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L0b56
L0b56 New Reader
1/7/24 1:57 p.m.

V2 because I accidentally posted this question in aerodynamics since I thought technically hardtops affect aero, but anyway.

I've been looking into installing a cage into my car that complies with the ARA rule book as I've been planning on entering my Miata. However, before I can go about designing, or if I'm really lazy buying a FIA compliant cage, I need to address the fact that the top that I'm running now will probably not be the same the top that I run in events. From my understanding of the 2023 ARA rules (which might change since it's 2024 now), I have to run a metal top which doesn't seem to exist. I've been contemplating making one from scratch and using the current one that I own as some kind of mold, or using the top off of a different car which has a similar form that I could also use save me the effort of making a completely new top. I'm curious to see if anyone has given a metal top a try and if anyone has any potential input they could give me.

Keith Tanner
Keith Tanner MegaDork
1/7/24 2:20 p.m.

I've never heard of one, but without that rule requirement there wasn't really much need. 

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
1/7/24 2:42 p.m.

Does it have to be a metal top or a FACTORY metal top?

 

I would assume that cage rules would preclude its being removable, too.

L0b56
L0b56 New Reader
1/7/24 2:57 p.m.

"2023 Edition ARA Rally Technical Rules pg. 19
4.1.2 Exterior Bodywork
a) All bodywork changes from OEM must be submitted to ARA Technical Director for
approval a minimum of 45 days before start of event and approved by ARA before
being used in competition.
b) Roof, A & B pillars must be metallic and retain factory profile. C pillars must retain
factory profile."

"2023 Edition ARA Rally Technical Rules pg. 9
2.2.12 Roofs
Movable metal sunroofs and/or roof panels must be fixed in the closed position.
Sunroofs and/or roof panels of any other material must be replaced with metal of
equivalent strength of the roof panel and must be fixed in the closed position by welding
or steel fasteners."

It looks like they would prefer that the top would follow a similar form that the OEM top does, but there seems to be some flexibility if you console the technical director.

 

Also didn't some early gen Miatas come with a fastback from factory? If I can find a crashed one I might be able to cut it up and put it on without pissing too many people off.

Keith Tanner
Keith Tanner MegaDork
1/7/24 3:32 p.m.

In reply to L0b56 :

There are about 150 fastback NB Miatas from the early 2000s. They were JDM only and command a significant premium. AFAIK you need to provide a vin to get replacement parts. Not really a viable source :)

Jesse Ransom
Jesse Ransom UltimaDork
1/7/24 4:01 p.m.

I think I'd be submitting a clarifying query before taking other action.

 That seems like a really prohibitive requirement. Maybe that's really what they require, but an email is a much smaller investment than unnecessary scratch-building a metal hardtop replica.

 I'd wager a trivial sum that the rules were written not considering this car, and the intent is that you can't replace a metal rod with a composite one.

L0b56
L0b56 New Reader
1/7/24 4:03 p.m.

In reply to Keith Tanner :

I'll keep digging and see if I can find a top off of another car that shares a resemblance to a Miata top. There's definitely got to be one out there.

Stampie
Stampie MegaDork
1/7/24 4:23 p.m.

In reply to L0b56 :

Using one from another car is changing it from OEM. 

All bodywork changes from OEM must be submitted to ARA Technical Director for

approval a minimum of 45 days before start of event and approved by ARA before

being used in competition.

Email the dude. But I give you this, you sound like FrenchyD trying run his XJS in vintage racing. 

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
1/7/24 4:41 p.m.

One thing for sure for stage rally: don't rally a car you are attached to, because you will total it.  Maybe you can be attached to a chassis, preferably one you can find parts for easily, but not a specific car.

Keith Tanner
Keith Tanner MegaDork
1/7/24 4:58 p.m.
L0b56 said:

In reply to Keith Tanner :

I'll keep digging and see if I can find a top off of another car that shares a resemblance to a Miata top. There's definitely got to be one out there.

Second gen CRX might be the right scale. 

SV reX
SV reX MegaDork
1/7/24 5:32 p.m.

When I built my fastback Miata, I used a fifth gen Mustang (S197) to make the molds. It was too wide, but the length and the curves were surprisingly close. 
 

Mine was fiberglass, but it would be possible to make a metal one out of the S197 roof (if you can weld)

But it sounds like a butt load of work (and it definitely would not be OEM). 
 

Sounds like a couple emails are in order. Is the intent of this rule that they simply don't want convertibles running at all?

GameboyRMH
GameboyRMH MegaDork
1/7/24 5:34 p.m.

