lefrog

I am getting my C5Z ready for a custom rollcage and while I pretty much know what I want, I am still puzzled whether I need a bar across the dashboard or not. For this year, I'm still going to stick to HPDE but SCCA/NASA compliance will be required in the future.

If you look at the pictures in this thread: http://forums.nasaaz.com/showthread.php?t=3848 they welded the front to the bar that runs across below the steering column.
Is that a common practice and is that strong enough?
Is there another way of routing a bar through the dash and is it necessary?

All comments and suggestions are welcome.
Thanks

RX-Ben

I would never "anchor" my main hoop like that or let it pass tech if I was a tech inspector.
Anyway - I like the dash bar for its utility - it is great to have something to hang wires from and support a switch panel. Does not need to be as thick or big as the rest of the tubing. I don't think it does much in terms of cage integrity or stiffness (it is an optional bar for NASA), though if you wanted you could tie it into the tunnel which may have a marginal benefit.

lefrog

So you would say better no dash bar than the welding they have done on that existing bar?
If I want to keep the original dashboard, where should I run the dash bar?

0Randy@DRM

Welding to the chassis is never a bad idea, but they do count it as a "point". Check rules or bring a sawzal.

You can run a full sized dash bar from "a bar' to "a bar" right under the steering rack.

Randy

RX-Ben

The welding on the dash bar is fine. The attachment point of the main hoop is inadequate, in my opinion.
I don't think you need the OEM dash bar to use the OEM dash. Run it as Randy has suggested (under the steering column).
Careful as the OEM steering column support is magnesium (intensely flammable).

lefrog

Does a straight bar clear the tunnel or does it need to be bent?
Anyone has pics?

Thanks again for the info.

RX-Ben

a straight bar fits over the tunnel with plenty of room to spare. I am sure there are pics on the forum as there have been a number of roll cage threads.

lefrog

I compiled all the pics I could find in this doc: https://dl.dropboxusercontent.com/u/...0rollcages.pdf

The only shots of dash bars are on page 18/19 for under dash and page 20 for over the dash.

Would the under dash bar prevent the removal of the steering column?
Still trying to figure out the pros and cons. If it doesn't provide any additional rigidity to the cage structure I'm wondering if it's worth the extra trouble.

0Randy@DRM

I know the car from page 18-19. The cage was done up at our shop in MN and the only one pictured that I would get into. That bar was straight, with some of the tin in the dash area cut.

Some of those cages are scary.
Randy

rmackintosh

Dash bar = must have to complete structural integrity of the cage.

RX-Ben

Don't show those cages to a builder. You want the bars to be anchored on top of the frame rails, not to the side. The floor of the car is unbelievably flimsy and cannot be used as a cage support. Door bars should really be anchored to plinth boxes or plates on top of the frame rail. The main hoop should be anchored on top of the frame rail. Like these:
http://forums.corvetteforum.com/auto...-progress.html
http://forums.corvetteforum.com/auto...pta-build.html

You should build the cage to NASA or SCCA specs or else it will be more difficult to sell the car.

Bill Dearborn

Was wondering what was wrong with the main hoop anchoring? He has it attached to the B Pillar with a box section and then fastened to the frame at the bottom through an L Shaped Plate. That is sort of what GM recommends. Weld to the B Pillar so the hoop transfers its load to the B pillar which is designed to support heavy loading. Front hoop is fastened to the frame like hundreds of other cages I have seen.

Bill

RX-Ben

The only part of that bar that is firmly mounted is the part on the side that is welded to the frame rail. The floor offers zero support in a mild to serious crash where the car is on the roof. I cannot think of a compelling reason to anchor the main hoop on only the side of the tube when an ideal alternative is readily available and also allows mounting the hoop more vertically.
The B pillar attachment points in those pictures ire relatively thin gauge, and certainly much thinner than the frame rails.
The welds on that cage do look great.

RapidC84B

I anchored my cage into the OEM dash bar. Couldn't afford to lose any leg room and saw no need for the added weight of another bar. No issues.

rmackintosh

The OEM "dash bar", at least the one in my car, and the 1/12" square tube shown in the link in the first post is nothing more than a dash mounting bracket. And if I remember it was bent up and over the transmission tunnel, losing any structural integrity it had even if it was made out of a proper tube.

As one who has tested a cage more so than most ever will, I STRONGLY SUGGEST you build any cage with the utmost in safety design possible. You just never know when you might find yourself flipping violently in a cow pasture 7 or 8 times at 140 MPH....

jwebsta32

That sounds like a good story

ScaryFast

Here is a Phoenix dash bar:

RX-Ben

Race cars don't have HVAC!!

ScaryFast

I was very disappointed when I pulled out the heater core and found that it only weighs like four pounds. It was not worth the effort to pull it out, especially since the dash bar makes it difficult.

I also forgot to mention that the dash cover fits nicely over that bar. It keeps the car looking stock

drivinhard

As a driver I'd rather have the dash bar over the column than under it. it's a potential shin buster below it in a crash, and it generally gives you more room in that area for getting in/out and tinkering