Re: roll bar in a street car?
[Re: justinp61]
#2977289
10/22/21 03:31 PM
10/22/21 03:31 PM
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Joined: Oct 2007
Posts: 4,213 New York
polyspheric
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master
Joined: Oct 2007
Posts: 4,213
New York
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That was so helpful. My point is that they see no reason to discuss decisions that have been made with little input from engineers.
Boffin Emeritus
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Re: roll bar in a street car?
[Re: jcc]
#2977291
10/22/21 03:35 PM
10/22/21 03:35 PM
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Joined: Oct 2007
Posts: 4,213 New York
polyspheric
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New York
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I agree, larger diameter is much better, but very difficult to live with in the car. I limit my remarks to a single point of attachment, in which bending allows collapse of the adjacent tubes.
Boffin Emeritus
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Re: roll bar in a street car?
[Re: justinp61]
#2977375
10/22/21 08:58 PM
10/22/21 08:58 PM
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Joined: Oct 2007
Posts: 4,213 New York
polyspheric
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master
Joined: Oct 2007
Posts: 4,213
New York
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I wrote something about a new product as sarcasm about 30 years ago, can't find it. Ever hear of NIH? A force stronger than the hydrogen bomb, it protects important people from new ideas. Used by all car manufacturers and defense contractors. NIH = not invented here.
Boffin Emeritus
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Re: roll bar in a street car?
[Re: polyspheric]
#2977380
10/22/21 09:20 PM
10/22/21 09:20 PM
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Joined: Dec 2005
Posts: 11,739 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,739
Fulton County, PA
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I agree, larger diameter is much better, but very difficult to live with in the car. I limit my remarks to a single point of attachment, in which bending allows collapse of the adjacent tubes. A properly designed chassis is a series of triangles. To your other comments...I'm certain engineers who are very familiar with the chassis in question, and the forces involved in accidents, are involved in the establishment of these specs and rules. Chassis builders, OE factory engineers, safety experts, sophisticated CAD and analysis, etc. Fuel cars, Pro Stock, NASCAR, Big bucks. That all filters down to the lower classes. Unfortunately, it usually takes someone being killed to cause a serious look at the cars in question and get them updated.
Last edited by CMcAllister; 10/22/21 09:28 PM.
If the results don't match the theory, change the theory.
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Re: roll bar in a street car?
[Re: CMcAllister]
#2977396
10/22/21 09:36 PM
10/22/21 09:36 PM
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Joined: Dec 2013
Posts: 4,704 Wichita
GY3
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Wichita
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I agree, larger diameter is much better, but very difficult to live with in the car. I limit my remarks to a single point of attachment, in which bending allows collapse of the adjacent tubes. A properly designed chassis is a series of triangles. To your other comments...I'm certain engineers who are very familiar with the chassis in question, and the forces involved in accidents, are involved in the establishment of these specs and rules. Chassis builders, OE factory engineers, safety experts, sophisticated CAD and analysis, etc. Fuel cars, Pro Stock, NASCAR, Big bucks. That all filters down to the lower classes. Unfortunately, it usually takes someone being killed to cause a serious look at the cars in question and get them updated. He's smarter than all those people.
'63 Dodge 330 11.19 @ 121 mph Pump gas, n/a, through the mufflers on street tires with 3.54's. 3,600 lbs. 10.01 @ 133mph with a 250 shot of nitrous an a splash of race gas. 1.36 60 ft. 3,700 lbs.
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Re: roll bar in a street car?
[Re: GY3]
#2977453
10/23/21 02:14 AM
10/23/21 02:14 AM
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Joined: Aug 2003
Posts: 3,245 Between a rock & a hard place
cudadoug
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Between a rock & a hard place
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Another question: I haven't installed my subframe connectors yet. If I put in a 6-pt. roll bar, are the connectors still useful? Absolutely! They make a world of difference in a uni-body car! If they are welded to or through the floor!!
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Re: roll bar in a street car?
[Re: cudadoug]
#2977457
10/23/21 02:39 AM
10/23/21 02:39 AM
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Joined: Aug 2003
Posts: 43,315 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,315
Bend,OR USA
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Another question: I haven't installed my subframe connectors yet. If I put in a 6-pt. roll bar, are the connectors still useful? Absolutely! They make a world of difference in a uni-body car! If they are welded to or through the floor!! Both will work, I've used 2x2 as well as 2x3 .083 rectangular tubing for sub frame connectors in the past It is up to you which size and how to have it installed
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: roll bar in a street car?
