Hey guys, Well we 'finished' the cage in the Maverick with the exception of the two diagonal bars that come off the main hoop just below the cross bar. According to the NHRA rulebook, these are supposed to go to the subframe. But here's my problem, my main hoop plates are already covering the subframe. In essence if I put them in they would almost be vertical. Does anyone understand what these bars are supposed to do? My guess is that they are used to keep the main hoop from collapsing sideways (essentially triangulating for the sides). But I have not had that confirmed. So I took the car to Firebird Raceway and asked the tech guy there what he thought and his response was to run them to the driveshaft tunnel. This would certainly triangulate it, but I'm not sure that is within the spirit of the whole reason to have them since that part of the chassis is no stronger than any other part of the floor. I was thinking maybe I should cut a hole in the floor and attach them to my subframe connectors, but I'm not positive that would accomplish what I'm trying to achieve either. I eventually want to get this cage certified for 9's, but I don't want to do it twice either. Anyhow, sorry for the long post but has anyone else had any experience with these two bars...or information where you put yours? Thanks!
The sides for the main hoop should be close to the rocker panel. Then take the diagonal bars to your subframe connectors. They will probably be about 10" apart(guessing) at the bottom. You can also take them at a backwards angle if you need to lengthen them. If it doesn't hit directly on your frame rails just put it on the 6"x6" plate. It will pass like that. You are not required to have the floor cut out and tied to the frame. Not all the cars have subframe connectors. Call nhra or your local track if they do certifications and ask plenty of questions first. People like us give opinions on past experience but in the end it will be up to the one doing the certifying.
I'd weld a plate to the floor over the front mounting point location of your rear suspension...whether it be the stock leaf springs, ladder bars, etc..., and attach the bars there. This will tie the suspension points into the cage and stiffen the whole chassis. Not knowing what your rides intent is...full race...street driven, or both...just let me add this...if you do this, you WILL feel a difference in the ride. IE...if you drive it on the street, you will feel more bumps and such... I'm a little confused...you said your main hoop was already covering your frame rails, but then you said you were thinking about cutting a hole in the floor to attach them to the subframe connectors... I may be misreading it...but if it were mine, I'd attempt to connect those down bars to the forward suspension point locations. just my .02
weld the diagonals to your sub frame connectors that will strengthen your hole chassis your car will launch quicker and straighter you can also get good instructions from a supplier book like chassis engineering
Yeah, the local certification guy I hear isn't very helpful. I'm going to have to give it a try though. I did take it to the local track and that's where I was told to go to the driveshaft tunnel. I'm not sure that the track guy speaks for the certification inspector though. That's what worries me. Here's a more graphic picture of what I'm up against...not drawn to scale mind you... Full race (started as a street car but that went out the window!). Oh and the plates are over the front of the spring perches right now. The subframe connectors are not through the floor, but under it.
If you have a subframe car, you can run your supports to your driveshaft tunnel according to the rules. I believe if you have subframe connectors, you have to run them through the floor to the connectors.
Tony, The guy to talk to is Ben Wilson. He is the NHRA Pacific Division Tech Director. His # is 520-579-1426. He takes calls on Tuesday and Thursdays from 7-9 p.m. His email is benwilsond7@aol.com . Also he lives in Tucson.
Tony, Connecting them to the tunnel should be fine. We just did the cage in mine over the spring and that is where those bars go to. Ben has looked at my cage and as long as all the bars are the correct thickness then it will cert to 8.50 no problem. Ben is really the guy you need to talk to and he is very helpful. We welded a plate to the floor just like all the other bars. I would take a picture to show you but we just loaded it up last night. I might be able to get a picture of how mine is done this weekend if you still have questions. Matt
My car has rectangular tube frame connectors that run above the floor in the area behind the seat. The fabricator who did the installation ran a piece of tubing between the connector and the rocker channel. The main hoop is welded to that tube on each side. The short diagonal bars are welded to the top of the frame connector. I would post a picture but the area is covered in carpet and the seat is fixed. I plan to remove the seat in a few weeks and will post then if it's not too late for you...sorry.
Thanks for your input Maverick 8003. Maxx, the connectors are under the floor unfortunately and the plates and main hoop are over the rear subframe. Thank you Don, I will give him a call tomorrow. Sounds like he is more willing to help out than Ed is. Hey Matt, if you could get me a picture when you have a chance that would be great. It sounds like going to the tunnel is acceptable. It's good to hear that that is how you did it and that others have read that is an acceptable option (87saleen209). I didn't see it anywhere in the rulebook myself and that is what threw me. I would love to see how you've done yours as well Cometguy. It's probably too late to do mine like yours but it would be great to see other options.
Don't hold me to this...but I don't think the bars are a "requirement" to begin with. Those are the 2 bars that make the difference between a 6-point bar and an 8-point bar...and they're there just for added rigidity and triangulation. BUT...if you add them...they have to be the proper size and thickness! Is this a full "cage" car...or are you just adding a roll bar? The distinguishing factor being the Halo bar/bars along the perimeter of the roof, forward down bars-the ones that run beside the windshield pillars, and a dash bar (for those who were wondering what the difference between a rollbar and rollcage are...but were afraid to ask ) Are you adding a crossmember for the rear suspension, or a driveshaft loop? If so, you could tie it in there also...but hey, if you add them to the driveshaft tunnel, it will add more strength and rigidity than if they weren't there at all! Post some pics when you get a chance...and good luck! Have fun with it...isn't that what this is all about... Later,
Hi Maxx, it is a full cage without the dash bar (not needed because the firewall and floor have not been modified) but it has the halo and down bars. The size and thickness are not a problem as this is mild steel and I've gone oversized on the thickness in all instances (even to the extent of taking the bend thickness into account). My buddies are sticklers for safety and we've been very careful in all aspects of the rules. We've even made a 1 5/8" loop coming off the rocker bars for the seat (that way I go everywhere the cage goes as long as I'm in the seat). I will get some picks later today (kinda dificult in a dark garage with a black bar in a black interior...but I'm trying to hide it after all, since I was going for the sleeper look). Keep your eyes open for them, but keep in mind that I am trying to retain the rear seat (from former projects I hate metal interiors and want to keep the noise to a minimum). Thanks again Maxx...this is the fun part!
Well after much study and little input from the inspector (he never returned my call). I just went with my gut feel and ran the diagonal bar to the subframe connectors and added a plate on top. This has to be the best of both worlds, but we'll see when I get it inspected. Wish me luck!
