Seating/Roll Bar Height Concern - Need Some Help

[Xusia]

Let's start with the GOAL: I want to be able to do HPDE (High Performance Driving Events) in my daily driver 818, so I'm trying to build to the general requirements.

The Problem:
In order to meet the requirement that my head be below the roll bar in a helmet (commonly referred to as the "broomstick" test), I apparently need a seat that places my butt NO HIGHER than 1" off the floor of the car.

Relevant Facts:
At less than 6'1", I am not that tall. I have a 33" inseam, so I don't think I am overly long in the torso either.

Even if a seat existed that would place my butt 1" off the vehicle floor, I'm not putting such a seat in my car. It doesn't meet my other requirements. Also, at least one of the HPDE organizers had a requirement that the roll bar had to be 2" above the top of the helmet. I can't meet that requirement even if I sit on the floor!

The Question:
So what can I do? Here's what I've come up with thus far, and I don't really like either, so this is what I need help with:

1. Just forget about using the car on a track. I can probably get plenty of joy from the back roads around here. <sigh>
2. Replace the roll bar with a taller one. But if I do, it might look dorky. Also, this might jeopardize my use of the soft top. Or being able to go coupe with it in the future (Would a removable roll bar meet requirements? If so, then I could use the taller one only on the track).

Based on what I'm seeing, I just can't believe anyone over 6' tall is going to be able to pass the broomstick test - with ANY seat. How are you all doing it?!?

HELP!

[ClemsonS197]

You can get Kirkey seats and bolt them directly to the floor. Should put you about 1" off their floor with the foam cushion.

[Santiago]

Xusia, may I ask how you measured your current clearance?

I only ask because some seats are built with a steeper back incline, making you sit prouder in the car (and of course, some are adjustable). Kirkey has/had 10 deg, 15 deg, 18 deg, and 20 deg seats. So I would also make sure you factored that into your clearance.

Best,
-j

[RM1SepEx]

seat pan angle and seat back angle are key

I also feel like the cockpit does not have enough room, esp with the factory five tank... Being 5' 8" I can deal with it.

The tank should go up the center of the car...

The roll bar could easily be a couple inches higher. And as a kit you could do those modifications if you so desire...

[Xusia]

Regarding seat angle, with the seat as far forward as allows (because of the cross bar), my legs were very cramped and I was still too high. So I tried sitting on a board, which allowed a wide variation in back angle. That's when I discovered I could be no more than 1" off the floor with ANY position that was at all comfortable.

[Xusia]

You can get Kirkey seats and bolt them directly to the floor. Should put you about 1" off their floor with the foam cushion.

Thank you for the response. I don't want fixed position seats for a variety of reasons. Also, 1" of foam padding seems woefully inadequate for a car I'd like to drive daily and take trips in.

[wleehendrick]

I'll second that seat angle with a thinner tank is key...

I just finalized my ergonomics today; got the steering wheel location dialed in (I used the aft mounting holes for the column dropped about an inch, an NRG short hub, 1/2" spacer and 320mm wheel). Picked a spot for my VCP/K-tuned shifter and Lokar e-brake handle, and got the seat height/tilt/location chosen. Due to an old back injury (30deg compression fracture on T6) I much prefer to sit reclined. I adjusted the side-mounts for my NRG seats to give the desired recline.

So, after all that, the end result is that I have plenty of leg room and my head is at least 2" below the roll bar (without a helmet on) and I'm about the same size as you. This would not have been possible with the FFR tank, I have about 1/2" of clearance to my firewall, which is moved back more than 2" with the Boyd tank. I am using fixed back shell seats mounted very low, but from my experience, firm seats set up right are more comfortable than a cushy sofa that sags and doesn't offer support. If I need a bit more comfort, I can always change the foam... 1" of the right viscoelastic material (memory foam) can do wonders.

I am now extremely happy with the location I have dialed in for everything... since it's built around me, it's a better fit and more comfortable than a luxury car with dozens of adjustments.

Good luck!

