Jump to content
SAU Community

Recommended Posts

As it's a common issue for those who drag race they're high powered skylines. Dose anyone have the latest minimum cage requirements for a sub 10sec car to conform to ANDRA specifications?

Also, as this time bracket is being reached by more and more 'street' cars, it there a compromise to keep them street legal?

Cheers

Justin

Im with Brad, never used a single bend on each side of a main hoop.....except maybe a hotrod coming up

Justin - not currently for either ANDRA but I know they are reviewing this and there are something things being tested to support a change in the rules

I do hope they can review the rules to let more modern cars run and stay in the sub 140mph range without an overly intrusive cage... The current regs still only cater to the 'old' style, 2ton tin tops... the cars we're running now are so far superior in strength and engineering technology.

Personally I can't see what would be so wrong with a rear half cage with removable door bars for a sub 140mph car built after 1986.

... anyway just my thoughts (I hope ANDRA come to a similar conclusion soon)

Justin

Andra rules confuse me alot of the time.

It just goes against all the logic and structural design we do with cams cages.

Who decided that bent rear legs have enough strength to support a collapsing hoop. Let alone a leg with two bends.....

They don't even require diagonals or any triangulation. Unless the roof is removable you don't even need a roof diagonal.

Seems odd too when 95% of my cage work is CAMS/FiA related.

if is not good enough for the rear then one would more than safely assume it is not good for the front, especially since that is where the driver/passenger are situated but since it would be almost impossible to get in/out and see/drive, it is acceptable.

Hopefully no one sits in the back then

Fronts usually pass along the roof section and a pillar though which helps. Sometimes they get reinforced with straight bars too like a drop bar infront of the dash etc.

The entire idea is to attempt to keep the hoop upright and in position. Most rollovers result in frontal impact and the hoop is pushed rearward. The bent front legs usually are put into tension and the rears into compression.

A compression force put into the bent bar will cause collapse of the bar. A tension force will obviously try to straighten the bar which can't happen to a leg due to it's footing location.

When A front leg takes impact on the bend at roof height it won't straighten easily.

That was the massive argument that Peter muir had at the ANDRA council meeting which resulted in him walking out of the meeting and further arguments with Shultz carried on

Next time your around I'll show you the FEA simulation we did a comparison of.

Same cage same leg locations.

The roll simulated was a basic 100km/h right hand roll. Vehicle was 1200kg impact angles etc were consistent both times.

The cage was a typical two bend front leg, single side intrusion no roof diagonal, basic andra spec cage.

Single downwards bent rear legs allowed the hoop to move 30% further back than the straight legs, that's a realtivly low speed roll over as well.

Obviously the Sim does not take into account the original chassis construction or the strength of the mounting locations. It assumes them to be ridgid, which does leave some variable.

Steve power from andra was telling me the other day they have students at some university doing a study about safety cage design and extensive FEA simulations.

Should be interesting to see the results if they become available.

Just thinking out loud, so why wouldn't bent bars front and back be more desireable if they are unable to straighten since they both have footing locations? Then you could add the same style support to a rear leg as you would a front bar? But as you state, it is not required by ANDRA but doesnt mean a roll cage builder can't take it into consideration when designing the cage....if the owner/authroties allow it. Broadly speaking, one would think the more the merrier, especially when it comes to safety

Then I can assume that a CAMS cage is targetted at safety in the case of front impact being more likely then rear impact? Hence why the CAMS cages have straight backs to reduce the likelihood of the rear collapsing since they will be in compression?

Having said all that, front and rear impact at dramatically higher speeds with concrete barriers either side increase the likelihood of rear impact, or both front and rear for that matter since those concrete walls are within metres of each other

I heard about that argument....the saga continues and we will see what comes of it

It flattened the top bend of the front leg. The rear straight leg normally provides additional support to prevent that happening.

Mike I've done heaps of extensive half cages. Full X diagonals, leg supports, subframe pin reinforcements etc.

It flattened the top bend of the front leg. The rear straight leg normally provides additional support to prevent that happening.

