XS ruleset

[Mike Flanigan]

Alot of it is crystal clear to me......but struggling with the rear aero interpretation. Trying to figure out what I'd be able to do.

In my case.....a Mazda MX5 ND.

•A rear spoiler or a rear wing may be added, removed, or modified but must not extend past the perimeter of the original body (excluding non-integral bumpers). Endplates are allowed; size is not restricted. A rear spoiler may extend 10.0” (254 mm) maximum from the original body. A rear wing, components, and attachment points must be behind the centerline of the rear axle and may extend 6.0” maximum above the topmost portion of the roofline (or windshield frame for a convertible).

Question...... Is the (wing) "must not extend past the perimeter of the original body".....designated by the position on where it is mounted above the car? Meaning, since the rear of the vehicle tapers off dramatically.....that the wing can only be as wide as the area "below" where the wing is mounted to, or it can be as wide as the maximum width of the vehicle (the rear wheels/fenders area)?

Believe I'll have other questions too......Thanks

[Anthony P.]

designated by the position on where it is mounted above the car?

I don't see your wording in the rule. I see it being defined by the term body.

Overall width afaik is 68.3" including mirrors its about 74".

[Mike Flanigan]

Thanks for the interpretation Anthony. Seems way more beneficial than the way I was looking at it.

Reguarding a "spoiler" (maximum allowed)

End plates are allowed: no size restriction. (does not say wing/spoiler specifically)

Could I add very large end plates to the sides of the spoiler to better feed it, from the sides of the car? (spoiler would still be the 10" max allowable length, over the trunk limit)

[Anthony P.]

Thanks for the interpretation Anthony. Seems way more beneficial than the way I was looking at it.

Reguarding a "spoiler" (maximum allowed)

End plates are allowed: no size restriction. (does not say wing/spoiler specifically)

Could I add very large end plates to the sides of the spoiler to better feed it, from the sides of the car? (spoiler would still be the 10" max allowable length, over the trunk limit)

Idk about autox but for the track, its hard to get enough front downforce to balance out a big wing... Also, I think you would be ultimately limited on end plate size as it can't go beyond 10" from the original body. Idk, again, you could always write a letter or Marshall might chime in. What did you have in mind?

[Marshall Grice]

working from a basic definition of perimeter, a perimeter is a path that encompasses/surrounds a two-dimensional shape; my personal opinion is that "must not extend past the perimeter of the original body" means that if the wing is changing the shape of the perimeter of the original body then it is not legal. to make a simplified analogy, if you drew a rectangle (wing) on top of a circle (original body) the rectangle has to be completely inside the circle and not poking out anywhere. An *incorrect* interpretation would be 'the maximum width of the car is 80 inches therefore I can run an 80 inch wide wing even though width of the body where the wing is mounted is only 60 inches wide'.

[Anthony P.]

working from a basic definition of perimeter, a perimeter is a path that encompasses/surrounds a two-dimensional shape; my personal opinion is that "must not extend past the perimeter of the original body" means that if the wing is changing the shape of the perimeter of the original body then it is not legal. to make a simplified analogy, if you drew a rectangle (wing) on top of a circle (original body) the rectangle has to be completely inside the circle and not poking out anywhere. An *incorrect* interpretation would be 'the maximum width of the car is 80 inches therefore I can run an 80 inch wide wing even though width of the body where the wing is mounted is only 60 inches wide'.

^^This, thank you for chiming in.

[Mike Flanigan]

working from a basic definition of perimeter, a perimeter is a path that encompasses/surrounds a two-dimensional shape; my personal opinion is that "must not extend past the perimeter of the original body" means that if the wing is changing the shape of the perimeter of the original body then it is not legal. to make a simplified analogy, if you drew a rectangle (wing) on top of a circle (original body) the rectangle has to be completely inside the circle and not poking out anywhere. An *incorrect* interpretation would be 'the maximum width of the car is 80 inches therefore I can run an 80 inch wide wing even though width of the body where the wing is mounted is only 60 inches wide'.

Thanks Marshall for this interpretation too.......as it is in line with how I was originally "seeing" it.....though I was counting on Anthony's interpretation.....more.

But this does bring me back to a wing (inside the perimeter of the body) being smaller (in width) that I'd be able to use (but still could make the huge given a 8' max surface area).......but cost would be rather large as I would have to outsource the main parts. So that'll be less likely to happen.

Spoiler: Hard to explain, cause my idea is complex.

I'll bring my drawings to the next event so you can better see what I'm thinking might work.

Thank you both. Mike