Lee

[Xusia]

I have no gas tank and am actually planning on putting mine up front, so space behind the seats is no issue. Comfort isn't the only reason I don't want fixed seats - I'd like for others to be able to drive it as well (my wife, for one). My wife is 5'2", so if I mount any seat in a fixed location, that precludes her from being able to drive it. Not acceptable for me.

I'm looking for solutions that allow for seats with sliding rails and a recline function. If that just isn't possible, then I'll just give up on my goal of going to the track. I will NOT be using fixed seats.

[wallace18]

I have no gas tank and am actually planning on putting mine up front, so space behind the seats is no issue. Comfort isn't the only reason I don't want fixed seats - I'd like for others to be able to drive it as well (my wife, for one). My wife is 5'2", so if I mount any seat in a fixed location, that precludes her from being able to drive it. Not acceptable for me.

I'm looking for solutions that allow for seats with sliding rails and a recline function. If that just isn't possible, then I'll just give up on my goal of going to the track. I will NOT be using fixed seats.

If you can find someone close by with the Kirkey seats I suggest you sit in them before you condemn them. They are very comfortable for a racing seat IMO. I have raced in 6 hour endoro's and not had a complaint. They may not be your cup of tea but at least give them a try. JMO. Best of luck to you for a seat that works for you.

[DodgyTim]

818-4[1].png

These hoop additions wouldn't be legal for my local track, but you could ask

[wleehendrick]

My wife is 5'2", so if I mount any seat in a fixed location, that precludes her from being able to drive it.

At 5'2", I'm sure you'll have to cut the cross-member out in order for her to completely depress the pedals. The way my seat is set-up, I have ~2 1/2" of space for forward travel. I may put a slider in, or I may just remount the seat closer for my 5'5" wife (my seat's side-mount's have multiple lower mounting holes). On the very rare occasions that she drives my Z, all she needs to do is move the seat forward a bit, so I'm hoping this approach works. She's been supportive of my build, but I told her if she wants to drive it she has to get her hands dirty and help... hasn't worked so far.

[Santiago]

If you can find someone close by with the Kirkey seats I suggest you sit in them before you condemn them. They are very comfortable for a racing seat IMO.

Agreed. Looking at the Kirkey seats you would think they're torture devices. At least that's how I first felt. Then I sat in one. I do a lot of demo rides in my car and the last guy who sat in the pass. seat literally exclaimed in disbelief, "this is the most comfortable seat I've ever sat in." One Kirkey Intermediate Road Race Seat + 1" thick memory foam pad on the base = Comfy!

On the driver's seat I added wedges of foam here and there (sides/shoulders) to dial in the support for the tighter fit required for track duty. When I do a 3 hour road trip I just add a 1" stadium pad to the base (which I don't have under the cover because I want more seat feel on track, so less padding is better there). Even with a very stiff ride, the seat is surprisingly comfortable.

You can add sliders to any seat, but they'll typically bump you up 1" so that isn't always a feasible solution. Of course, style is every man's selection, so a Kirkey may not be the way to go but there are other styles of fixed back seats to consider.

On the bar side I'd like to see what someone comes up with in terms of raising the level of the upper bar on an S-car.

Best,
-j

[VD2021]

Option 2 is what a custom project like this is all about.

I say go for it. You have all the help and advice right here for a very successful mod.

[RM1SepEx]

I cut the front angled bar and added sliders.

I'm trying the stock seats, the tank location and shape UGH, the existing cockpit is far too small

the stock seat brackets provided now position the seat higher than the ones that went to SEMA in 2012, the car they wouldn't let us sit in. Thank god I'm the tallest in my family at 5'8". I redrilled them to lower the seat an inch but my sliders add 3/4 back

There should be room w/o the tank behind the drivers seat. I think that if you are creative you could do soln. with acceptable fuel capacity and improve weight distribution. I'm thinking a combination of a tunnel tank and a behind the seat tank allowing maximum seat travel

[Goldwing]

The more threads on this topic I read, the more I fear the stock seats will not work. I want sliding and reclinable seats as well. At just shy of 6 feet myself, I'm going to have to watch the roll bar clearance if I want to do track days. I haven't entered that world yet, but hoped to with this car. I am waiting, for now, to see what FFR's new tank does for room, but if its a split design, as rumored, adding room to the driver's side only, the firewall is going to be a pain to modify. (I.e.: not just a simple bend). The Boyd tank is starting to look really attractive, but will aftermarket seats also be required? Ugh, it's looking likely.

