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MGA floor boards are . . . boards !

7K views 15 replies 5 participants last post by  vht 
#1 · (Edited)
Has anyone tried to conform to NHRA or AHRA or even SCCA rules when building a wooden floor car?

Rules for everyone say that the floors can't be altered and require that the roll bar/cage base begin at the floor and go up vertically tying the rockers or interior panels to the floor. Something about certain number of square inches being required.

Floors can't be altered or used to form a belly pan and the usual restrictions on aero and the rest.

The floors in my MGA are wooden and come that way as-new. The rules don't allow changing to metal and yet require that the floors carry any number of safety features, from cage to seat mounts to battery hold downs. I'm trying to build a car that's legal for NHRA, AHRA, and SCCA so that I can race it at both New England and Lebanon Valley, autocross it, and compete in hill climb events with the front suspension in the lowered position.

Pretty much get the most fun out of the car as possible, you know?

Anyone been through anything like this and come out ahead?

Please lemme know, won't you? I'm sure that it can be done, but I don't know how to proceed.
 
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#3 ·
NHRA and IHRA allow floors to be changed. No rules I know of that would stop a person from changing to sheet metal floors. As for rollbars or roll cages; NHRA does allow them to be attached to floors, and not frames or braces. But there is a minimum square inch of plate size required if you attach to floors, and not the frame. Also a minimum thickness of the plate. I believe when I checked it was a 6" plate, of .125" thickness.
This wont help if SCCA differs. You may have to drill through your wood floor, and make up mounting system below the floor to get a roll cage or rollbar approved.
 
#4 ·
A.... Roll bars and braces must be attached to the frame of
the car wherever possible. Mounting plates, regardless of
whether welded or bolted to the frame, must be at least
3/16" thick.To Comply, SCCA............ roll bar on wood floor boards is insane...but hey knock your self out pun intended
 
#5 ·
Looks like I'm going to have to scale down my intended use for the car. Checking over the SCCA rules and requirements, Swapping out the floor from wood to steel would bump me up three classes and make the car uncompetitive. Essentially it would be classed with the "modifieds" which included purpose built track cars and most exotics.

In the lower classes, where most British race cars end up, you're really restricted in the ability to change anything that was installed by the manufacturer.

The rule book has wording like this:

If the rules do not specifically authorize a modification, it is not permitted.

A. It is not permitted to make any changes, alterations, or modifications to any component produced by the manufacturer unless specifically authorized by these rules.
B. Any minor modification, intended to allow or facilitate any allowed modification, is permitted as long as it does not provide any intrinsic performance benefit in and of itself.
Competitors are strongly cautioned to make the minimum amount of modification required to affix a given part and to not make tortured interpretations of this rule which will invoke Section 17.11 weight adjustments
e.g., moving frame rails inboard, regardless of the reason, is considered to be a tortured interpretation.)Refer to Appendix F for past clarifications of these rules.

Replacing the wooden floors and firewalls with steel would obviously stiffen the ladder frame considerably, change the weight of the car, and would require additional inner frame rails to weld the steel flooring to since the original wood sits on thin angled sheet metal shelves.

So . . . looks like I'm out of the SCCA sponsored Vintage Road Racing, Autocross, and Hill Climb game and relegated to the dirty old non-NHRA backwater dragstrips that really don't give a damn about bars and belts, cages or driveshaft hoops. Much easier to build a car to this absence of specs and techs, but limited to Lebanon Valley Vintage events and Test & Tune Thursday nights at New England.

Two thousand Fox Body Mustangs, three thousand Third Gen Camaros, and ME. All waiting in line for five hours for a single run. The alternative being Lebanon Valley where every third car fouls the track with fluids and everyone stops moving for the next hour and a half. Where the racers are SO damned old that they forget to drain the anti-freeze before coming to the track, where one old shitter actually forgot to tighten the drain plug on the pan and closed the track for the remainder of the meet. The Depends for Men Club, I swear ! ! !
 
#9 ·
Go to a NHRA track and bug the Tech Inspector. They are a wealth of knowledge and they are the ones to interpret the rules. So best of both worlds. I bugged the guy at my local track a couple of times before I got my car there. He actually remembered me and had good things to say about the changes I made to comply with the rules.
 
#10 · (Edited)
I really ought to just shut up and soldier on. It's just a car and yet I'm becoming fixated on making it into the solution for all my frustrations and failings.

Might be the weather, the coming dread of winter or just having a bunch of guys who'll listen to my rants. Sorry for all of this, really. Time to stop reading and worrying and just get back to doing ! !

I picked up a couple of TR7 roof panels from a buddy, planning on adding two cross members per side and welding in floor panels cut from the roofs. We'll runs some bead rolls across them (maybe an "X" would be best with a perimeter box) and go from there. Already have the cage partially built, just use the SCCA guidelines for the footing as it stricter than the NHRA, call it done and stop reading rules books.

Let the car fall into the class that it happens to fall into and just be thankful that I able to race it at all.

I guess that, because it's not being built for the street, I'm hoping to be able to play with it enough on the track(s) to make up for that. Could well be worth it to make a try at getting it titled, relieve ALL of this fuss and bother, you know? Increase my play time considerably if I could take it out on the public roads.

Thanks for putting up with this old man ! ! ! ! HONESTLY appreciated more than I can say ! ! !
 
#12 ·
Thanks for the sentiment Lash !

Discovered something today with the rear body clip that puts my petty complaining in perspective. What I thought were recessed shut panels for the doors turned out to just be splash guards for the rear fenders. Now I have to begin all over again on a second (far worse sheet metal) rear body clip that just happens to have good shut panels and body mounts. Lucky to have the second clip, kinda sucks that the weather is changing and I'll be going body work using a propane heater.

Makes fussing around with a wooden floor seems like a vacation.
 
#13 ·
Oh man I hate when crap like that rears its ugly head, but you know it happens to all of us..............but hey do the doors really need to open and close, how about welding the doors to the panels making a one piece body its been done a lot on smaller open cockpit sports cars.....food for thought
 
#15 ·
Thanks for the image ! That's something to shoot for, with maybe a smidge of Gasser thrown in around the edges. I DO love the rear fenders and front end treatment enough to try to mimic it with my car/project !

On closed cars the doors are required to open. I'm planning on installing a dealer option fiberglass roof on the car in order to get around some of the roll cage requirements and settle for a modified roll bar instead. With a roof and side curtains with nets I can also get past the arm restraint and collar ruling. Not that I don't want to be as safe as can be, but the car isn't going to break the 12s and I really don't have the extra money for a suit and additional date sensitive belts/restraints/etc. I'm old and cheap . . .

In addition, I just now remembered that the MGA doors are aluminum (as is the hood and trunk lid) and the fenders are fiberglass reproductions. Even if I went back to the original steel fenders, welding steel and aluminum all up into a solid simple shell would require a level of practical magic that I don't possess.

If the whole hardtop ruse falls through, I may try to bolt and tab the various body parts together, just to present a more ridged shell with a little more crash resistance. Thanks for the "idea."
 
#16 ·
Put steel floors in, I'll bet no one will ever check. Steel floors and make sure all holes and everything is sealed. I seen a guy loose a sight plug out of a Holley, car caught fire and before he could get it stopped and get out, it burnt his shoes and socks off, 3rd degree burns over a lot of his body. It was a small car, chevy Monza, and he had to take the steering wheel off before he could exit. Car wasn't real fast either. Stay safe.
 
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