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kmanmiata

track requirements for roll bar - miata?

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kmanmiata

Hi, I have a 2000 miata that plan to run in HPDE. I have read through the rules and it looks like the two roll bars I am considering - the hard dog M2 hard core hard top with double diagonals and the Ace with double diagonals meet the requirements of NASA. However, I also understand that tracks may have their own requirements. I plan to run at Sonoma Raceway and possibly Thunderhill and wanted to know if any additional requirements to be aware of.

 

I mocked both roll bars up using 1 1/2 PVC. I am 6'1" with 34" inseam and with the M2 hard core, my head is about 2" from the bar and if run plane from the bar to the windshield, my head is even with this. This is without a helmet. I prefer to run stock seats and seatbelt as will only be running a few HPDE events a year, so want to keep it easily usable as a weekend driver. Open to insights about the two roll bars suggested and issues with seats & clearance given my height.

 

Thanks!

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EricJo

The list is here. P. 29 of http://www.nasaproracing.com/rules/ccr.pdf

At all the tracks in my area the Hard Dog Hard Core is acceptable. The only group I've heard of that is real sticky about 2 in. below the bar with helmet is the BMW track groups. I think it's an insurance issue.

A foamectomy of your seat could get you a little lower; or bolt in a seat just for track days.

 

I have the Hard Dog Hard Core Hard Top version. It moves the bar rearward a little, which I think is a good thing on the street, but is a little lower. Be sure and get all the padding.

I also have the Marad seat from Goodwin. Without the cushion it is much lower. With the cushion it is DD'able, but not trips over 2 hrs. It has harness holes too. After a couple of track days you'll want harness' and a harness bar. And do remember, you need the same safety equipment for your instructor.

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brkntrxn

We have a 2000 Miata that we use for my daughters to drive on track and it is our youngest daughters' daily driver. I installed the Boss Frog Double Hoop rollbar in it. It passes tech at all DE events, but I am not sure how the height compares to the Hard Dog.

 

When I instruct them, I run my seat slightly more forward and recline the seat back to ensure helmet clearance (5'11"). Maybe you could adjust your seating position slightly in the stock seats similarly.

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kmanmiata

Good info. I had been leaning toward the Hard Dog Hard Core Hard Top with Double Diagonals. However, now considering the Boss Frog Clearview Vmaxx as it sits back an additional 1.5". Figure that can make a big difference in safety for street driving. It also appears to make better use of the rearview mirror as the double diagonals are spaced 7" apart on the main hoop. I do not plan to use a hard top, so that is not an issue. The Boss Frog bars are not listed in the rules (which are stated as examples only), but it appears they meet all requirements for NASA HPDE. I did notice the Boss Frog has an option to use a different seat belt guide. However, from my the rules, it looks like that may change the "stock" seat belt configuration, and thus be an issue. So- would I need to retain the stock seat belt guides?

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brkntrxn

You can use it without the seatbelt guides, but the belt will rub against the plastic trim on the sides. The seatbelt guides do not change the OEM mounting orientation, they just help the belts retract easier through the plastic trim.

 

The space between the hoops for better rear visibility is one of the things I like about the Boss Frog. Plus, it just looks better with the top down.

 

I daily drove the car for eight months and never once came close to hitting my head on the bars behind the seat. We keep high density padding on the bars year round and I still never have any issues.

 

If it worries you that much, do yourself a favor and look up and to the left the next time you are driving the Miata. The uncovered metal folding frame of the top is about 3" from your head. I am more worried about hitting that in a wreck than the rollbar behind my seat. Since it is OEM, no one seems to give that bare metal a second thought. My Mustangs were the same way.

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kbrew8991

The full width bars seem to be beefier if you were to ever use it. Could be a good foundation for a cage later on if you go that route too. No engineer here though yadda yadda

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zeusbap

For what it's worth, for anyone else in the future with similar concerns, I've driven a 2002 NB Miata at a handful of NASA events - different tracks and regions (Great Lakes, Midwest, Mid Atlantic) and haven't had any issues with my Hard Dog (double diag) rollbar. I'm 6'2", which is just about the upper limit of the miata's reasonable comfort range. If I slide the seat forward and slouch the back of the seat, I can pass the broomstick test, but it's not very ergonomic.

 

That being said, usually I go the "safer" route and lean the seat back (see above) while on track, but twice now I have accidentally bumped my ignition key with my knee in the middle of the corner, and turned the car off. I can confidently say you can easily bump start the car to carry on, but you'll confuse the crap out of the guy behind you!! Now I position my seat for comfort while on the track. One time at Putnam Park, someone allegedly got on the radio with concern about my helmet sticking two inches above the rollbar, but that was deemed acceptable for HPDE.

 

The hard dog is taller (1.5" I think) than the Boss Frog bar, so that's the reason I went that route.

 

I have done the foamectomy, which does make a big difference in seat feel, but doesn't lower you in the car as much as I hoped. My ultimate goal was to install low-profile seats (Ultrashield seems to be popular), but I bought an E46 M3 instead!

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getfast
I installed the Boss Frog Double Hoop rollbar in it. It passes tech at all DE events

 

Except I have seen those not pass tech (from memory it was for broomstick test reasons, or it may have been a track rule requiring a full width bar.)

 

It's more rare for a Hard Dog to not pass from what I have seen, so that's what I recommend, and that's what I had in my Miata back in the day

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