Roll bar and Cage pics questions?

[sykikchimp]

I am looking to put a roll bar, or cage in the car in the very near future. I would love a well built custom cage, and this is the route I will most likely go (If I can find someone good and cheap to do it.)

I would love to see pics of your cages or roll bars so I can get some ideas about mounting points etc. Maybe your thoughts on what works and what doesn't would be great too!

Charles

[TRUENOCOUPE]

For what Race?

[DSC]

I've been gathering pics while working on a cage design myself.
Here is the directory of examples.

Many of the designs won't be legal for (amature) competetion but they get you thinking
I think I'll craft my cage out of empty paper rolls, tow the car up to the fabricator and say "do this please, how much?" haha
Gotta check with THE book for diamater and wall thickness specs...

LINKS
http://www.honda-tech.com/zerothread?id=651229
http://forums.corner-carvers.com/sho...&threadid=7978
http://e30m3performance.com/tech_art..._symposium.htm

After staring at my shell of an s13 for a while I decided that the main hoop should mount to the front of the rear seat if possible, rather than the floor, in order to give the best clearance. I'm not sure what the rules are like and I'd like to debate and talk with a cage fabricator about how it would affect the chassis rigidity and more importantly the safety of the cage. Just looking at it...I think that's the best place to mount the main hoop. I strongly suggest the rear braces to the main hoop mount to the shock towers rather than a random point of the floor or the wheel wells...this is how most of the pics have it done and should give the best strength improvements. If at all possible, brace the front shock towers. I should have a bar going straight to the shock tower from the forward part of the cage going through the dash and another from the base of the forward bars up at an angle meeting the other bar at the same mounting plate on the shock tower.

[sykikchimp]

Originally Posted by TRUENOCOUPE

For what Race?

just for HPDE's and track days right now. Could eventually run ITS with it, so I would want to make sure the cage is scca legal.

[sykikchimp]

DSC - is shooting a bar through the firewall and connecting it to the front strut tower legal?

[DSC]

It is not IT legal as of 2003, being scca, prolly still isn't but should be!

[SleepySR]

charles i'm in the processs of puting together a 4 pt cage for my s14 and will post some pics . for idea purposes

[HippoSleek]

4 pt. is not a cage, it is a roll bar. Cage = 6-10 pts, depending on sanctioning body.

Charles and Dave -- I would advise you to hit a few races and check out the way ITA and ITS s13's have done their cages before you get started. There are now two IT s13's in the MARRS series (both of which will likely run at VIR this spring/summer). I'm not sure if there are any in the local regions near you (look up the website for your local SCCA and check out the results). Both are well built cars -- one often runs top 3 ITA and the other is a new creation from Joe McG (NASA instructor who drove green s14). Also, any pics of Bob Stretch's set up can only help.

Charles - if you are just putting it in for HPDEs, I would consider talking to a good shop about having them do a custom 4 point bar that could later be upgraded with the additional mounting points. If you are going to drive the car on the streets as well, you might as well be able to get in an out w/o crawling over door bars. Not to mention the reduced risk from not having all that metal near you inside. Having ridden in a fully caged s13, ingress and egress was not something I could stand on a daily basis.

[hurleyboi514]

ive got a friend that can weld, another friend with a pipe bender, and a race shop in town that has roll bar piping, so i may end up making my own cage. im in the same spot charles is though, except im not sure if i wanna do a legal cage, or not b/c i probably won't race this car in a series ever... dunno yet...

[Bone]

From my experience building off road cages I was instructed that it is unsafe to build a cage and attache the seats to the car itself. The reason being if you were in a serious crash the cage could actually hurt you worse than not having one providing the body was shifted. I noticed that all the pictures I have seen in the link above the seats were not mounted on a loop from the cage. It may not completely apply for a reason I am unaware of in this case, However If I was to build a cage for mine I would attempt to mount the seats to the cage itself. Am I correct that the seat(s) should be mounted to the cage or am I over looking something that is obvious?

[DSC]

You are correct bone but only for some seats. The solid framed seats should have a seat back brace that attaches the back of the seat to the roll cage/bar. Other seats are designed to flex slightly (non-adjustable seats so they don't snap back onto the roll bar) to actually absorb some of the impact of you coming to a dead stop...
Much like factory crumple zones. since those were taken out when you put a cage in, it's nice if the seat can do some of that work

[sykikchimp]

Mark, that's pretty much what I was thinking. A custom roll bar that I could expand to a full cage later.

I saw vid's of Joe's new S13. I'm glad he's finally got it on track. I'll have to get out to one of the races and check out the car. He has an AWESOME cage builder. The cage in his s14 is super nice.