Mike I've done heaps of extensive half cages. Full X diagonals, leg supports, subframe pin reinforcements etc.

  • 2 months later...

350mpa cds pipe or get chromolly if your worried about weight.

hit up racetechsteel.com.au.

they were very helpfull when i ordered my stuff through them and delivery was fast aswell

So with the base mounts what are the exact rules, how high can they be? and what thickness plates are they made from? is it basically just a welded up rectangular box which you then weld straight onto the floor?

Also with the front legs what the best way in mocking it up to work out what bends you need?

Plates are 3mm with a minimum size as per te cams manual.

Height isn't an issue just as long a they look strong an aren't silly high.

There is a few ways to do tight fitting front legs, the best ways are kept close and that's why cage builders are in the bussiness and everyone doesn't do their own cage.

  • 7 months later...

When you weld Thr roof piece In how do you weld ontop assuming its a tight fit

You either make the cage with box mounts under the hoop and front legs so when you remove them cage drops and you weld the top then put boxes back and weld it up or you cut a hole in your floor where the cage drops down and you weld the tops.

Edited by boostn0199

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • I guess one thing that might be wrong is the manifold pressure.  It is a constant -5.9 and never moves even under 100% throttle and load.  I would expect it to atleast go to 0 correct?  It's doing this with the OEM MAP as well as the ECU vacuum sensor. When trying to tune the base map under load the crosshairs only climb vertically with RPM, but always in the -5.9 column.
    • AHHHH gotchaa, I'll do that once I am home again. I tried doing the harness with the multimeter but it seems the car needed a jump, there was no power when it was in the "ON" position. Not sure if I should use car battery jump starter or if its because the stuff that has been disconnect the car just does send power.
    • As far as I can tell I have everything properly set in the Haltech software for engine size, injector data, all sensors seem to be reporting proper numbers.  If I change any injector details it doesnt run right.    Changing the base map is having the biggest change in response, im not sure how people are saying it doesnt really matter.  I'm guessing under normal conditions the ECU is able to self adjust and keep everything smooth.   Right now my best performance is happening by lowering the base map just enough to where the ECU us doing short term cut of about 45% to reach the target Lambda of 14.7.  That way when I start putting load on it still has high enough fuel map to not be so lean.  After 2500 rpm I raised the base map to what would be really rich at no load, but still helps with the lean spots on load.  I figure I don't have much reason to be above 2500rpm with no load.  When watching other videos it seems their target is reached much faster than mine.  Mine takes forever to adjust and reach the target. My next few days will be spent making sure timing is good, it was running fine before doing the ECU and DBW swap, but want to verify.  I'll also probably swap in the new injectors I bought as well as a walbro 255 pump.  
    • It would be different if the sealant hadn't started to peel up with gaps in the glue about ~6cm and bigger in some areas. I would much prefer not having to do the work take them off the car . However, the filler the owner put in the roof rack mount cavities has shrunk and begun to crack on the rail delete panels. I cant trust that to hold off moisture ingress especially where I live. Not only that but I have faded paint on as well as on either side of these panels, so they would need to come off to give the roofline a proper respray. My goal is to get in there and put a healthy amount of epoxy instead of panel filler/bog and potentially skin with carbon fiber. I have 2 spare rolls from an old motorcycle fairing project from a few years back and I think it'd be a nice touch on a black stag.  I've seen some threads where people replace their roof rack delete with a welded in sheet metal part. But has anyone re-worked the roof rails themselves? It seems like there is a lot of volume there to add in some threads and maybe a keyway for a quick(er) release roof rack system. Not afraid to mill something out if I have to. It would be cool to have a cross bar only setup. That way I can keep the sleek roofline that would accept a couple bolts to gain back that extra utility  3D print some snazzy covers to hide the threaded section to be thorough and keep things covered when not using the rack. 
    • Probably not. A workshop grade scantool is my go to for proper Consult interrogation. Any workshop grade tool should do it. Just go to a workshop.
×
×
  • Create New...