8 pt roll cage question

[inri]

Hi guys,

I may be getting my roll cage re-done due to the fact the previous owner had the rear two bars go through the upper portion of the rear seat. Because of this the upper rear seat can't be installed.

I'm looking to have the bars come up and over the top rear seat and into the trunk.

The car is expected to make a few runs per year at the track sub 10.99 (when it's finished, so a long way to go so to speak).

I'd like to know if a removable rear seat bar is acceptable to the "Track Inspectors". I'd like to have that installed so a 3rd person could have access to the rear seat on occasion?

Thank you all in advance.

 

[Woody01]

I dont think it is. Its not over here in the uk. Mine go from loop bar back through shelf by back window. That way you can still use rear seat.

 

[dvw]

Removable shoulder bar is illegal. That being said no one ever checks. Put it in with the same hardware as a swing out bar and cover with rollbar padding.
Doug

 

[Cranky]

I wouldn't try to cheat or cheap out on safety. It's your butt that's on the line if something happens. Welded roll bars with as few bends as possible is always the best way to go but if you're willing to gamble with your life, go for it.

 

[dvw]

I wouldn't try to cheat or cheap out on safety. It's your butt that's on the line if something happens. Welded roll bars with as few bends as possible is always the best way to go but if you're willing to gamble with your life, go for it.

NHRA allows swing out side bars why not a shoulder bar? In fact they allow the entire roll bar assembly to bolted instead of welded to the car itself. I don't think safety is an issue with a properly bolted in bar. Heck NHRA allows new vehicles to run below 11.50 with no roll bar if the car is unmodified. Some welds I've seen on 8.50 certified NHRA cages would probably have been safer if they were bolted together.
Doug

 

[mmissile]

I wouldn't try to cheat or cheap out on safety. It's your butt that's on the line if something happens. Welded roll bars with as few bends as possible is always the best way to go but if you're willing to gamble with your life, go for it.

+1

 

[Crizila]

+2 - I'm not even in favor of swing-out bars. The stiffer the cage, the less body flex you will have.

 

[daytona kid]

+2 - I'm not even in favor of swing-out bars. The stiffer the cage, the less body flex you will have.

X2.. These are legal and won't flex like a swing-out coupling could. >

 

[dvw]

A properly bolted bar can be plenty strong, just not legal. Just like many other NHRA rules, some make sense, some not. Personally my car has 13 bars more than mandated, a fire system, and a diaper. None are required. If I didn't feel it was safe, it wouldn't have been suggested.
Doug

 

[daytona kid]

Doug, Am I correct in assuming you mean "not legal- if not bolted the way the rules describe"? From part of what I read in the nhra rule book (below) bolting in is legal, when done as described.. Right?

Unibody cars with stock floor and firewall (wheeltubs
permitted) may attach roll bar with 6-inch x 6-inch x .125-inch
steel plates on top and bottom of floor bolted together with at
least four 3/8-inch bolts and nuts, or weld main hoop to rocker sill
area with .125-inch reinforcing plates, with plates welded
completely. Also, the roll bar may be welded to frame connectors
that are fully welded in place and are 1 5/8 inches x .118-inch
MS or .083-inch CM round and/or 2 inch x 2 inch x .058 MS or
CM rectangular

 

[dvw]

What I meant is that yes the entire cage assembly can be legally bolted in. Side bars can be legally bolted in. Poor welds will often pass tech. However a well designed bolt-in shoulder bar is illegal. I never have said to compromise safety, just the rule book.
Doug

 

[66Satellite47]

I'm not sure what sure what roll bar/cage you're talking about, but I've gone 3 endo's & 3 barrel rolls and walked away with no problem. A good moly cage is worth a lot.

 

[daytona kid]

Forgive my stupidity, again, but what is a shoulder bar?

 

[dvw]

Forgive my stupidity, again, but what is a shoulder bar?