[Re: Cab_Burge]
#2977509
10/23/21 09:29 AM
10/23/21 09:29 AM
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Joined: Oct 2007
Posts: 4,213 New York
polyspheric
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master
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New York
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2 X 3 is much, much stiffer than 2 X 2, not just the obvious 50% height increase.
Boffin Emeritus
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Re: roll bar in a street car?
[Re: polyspheric]
#2977526
10/23/21 10:23 AM
10/23/21 10:23 AM
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Joined: Oct 2003
Posts: 11,686 W. Kentucky
justinp61
I Live Here
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I Live Here
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Posts: 11,686
W. Kentucky
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I agree 2x3 is stiffer, but the roll bar helps too.
Last edited by justinp61; 10/23/21 10:24 AM.
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Re: roll bar in a street car?
[Re: gregcharger72]
#2977564
10/23/21 12:33 PM
10/23/21 12:33 PM
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Joined: Mar 2003
Posts: 6,341 Heaven
EvilB1Dart
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Heaven
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Do any of you get away with running mid 10 second passes at the drag strip with out a roll bar? my car is primarily a street car that i take to the track a couple times a year. what are your thoughts about roll bars in street cars. I see there are several newer challengers that are that fast and faster and are not required to have roll bars. If you can’t bend/weld a bar in yourself, find a quality shop to install a moly 8.50 cert setup. Make sure you’re at the shop when they’re measuring/cutting and welding-in the main hoop and halo so they can build it around your actual sitting position while in the car. Not sure what belts, seats you’re using, but consider Kirkey’s or seats that would not allow your body and head to flop around a lot in the event of an accident on the street, i.e, keeping your body, head from contacting the main hoop and halo. If most of your time spent in the car is on the street, then I’d install door-side swing-out bars. Lastly, unless you’re wearing some sort of head protection, no way in hell would I ever run a car on the street with a funny car cage. I personally know two guys who died from head injuries when their heads smacked their funny car cage bars on the street. They were driving normal and were hit on the driver and passenger sides of their cars. They weren’t hot-rodding or acting like hooligans, just freak accidents. If anyone were to install or currently has a funny car cage they run on the street there is a company that makes a helmet shaped like a baseball cap that doesn’t look too goofy. It would at least allow you to live most likely.
"Any fool can know. The point is to understand"
- A. Einstein
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Re: roll bar in a street car?
[Re: EvilB1Dart]
#2977579
10/23/21 01:34 PM
10/23/21 01:34 PM
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Joined: Oct 2006
Posts: 1,264 New York, USA
Chargerfan68
pro stock
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pro stock
Joined: Oct 2006
Posts: 1,264
New York, USA
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Do any of you get away with running mid 10 second passes at the drag strip with out a roll bar? my car is primarily a street car that i take to the track a couple times a year. what are your thoughts about roll bars in street cars. I see there are several newer challengers that are that fast and faster and are not required to have roll bars. If you can’t bend/weld a bar in yourself, find a quality shop to install a moly 8.50 cert setup. Make sure you’re at the shop when they’re measuring/cutting and welding-in the main hoop and halo so they can build it around your actual sitting position while in the car. Not sure what belts, seats you’re using, but consider Kirkey’s or seats that would not allow your body and head to flop around a lot in the event of an accident on the street, i.e, keeping your body, head from contacting the main hoop and halo. If most of your time spent in the car is on the street, then I’d install door-side swing-out bars. Lastly, unless you’re wearing some sort of head protection, no way in hell would I ever run a car on the street with a funny car cage. I personally know two guys who died from head injuries when their heads smacked their funny car cage bars on the street. They were driving normal and were hit on the driver and passenger sides of their cars. They weren’t hot-rodding or acting like hooligans, just freak accidents. If anyone were to install or currently has a funny car cage they run on the street there is a company that makes a helmet shaped like a baseball cap that doesn’t look too goofy. It would at least allow you to live most likely. Excellent, excellent advice!! As much as most of us do not want to hear that, it is very true. Thanks!!
