Its actually better to keep the front A-pillar bars away from the pillars themselves. With plates attaching them together like you have it creates an "I" beam in an area that needs all the help it can get. You can gain a lot of torsional rigidity in the chassis by strengthening the pillar and cowl area. Add a plate above and below the one you have. One down by the base of the pillar by your dash bar will do the most good.

 

That' if its class legal..

 

Yeah, i think maybe another intrusion bar would be good. I'm not into the massive bars you guys in the states use! Pretty ugly! And i'd imagine very heavy!

The interior has already been painted and trim put back in. It's my mates car, not mine! I just asked him if i could put some pics up to see what you guys think, because i'll be getting an almost identical cage fitted to my first gen. Hence why i wanted to know what you'd change and improve!

 

That was in the plan as well I will be adding a bit more bracing to the A-pillars on my cage as long as it stays CAMS approved (the pics are of my mates cage that re just got done). The problem with keeping them away from the pillars is that they start getting a bit close to you!

 

Not racing in a specific class, just track days for the time being, so anything goes as long as our motorsport body is happy with it!

We don't have specific class "spec" cages. As long as it's CAMS approved for that vehicle, and the vehicle and current mods meet the rules, you can use it.

 

A Spec Miata just completed:


http://www.izzyscustomcages.com/SpecMiata.html

 

You might also look into "line of sight" issues with A pillar bars. I like to make them asymetrical and line them up with the pillars as I look at them from the drivers seat. Just something to think about as you build yours.

 

I'd like to keep the cage as "low key" as possible, and keep visibility high so things like this are important. I'll be trying to keep a close eye on what they do with the cage as it's being done. Hopefully it comes out as planned.

 

You have to understand that the big door bars come from US circle track usage. It's quite easy to spin right in front of a 3400lb car and get hit directly in the door. I believe 2 fore/aft tubes tied together are the minimum any more in SCCA. NASCAR requires more. Most drag racing only requires the one side bar. Cagedruss knows the requirements much better than I as he actually fabs cages. I just like to be knowledgable, go racing and not kill myself.

 

I drafted the above cage to give the person helping me an idea of what I was looking for, figured I'd post it here and see if anyone with some experience had some suggestions or input on the overall design.

I'm only building a the rear half as I plan to drive it on the street for the remainder of the summer. This will be built in a '88 RX-7 that I'll be preping for IT/GT and the cage should be able to cross over to CARS (Canadian Association of Rally Sport) rules and regs. I'll be using 1. 3/4 inch DOM mild steel.

 

the bends in the main roll hoop total more than 180 degrees, so it will have to be built out of the next larger size tubing (according to SCCA rules.)

 

Is this count ? LOL

 

WAAAIIIITTTT a minute here... this isn't the same Josh that used to run a 66 Dart /6 is it????

 

Bent bars act as springs... straight bars transfer loads.

Your "dashbar" is a little bit unrealistic.... You'll probably want the downbars to follow the contour of the A pillar instead of just straight down to the floor. I assume that all of the straight bars for the downbar/halo are just representative and not planned to be straight bars welded together?

Remember, you'll be building a ship inside a bottle. Unless you have the dimensions of the bottle when modeling the ship... you're really just playing around. The design of the hoop as well as the downbars and doorbars aren't practical in a real 2nd Gen.

Just my opinion...

 

Yeah I'd have to break out the CAD program and the measuring tape to be somewhat accurate. This was supposed to be about as good as a rough sketch to give the builder an idea of the overall design I wanted.

What do you think of bringing the front bars through the firewall and to the strut towers? I'd imagine it would be difficult with an FC as the engine bay is a bit cluttered on the drivers side, though doing that would be ideal for stiffening the chasis would it not?

I was unaware that the main hoop had to be 180 degrees or less for total bends. I was under the impression that 1 3/4 was already relatively thick for building a cage. Although SCCA is not the sanctioning body up here in Canada they eventually seem to adapt overtime what SCCA does. It would be nice to be prepared for that.

 

The rule says 180 degrees +/- 10%. If you wanted to do that to the main hoop, I would be willing to bet that the tech wouldn't even bring up. Sometimes going up in size for the complete cage has its benefits. Check out the weight per foot of 1.5"x.120" and 1.75"x.095". Weight could be same or a little higher with much more structual rigidity.