[B96v6]

Just an FYI, guys. An SCCA legal roll cage will be attached to the car at six points (rear bars, main hoop behind the front seats and front bars that run down the A pillars to the floor). There are provisions to add two additional bars to the cage, but no bars can pass through the firewall. The bars also cannot attach or connect suspension mounting points. You'll need to get a copy of a GCR for more info on mounting plates and other technical info. As for tubing, you'll need to check on that also, but I can tell you that you are allowed to use either 1.5" or 1.75" diameter tubing, but I don't recall the wall thickness off hand. We are using the 1.5" tubing in one of our ITS S14's (just started the bending today!) and 1.75" in the other. There are advantages to using either.

B96v6

[adamhu]

guess i will pipe in ,

for our cars per FIA/CASC specs..for a roll bar we must use min 1.75 inch dia mild steel DOM tubing

for a roll cage 6 points we can use min 1.5 inch dia mild steel DOM tubing

in many areas and series both ERW and chromoly are being banned

adam

[adamhu]

here is a link to the exact specs with wall thicknesses...in pdf...

http://www.casc.on.ca/documents/CASC...ons%202004.pdf

[sykikchimp]

I do have a copy of the GCR.. Thanks for the info though.

What I'm looking for here really is more of design ideas.. like ways to do the door bars.. I'd like a 6-point, but the door bars is what is keeping me from that... I've seen some setups where the door bas run down near the door trim, but not in a 240.. any other ideas are welcome too. Pretty much the entire front half of the 6-point has a lot of options..

For example I saw some a-pillar bars in one of the FL cars where he had the bars curved around the dash. I wouldn't think that would be as safe, but it certainly makes things much easier to build, and you don't have to maim you dash..

And dash bars.. do you think it wise to run a dash bar? Many of the other things are pretty obvious like where the main hoop attachment points are going to be, and the rear support bars.. etc..

But anything where some creativity could be used is what I really would like to hear about.

[HiPSI]

i've seen what you're talking about with the door bars swooping down almost to the floor along the front half of the door jamb, which would make getting in and out much easier for sure. as for the a pillar bars coming down and curving around the dash, i don't think that is legal by most sanctioning bodies is it? i've seen that done with "style" bars for showcars but never in a race legal cage.

[HippoSleek]

While it isn't fun to accept, having a good cage means your car will become otherwise useless.

Personally, I would not skimp on door bars. I'd get full NASCAR bars (two bars with inter-supports, not the "X" deal) that run at bumper height. While getting in and out easily is a nice idea, the whole idea is proection. A car can come over the lower ones and impact the cockpit. While the X bars look like a nice compromise, it is harder to angle them out into the door skin. By angling out, you keep strengh and you give yourself more room -- plus you move the crush zone out (instead of it being w/n 4" of your seat).

Same thing with the a-pillar bars. Once you put a cage in a car, it becomes a race car. I've never seen a race car that later became a street car. That said, it's only a dash! Yes, you can make it so that they don't go through the dash, but why? Here, it is not really a question of strength b/c the rules won't allow you to bend *around* the dash. Instead, you just have to bend down and hit the floor sooner. This results in a sub-optimal attachment point as well as a bar and an a-pillar taking up your vision (not to mention a smaller area to get in and out of the car).

God willing, you only build one cage for the car...

(note: if it weren't for the fact that the car will become 100% useless off the track, I'd have a cage in the meeoter. But until I'm ready to go full blown racing, a nice sturdy bar suits me just fine.) JMO

[TBreu007]

Definitely study your GCR before committing to a cage design. The last thing you want is to start building a cage just for HPDE's only later to decide you want to run in ITS or ITA and have an illegal cage that needs to be fully redone. SCCA's top priority is safety and inspectors are usually sticklers on cages.
The size tubing allowable is 1.5"x.125" or 1.75"x.095 mild steel DOM (that costs about $3.60 a foot)...ERW tubing will not be allowed by the SCCA. You can use CroMo, but its price and weight usually discourage its use.
1.75" tubing is slightly lighter and slightly stiffer. The 1.5" tubing will give you slightly more room inside the car and is easier to bend. The GCR states roll cage tubing bends will have no signs of crimping or wall failure, so a GOOD tubing bender is a necessity...the $60 one at Harbour Freight won't do it...believe me...I tried.
I'll take some pics of my ITS car. I designed the cage after studying cage designs in other cars, books and developing some experiments of my own. My cage is overkill, but is as safe as any cage and is VERY stiff.
I would definitely recommend NASCAR style door bars. I have a triple bar setup with three vertical bars tying them together.
Have your cage builder build a frame that wraps around your seat out of 1" tubing. It should be a single piece bent in a "U" that attaches to the cage behind the seat and to the floor in as many places as practical. With this setup and a FIA approved seat, a seat back brace is not needed. Some people (myself included) don't like the idea of a seat back brace since in a bad accident, it can actually poke through the seat severing your spinal cord. FIA seats are rated up to like 50 G's or something...if you take a 50 G hit hard enough to brake the seat, you're dead no matter what.
Instead of paper towel tubes, try taping straws together to make a miniature mock cage to test different designs and to show your cage builder what you want.

