Miata classing question

FrancisChan · **Posted:** Mon May 25, 2015 2:46 pm

Hey y'all,

So I was looking underneath my miata today as I was changing the oil and the frame rails look to be a little squished. I only think they are used for stiffening the floor boards and aren't a major structural concern, but to avoid further damage I've been thinking of putting on some FM frame rails (https://www.flyinmiata.com/fm-frame-rai ... t-kit.html).

I'm currently running in CSP due to the AC removal and lightweight flywheel, but I'm wondering what class the rails would through me in? The only other changes have been aluminum radiator, oil filter relocation, swaybar end links, coil-overs, racing beat intake, catback muffler and mid-pipe w/ high flow cat. A set of sways will probably be going on soon to complement the coil-overs.

I'm not too concerned about being competitive, just want to make sure that I don't have to also get a hard top or roll bar to stay legal in class.

Thanks in advance!

Karl Shultz · **Posted:** Mon May 25, 2015 10:35 pm

I'm not certain about what class those would put you in, but I'm sure you won't need a hard top or a roll bar for autocrossing.

RobLupella · **Posted:** Mon May 25, 2015 10:44 pm

FrancisChan wrote:

Hey y'all,

So I was looking underneath my miata today as I was changing the oil and the frame rails look to be a little squished. I only think they are used for stiffening the floor boards and aren't a major structural concern, but to avoid further damage I've been thinking of putting on some FM frame rails (https://www.flyinmiata.com/fm-frame-rai ... t-kit.html).

I'm currently running in CSP due to the AC removal and lightweight flywheel, but I'm wondering what class the rails would through me in? The only other changes have been aluminum radiator, oil filter relocation, swaybar end links, coil-overs, racing beat intake, catback muffler and mid-pipe w/ high flow cat. A set of sways will probably be going on soon to complement the coil-overs.

I'm not too concerned about being competitive, just want to make sure that I don't have to also get a hard top or roll bar to stay legal in class.

Thanks in advance!

I think the frame rails would keep you in CSP. Probably someone lifted the car by them

JamesMilko · **Posted:** Tue May 26, 2015 9:47 am

I think it knocks you into prepared or modified. For sure not CSP legal, and I'm 90% sure not SSM either.

FrancisChan · **Posted:** Tue May 26, 2015 10:26 am

JamesMilko wrote:

I think it knocks you into prepared or modified. For sure not CSP legal, and I'm 90% sure not SSM either.

Hmmm, so looks like I'd fall into DP and require at least a roll bar.

At least the PAX is slightly better than SSM though.

RobLupella · **Posted:** Tue May 26, 2015 8:52 pm

FrancisChan wrote:

JamesMilko wrote:

I think it knocks you into prepared or modified. For sure not CSP legal, and I'm 90% sure not SSM either.

Hmmm, so looks like I'd fall into DP and require at least a roll bar.

At least the PAX is slightly better than SSM though.

You shouldn't need a roll bar for AX. I forgot that frame rails count like chassis stiffeners. :oops:

FrancisChan · **Posted:** Tue May 26, 2015 9:35 pm

Quote:

17.12 SAFETY
A. Roll Bars/Roll Cages (Aluminum is not an allowed material.)
1. All open Prepared Category vehicles shall have at a minimum a roll
bar complying with Appendix C.

So is my car not open? I don't have a hardtop.

JamesMilko · **Posted:** Tue May 26, 2015 10:57 pm

I wouldn't worry about it. Don't forget this is what a 'real' DP Miata looks like.

Arthur McDonald · **Joined:** Fri Aug 29, 2003 1:54 am **Posts:** 2052

These sound like subframe connectors, almost:

page 67 — 2015 SCCA® National Solo® Rules

section 12. Definitions

Subframe/Cross Member
A component welded or bolted to the frame/tub/chassis of a car in order to
increase its strength and which may serve as a platform for mounting suspension
or drive train components.

page 82: section 14.2 Street Touring (I'm not sure the part you describe matches H.1. or H.2.)

H. Longitudinal (fore-aft) subframe connectors (“SFCs”) are permitted
with the following restrictions:
1. They must only connect previously unconnected boxed frame rails
on unibody vehicles.
2. Each SFC must attach at no more than 3 points on the unibody (e.g.,
front, rear, and one point in between such as a seat mount brace or
rocker box brace).
3. SFCs must be bolted in place and not welded.
4. No cutting of OE subframes or floorpan stampings is permitted. Drilling
is permitted for mounting bolts only.
5. No cross-car/lateral/triangulated connections directly between the
driver’s side and passenger’s side SFCs are permitted. Connections
to OE components such as tunnel braces or closure panels via bolts
are allowed and count as the third point of attachment. No alteration
to the OE components is permitted.
6. SFCs may not be used to attach other components (including but not
limited to torque arm front mounts or driveshaft loops) and may
serve no other purpose.

page 93 - 15.2 Street Prepared (Again, see E.1 and E.2) - Street Mod rule is same as Street Prepared.

