Roll cage question for a Coupe
#1400415
03/10/13 06:51 PM
03/10/13 06:51 PM
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Joined: Jan 2003
Posts: 7,496 Minnesota
Hemi_Joel
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Is there a way to build a NHRA legal (8.50 and slower) cage for a coupe like this without the rear down bars poking thru the rear of the body? Are the angled rear down bars required, or what is the alternative? I'm toying with the idea of building this '31 Plymouth for the Drag Week Hot Rod Class. Thanks, Joel
[img]http://i.imgur.com/boeexFms.jpg[/img]31 Plymouth Coupe, 392 Hemi, T56 magnum RS23J71 RS27J77 RP23J71 RO23J71 WM21J8A I don't regret the things I've done. I only regret the things I didn't do. "Wise men talk because they have something to say; fools because they have to say something. ~ Plato"
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Re: Roll cage question for a Coupe
[Re: Hemi_Joel]
#1400416
03/10/13 09:21 PM
03/10/13 09:21 PM
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Joined: Nov 2004
Posts: 4,330 Lynchburg, VA
Leon441
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I ran into this with a truck I was doing for a customer. Yes, basic cage has to have the down bars per NHRA. If you go to a funny car spec type cage you do not have to have them.
My recommendation is.. You fit the hoop right behind the doors. Build a hooped seat bar that goes behind your seats. Then bend the rear suport bars to curve behind your head and seat down to the seat bar. From the seat bar you can go through the trunk firewall to the frame. You could get creative with this and do just the rear portion of a funny car cage. The NHRA rulebook has some pictures of roadster cages. They are similar in shape to what I have in mind.
Just remember the reason for these rear bars is to keep the cage from flipping out of the car with a rollover and hard roof impact. Such as sliding down the track 100 MPH and hitting something stationary.
Leon
Career best 8.02 @ 169 at 3050# and 10" tires small block power.
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Re: Roll cage question for a Coupe
[Re: B G Racing]
#1400421
03/11/13 12:02 PM
03/11/13 12:02 PM
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Joined: Jan 2003
Posts: 7,496 Minnesota
Hemi_Joel
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Thanks for the replys!
THis would be a street car, I am concerned that a funny car cage would make it no fun as a street car. I need something more like a normal roll cage, like what you put in when you hit 9.99 ET.
[img]http://i.imgur.com/boeexFms.jpg[/img]31 Plymouth Coupe, 392 Hemi, T56 magnum RS23J71 RS27J77 RP23J71 RO23J71 WM21J8A I don't regret the things I've done. I only regret the things I didn't do. "Wise men talk because they have something to say; fools because they have to say something. ~ Plato"
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Re: Roll cage question for a Coupe
[Re: Hemi_Joel]
#1400422
03/11/13 01:57 PM
03/11/13 01:57 PM
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Joined: Mar 2006
Posts: 9,910 Eighty Four, PA
B G Racing
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Quote:
Thanks for the replys!
THis would be a street car, I am concerned that a funny car cage would make it no fun as a street car. I need something more like a normal roll cage, like what you put in when you hit 9.99 ET.
You dont have to build it like a typical Funny car cage,just put the main hoop forward the driver and the cross bar behind the seats and curve the bars back from the main hoop to the cross bar.You must support the cross bar at or near where you attach the two rearward Funny car syle hoops to the frame.
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Re: Roll cage question for a Coupe
[Re: B G Racing]
#1400423
03/13/13 04:56 PM
03/13/13 04:56 PM
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Joined: Oct 2008
Posts: 411 Harleysville, PA USA
Tommy D
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mopar
Joined: Oct 2008
Posts: 411
Harleysville, PA USA
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Joel,
Have you looked at the NHRA rules for a "Street Roadster"? They are convertible, left hand drive. I can't seem to find my rule book, and it's a few years old at least, but I seem to remember the roll-bar configuration to be less than FC, but more than a typical cage.
BTW, I love the coupe. It looks like a nice car, and more of a traditional car. I know you build fast stuff, but will this thing go faster than 10.0??? If not a bar will suffice with no halo or dash-bar. Good luck either way.
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Re: Roll cage question for a Coupe
[Re: Tommy D]
#1400424
03/13/13 10:16 PM
03/13/13 10:16 PM
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Joined: Nov 2004
Posts: 4,330 Lynchburg, VA
Leon441
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We are not talking a full funny car cage. Not even a helmet bar. But, the main hoop will be over your head instead of behind it.. This means instead of coming off the level top portion of the hoop with two rear support bars not less than 30 degrees or whatever the book states you do something else. What we are suggesting is bending the seat back brace bar. If you took a yardstick and stood it up against your rear window the seat bar would be just inside the stick. Then you build your rear support brace to curve around the back of your helmet and but into the seat back brace. Then you follow on the other side down to your frame. Then another bar to the rear from the same joint over the seat back brace. This does not constitute a funny car cage but the shape of the bars you use are the same as some used in a funny car cage.
Leon
Career best 8.02 @ 169 at 3050# and 10" tires small block power.
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