In reply to SV reX :

Was just thinking a Mumpkin-style Mustang roof would be the ticket:

https://grassrootsmotorsports.com/forum/grm/presenting-the-mumpkin-unsocialized-2015-challenge/108065/page1/

SV reX
SV reX MegaDork
1/7/24 5:38 p.m.

In reply to GameboyRMH :

I'm impressed that you found that faster than me!!

SV reX
SV reX MegaDork
1/7/24 5:52 p.m.

Warning on that idea...

There is ZERO possibility that you could ever make window work with that. 
 

But mine was removable, and the windows worked fine when the roof was removed. 

L0b56
L0b56 New Reader
1/7/24 7:35 p.m.

Thank for the input guys, I'll be sending an email off this afternoon and will come back with my findings.

As for the ideas regarding what cars I could scalp, I like the idea of running a CRX top since the style is similar to the NA Miata. But if I can't find a one or it doesn't work for whatever reason, I'll give the Mustang top a try since there's an unlimited supply of crashed Mustangs in Georgia.

Stampie
Stampie MegaDork
1/7/24 8:02 p.m.

In reply to L0b56 :

I would keep the email simple like "How can I make a 199x Miata legal inside the rules for a metal roof?"

Ranger50
Ranger50 MegaDork
1/7/24 8:13 p.m.

Weld in steel panels on top of the cage structure with a reg miata hardtop over it?

triumph7
triumph7 HalfDork
1/7/24 8:47 p.m.

What about the roof from a TR7 coupe?

MyMiatas
MyMiatas HalfDork
1/7/24 10:42 p.m.

I was thinking of using a roof from one of these

 

Here is a example 

You could go this route.

Tom1200
Tom1200 PowerDork
1/7/24 11:01 p.m.
MyMiatas said:

I was thinking of using a roof from one of these

 

Here is a example 

You could go this route.

I was so bummed we didn't get a MX5 coupe.

GameboyRMH
GameboyRMH MegaDork
1/7/24 11:22 p.m.
Stampie said:

In reply to L0b56 :

I would keep the email simple like "How can I make a 199x Miata legal inside the rules for a metal roof?"

Probably the question that led to some Miatas running a roll cage with a sheet metal "bikini top"...

SV reX
SV reX MegaDork
1/7/24 11:51 p.m.
L0b56 said:

"2023 Edition ARA Rally Technical Rules pg. 19
4.1.2 Exterior Bodywork
a) All bodywork changes from OEM must be submitted to ARA Technical Director for
approval a minimum of 45 days before start of event and approved by ARA before
being used in competition.
b) Roof, A & B pillars must be metallic and retain factory profile. C pillars must retain
factory profile."

"2023 Edition ARA Rally Technical Rules pg. 9
2.2.12 Roofs
Movable metal sunroofs and/or roof panels must be fixed in the closed position.
Sunroofs and/or roof panels of any other material must be replaced with metal of
equivalent strength of the roof panel and must be fixed in the closed position by welding
or steel fasteners."

I'm looking at these rules again, and wondering if we are all over-thinking it.  
 

It says the roof needs to be metallic, but it doesn't actually say there needs to be a roof. It says sunroofs and roof panels that are not metal need to be replaced with metal and secured, but it doesn't say a car with no roof needs a metal roof fabricated. 
 

I'll be interested in hearing what responses you get to your emails, but I agree with Stampie.  Keep it REALLY simple. Don't assume things. 

Keith Tanner
Keith Tanner MegaDork
1/8/24 1:34 a.m.
MyMiatas said:

I was thinking of using a roof from one of these

 

Here is a example 

You could go this route.

That's not a Miata with an RX7 roof, that's one of the factory NB coupes. I think an FD RX7 greenhouse would be too wide as the car is about 4" wider. 

Driven5
Driven5 PowerDork
1/8/24 1:36 a.m.

In reply to SV reX :

That's more how I read it, except I'm wondering if they may simply not allow convertibles regardless of removable hard tops... Either way they should probably call it out somewhere. When any rule set I can recall reading talks about roofs, it's specifically talking about tin-tops and not convertibles. There is generally then a subsequent section clarifying what is required for convertibles. Not only does the Miata not have a metal roof, it als does not have B or C pillars. At this point though, you'd have to be emailing them anyway, as making a metal roof that meets the noted installation standards would also likely fall under 'bodywork changes from OEM'.

SV reX
SV reX MegaDork
1/8/24 8:41 a.m.

In reply to Driven5 :

I agree. Those look like rules for tin tops.

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