Regarding roll bar extension. There is a whole wall of steel bars underneath the top roll bar. Seems it would offer plenty of cantilevered bolting locations for a bolt on solution. Whether a hoop at the drivers side only or a full width bar, with welded on plate steel on front and back to extend to bolting locations below. Install for track days, leave off for factory top options. The bolt holes will be hidden out of sight. If you modified the factory bar, having a top doesn't necessarily have to be out. It might mean modifying a packaged solution, or making your own. I've toyed with the idea of trying to make my own, but that will be another winter project after I give FFR time to come up with their top options.

[Xusia]

First of all, I really want to thank everyone who posted. It means a lot to me, and is one of the reasons why I love this community. I have decided on a direction, and am going post the details of my findings and my reasoning in the interest of helping those who will face similar issues. For those who don't want to read the details, I'm going with the stock seats (<gasp!>, I know!). For those who want the details, read on. (and I'm happy to address questions)

BUT, before we get to the details, let me post some feedback for FFR. You guys are great. I mean, seriously - who else could make such a kick *** car affordable and easy to build. I truly appreciate that. Really. Now that said, the 818 cockpit is too small. SERIOUSLY. I know I'm not the first to say it. It's also not ergonomic. I'm happy to provide more details if you want, but suffice it to say the fore-to-aft cockpit length is simply too short. And the gas tank makes no effective difference in this because at some point the top of the seat hits the frame (leaving plenty of space for a gas tank in that spot).

Oh yeah; Details... Let's start with the facts. I'm just over 6' tall, 33" inseam, and 180 pounds. I fit comfortable in every car I've ever been in, except for a DeLorean. Just doing some math here, 6' = 72 inches. 72 inches - 33 inches of inseam, leaves 39 inches. 39 inches just happens to be the distance from the top of the roll bar to the cockpit floor. I'm probably not a full 39" tall when seated (I'm about 38"), but you can start to see the problem and how important the lean angle is. Except that there isn't enough space to get a decent lean angle - hence the basis for my feedback to FFR. The top of the seat can only go back as far as the frame rail / roll bar, so any increase in seat angle pushes the seat bottom forward, which cramps the legs and increases knee angle. It's all related and not good news IMO.

I had a friend come over and we fitted both the stock seats and the NRG seats I bought in a number of ways. The pedals and steering wheel were mounted, and there was no gas tank, so we could get a good idea how each would fit. What I found was that the NRG seats only put me about an inch lower. In my case, not near enough. I also found that because of the angle of my knees, sitting a bit higher off the cockpit floor was more comfortable. It also put the steering wheel lower (at one point I was sitting low enough the steering wheel was literally in my face). I know you can lower the steering wheel, but sitting higher just plain felt better and more natural in this particular cockpit. I also found the stock seats more comfortable because the seat base was longer and had a steeper lean angle than the NRG seats. The stock seats also have a raise/lower function that my wife found useful when we had her do a test fit. These are the reasons I am going with the stock seats.

In terms of mounting, I have a plan that will basically put the sliding rails of the stock seats right on the cockpit floor, while being easily removable from within the car (no under car, or side access required). I am confident this will yield the most comfortable configuration for daily driving. The only problem is that head is slightly above the roll bar. Personally, I am not worried. Previous convertibles haven't even had a roll bar. Neither does my sportbike. So really, this is still safer.

