1 2
P71
P71 SuperDork
12/26/09 11:11 p.m.

It looks like I'll actually have a chance to do HPDE's again next season and decided to make the RX-7 a "dedicated" race car. SCCA allows bolt-in rollbars with no penalty in autocross and if something goes wrong at a "big" track having a rollbar will help me sleep better at night.

It seems all I can find for the RX-7 is the Autopower (though all good things). I'm thinking about the "Street/Sport" bar since it has a harness bar (and I already have race seats with harness holes). I would be leaving in the factory belts as well.

Any thoughts or advice?

JeepinMatt
JeepinMatt Reader
12/26/09 11:13 p.m.

Does it have to be a bolt-in? A local shop (do your research, I wouldn't pick anyone with a less than stellar reputation) could build and install one for not that much.

Appleseed
Appleseed Dork
12/27/09 12:14 a.m.

Don't skimp on padding. Even in a race car with helmets. Home Depot, by the way, does NOT sell race padding.

P71
P71 SuperDork
12/27/09 10:34 a.m.

Autocross rulebook says bolt-in only, so yes, I'm stuck there. I'm not doing any wheel-to-wheel racing, just autocrossing, pro solo, and HPDE so the risk level is pretty low. I just want to have the safest car possible if something does happen.

I'm not planning on skimping on the padding. I think I'm going to go with the dual-density stuff as the car is street driven w/o a helmet on a regular basis.

mad_machine
mad_machine SuperDork
12/27/09 10:36 a.m.

just because it says bolt in only.. does not mean you cannot reinforce the mounting points in the floor?

Izzy's Cages
Izzy's Cages New Reader
12/27/09 2:58 p.m.

I'd suggest finding a custom builder for your bar. This way your bar will fit the car as tight as possible, your harness bar will be at the right height for your shoulders/harness' and they can make it exactly how you want it. It really won't be all that much more expensive than a bolt in, especially after shipping.

IF you have to go with a mail order, I'd go with Kirk Racing over AP. Let us know where you're located. I'm sure there's a custom builder near you somewhere... and if you're in the Midwest, let me know ;)

fifty
fifty Reader
12/27/09 3:48 p.m.
P71 wrote: . SCCA allows bolt-in rollbars with no penalty in autocross

I'm not sure that's correct - maybe it's class dependent, but I see plenty of Mod class (DM, FM etc) with weld-in 4 point bars. I'm looking at this myself for my SM car - a local builder quoted $500 - $700 for a weld in 4 point roll bar that I could upgrade to a full cage later if I chose to.

wbjones
wbjones HalfDork
12/27/09 4:40 p.m.

In reply to Izzy's Cages:

from P71's profile: Location: Kelso, WA

dyintorace
dyintorace Dork
12/27/09 5:47 p.m.

Excuse the hijack, but Izzy, do you know of any reputable cage builders in north central Florida? My FC RX-7 currently has an S&W weld in 6-point cage, but I'm not thrilled with the gap between the top bar and the roof of the car. Also, the bar lands on the floor behind the seats, which brings it closer to my head. I've looked at your page and see that you typically land 2nd gen RX-7 roll bars farther back, on the rear shelf instead.

For background, I am looking for a 4 or 6-point roll bar for open track days, HPDE's, etc. Not planning on wheel to wheel with this car.

Thanks!

P71
P71 SuperDork
12/27/09 5:52 p.m.

I'm about 45 minutes north of Portland, OR. SCCA rulebook says bolt-in bars only for my class (STS/STR). I'd love a custom "weld-in" but again, I'm limited by what the book says.

My Hornet will be getting an NHRA-legal weld-in after the 401 goes in for sure, for both driver protection and chassis stiffness.

tr8todd
tr8todd New Reader
12/27/09 6:17 p.m.

Safety is the one place you don't want to skimp on. By the time you buy the Kirk bar and have it shipped to you, how much have you really saved? Remove your interior/seats and take the car to a shop that has done SCCA cages. A drag racing cage isn't the same thing, and don't let the local circle track/import drag racer clown tell you it is. A custom main hoop with proper diagonals and cross bar and two rear down tubes will take a full day to fabricate and use 30 feet of pipe or so. The tube, plates, and grade 5 or better bolts alone will run $200.

Jensenman
Jensenman SuperDork
12/27/09 6:35 p.m.

I had a AP bolt in 6 point cage in my '79 RX7, it bolted to the 20 gauge steel floor pan just behind the seats with rather small plates (about 2" x 3") and that didn't set too well with me. Had I ever gotten around to track days etc with that car, reinforcements would have gone in.

There's no reason you can't reinforce the floor pan. Use .125 mild steel, have it welded to the inside of the floor (get a pro to do this!) and then bolt the roll bar to that. Here's the thing: you are trying to spread the load so make the reinforcements as large as practical. If you can go up on a vertical member nearby like a rocker panel that adds a tremendous amount of strength. I'm with tr8todd, most drag race shops have no real idea of what a SCCA legal bar or cage requires.

The GCR will tell you it's better to overbuild than underbuild. At a minimum, you need: a main hoop as close to the roof as practical, bent in one piece with the total of all bends equaling 180 degrees maximum, two braces to the rear (I'd go to the 'frame rails' instead of the rear inner fenders), a diagonal on the main hoop and a harness bar. I recommend the harness bar being part of a full width tube and being made of the same tubing as the roll bar (none of that flat strap stuff I have seen). I'd go with a diagonal on the rear braces as well.

About tubing: in your weight class you can go with either 1.625 x .120 wall DOM or 1.750 x .095 wall DOM. The 1.750 is a good bit lighter, that's worth about 25-30 pounds on a full cage.

P71
P71 SuperDork
12/27/09 9:57 p.m.

You guys aren't listening...