E. Longitudinal (fore-aft) subframe connectors (SFCs) are permitted with
the following restrictions:
1. They must only connect previously unconnected boxed frame rails
on unibody vehicles.
2. Each SFC must attach at no more than three points on the unibody
(e.g., front, rear, and one point in between such as a seat mount brace
or rocker box brace).
3. SFCs must be bolted or welded, but welding must be to the OE subframe
stampings, not to the floor pan in between.
4. No cutting of OE subframes or floorpan stampings is permitted. Drilling
is permitted for mounting bolts only.
5. No cross-car/lateral/triangulated connections directly between the
driver’s side and passenger’s side SFCs are permitted. Connections
to OE components such as tunnel braces or closure panels via bolts
are allowed and count as the third point of attachment. No alteration
to the OE components is permitted.
6. SFCs may not be used to attach other components (including but not
limited to torque arm front mounts or driveshaft loops) and may
serve no other purpose.

Finally, I searched for the word "reinforce" and the first relevant mention is in the Prepared class rules, section 17.2 on page 115:

B. Chassis, frame, or subframe may be reinforced provided components
and attachments are not relocated except where specifically permitted.
Reinforcing does not authorize the use of underbody or belly pans forward
of the firewall or aft of the front edge of the rear wheel opening.
It is permitted to have jack points recessed into the rocker panels or to
have one tube per side extending downward through the bottom of the
door provided they do not extend beyond the overall width of the car
or in an unsafe or dangerous manner. No part of the bodywork or chassis,
to the rear of the front wheel opening, shall touch the ground when
both tires on the same side of the car are deflated.

Roll bars are required for open cars in prepared class and some modified classes where roll cages are not required. (see section 3.3.2)
On the street, if your bare head whacks an unpadded roll bar in an accident, you're going to get a nasty injury. I guess adding FIA-spec padding will mitigate that, but you're still going to be hurting. It's a compromise, at best.

Andrew Jonell · **Joined:** Mon Mar 23, 2009 6:43 pm **Posts:** 1350

I'd skip the FM frame rails. They attach by drilling 2 dozen sheet metal screws into the car and it's at best a marginal improvement. Also, don't install a rollbar unless if you're planning to track the car; it's 50 lbs at the highest point of the car and you can easily crack your skull on it in a minor traffic accident.

I'll try to have the passenger seat in my car for the next event and I'll offer you a ride-along.

JasonWatts · **Posted:** Wed May 27, 2015 12:19 am

Andrew Jonell wrote:

I'd skip the FM frame rails. They attach by drilling 2 dozen sheet metal screws into the car and it's at best a marginal improvement. Also, don't install a rollbar unless if you're planning to track the car; it's 50 lbs at the highest point of the car and you can easily crack your skull on it in a minor traffic accident.

I'll try to have the passenger seat in my car for the next event and I'll offer you a ride-along.

This... but it does make the entire frame rail a jack poibt according to fm.

I think to get the full benifit of the frame rail you need the butterfly brace to go with it. Plus you will have to pound the factory frame rails back into shape to get the fm ones on. Unless you have another specific goal I would say skip

jeremy gast · **Posted:** Wed May 27, 2015 8:21 am

that looks like a pretty good specific goal!

JamesMilko wrote:

I wouldn't worry about it. Don't forget this is what a 'real' DP Miata looks like.

FrancisChan · **Posted:** Wed May 27, 2015 9:18 am

Andrew Jonell wrote:

I'd skip the FM frame rails. They attach by drilling 2 dozen sheet metal screws into the car and it's at best a marginal improvement. Also, don't install a rollbar unless if you're planning to track the car; it's 50 lbs at the highest point of the car and you can easily crack your skull on it in a minor traffic accident.

I'll try to have the passenger seat in my car for the next event and I'll offer you a ride-along.

That's be much appreciated!

I guess I'll hold off the frame rails for now. I only really want them to prevent any further damage to my frame rails. The more pressing use of the money would be for some sway bars to complement my coilovers. Then just tightening up the nut behind the wheel.

I would daily drive the heck out of that DP Miata! But I guess I'd have as much luck convincing the wife as I did with the Polaris Slingshot.

JamesMilko · **Posted:** Wed May 27, 2015 10:34 am

I wouldn't worry about new damage. Unless you put a jack on them, or high center the car they'll be fine. The ones on my old NA were pretty mangled.

JasonWatts wrote:

This... but it does make the entire frame rail a jack poibt according to fm.

The entire framerail that runs below the door sills is a jack point.

Jordan Normark · **Posted:** Wed May 27, 2015 3:06 pm

JamesMilko wrote:

I wouldn't worry about new damage. Unless you put a jack on them, or high center the car they'll be fine. The ones on my old NA were pretty mangled.

JasonWatts wrote:

This... but it does make the entire frame rail a jack poibt according to fm.

The entire framerail that runs below the door sills is a jack point.

Yup, the pinch weld is stronger than the 'frame rails' (at least in the middle of them) and the CG of the car is easy to locate since it is more or less under the mirror.

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