So what to do about the track? For now, nothing. BUT I have left myself with options:

1. Replace the stock seat with a race seat if/when I want to do a track day. This is why i devised a seat mounting that allows for easy removal.
2. Modify the roll bar. I also had the idea of modifying it with a bolt-on solution and 2 options: Stock height and race height. Not sure if that would be OK or not. I'm not against permanently modifying the roll bar, but I want the the soft top to work. And I'm assuming here it IS taller than the roll bar, because if it isn't, well, I can't use it and won't be buying it.

These problems are only exacerbated as you get taller. How you carry your height does factor in (legs vs. torso), but I really feel that anyone over about 5"10" is going to be making some compromises when it comes to comfort to keep their head below the roll bar. Fixed mount race seats will get you low, yes, but I really found that position just too low - and it wasn't comfortable for me (and this isn't a seat issue - it's about your body being just too low in the car).

So would I call the 818 "wookie compatible?" I guess that depends on your definition of "compatible." I mean, there are ways wookies can "fit" but I don't see how they would be comfortable. So how important is comfort to you? (Or having your head below the roll bar?)

[Goldwing]

My thoughts with the stock seats were also to mount it directly to the floor, but I hadn't fully worked it out yet. Removing the brackets below the slider and mounting the slider to the frame or an equivalent . What did you come up with for attachment? You're a bit ahead of me, but I did just mount the pedal box and steering wheel. Time to start planning.

[FFRSpec72]

Anyone tried these http://wedgebrackets.com/seat-brackets-home/ ?

[K3LAG]

Xusia,

I'm also interested in how you plan to mount them. One of my options is also to put the OEM seat sliders on the floor with some brackets, but I hadn't gotten to planning the install yet.

Larry

[Goldwing]

I hadn't seen those, something to keep in mind. It looked like you could just bolt the oem slider right to the car as long as you didn't use a bolt that was too proud that would interfere with the slider. Either directly, passing through the floor, not my favorite as it could get sheared in a crash, or using brackets to orient the bolts horizontally. That would be a custom setup. This is where I was eager to learn of Xusia's idea for the mount. A top of my head solution for the direct bolt through would be a button head bolt (inside the slider) to a special nut. I don't know the name of the fastener so I'll describe it. A washer with a welded and threaded sleeve as to have a very low profile under the car. Ideally, that sleeve would be the thickness of the square tube so as not to crush the tube.

[DodgyTim]

It doesn't help you Xusia, but the R roll hoop looks to be higher than the S, perhaps FFR needs to consider an option on the S order form of "S chassis with R hoop"

The S
DPM21782-694x413.jpg

The R
r frame.jpg

[Xusia]

Anyone tried these http://wedgebrackets.com/seat-brackets-home/ ?

I have not tried those, but the various options I saw looked to have added height vs. mounting more directly to the floor. The slider mechanism in many of the pics looks very similar to what comes with the NRG seats, and will almost certainly interfere with the frame bar that runs between the center tunnel and the outside frame.

My thoughts with the stock seats were also to mount it directly to the floor, but I hadn't fully worked it out yet. Removing the brackets below the slider and mounting the slider to the frame or an equivalent . What did you come up with for attachment? You're a bit ahead of me, but I did just mount the pedal box and steering wheel. Time to start planning.

Xusia,

I'm also interested in how you plan to mount them. One of my options is also to put the OEM seat sliders on the floor with some brackets, but I hadn't gotten to planning the install yet.

Larry

I will try my best to describe my idea. I have nothing to actually show yet, but will happily provide that when I do.

On the seat side of the equation, I plan to remove the mounts that are attached to the sliders (i.e. where the bolts go that hold the seat in the car), and fit a steel plank to the bottom of the sliders that extends both fore and aft of the seat. <-- This is for easy access to the bolt from "above." There will be holes at both ends of the plank for bolts to go through - LARGE bolts! One thing to note here for anyone considering this on their own, is that the sliders are not level. If you remove the mounts as described above and set the seat on a level surface on it's sliders, it leans inward slightly. I plan to compensate for this by either using a washer or two when mounting, or by using thicker steel for the inside plank.

