Roll Cage / Chassis requirements - to meet scca pro racing regulations

[Full-Race Geoff]

hey guys - its been a while since my last post (evos keeping me busy) but im starting back up on my new R14 and wanted to get some input on chassis/roll cage design.

my good friend Forrest Wang at Get Nuts Labs in las Vegas will be doing the cage. cromoly 1.75 0.095 wall is the matl of choice, but need to get things straight on the game plan. the RB is a porker big fat pig of an engine so need to keep the chassis light. If you guys have any good photos to post of textbook s-chassis cages or even z33 id appreciate it.

moton susp, kognition wing, EFR turbo, drysumped, engine moved back is the overall

[Matt93SE]

http://blehmco.com/pics/240SX/roll_cage/

Built for a 2700lb car within IT specs here, but it's a good basic cage.. (Will be adding more to it later, but wanted to get in and get racing for now..)
Tubing is 1.5" x .120"
It meets SCCA's specs for any class, including Pro Racing.

also keep in mind chromemoly is allowed in pro racing only on an approval basis. their specs are for 1020 or 1025 DOM.

[Def]

I say dom as well over chromoly.

[djsilver]

SCCA really doesn't like chromoly because it requires post weld normalizing and is difficult to repair in-car if needed. I think even NASCRAP requires mild steel used in the chassis/cages.

[PerilousActs]

Good cage work here: http://www.motoiq.com/magazine_artic...-part-one.aspx

And here: http://zilvia.net/f/chat/362308-hot-...e-turbo-3.html

[Sleepy_Steve]

Didn't corner carvers have a long ass thread on the subject?

I made a model cage at 1/10th scale out of 1/8'' wire for my S14, but I doubt you'd be interested in pictures of that.

[OnTheChip]

Have a read here: http://www.sccaproracing.com/pro.php?page=prr

[veilside180sx]

Definitely DOM imo as well.

[PoorMans180SX]

I only believe in one type of "proper" cage.

[PerilousActs]

Yeah, that cage is awesome. Weld quality is amazing too.

[Jeremiah]

Based on my experience building one, I would say avoid using a halo bar and go with one of the other ways of doing the front. A halo bar doesn't give enough head room. I didn't like mine so much that I chopped it out and converted it to a roll bar. Mild steel DOM is really the way to go as it will be much easier to pass tech in both SCCA and NASA events. For the main roll hoop I would put the floor plates on the platform where the rear seat used to be. It has a lot more structure below it than the floor pan right behind the seat. Plus you can put the seat back a lot farther.

[Def]

I also second putting the floor plates on the rear seat shelf. That's what I did with my roll bar. If you put them down on the floor then you've got to angle back the main hoop a ton to get a taller driver to fit. This makes it significantly weaker in a roll over vs. a more upright main hoop.

[Invisible_Saddle]

Geoff, I've been to forrest shop and have looked at the cages he has prepped. I believe you are in great hands. how much does the car weigh now prior to cage construction. If anything, check the rulebook if it will allow you to 'tube' the front end or 'backhalf' the rear of the car. Many formulaD cars are built in an off form of the scca rulebook. I'd say pick which class you want to run first (nasa/scca). then decide on how extensive you want to be. Provisions for ballast, etc...

I'm saying all of this because i'm building a spec e30 right now, which will prolly become a PTD car.

[PerilousActs]

Out of curiosity, what is the standard procedure for adding ballast to a car and securing it? I've never seen this done in person.

[Def]

The rules for a series usually cover ballast retention. It's usually a 3/8" bolt and a 2" dia washer or something similar per 10 lbs of weight IIRC.