The rules are a guide that techs do not seem to follow. I have seen real **** that has been passed by techs. If the welds are solid (clean) and the bends are nice, I do not see a problem. Main hoop would probably be a little safer on a side impact being tucked up to the b-pillars but more difficult for the door bars.

Bends in the tubes are not a bad thing if the bends are out, not bent in, away from driver. The cage is not a completely rigid thing. It must move and bend to absorb kinetic energy protecting the driver. Fab the door bars with mininum bends, 2, both out like a stock car ( \_____/ ). Try to avoid a 3rd bend allowing it to get to the main hoop ( see example below ).

Lots of fabricators use this type of door bars because the main hoop is so far behind the b-pillar or they are trying to get maximum clearance. I personally believe the bar has a structual weakness built in with the door bar bent in and then out. Under impact (load) the bar could continue bending in to the drivers seat. I am not saying this is a bad thing for all cars, just my opinion.

 

Dang, I'm busted! The 225 blew up so I went V8. I sold the car at the begining of the year to a guy on the East Coast. If I still made the same money and had the same expenses as I did in 2000 I'd still be racing the car.

 

You might also want to check on the bars that go behind the seat. Taller drivers need a little more seat recline room.

For example the autopower roll cage bows that bar back a few inches.

It matters in long road racing that you should be comfortable.

ed

 

This is me: http://www.angelfire.com/mo2/radrodder

Have they kicked you off of MoPax yet

 

Hey Scott,

I see you are a Mopar guy. I am finalizing a long term project after many years for a good friend. Josh is aware of the car. It is a 66 Fury III. I have been waiting for the engine to get here for the past year so I could finish her.

Car has been mini tubbed, relocated leaf springs inboard, left room for the biggest drag radial tire made with 2" clearence for a bigger slick if wanted. Engine is a bored and stroked poly head 318, I think CID is close to 350 now. Engine dyno'ed with a sigle 4 barrel at 440 horse at 5500rpm. Project HP's is around 500. Has custom pistons, rods, cam. Has dual carb custom sheet metal manifold, custom headers, 727 trans with brake.

Has 100 shot of Nos, all the bling a new car should have. Installed new Dana 60, disc brakes all the way around. Finishing interior now with a custom Aluminum dash inserts and a full console. All electrical is in the console except lights for the dash guages. all replated interior chrome, new cage, all new glass and will have leather interior.

I gutted all heavy parts such as factory dash pods and lightened up the bumpers, hood and deck lid. Car was extremely over weight.

When I am done I will post some pics.

 

Now that's cool... very cool russ. Definitely post some pics. Someday, I'll get back to my Dart projects

 

One of the top National SCCA tech inspectors lives in my town, and when he did my annual inspection he definitely questioned the total bends being a little more than 180 degrees on my main hoop. Fortunately I followed the letter of the law, and used the next larger size tubing in my cage, so I was completely legal. He gave my car a very thorough inspection, an he even made me drill extra inspection holes in various right side tubes just to prove the wall thickness in each of them!

 

I am glad to see your tech is on the ball. I wish I could say the same here in the NW. I Have seen cars that had kinks in the bends, stick welded, and different diameter tubes used throughout the cage. I have seen cages in Miatas that had 5 bends in the main hoop and still use the mininum diameter tubes. I Have seen other Miatas done by another local shop that has a 16"x10" attaching plates and extra mounting points in the cage and was defended by saying " it is for saftey of the driver".


I think they are afraid of offending the owners of the cars so they will stay in the club. I get to worked up on this subject. I spend a lot of time in perfecting my bends, welds and follow the intent and the rule of the GCR so I can fab a really nice and safe cage. Then I see crap done by other shops that charge a few bucks less.

I wish driver's would demand more when it comes to their safety instead of saving a few dollars so they can put it to tires or similar! Enough of my ranting, show me more pics!!!!

 

A friend of mine bought a BMW 2002 and decided to redo the cage. It's a good thing he did. He actually found that some of the tubes were plain old exhaust tubing.

The new cage was a little more complicated than the usual club racer so the SCCA inspector started giving him a rough time asking him to justify why he replaced the cage.

My friend saved the section of tube that had the SCCA inspection sticker on it. It was one of the thin walled tubes.

The inspector stopped giving him lip and passed his new cage.

ed

 

As far as the tubing going to the strut towers through the firewall, this will be scca IT illegal. In IT tubes cannot pass foreward of the firewall, so if you want to keep your cage SCCA compliant (even though your running in canada) it might be a good idea to keep them behind the firewall.