Roll Cage Construction.

[XRATED]

Ripper of a thread... Great work.

[Risking]

Well today I got the main hoop finished.

To me this is how a hoop should be done.

A full cross from corner to corner with a horozontal bar across the center os the cross intersection

Basicly we run a string line from point to point where the center of the 38mm tube will line up. From there I use an angle finder and set the desired angle in the knotcher.

Knotch out the end and measure the total length of the bar required. Set up for the other end of the tube and knotch it out at the length needed.

That gives me one solid diagonal bar which is then Tacked into position. Next I string line up the other side of the hoop which in theory should be identical if you've done the job properly.

Mine was roughly 1 degree different which is nothing.

So we make an indentical bar for the other side but this one needs to be knotched in half to intersect the solid bar. So the distance is measured and the angle measured.

Then the solid bar we have has the knotcher put through it at the distance and angle needed to make the joint.

In theory if you do it right then the two bits your left with should fit into the hoop perfectly and make a neat cross.

Then we cut the horozontal bars and calculate the same type of angles for the interesection. These are a really tight fit and can require some persuasion with a rubber hammer to fit and get level.

The exact same method is used to do the cross in the rear legs. One solid bar, the other knotched out where the interection is and fitted into place.

Its a time consuming process of measure 3 times cut once

The dash bar has also been done, I make them fro 44mm tube same as the main hoop as when running bracing off through the fire wall there can be alot of load put on this bar. With the dash bar fitted and holding the legs out where they should be the front legs sit hard up against the body of the car, there is not even 5mm between the tube and the body.

Still left to do is the bar between the two rear shock towers, two bars on each side from the intrusion bar/hoop intersection to the rear leg mounting plates. and the final difficult part the 6 bars that will penetrate the fire wall.

From both upper and lower intrusion bar/front legs points to each shock tower and then from the center of the dash bar out to teach shock tower as well.

Sorry the photos are average they are shitty I phone jobs but will get some good quality shots of the cage latter today or tomorrow

[BOZ22N]

Looking good.

[Risking]

A few better quality photos of what has happened over the last few days and from the write up above.

Still have to plate the cage in only have the top plates done now not the full box sections. Over the next few days ill finish off the bases and get the rest of the car cleaned up ready to be painted.

Also need to go over each weld and tidy up a few tight places to get to like inside the intrusion bars etc

From this photo you can see how close the drop part of the front leg is to body of the car.

Edited September 6, 2009 by Risking

[Tektrader69]

risking, you sure there is enough rearward room for your seat ? Seems awful close.

Here's my cage. maybe not quite a strong vertically as what you have built but strong enough IMO, and behind seat room is maintained.

Edited September 6, 2009 by Tektrader69

[Marlin]

Risking, do you drop the main hoop through the floor to weld the top or do you leave it un-welded like I know dozens of others do?

[Risking]

There is ample room for a good seating position with that hoop. Besides that Boz is a short arse and will be seated well forwards anyways, my gtr is donethe same and no problems.

You are aware that you need some form of diagonal inside that hoop?? It won't pass anything like that. It also seems along way off the roof line at the top? Any particular reason you did it that way??

Marlin I drop every cage through the floor and TIG weld every joint the full 360 degrees.

Back a few pages there is some good photos of how I drop them and do the roof bars etc.

I ant see the point doing a cage if you don't welded it and finish it off properly.

[Marlin]

Ahhh ok, I must have missed/forgotten that bit. I agree with you, but I still see many many that aren't completely welded.

[sav man]

you should still still pass cams certification with no diagonlan in the hoop, as the diaginals are in the rear section. if it dosn't pass, i'll be happy to have the motec for free

[hrd-hr30]

You are aware that you need some form of diagonal inside that hoop?? It won't pass anything like that. It also seems along way off the roof line at the top? Any particular reason you did it that way??

diagonal can go in either the main hoop or rear stays. I had mine in the rear stays with my old IPRA spec 1200 and just a horizontal harness bar in the main hoop.

[Tektrader69]

you should still still pass cams certification with no diagonlan in the hoop, as the diaginals are in the rear section. if it dosn't pass, i'll be happy to have the motec for free

Gee Thanks, MOTEC for free= LMAO

The cage was already in the car when i bought it as an unfinished project. Its a work of art. All chrome molly TIG welded, must have cost a fortune.

Its very strong in the front with firewall and front cross brace going through to the front shocker towers.

BTW Risking I am loving the thread. Should be more like this

Edited September 7, 2009 by Tektrader69

[Risking]

My apologies I forgot about the first two drawings showing the compulsary diagonals.

Being a molly cage has it been engineered or did they use nominated thickness materials?

Once this cage is done ive got one to do for another member on here then a full molly cage in an R34. Have had to submit drawings of the molly cage to the engineer before I begin so he can do the simulated testing.

Ill be sure to log the progress of the molly cage as its a totally different procedure to get it approved.

Alot of work has gone into that Z car cage thats for sure.

The firewall work is very similar to what ill be doing with this cage. Ill have the bars located slightly different on the shock tower but the same layout.