1.50 60Ft. , 10.75@ 127MPH Hauling 3900 LBS.
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Re: roll bar in a street car?
[Re: Chargerfan68]
#2977613
10/23/21 03:21 PM
10/23/21 03:21 PM
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Joined: Mar 2003
Posts: 9,102 Rogue River, OR
Jeremiah
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Rogue River, OR
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I agree on using a racing seat and harness if you have a roll bar/cage. Anything lees than that (stock seats and lap belts bar or no bar) and you are at the mercy of a higher power in the case of an accident. The crash tests from the 60-60s era were brutal. One of the reasons I like beating on my cars at the track. Chances of a hard, head on front end collision are much lower with no telephone poles etc. At that point you end up abiding by the rules of where you race and add safety precautions for the street use.
A few things also come into play with design of the cage too. You don't want to be under the hoop. I have seen taller guys do this when laying the seat back or using a factory bench. It is acheived with a kicked out horizonal bar in the hoop instead of running it straight across so it does it's job. Bad place to be without a helmet, padding or not.
The other problem I see with the factory flip up seats of 67 and back is that they do not lock in position. Then you see the harness bolted to the floor behind the seat just right so in an accident the seat will fold you up as both it and you torso get intiment eith the dash. My 66 b bodies both have race seats because of this.
The rules say the hoop must be higher than you helmet so definitely check that as you put it together. For sure use swing out bars unless you are really throwing the world at it lol. I also like forward bars in our unibody mopars. Cab turned me on to the idea of running them outside of the fender apron. Way easier to work on the car with the bars out of the way.
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Re: roll bar in a street car?
[Re: DrCharles]
#2977615
10/23/21 03:33 PM
10/23/21 03:33 PM
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Joined: Jan 2003
Posts: 11,729 Portage,michigan
B3422W5
I Live Here
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I Live Here
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Portage,michigan
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Another question: I haven't installed my subframe connectors yet. If I put in a 6-pt. roll bar, are the connectors still useful? Angling two bars that intersect the frame connectors from the main hoop( making it an 8 point) are extremely worthwhile regards chassis rigidity upgrade and making the car “ one piece” In other words, these two angled bars would go through the rear seat footwell and weld to the frame connectors on each side.
Last edited by B3422W5; 10/23/21 03:34 PM.
69 Dart GTS A4 Silver All steel, flat factory hood, 3360race weight 418 BPE factory replacement headed stroker, 565 lift solid cam Best so far, low 10.30’s 1/4 1.41 best 60 foot 6.56 at 104.17
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Re: roll bar in a street car?
[Re: B3422W5]
#2977624
10/23/21 04:20 PM
10/23/21 04:20 PM
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Joined: Dec 2005
Posts: 11,739 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,739
Fulton County, PA
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In the drivers compartment, the only adjustment to be made to the bar locations would be fore and aft on the main hoop for leg room if using stock steering and pedals. Unless the driver is freakishly short or tall, that's pretty much a standard location. Back in the car a bit. The seat doesn't need to be against it. And the next guy to own it might want the seat to go back. The rest of it gets put in as close to the body/headliner/B pillar/ doors as possible to give as much room as possible. This usually takes some planning and effort to get it all welded up 100%. Helps to get the windshield out, Fast Super Stock and other stock body 25.x type deals or cars like a SN95 Mustang often have the roof removed to get it all done.
Frame ties are 2x3x.083, stood on end through the floor. Mopars get the back of it poked into the front of the stock frame rail, maybe half above and half below the floor. Section it up in so it fits up against the torsion bar X member, Outriggers from the frame rail to the rocker, also sectioned into the floor, provide solid mount points for the cage.
If the results don't match the theory, change the theory.
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Re: roll bar in a street car?
[Re: B3422W5]
#2977625
10/23/21 04:23 PM
10/23/21 04:23 PM
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Joined: Dec 2003
Posts: 22,734 Bitopia
jcc
If you can't dazzle em with diamonds..
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If you can't dazzle em with diamonds..
Joined: Dec 2003
Posts: 22,734
Bitopia
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I would add the need for .125" wall FC is IMO reduced as one installs more cage components. I don't see many cases that .125" is required once one starts adding a roll bar+.. A pair of .125" 2x3 tubes are heavy for little gain.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
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