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The pertinent rules as I understand them:

2008 SCCA Rule Book:

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

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. Associated hardware including
latches, hinges, and window washer nozzles may be modified,
removed, or replaced. This does not permit removal of the remainder
of the window washer system. 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.

I managed to melt my rear bumper cover in El Toro this year running without a muffler.  I have since replaced the exhaust to prevent it from happening again, but am getting ready to paint the car so I am replacing the bumper cover with an aftermarket body kit rear cover.

My question is:

The stock rear bumper has a molded plastic piece that bolts under it to maintain its shape.  Of course my aftermarket rear bumper isn't the same shape.  Does anyone see a problem/possible protest if that bumper cover support is removed?  I of course believe it to be legal to remove.  The only concern is that it is a separate piece.  With it in place, it pushes the new bumper cover out to the point it wont align and bolt up.

Thoughts anyone?

Picture of conflict

With bumper cover support

Without bumper cover support

Car with offending support

car without offending support

Chris,

The offending "support" piece you're referring to is actually part of the bumper, and can't be removed in SM/SM2.  You can do whatever you want to the bumper covers, but need to leave the parts under them in place.

You do have the 1 lb rule, so if you just need to trim a little material off for the new bumper cover to fit, that should be legal. 

 -Steve

p.s.  Or you could just take those silly bumpers off, and come join us in XP. 

MNbiker:

Chris,

The offending "support" piece you're referring to is actually part of the bumper, and can't be removed in SM/SM2.  You can do whatever you want to the bumper covers, but need to leave the parts under them in place.

You do have the 1 lb rule, so if you just need to trim a little material off for the new bumper cover to fit, that should be legal. 

 -Steve

Why do I not feel safer with a molded plastic part that won't support my weight as part of the bumper.

The parts list shows the whole assembly as

But the individual part number NA01-50-260 is the metal brace ( again somewhat flimsy but sturdier than plastic ) as the bumper reinforcement.  I can't find an individual part number for just the plastic part, either on the drawing or the part itself.  I can probably trim away a good portion of it and stay within the pound but it seems a shame to cut up a part that I am sure could find a nice home on a needy spec miata. The whole part according to my hyper accurate bathroom scale only weighs about 5 and a half pounds.

MNbiker:

p.s.  Or you could just take those silly bumpers off, and come join us in XP. 

 I may one day, but I am giving SM2 a couple more years

gtfour77:

That definitelly looks like part of the bumper support, attached to the car and not the bumper.  I am assuming a polystyrene/foam piece that's usually found in a regular bumper can be removed correct? (not attached to the car but only to the bumper cover)

I DO NOT believe it is safe to assume that the current rules permit removal of polystyrene/foam components of a bumper.  These parts are integral to the bumper's operation - being installed by manufacturers to help absorb impacts.  Just because they don't weigh much doesn't mean they don't serve a useful purpose.  In any case, the rules seem pretty clear on only allowing fascias/covers to be modified.  Under the general guideline "if it doesn't say you can, then you can't", all the underlying pieces must remain in place.

 -Steve

p.s.  If there is a vehicle that has an impact-absorbing component attached ONLY to the bumper cover, I'd think you could argue that it's removel should be allowable.  However, I haven't seen any covers constructed in this manner.  On the Miata, the plastic impact beams are clearly fastened to the bumper.

geewiz:

Yeah, I'm no expert but I considered that piece of plastic to be "bumper" rather than "fascia" and I didn't remove it until I went to XP. Dan didn't remove it either when he owned the car and ran it in SM2, so I think the general consensus is that the piece is part of the bumper. (Again, not that "consensus" should be read in any way to be an "expert opinion" or "binding ruling".)

 

Sorry, Chris. 

-- Glenn 

No need to be sorry.  It's just an appearance mod for me.  The local mazda dealer asked if I would display the car at an upcoming Pikes Peak Hill Climb Fan Fest.  That and some friendly comments on the krylon finish around the wheel arches and hood, lead me to the decision to paint the car.  I had picked up the rear facia cheap a while back and was going to put it on before paint.  I have no performance reason to remove the rear doohicky ( still can't quite call formed plastic a bumper).  Loosing the 5.5 pounds just means I have to run another gallon of fuel.  

So, If I were to invoke the minor modifications rule, and notch/heat it enough to fold up inside itself and the body kit bumper cover, do you guys think that would be a tortured interpretation?  I would cut off 15 ounces of it, so I had less to fold up, then make the rest of it fit.  This is quickly becoming more effort than it's worth.  I could just have some vinyl printed up that says "chicks dig scars" and strategically place that below the melted part and call it a day.

MNbiker:

I DO NOT believe it is safe to assume that the current rules permit removal of polystyrene/foam components of a bumper.  These parts are integral to the bumper's operation - being installed by manufacturers to help absorb impacts.  Just because they don't weigh much doesn't mean they don't serve a useful purpose.  In any case, the rules seem pretty clear on only allowing fascias/covers to be modified.  Under the general guideline "if it doesn't say you can, then you can't", all the underlying pieces must remain in place.
<> -Stevep.s.  If there is a vehicle that has an impact-absorbing component attached ONLY to the bumper cover, I'd think you could argue that it's removel should be allowable.  However, I haven't seen any covers constructed in this manner.  On the Miata, the plastic impact beams are clearly fastened to the bumper.