FlyingDog

There are two other choices:
The Mitch Piper way, which is to make the main hoop and front downpipes 3-5" short, sit the cage on the floor of the car, weld the tubes, lift the cage into place, and weld boxes made up plate under the tubes.
My way (not done yet, just planned), which is to make all the cage legs 1/4" short, drill holes in the floor directly below them, assemble the cage in the car but 6" below where it will eventually be, weld the tubes, lift it into place sliding 1/4" plate under the legs, then weld it in place.

Piper Motorpsorts charges ~$3500 for a 944 cage and a 928 cage would be more expensive due to more tubing and possibly thicker tubing (depending on rules and final weight).

atb

I noticed that Ken's cage has no cross bracing between the kickbacks. Is this typical?

FlyingDog

It is not required. The are many different ways of adding extra bracing. Some people find the X or / in their rearview mirror to be distracting so they find other ways to brace (ie: extra downtubes or side triangulation).

After spending 3 hours in Synergy Racing's shop yesterday, I wish we could build FIA/Grand Am style cages for NASA/SCCA/PCA use without having to get an FIA or Grand Am logbook for the car. Those fully triangulated cages are amazingly better (at least in theory) than the standard hoop based cages.

mark kibort

a couple of comments . on the driver side, i would angle a bar up to attach near the shoulder area of the driver. the nascar style bars are a good idea on the driver side. I dont think you need the bar across the dash board, as the stock bar might be sufficient, if it is also joined to the down bars. the 928 chassis is already pretty rigid, so i dont know if the x'ing in the rear is really nessesary. I guess it really depends if you are running a 500rwhp 928 racer on slicks vs a 300rwhp racer on DOTs.

Great shots and some nice designs. Thanks for posting.

Mk

Jim bailey - 928 International

Mark the stock dash cross "bar" is a thin sheet metal tube it has little strength.

kccampro

Great thread... taking notes, thanks for the pics

mark kibort

I thought anderson used the savaged 928s for these bars to make his cage out of them

I guess i retract that advice. I thought they were good (but small diameter) steel tubes.

MK

Jim bailey - 928 International

The hard part of this is you spend hours removing a few pounds of undercoating only to start adding back the weight of each and every foot of roll bar ! How much is enough ?? safety vs performance when is it "good enough". In designing you must determine how force will transfer from one tube to another ...Squares are weak , T is bad , triangles are good , tubes with bends just want to bend ... as mentioned and shown even small gussets added where tubes join makes a much stronger connection with very small increases in weight. Usually only the main hoops and diagonal must be of a specific size and thickness so using thinner tube for the "extra" braces is an option. Build the whole thing to NASCAR standards and it will weigh 3,400 lbs

FlyingDog

I forget whether it was here or on NASAForums that somebody said their (nice, well braced) 944 cage used 140-something pounds of tubing and plates. That is all of the asphalt floor insulation and the complete A/C system.

Black Sea RD

How about following the lead from a Factory 996 Cup Car? Their cages seem well designed and seem to work quite well for all the heavy racing they do.

One thing I would really watch is the bar above the driver's door. High and tight against the roof/body to keep your helmeted head away and under it is a must. The helmet adds a few inches of dimension all around and should be factored in while building a cage.

Cheers,
Constantine

69gaugeman

Just subscribing.

Please carry on.

Stan.Shaw@Excell.Net

A data point:
I paid $1500 for labor and materials, with the interior in place, way back in 2000.

Mike Simard

Adam and Tom, you guys are really fornunate to have a cage guy like that. that's alot of nice work for the $. You should gather up all the 928s you can find and have him do cages while he's still willing!

Darrin, your instrament panel looks like mine. Great minds...

FlyingDog

FIA style cages are generally not allowed in NASA/SCCA unless the cage is factory or the car has a logbook from a sanctioning body that specifically allows FIA style cages (ie: Grand Am or IMSA). I am trying to find out if GTS Challenge rules (which supercede NASA rules) allow for newly built FIA cages.

mark kibort

I was under the impression that the cage requirements for NASA and SCCA club, were mininimums. why would a FIA cage not be allowed. what is the major difference? (bars from cage tied to front shock towers, etc?)

Here are some shots of my simple cage. notice the halo bar up top. saves some time . I would have liked tohave the side bars bent outward like nascar style bars. kind of a modified "ladder" bar, with out so many of the ladder pieces. as it is now, it protects the shoulder area, but i would like to have one more cross member around the driver seat area to strengthen it up a bit.

mk