This car spends 95% of it's life at SCCA Autocross events. In order for me to NOT be moved to a ridiculous class (like Prepared) and STAY in Street Tire, I HAVE to have a BOLT-IN bar only.

Yes, I understand a "real" cage will be safer, better, and probably cheaper. But I CAN'T have one. I'm all for welding large plates to the floor for the cage to bolt to, but I have to follow the rules here people!

2002maniac
2002maniac Reader
12/27/09 10:03 p.m.

custom cage shops can usually do bolt-in bars.

Wally
Wally SuperDork
12/27/09 11:13 p.m.

Does it say a bolt in bar can't be welded in place? After the cage is installed put for bolts in each of the plates on the floor.

bludroptop
bludroptop Dork
12/28/09 6:07 a.m.

I think that the rule allows for welded-in "roll bars" with a maximum of 4 attachment points, but "cages" must be bolt-in. Referring to 2009 Solo Rules 13.2 (H) - that's how I read it anyway.

The bigger question for me is this: Is a car with, let's say a Kirk bolt-in roll bar and fixed back seats actually safer, especially if it is driven on the street regularly?

I'm planning to get the seats for autocross in one of the street touring classes, but they are fairly easy to swap in and out. A bolt-in roll bar doesn't easily come out for a trip to granny's house, so it needs to be safe for street use, and I'm not convinced yet that it is. If you say that you have to have all three - bar, seat and harness, then that's not practical for street either.

The point about a custom built bar being equally cost effective is taken, but a bolt-in bar from either of the sources mentioned has potential resale value. Also, others have gone before you, so you know exactly what you are getting.

aeronca65t
aeronca65t HalfDork
12/28/09 6:39 a.m.

Call Kirk Racing ~Here~.

Their website is pretty limited so you'll have to use the phone. I believe they make just what you want (one for RX7).

P71
P71 SuperDork
12/28/09 9:13 p.m.

OK, correction, after much reading of the GCR I'm just flat confused.

Street Touring section says roll cages have to be bolted-in, roll bars are as you please. Appendix C (roll bars/cages) states that all unit-body cars (like my RX-7) have to be bolted.

So which is it? Will anybody really care if I weld in a large, heavy, safety device?

Arrrrrgh!!

Jensenman
Jensenman SuperDork
12/28/09 9:30 p.m.

Okay, from a safety standpoint no one will make a sound. I did once stand behind a guy who was saying that he planned to protest some aftermarket turn signal lenses. By the strict interpretation of the rules he was correct.

So my recommendation is: Remove the carpet. Reinforce the floor. Paint it. Cover it with the same carpet. Then bolt the roll bar to the floor with the carpet trapped in between so Mr Hair Splitter can't see it without ripping the car apart (not bloody likely) then motor away knowing you have added .125 of steel between you and a unplanned height reduction.

P71
P71 SuperDork
12/28/09 9:47 p.m.

Jensenman,

I like that idea! The GCR even specifically states that backing plates should be welded in in all cases. The whole interior is currently out except the steering column/drivers seat (and that comes out in 10 minutes) so it should be pretty easy to have the plates made and welded in.

Maybe I should pick up the Autopower unit and have new plates made for it? Then I know it will fit, it's a "standard" accepted SCCA part, and I maximize my safety while being in the letter of the rules.

Nis14
Nis14 New Reader
12/28/09 11:23 p.m.

I have the same issue with the same car actually. 2nd Gen RX7 mostly going to be autocrossed and a weekend car.

Thinking about getting a racing bucket seat, because I'm 6'3" and I need to drop the seating as much as I can. And seeing that it is a 20 year old car, try to make it a bit safer.

I was going to go with the autopower roll bar and because I don't really trust the 2x3 mounting points weld in a wider L-shaped piece of steel (spotwelded to the floor and seam welded to the rocker) and bolt the mounting plate to that.

Let me know what you guys think.

tr8todd
tr8todd New Reader
12/29/09 2:43 p.m.

Bolted means that the bar must be bolted to the structure of the car. That means everything is welded together into one piece, and then it is bolted to the floor of the car. Minimum plate size is 2X3 inches on both sides of the floor where the bar is mounted. The sheet metal floor becomes the meat in the sandwich. This also goes for the down tubes. This does not mean that every bar within the hoop is bolted to each other. The diagonals, cross bars, and the down tubes are welded to the main hoop. You can fabricate the down tubes so they can be unbolted if that is what you really want to do. The advantage to having a custom made bar, is that the fabricator can get the bars nice and tight to the pieces it is adjacent to. On the mass produced bars, you can often pass a tennis ball between the bars and the interior panels. You need the bars to be as unobtrusive as possible.

P71
P71 SuperDork
12/31/09 9:20 a.m.

OK, quick update. I found a local shop recommended by other SCCA autocrossers in my region. He wants to do a custom DOM install with a main hoop, diagonal, horizontal, two down bars, and an "x" brace plus gussets and feet for around $750 installed. He'll build it right to the specs of the GCR (again, multiple competitors of mine have his custom bars/cages). Does that sound like what I need? It'll be fully welded, custom-made to the car (so as tight to the roof as possible), and done correctly w/bracing and feet so if something happens I'll be safe.

Any other suggestions? I'm already planning on adding 5-point SFI belts and dual-density padding. The car already has Ractive racing buckets (suede, proper belt holes). Any other safety items for HPDE?

John Brown
John Brown SuperDork
12/31/09 9:29 a.m.

Michael, that is a hell of a deal. My last "Legal bolt in cage" cost $2335.00

turboswede
turboswede SuperDork
12/31/09 11:28 a.m.

"Do it. Dooooiiiit."

1 2
Our Preferred Partners
kATGUKEFxG969KS5sZY36ZAtn4TVDrm6