On the car side, I plan to weld a solid mounting bar or triangular plate (haven't totally decided yet) just behind the aforementioned frame bar that runs in front of the seat (on the inside of the "X" under where the seats sit). It will either be thick enough to be tapped, or I'll weld a nut on the other side. This will eliminate the need to have any access from below, while keeping the underside of the car tidy. It should also allow me to keep the existing frame bar that runs in front of the seats (I don't really "like" that bar, but I'm trying not to just cut stuff off...). I do not plan to use any of the frame for direct mounting because I don't trust rivnuts to hold the seat in place should a collision occur, and I don't want to go all the way through those pieces (i.e. with a bolt) because that means something on the bottom side of the car and I don't want that. My overriding goal (besides safety) is to keep it clean, simple, and easily accessible (such as for swaps).

I hope this makes sense. If not, ask away!

[K3LAG]

The first half of your idea sounds the same as what I was thinking. I didn't realize the heights were different. I'll have to look at that more closely. I haven't decided how to mount to the frame yet.

Larry

[Frank818]

Ok I see your point Brian. Maybe the guys at FFR are short? Who knows. Fortunately for me, that's a problem I probably will never have to deal with, tnx to the beauty of being 5'6", I can fit and sneak pretty much everywhere.

I guess an extension to the OEM roll bar or a tilted seat could be options? And how bad for you if you never go on the track by the books? I mean, you could still go on the track for the fun of it, on those tracks and events you don't need to respect regulations, right?

Other options, let's see... chop off your head, which I really don't suggest, or build your car with an F1 style seat orientation, which is almost 100% flat on your back. That way you could even "sit" (or lay down should I say) above the dash level, assuming the pedal box is installed "in" the dash.

Obviously, my options are jokes which aren't funny, cuz I wouldn't want to find myself in that situation, when all solutions don't seem to meet at least 1 requirement. But I am sure someone will guide you to something realistic. And how about tilting the seat, seriously?

[Goldwing]

I pulled my driver seat back down from the attic today and noticed the different levels the sliders sit at. My memory left that out, lol. So, different size brackets/ bars, etc will be needed to level the seat, as you said. The back of the oem seat is pretty thick. I'm concerned that alone might push the issue, but I'm still game to try it. My only reservation is dismantling the brackets will make the oem seats more difficult to sell if I opt out in the end. Decisions.

[Xusia]

And how about tilting the seat, seriously?

LOL - Frank you crack me up! To answer your question, the seat backs are tilted at an angle. I tried several angles, in fact. When looking only at the relative positions of head & roll bar height, increasing the angle is effective, sure. The problem, however, is that seat back very quickly hits the frame. This means additional angle can only be achieved by pushing the seat bottom forward. This cramps my legs, which are already bent quite a bit. So in essence it's a trade off between leg room and head height, and it only gets worse as you get taller.

Based on what I tried and what everyone else has said, I think the only solution that allows for adequate leg room with your head below the roll bar is a fixed position racing seat mounted basically directly to the floor. Based on people's feedback, this would probably be more comfortable than I imagine - from a seat perspective - but it doesn't address the other issues I had at such a low seat height. Your mileage may vary as they say..

I pulled my driver seat back down from the attic today and noticed the different levels the sliders sit at. My memory left that out, lol. So, different size brackets/ bars, etc will be needed to level the seat, as you said. The back of the oem seat is pretty thick. I'm concerned that alone might push the issue, but I'm still game to try it. My only reservation is dismantling the brackets will make the oem seats more difficult to sell if I opt out in the end. Decisions.

Something I found a bit odd is that I was able to get the WRX seat further back than the NRG seat. The reason is because of the shape of the NRG seat hit the frame and/or roll bar more easily than the WRX seat. Generally a lower back / smaller head rest is better (in terms of getting the seat further back), so if you don't want to experiment on the stock seats, you could try some other ones (armed with this knowledge).

I hope that helps you.

