Materials science tells us that materials are 1/2 as strong in shear vs. tension. In this case you're not loading the eye bolts in pure shear either, you're adding a bending moment from the loading (the eye) being some distance from the surface, making it worse still.

Better yet, rather than using eye bolts, just wrap the harness around the bar.

 

Here's some front leg positioning - and mini Sainz bar - requires some cutting of the dash, removal of the door window duct end pieces, and my favourite, assembly of the dash working from the back!



Checked harness to seat cut-out alignment - unless the tunnel mod fixes it? Found this out after the fact and makes Hans use problematic, wrap as mentioned in the preceding post seems like the best deal, but will require removal of the weld-ins.

 

There are two parts working together to make the Hans work.

1. The tunnel mod to get the seat a little further over to the left
2. Using the bolts with clips allow the right harness strap to be 1.5 inches further to the right than the wrap around method which we tried to use

Will be months before I have the seat and harness in the car (will take pics then) so you'll have to take my word for it in the meantime.

 

Another consideration, distance from bar to seatback. Found in my case, with pretty much the same set-up it was ~ 400mm. With 3" belts, the FIA spec for use with Hans called for 55mm separation....so belts have to position next to one another. From memory, 2" were 15mm.

Believe there's one HNR manufacturer - who shall remain nameless , who makes a selling point of using one poor sob, who's belts slipped off his shoulders in a HANS fatality, with this problem in his installation......so just a heads-up!

 

Thanks for the heads up on that - will check that once the seat is in the car.

 

A couple of my cage in progress. Still have to mount the seats and install the side intrution.

 

Didn't see any Autopower bolt-in cages like I'm planning to put in my FB. Anyone have any thoughts on that as far fitment problems or hints, and safety? Intended use is road racing. Thanks.

 

Looking good - who's doing the cage for you? You going to replace the dash bar and make that part of the cage as well?

 

Cage is being buit by Carl at Macbilt engineering/race car prep in wellington. Im not too sure. I will have to see tomorrow when I pick up the car. Not too fussed if its not. Its only going to be used for low level clubsport events. Was really just for piece of mind and so it can go back to the strip (has run sub 10.99 so needs a cage next meet).

 

Cool - so you're in Wellington also then!? I have another couple of mates with caged bats - should catch up for a beer, talk rotors and b.**** ...

 

yeah for sure! PM me your details and Ill get in touch. I have a few other mates with bats that would be keen! Should organise a BBQ or something.

 

cage is done. Paperwork getting approved today the its time to paint and install the interior.

 

Looks good - plenty of weight you can take out of there. Are you putting all the interior back in there?

 

yeah most of it will go back in. The plan for the car is that its a drive to and from the track street car will full interior and street tyres etc. Will even have a basic stereo.

Then when I want to go faster it will all come back out.

Goal is to get top 10 at super lap and 10 sec down the quarter on pump gas, then Ill go nuts on the C16 tune and try for a 9 with slicks.

hay dreams are free

 

how much does a typical gutted, caged FD weigh?

 

yummy cages i love me some tig welding

 

Mine weighs 1320ks with me in it and instreet trim (about half the interior, no carpet, full exhaust, half a tank and 18s)

 

Been a while since I've done anything rotary powered. Just finished a 2nd Gen RX7 for SCCA's ITS.








Should have more pics of the build up soon:
http://www.izzyscustomcages.com/MazdaCages.html

 

^^^ is it stronger to have the door bars cross over each other like that? Or is that just the way you do it? Or are those SCCA rules?

 

I've been looking for a different way to do the X bars. The traditional 3 bar X's have been seeing a large number of failures lately where the main bar will tear at the HAZ of the joint.


The double bend X's are a good alternative (and I've used them myself), but the amount of tubing available to enter into the cabin makes me uncomfortable. This design keeps the tubes short and uncut.

I typically gusset them as well, but the owner was tapped out by the time we got to that point.

 

ya the solid ones def work better, my uncle was saved using that method

 

Can someone please show me where the rear bars mount to on a bolt in 6 point cage for a fc please as my rear bars wont fit ???

 

Which manufacturer? The rear bars on a bolt-in Autopower cage go to the front side of the rear wheel-well sheet metal.

I think that I may have a picture around. I'll post it if I can find it.

-b

 

My "5 year plan" FD work in progress at Design Craft in Westminster.


rear base plates





The main hoop is also dimple die gusseted to the chassis, cant really see it in these pics

 

Couple of Questions:

1) Anybody know how much space is required between the cage and the driver's helmet?

2) Also, several times it has been asked whether a bolt in cage is safe or not. Well, what is the answer?

3) Let me ask another way: What would make a bolt in cage less safe than a weld in cage. Furthermore, what about a bolt together cage?

4) I have an autopower bolt in cage with a "nascar style" door bar that was added on the driver's side. It is also bolt in. All of the pieces are bolted together using "sleeves" and then bolts running through both pieces of tubing. Is this a safe way to hold the cage together?

5) Are there any bars I can add that would be beneficial? (Like a big "X" bar going towards the rear of the car)

Thanks!

Rob