" due to clearance issues.