[Frank818]

Brian, if you put the tank in the front, maybe you can modify the bars behind the seats and allow you to push backwards and tilt down the seats a little more, without cramping your legs?

[wleehendrick]

Based on what I tried and what everyone else has said, I think the only solution that allows for adequate leg room with your head below the roll bar is a fixed position racing seat mounted basically directly to the floor.

Yup... that's my solution. Too bad it conflicts with your other requirements (something's gotta give). To me, this is ideal for the spirit of the 818... simple, custom, raw, track capable sports car.

I'm a stickler for ergonomics; a friend asked me how I can buy a car without ever driving or even sitting in it first. My answer was: 'the concept is brilliant and I'm building it around me, so it'll be right'. As I mentioned, I spent a good part of this past Saturday getting the steering wheel, seat, shifter and e-brake positioned. Since then, all my other cars (which are pretty well dialed-in) have felt a bit off! I'm now really, really happy with how it all turned out (well, I still have to mount my harnesses), but like I said it would not have been possible with the FFR tank, and stock seats.

[Bob_n_Cincy]

The problem, however, is that seat back very quickly hits the frame. This means additional angle can only be achieved by pushing the seat bottom forward. This cramps my legs, which are already bent quite a bit. So in essence it's a trade off between leg room and head height, and it only gets worse as you get taller.

Xusia
I went through the same exercise back in October.

P1040727s eyes.jpg

criteria:
Legs not cramped
head below roll bar
eyes above steering wheel
comfortable

Considered solutions:
1. Move pedal box forward 2-3" (designed but not installed yet)
2. Move steering wheel forward (will do)
3. mount kirkie seat on floor (done)
4. Reshaped seat (done)
5. move gas tank to front of car. (doing, the Boyd tank is 2" to thick)
6. lengthen cockpit (not doing, but still on the table)
7. 1.5" spacer to lower steering wheel.(done)

KIR_47900Drawing.jpg

These are the kind of things that have really slowed my progress.
For my 5'4" daughter to drive, I will use a seat insert.

I guess I'm bigger than a wookiee
According to http://starwars.wikia.com/wiki/Wookiee They are 6'10" average
Bob

[Xusia]

Brian, if you put the tank in the front, maybe you can modify the bars behind the seats and allow you to push backwards and tilt down the seats a little more, without cramping your legs?

That bar seems like a key structural component to the frame. I thought about modifying it for about half a second, but quickly dismissed it after that!

Xusia
I went through the same exercise back in October.

P1040727s eyes.jpg

criteria:
Legs not cramped
head below roll bar
eyes above steering wheel
comfortable

Considered solutions:
1. Move pedal box forward 2-3" (designed but not installed yet)
2. Move steering wheel forward (will do)
3. mount kirkie seat on floor (done)
4. Reshaped seat (done)
5. move gas tank to front of car. (doing, the Boyd tank is 2" to thick)
6. lengthen cockpit (not doing, but still on the table)
7. 1.5" spacer to lower steering wheel.(done)

KIR_47900Drawing.jpg

These are the kind of things that have really slowed my progress.
For my 5'4" daughter to drive, I will use a seat insert.

I guess I'm bigger than a wookiee
According to http://starwars.wikia.com/wiki/Wookiee They are 6'10" average
Bob

In the long run, I think modifying the pedal box is the way to go. Early on I toyed with this idea, but it seemed fairly complicated because of the proximity of the LCA mount, clutch pedal tavel & clearance, and a horde of other issues. I think what's really needed is different pedal box (but one that mounts on the firewall or from under the dash, because floor mounted won't work with the LCA mount location) that has a different pedal shape/structure so that it can clear the LCA mount while mounted further back. If you come up with something, PLEASE let me know. I will certainly still consider it.

[Grintch]

Actually the broomstick test is a much harder test. It involves checking to ensure that the helmet head remains below a line from the main hoop to the front hoop. This is typically a much harder requirment than getting the helmeted head 2" below the main hoop. But as an S doesn't really have a front hoop, and full cages with them are only required for racing the broomstick test is not an issue for you.

