CMC Rules - Ballast, Fire, Battery and Accusump placement

Newbie questions here. Looked over the rules and also tried to search the forums but couldn't find an answer.

I gutted the car I bought and am remounting everything in the car. I want to balance it out better but also don't want to break the rules. I see in the rules Battery boxes may be considered ballast. What would specifically determine if it is or isn't considered ballast? I'd prefer to mount it in the trunk area of the car if possible.

Same goes for the fire bottle and accusump. To balance the car better I would like them in the trunk. Is this permitted??



6.7 Ballast
Up to 150lbs of ballast is allowed, but no farther rearward than the plane of the front of the main hoop of the roll cage. Each ballast piece may not be taller than three inches or stacked higher than three inches. Ballast must be securely fastened and approved by NASA tech/safety officials. Battery boxes, cool suit mounts, and other added components made excessively heavy may be determined by NASA tech or CMC Officials to serve as ballast and therefore not allowed farther rearward than the plane of the front of the main hoop.

Battery, Coolsuit, and Accusump can be mounted wherever you wish. The main thing for a battery box is its sole purpose must be to protect the battery, not add extra weight. If you have a box that weights a couple of pounds you are good, 50 lbs would not be accepted.

Same with a coolsuit. A standard size cooler is acceptable, a 20 gallon home-made cooler would not be.

I don't know off the top of my head about the fire bottle placement though. Not sure if it needs to be in a place protected from a possible impact.

Thank for the clarification, that's great news. I'll only be using a marine style plastic case so should be no issue. I may just mount the fire bottle in the back seat. You make a good point about impact. Rather it save my ass then help balance the car .05% or whatever

Fire bottle as in for an extinguisher system can be mounted anywhere. Fire extinguisher, as in hand-held, must be mounted within the driver's reach when they are in the seat (technically and strapped in but that I've not seen enforced very much, so just be reasonable).

Mike hit it on the head, the point is not to create mounts or assemblies that quite obviously are designed intentionally to add weight. The marine box is a good idea but keep in mind a plastic box goes around the battery, it does not have anything to do with securing the battery. Most marine boxes come with little J hook mounts and these are not allowed. If you want to go with the simple two point strap type mounting, use 3/8" threaded rod and washers > 1.5" on the underside of the car.

I don't plan to use J-hooks. I was thinking to use Riv-nuts in the floor to secure things. I've found them to be very solid when installed correctly but has anyone had issues with riv-nuts coming lose on impact? If so I could thru bolt them but that's always a pain to tighten by yourself

the failure mode of a typical battery mount is the strap pulling out of the fairly thin sheet metal floor. For this reason nasa techs are instructed to look for how thick over how much area the mounts have in order to eliminate that pull through. It’s up to you how you make them comfy given a lack of an actual spec.

Quote:

---

Originally Posted by michaelmosty

Same with a coolsuit. A standard size cooler is acceptable, a 20 gallon home-made cooler would not be.

---

What if the intent is for it to last the entire weekend? Maybe it's an enduro cooler. :cool: Says the guy with no cool suit.

Quote:

---

Originally Posted by Gerno

I was thinking to use Riv-nuts in the floor to secure things. I've found them to be very solid when installed correctly but has anyone had issues with riv-nuts coming lose on impact?

---

If you were talking about a threaded fastener in 1/4" material I might be able to agree, but not the sheet metal on these cars. I would not personally use a riv-nut to mount anything substantial - I did use them to mount the brake prop valve. For the battery, I ran a strap of 0.90" from bolt to bolt, so a giant "washer."

You don't want that stuff coming loose.

I'll take your advice and thru bolt it for sure...Thanks for the feedback

Anything that goes through the floor should have fender washers ideally. They also make heavy duty fender washers, I found those at Fastenal. I like using those for ballast.