AKADriver

I mentioned this in another thread, but I thought I'd start a new one for more in-depth discussion.

The NC Miata (2006+) has a convertible top design which will prevent the owner from installing a traditional roll bar without removing the entire top mechanism. There's been some discussion on Miata.net and the only solution offered thus far has been extending the downtubes forward instead (like a cage for an Elise). To me this means no roll bar in a street car, as I see it.

However the car does seem to have some actual structure to those hoops behind the seats. Here's the part from the parts catalog:



Will the NC Miata get exempted for HPDE like the S2000 etc. are, or will NC owners just be SOL? It seems to have just as much factory roll protection as the S2000 but I'm no structural engineer - I just know what I can see and what Mazda and Honda have told us about these cars. They both pass FMVSS rollover standards for hardtops even though they're not required to do so, but this test is only a load of 1.5 times the weight of the vehicle and the A-pillar is allowed to deflect 5" so it's really not that big of a deal to pass.

Solracer

Actually I will bet the the S2000 will soon not be exempt, and to be honest I would not drive any convertible on track with "factory" roll over as they do not extend high enough to protect you with a helmet on.

Markus

^^^ Yeah what he said.

I guess my feeling is that the factory roll protection in most convertibles (NC Miata, S2k, etc) would be ok for first-time people in the lowest levels of HPDE. Let them get a feel for it, have the instructor keep them in check, etc.

Then, if an owner enjoys HPDE they will either need to add better rollover protection or buy a new car. I just really don't think it's safe enough otherwise. But then again I almost feel like rollbars should be required for enclosed cars at upper levels - if you've ever seen the results of a roll before it ain't pretty.

Note I'm a Miata guy too, I'm looking forward to seeing an NC on the track. I'm sure Hard Dog and the other aftermarket companies are working on something.

- Mark

tnord

it seems to me that those roll hoops are just bolted in. if that is the case, i don't see what the big deal is about treating it just like the older model miata's and requiring roll protection. whoever is capable enough of bolting in or welding in a roll bar/cage, is capable enough to unbolt the factory roll hoops. no biggie.

like others, i could see if they don't require upgraded protection for the bottom levels of HPDE, but i think i would want it myself.

<---- anxiously awaiting club sport model for $20,000.

madhatter07

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tnord &raquo;</TD></TR><TR><TD CLASS="quote">
&lt;---- anxiously awaiting club sport model for $20,000. </TD></TR></TABLE>

Is that actually going to happen or owuld you just like it to?

tnord

it's on the official options list on the site where you get to build your own miata.

http://www.mazdausa.com/MusaWe...hcp=1

no 17'' wheels, 5sp instead of 6, no LSD, no leather, but you do get power windows, locks, mirrors, and a CD player. only available in red, white, and blue.

i figure a call to mazda motorsports will be able to solve the LSD problem for $1000. now you have a brand new 170hp 2400lb sports car for $22,000 +ttl. not too shabby at all.

AKADriver

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tnord &raquo;</TD></TR><TR><TD CLASS="quote">it seems to me that those roll hoops are just bolted in. if that is the case, i don't see what the big deal is about treating it just like the older model miata's and requiring roll protection.</TD></TR></TABLE>

Because, as I noted, the convertible top is uncompatible with any roll bar design I've seen. So no dual-purpose cars.

Solracer

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AKADriver &raquo;</TD></TR><TR><TD CLASS="quote">

Because, as I noted, the convertible top is uncompatible with any roll bar design I've seen. So no dual-purpose cars.</TD></TR></TABLE>

I would expect due to insurance and such, that convertabiles with out roll over protection that is not high enough to protect a driver with a helmut on will not be allowed on track as early as next year with most groups. This includes, s2000, miata's, z3/z4's, so this could be a mute point. Even if not, I think it is really risky to drive a car on track where you helmut is going to part of your roll over protection...

jlucas

That roll bar structure is very similar to the S2000. Assuming you can't pass the broomstick test with the stock one, you have a replacement made that bolts to the factory location (basically all the way up, to just not touching with the top up) and then where you cut the plastic trim off, apply a shifter boot like "adapter". One of the local S2000 guys did that for HPDE. Looked just fine.