One key thing with a more reclined seat is that the seat bottom needs to "recline" as well to be confortable. Think of how the seat bottom on a rocking chair "reclines" as the chair rocks back. If you just recline the seat back of a normal street style seat, it gets uncomfortable rather fast. But if the entire seat is tilted it stays confortable longer with more recline. And you don't end up with your legs flat on the floor with a low mounted seat.

[Xusia]

One key thing with a more reclined seat is that the seat bottom needs to "recline" as well to be confortable. Think of how the seat bottom on a rocking chair "reclines" as the chair rocks back. If you just recline the seat back of a normal street style seat, it gets uncomfortable rather fast. But if the entire seat is tilted it stays confortable longer with more recline. And you don't end up with your legs flat on the floor with a low mounted seat.

Absolutely. This is an area where the WRX seat was superior to the NRG seat. It had a steeper recline and was therefore more comfortable.

[custome]

I have some ideas about roll bar mods that involve a street version and a track version as you stated above. I'm 6'-3" with a 32" inseam so we'll have to "bend" that broomstick a little!

[flynntuna]

I have some ideas about roll bar mods that involve a street version and a track version as you stated above. I'm 6'-3" with a 32" inseam so we'll have to "bend" that broomstick a little!

Like this one?

[BC Huselton]

Is it impractical or structurally impossible to add a second bar to supplement the top of the current S roll hoop. This second loop could add 2" sleeved in with an additional grade 8 bolt plate. it would look like the R bar and come up both sides of the S hoop with two additional vertical 2" bars directly over the Helmet site. All Grade 8 bolt in. It may be ugly for racing, but meets specs and makes all the other options for passing the Broom Test unnecessary.

We did this for the Ford Spec Racers to pass new requirements. Perhaps it is an option here...what am I missing other than UGLY?

BC

[07FIREBLADE]

Pics??

[Xusia]

I was under the impression that a bolt on roll bar addition was not permissible. If it IS permissible, then I would absolutely do it for track days.

[Grintch]

Is it impractical or structurally impossible to add a second bar to supplement the top of the current S roll hoop. This second loop could add 2" sleeved in with an additional grade 8 bolt plate. it would look like the R bar and come up both sides of the S hoop with two additional vertical 2" bars directly over the Helmet site. All Grade 8 bolt in. It may be ugly for racing, but meets specs and makes all the other options for passing the Broom Test unnecessary.

We did this for the Ford Spec Racers to pass new requirements. Perhaps it is an option here...what am I missing other than UGLY?

BC

It's an old joke that the SRF roll cage is only legal because it is made by the SCCA.
The orginal main hoop height was apparently designed for female gymnists, but they already had a couple hundred frames build (and more on back order) before they figured out anything close to an averge size american male wouldn't fit.

Note that the "tallman kit" add on is welded in place, and includes new front and rear brace sections (hard to see in this photo), and even this would not be allowed on any other car. Racing rules require the main hoop be made from a single piece of tubing.

NASA 11.4.7 [HPDE requirement]
All open cars should have a roll bar installed to help protect the occupant(s) from injury during a roll-over. The
main hoop shall be one continuous piece with smooth Mandrel bends with no evidence of crimping or wall
failure.


The really weird thing is all SRF still get made with this double decker main hoop rather than replacing it with a simpler, lighter, cheaper, and probably safer once piece design of the proper height.

[Xusia]

So what about NOT racing - just HPDE? Is an add-on generally permissible?

[Santiago]

For HPDE your bar doesn't have to meet the wheel-to-wheel requirements. For that matter, it doesn't have to do so for Time Trial as well. This isn't to say you should feel good bolting on any ole' bar configuration you dream up or find...*cough*Autopower*cough*... just that you don't have to meet all the rule requirements.

I use a Maximum Motorsports bolt-in roll bar in my Mustang (I run NASA Time Trial), and it is very well designed and built. The keys to this are mainly how they tie into the existing structures, both in terms of location and mating method.

Best,
-j