Evolved Member
Quote:
This is true in SM, not 100% certain in ST, but many of the rules in this case overlap in this area.
The way I am reading it the rules are very different. Originally Posted by chrisw
you are not allowed to change the undertray in front as the rules are written. But you are allowed to remove and or re-enforce the stock undertray in order to mount a splitter on the front of the car.This is true in SM, not 100% certain in ST, but many of the rules in this case overlap in this area.
ST :
14.2.F
Addition of spoilers, splitters, body kits, rear wings and nonfunctional
scoops/vents is allowed. The intent of this allowance
is to accommodate commonly available appearance kits, and
replicas thereof, which have no significant aerodynamic function
at Solo speeds. Body kits are limited to bumper covers, valances,
side skirts, and fender flares. Standard parts may not be
removed except for the substitution of spoilers, rear wings,
bumper covers and valances. Rear wings must attach only aft of
the rear wheel centerline. Total surface area of all spoilers, splitters
and rear wing may not exceed
scoops/vents is allowed. The intent of this allowance
is to accommodate commonly available appearance kits, and
replicas thereof, which have no significant aerodynamic function
at Solo speeds. Body kits are limited to bumper covers, valances,
side skirts, and fender flares. Standard parts may not be
removed except for the substitution of spoilers, rear wings,
bumper covers and valances. Rear wings must attach only aft of
the rear wheel centerline. Total surface area of all spoilers, splitters
and rear wing may not exceed
5 square feet as seen from
above (see 12.9). Substitution of rear spoilers or wings must
retain any original third brake light functionality unless otherwise
equipped. No underbody panels may be added or substituted.
The drilling of holes for the purpose of mounting these pieces is
above (see 12.9). Substitution of rear spoilers or wings must
retain any original third brake light functionality unless otherwise
equipped. No underbody panels may be added or substituted.
The drilling of holes for the purpose of mounting these pieces is
permitted.
Key points highlighted. Splitters can be added. Size of splitter is added to size of wing and must be under 5 square feet. Splitter can not be an undertray - must protrude only forward from the front fascia/bumper cover. I think I read somewhere that they now allow you to remove the plastic undertray, but I can't find the rule.
SM:
16.1.I
Hoods (engine covers), front fenders, front & rear facias, and side
skirts may be modified or replaced, and may be attached with
removable fasteners.
Hoods (engine covers), front fenders, front & rear facias, and side
skirts may be modified or replaced, and may be attached with
removable fasteners.
Mid and rear engine cars may choose to
modify or replace the front hood or rear engine cover, but not
both. Fenders may be flared as per Street Prepared. Non-metallic
fender liners may be modified, replaced, or removed.
modify or replace the front hood or rear engine cover, but not
both. Fenders may be flared as per Street Prepared. Non-metallic
fender liners may be modified, replaced, or removed.
16.1.M
Front splitters are allowed and shall be installed parallel to the
ground (within +/-3 degrees fore to aft) and may extend a maximum
of 6 inches forward of the front bodywork/fascia as viewed
from above. Splitters may not extend rearward past the centerline
of the front wheels. No portion of the splitter may extend beyond
the widest part of the front bumper/fascia as viewed from above.ground (within +/-3 degrees fore to aft) and may extend a maximum
of 6 inches forward of the front bodywork/fascia as viewed
from above. Splitters may not extend rearward past the centerline
of the front wheels. No portion of the splitter may extend beyond
So in SM you can remove the stock undertray and replace it with a huge 1-piece splitter/undertray that is huge. Splitter area is NOT added to wing area when calculating total area. There is no area restriction on splitters in SM.
There is a distinct difference between splitter and undertray. A splitter being a completely flat plate. ie no diffusors.
Evolved Member
Not entirely accurate. You can have a completely flat undertray. Also, a splitter technically is only the part that sticks out from the lower most part of the front fascia.
Evolved Member
thanks for the clarification. It's been a while since I have thought about STU