No question is stupid. It is the bar that goes left to right between the main hoop legs at shoulder height.
Doug

 

[383man]

+2 - I'm not even in favor of swing-out bars. The stiffer the cage, the less body flex you will have.

I agree with this as I did not put a swing out bar on my drivers side bar like many friends told me to. And its because I wanted my 6 point bar to help stiffen the car as much as it could as I feel the 6 point bar stiffens my 63 more then the frame connectors do.
But I also agree with Doug that swingout bars can be plenty safe and strong but I feel it has to be even stronger without any swingout bars. And since my 63 does not have a cage and is mostly a stock frame I wanted my rollbar as solid as I could make it. Ron

 

[dvw]

I'll bet that a bolted in side bar is far stronger than a 40 year old spot welded rocker or frame rail.
Doug

 

[daytona kid]

Very good point Doug. I think a lot of guys have probably done the same thing I did, but it appears to me there is another benefit to adding sub-frame connectors if you're adding a roll bar, bolt-in or weld-in. I sat and thought for quite awhile about how to tie my bar/s in best. By making the under floor mount plates a little larger than required I was able to weld them to my connectors, rockers and frame rails while I had the floor pans out. Then the plates inside on the bottoms of the tubes bolt down and sandwich the floor. That is the strongest way I could think of doing them for my 10 pt. bolt-in roll bar. I still have to add the belt tabs and paint.

 

[dvw]

Very good point Doug. I think a lot of guys have probably done the same thing I did, but it appears to me there is another benefit to adding sub-frame connectors if you're adding a roll bar, bolt-in or weld-in. I sat and thought for quite awhile about how to tie my bar/s in best. By making the under floor mount plates a little larger than required I was able to weld them to my connectors, rockers and frame rails while I had the floor pans out. Then the plates inside on the bottoms of the tubes bolt down and sandwich the floor. That is the strongest way I could think of doing them for my 10 pt. bolt-in roll bar. I still have to add the belt tabs and paint.

I agree. Full on race car can't be to stiff. Street strip is a compromise.
Doug

 

[inri]

OK guys.... A local fab shop owner came to my house to inspect the car (it doesn't run). He said he would need the rear window removed and the headliner too because sparks could damage them as well as it will be easier for him to drill the two holes above the top reach seat and adjust the bars with the window out.
I was quotes apx. $400 for 1 3/4 DOM materials and $1200 for the custom roll cage.

I've since went online and found that Art Morrison Mopar 8 pt. Roll Bar - not roll cage like I have, sells for $440 in Chrome Moly! If I went this route the cage would because "bar" and it wouldn't be custom anymore. I'd like to know if there is is a significant difference between the two; roll bar vs. roll cage and art morrison kit vs. custom. I realize some JEgs or Summit universal kits will have more shortcomings than some of the other companies. Art Morrison seems to sell a solid product that fits well.

Lastly, the car has subframe connectors that are welded in. Would I need to go back with a roll cage? I'm tall (6'6) but lean (220 lbs) and the extra bars in the front may not be necessary. Car will be a 95% street driven, just want the increased body strength and the look, but don't want to overdo it if not necessary.

Thanks guys.

 

[daytona kid]

One thing to think about is the safety factors of a roll cage vs roll bar on the street. It could actually be more dangerous with a cage. Bare head to front and/or side top bars of a cage could be a problem in a wreck, even with padding. There is the same risk with just a roll bar just not as much. I guess you could just wear some good tight racing shoulder belts all the time you're driving on the street, but that may not be street legal, not sure on that. And I'll bet your head could still hit somewhere. Or just wear a helmet, lol..
Also, I realize that talking about cheap safety parts is an oxymoron, but I only paid $350 for a jegs 8pt roll bar kit that was made/bent for my specific car, the main hoop anyway. Then I added a couple more from the side bars to the fire wall and from there forward to the shock towers. But if your money is not as tight as mine get the best you can, just make sure it's welded right and attached right.