Very close to what I do with the GTR's as well. On the inside where the bar meets the lower point of the leg it would have been nice to have it lower but im guessing the way the fire wall is done made that not possible.

Edited September 7, 2009 by Risking

[Tektrader69]

Being a molly cage has it been engineered or did they use nominated thickness materials?

Once this cage is done ive got one to do for another member on here then a full molly cage in an R34. Have had to submit drawings of the molly cage to the engineer before I begin so he can do the simulated testing.

It was designed by an engineer who works at PWR, I have his contact details.

Unfortunately I have no paper work on its construction etc. So I spose I will cross that bridge fairly soon. It was designed to be used in IPRA races. But I think they would have had a bit of trouble getting the car over the line for IPRA after reading the rules. I dont think a Twin turbo 300zx is possible for inclusion.

I am due to start assembly in the next 4 weeks after not having a garage for the last 9 months.

Edited September 7, 2009 by Tektrader69

[Risking]

providing you can get the right paper work and in touch with the original cage builder you should be right.

Or if its built using the nominated material diameters then log it as a CDS cage and dont worry about the hassle.

I know alot of people that do it this way but really using the same diameter material etc is defeating the purpose of a molly cage.

Im not sure if the z is elligable for IPRA, im sure someone would be aware if it is or not.

I have the same problem with garage space and my own race cars. Ive been building a spaceframe Sports sedan in my oversized single car garage. Gets tedious at times.

[Duncan]

Gary Cook (Sydneykid) is the NSW IPRA eligibility officer so he will be able to confirm re the TT Z. But I'd be very surprised if you weren't welcome. Your issue is you will need to run 2x 28mm air intake restrictors if you do full on racing which will limit you to about 250rwkw at best.

[Tektrader69]

Gary Cook (Sydneykid) is the NSW IPRA eligibility officer so he will be able to confirm re the TT Z. But I'd be very surprised if you weren't welcome. Your issue is you will need to run 2x 28mm air intake restrictors if you do full on racing which will limit you to about 250rwkw at best.

I reckon you are right. A reletively heavy car and restrictors doesnt sound like much fun. Though i am hoping to cut it down to 1150kg through dieting. Mine and the car LOL.

I was actually wanting the car for Time attack and Marque sports.

So what it was originally intended for isnt so much of an issue for me. As long as I can easily convert it back to IPRA specs if need be, I will be happy.

Edited September 7, 2009 by Tektrader69

[Bozman1]

Not sure about the 300 being IPRA legal

The only sportscar that I think is eligable is the RX7 S1, 2 or 3.

If this is a 2 seater Zed, it will be a no go for sure!!

Don't let the restrictor thing put you off, Lofty and I ran our R32 GTR's in IPRA and did ok

[Boss-zilla]

Very good read, I have been keeping an eye on this thread.

When it comes to side intrusion bars is the following any good?? I like it as it seems to better to get in and out off (not that this is a big concern for me)

I have a r32 and being over 6 foot I will be moving the seat back a bit. So is it better to have the main hoop mounted to the floor in the corner were it rises for the rear seat or is there similar strength in moving it back so it sits on the rise were the front of the rear seat is like bellow?

Cheers Ross

[Sydneykid]

Gary Cook (Sydneykid) is the NSW IPRA eligibility officer so he will be able to confirm re the TT Z. But I'd be very surprised if you weren't welcome. Your issue is you will need to run 2x 28mm air intake restrictors if you do full on racing which will limit you to about 250rwkw at best.

Thanks Dunk. Improved Production (3J) is a Touring Car category. so if it's a 2 seater Zed, then it's definitely a Sports Car (FIA Group B). There is no history of 2+2 Zeds in Improved Production and I haven't seen any separate FIA Homolgation Papers for them either. If it is a 2+2 and you can't find FIA Touring Car (FIA Group A or Group N) Homologatiion papers for it then it would have to pass the Touring Car Dimension Test which specifies minimume distances, pedal to steeering wheel to driver's seat (that would be OK), then seat to rear window (where most "sports cars" are too small and fail the test).

PM me if you want to get into more detail

Cheers

Gary

[Tektrader69]

Thanks Dunk. Improved Production (3J) is a Touring Car category. so if it's a 2 seater Zed, then it's definitely a Sports Car (FIA Group B). There is no history of 2+2 Zeds in Improved Production and I haven't seen any separate FIA Homolgation Papers for them either. If it is a 2+2 and you can't find FIA Touring Car (FIA Group A or Group N) Homologatiion papers for it then it would have to pass the Touring Car Dimension Test which specifies minimume distances, pedal to steeering wheel to driver's seat (that would be OK), then seat to rear window (where most "sports cars" are too small and fail the test).

PM me if you want to get into more detail

Cheers

Gary

Its a 2 seater, and what you have outlined is exactly how I read the rules. In some ways its a pity the IPRA door is closed

shut on Jap sports cars as most are heavier than sedans in any case.

Thanks Gary

When I get further along the assembly path I will examine the FIA group B rules and try to fit it into there. Or at least be easily reversable to fit in that catagory.

Back to cages. Sorry Risking

Edited September 8, 2009 by Tektrader69