[sykikchimp]

excellent advice!

I would LOVE to see some pics of your cage TBreu..

I'm thinking I'll get the cage built minus the door bars for now so that I can still daily drive it if necessary. I usually only drive it 2 or 3 days a week anyway. Then when I finally get myself a Daily driver, I'll go all out on the NASCAR bars. good idea?

TBreu - I'm sure I totally understand the seat brace your talking about.. (the U bend one) Do you have this in your car?

[TBreu007]

Instead of going full NASCAR style ladder door bars, you can make a modified X door bar that protrudes into the door like a NASCAR style, but is lower in the middle making it easier to get in and out of. Porsche does this in their Supercups and GT3 RS. It's not quite as beefy as NASCAR style ladder bars, but much easier to get over while getting into the car. If it's safe enough for Porsche it's safe enough for me...just something else to think about.

If you're going to do track events and not race wheel to wheel for a while, door bars aren't a necessity since the chance of getting t-boned at a HPDE is fairly low. In roughly two years of teaching at HPDEs, I have never seen or heard of two cars coming together.

I have the U bend seat bracket and it's very sturdy. I'll take some pics. of it too possibly tomorrow.

[DS 240R]

There are a bunch of pics of my cage up on monkey-r.com. Here's one of the door bars. http://monkey-r.com/jim/pages/DSCF0010.htm

The car is a B13 NX2000.

There's also some good S and B chassis cage discussion over at http://sr20forum.com/showthread.php?t=62007 and a couple of other topics under the SE-R Cup. Good pics, too.

[TBreu007]

Keep forgetting digicam
Have it by my wallet to take to the shop tomorrowto take some pics. of my cage.
Here's a pic, but you can't see the cage http://www.chinmotorsports.com/galle...e=IMG_0131.JPG

[DSC]

cool pics DS240r

This is what I was talking about for the s13 main hoop.
http://monkey-r.com/jim/pages/DSCF0013.htm

For little 2dr cars that just seems like a better place to mount them...unless the spot is too weak?

Edit: Your my hero!
http://monkey-r.com/jim/pages/IMG_2659.htm

[thx247]

TBreu007, people have survived impacts of over 90G's before, 50g's is not necessarily going to kill you, and seat back braces ARE useful.

[DS 240R]

Originally Posted by DSC

For little 2dr cars that just seems like a better place to mount them...unless the spot is too weak?

I think the seat is a lot stronger than the floorpan. In the NX it is thicker and a has a 90 bend in it, much better than the flat floor. The big problem you run into then is that it sets the main hoop more towards the rear of the car and then you have to get creative with the door bars. The work was done by Steve Scott out in LA.

Originally Posted by DSC

Edit: Your my hero!http://monkey-r.com/jim/pages/IMG_2659.htm

Shoot, it is a race car, you gotta get rid of that stuff. It makes a difference, too. With a stock weight of about 2440 lbs, the NX is down to 2170 with 1/8 tank of gas and no driver. There's probably another 100 lbs I can take out and I still have the stock steel hood.

[DSC]

hehe, yeah. I was just saying how you did it. I did my entire floor from the top of the gas tank to the firewall using a heat gun and scraper. Seeing you do it with dry ice makes me want to cry.

[TBreu007]

THX, seat back braces are used almost no where else in the world in motorsports. It was originally brought about by roundey-round racers that want to use their aluminum Kirkeys and Ultra-shields that they have been using for years instead of dropping some major cash on a FIA seat that they might not even like. Yes, they are useful (and even mandatory in some sanctioning bodies)...especially for Aluminum seats.

If 40G survivability is good enough for the Naval Aerospace Medical Institute in jet fighters, it's good enough for me (and the FIA). Sure, accidents aren't though of as 100% fatal until over 90G's, but 27G's is enough to rupture your bladder and how many cars and cages will stay intact at anything over 50G's to protect the driver? The G's don't normally kill people...foreign object intrusion does.

Back on topic

Can anyone host my pics? They're way too big to post here and if I reduce them down, you won't be able to see much.

[DSC]

I can host them if you can send them to me. PM me for an e-mail adress that will take large files.

[DSC]

Sweet! Nice pannel for the door badass cage!
http://www.240motorsports.com/zilvia/cage/s13cage/

I've seen seat mounts like that before...similar anyway. cool stuff.
http://www.240motorsports.com/zilvia/cage/teg4.jpg