Roll Cage - AE92 sedan?

[azee]

Gearing up to do some work on the blue bomber. Near the top of my list is a roll cage for some peace of mind/chassis stiffening for track days.

I know Flashmn has done one in his sedan, but unfortunately the photos from that old thread are no longer visible. (Flashmn - I sent you a PM about this) Anyone else done one in an AE92 sedan that can share some pictures/details?

We test fitted one for a coupe into my sedan a while back. While it could be made to work, it was far from ideal.

Any and all info would be much appreciated.

Thanks,

Alan

[jmaz87]

i know the safety 21 cages by cusco i think, are decent and should fit with some dash mod. ect...

but personally i'm paying someone to fabricate one from chromoly... its lighter, stronger and welded onto huge pads for reinforcement so all in all it's worth the extra loot IMHO

a basic 4pt with harness bar and cross beam (roll-bar corner to C-pillar corner) around 500ish

i'm currently trying to save up enough to extend it to the front dash with floor and door bars and possibly even dash bar... this will be in the 1100 range

[azee]

As I mentioned before, we did test fit a cage made by Stand 21 meant for the coupe, and it was not ideal. It did not take advantage of the higher roofline the sedan has, but more importantly the vertical legs of the main hoop were too close to the seat. As far as I have seen, there are no prefab cages made specifically for the AE92 sedan, only the coupe. Granted, it's been YEARS since I've researched this, but it seems doubtful anyone has decided to mass produce one for the sedan after all these years. I mean, it's such a common race car platform and all.

You may want to reconsider using chromoly and opt for mild steel. Granted, I have no ideas how you use/intend to use your car, but SCCA regs no longer allow the use of chromoly in roll cage fabrication, unless it was approved prior to the revised regs. I know the chromoly weighs less than the mild steel, but SCCA has good reason to no longer allow it.

$1100 for a 6 point custom cage is surpisingly CHEAP. I've been calling around local race shops and have gotten ballpark estimates ranging from $1600 as a start to upwards of $4500 for a full blown deal. There is a semi local shop that can custom bend the tubes for you and provide all required brackets, plates, gussets, etc, but even the parts alone cost around $500ish.

[jmaz87]

well it is a friend... but yea a "full deal" probably includes fender bars and the whole bay is caged.

im very interested to know whats wrong with chromoly??? a ton of people use it in the circle and dirt tracks around here and they constantly smash into each other with no problems what so ever...

in fact they made my buddy cut a section out for his trunk bar and cross bar and add weight because they said he handled "too"well for his class...

[Flashmn]

$1100 for a 6 point custom cage is surpisingly CHEAP

yikes DDD my cage material was 380euros, plus some tig sticks and welding gas and paint and few days to work on it granted I didnt count man hours doing it.

im very interested to know whats wrong with chromoly???

You have to heat treat it post-welding...

[canadianae92]

what material did you use for your roll cage flashmn?

I've been thinking about a roll cage but I don't need one yet but I would like to make it so the firewall/strut tower are connected and then reinforced on the other side of the firewall by the side bar stopping at the same point on the opposite side. Cusco is one I though of but I'm not sure on that. Plus its $$$$ compared to diy and I CAN weld so...

do you have any pics of your roll cage flashmn?

[azee]

Hmm....been doing some research this morning, and I'm a little confused. I know I had seen it in the SCCA GCR before, but I can't seem to locate it anymore. The 2009 SCCA GCR states:

"F. TUBING
1. Seamless or DOM mild steel tubing (SAE 1020 or 1025 recommended) or alloy steel tubing (SAE 4130) must be used for all roll cage structures. Alloy and mild steel tubing may not be mixed. ERW tubing is not allowed."

Chromoly *IS* SAE 4130 alloy steel tubing, so it sounds like you might be okay using it. I'll try to find out more info about that. I swear it used to be in the regs about no longer allowing it.

Flashmn - your 380 euros for materials is right in line with what I've found out (380 euros = $570). It's the labor (if you're having someone else do the fabrication) that'll getcha! Also, I'd really appreciate it if you could please post some picts of your cage since they are no longer on the archived post so others could learn from your specific experience on building a cage in an AE92 sedan.

Thanks,

Alan

[Donald]

Originally Posted by jmaz87

im very interested to know whats wrong with chromoly??? a ton of people use it in the circle and dirt tracks around here and they constantly smash into each other with no problems what so ever...

I wonder myself since it is approved for aircraft structure (light weight fabric covered aircraft)

[Flashmn]

canadian92: Seamless cold rolled mild steel 45mm the main pipes and 38mm the secondary ones. Its certified material from the national motorsports body.

Also, I'd really appreciate it if you could please post some picts of your cage since they are no longer on the archived post so others could learn from your specific experience on building a cage in an AE92 sedan.

I'll do that when I get back from my parents place, pics are on my computer at my place.

[azee]

Here's a good discussion on the use of mild (MS) versus chromoly (CM):

http://sccaforums.com/forums/thread/28552.aspx

Since the welding process for CM requires TIG and proper normalizing after welding to prevent cracking, there's alot more room for error/potential for cracking if it isn't done properly, whereas MS can be done (assuming proper penetration) with MIG.

Donald - since you're in the aircraft industry, I'm sure that the fact you're dealing with *lightweight* aircraft fabrication is the key. Since you can use thinner tubing for equivilent strength, it's definitely the choice if you're trying to make everything as light as possible. Granted, you can say the same for race cars, but the majority of racing bodies recommend MS, so that's what I'll be sticking with.

Flashmn - that would be awesome. Looking forward to checking the picts out!

Alan

[Flashmn]

and light aircraft frames are usually bolted, as they have to fold away (hang gliders and such) and alot of the frame structures are actually aluminum...

[jmaz87]

that has more to do with the rigidity of steel versus the give of aluminum than overall strength...

weight is really the only reason i would opt for chromoly over MS ill definitely check into the welding procedures but I've personally seen many cages by the same guy and they all look very solid definitely no cracks

[Donald]

Originally Posted by azee

[

Donald - since you're in the aircraft industry, I'm sure that the fact you're dealing with *lightweight* aircraft fabrication is the key. Since you can use thinner tubing for equivilent strength, it's definitely the choice if you're trying to make everything as light as possible. Granted, you can say the same for race cars, but the majority of racing bodies recommend MS, so that's what I'll be sticking with.

Alan

Good point

Originally Posted by Flashmn

and light aircraft frames are usually bolted, as they have to fold away (hang gliders and such) and alot of the frame structures are actually aluminum...

Actually I was refering to older aircraft ....... Now I think of it.......MUCH older aricraft!
Dam! Am I giving my age away?

[jmaz87]

hehehehe ouch donald no self-bashing on this forum!!! you can only bash others!!!

[Flashmn]

Donald, yeah I know you worked on WW1 aircraft

weight is really the only reason i would opt for chromoly over MS ill definitely check into the welding procedures but I've personally seen many cages by the same guy and they all look very solid definitely no cracks

You wouldnt see the cracks, we're talking microscopic cracks if anything. Main reason is you have to heat treat chromoly tubing after welding.