HPDE Seat Height Issues
 

I'm sure this has been handled many many times, however the only solutions I can see require cutting seat mounts or custom brackets.

I want to try a HPDE, however I am unsure about the broomstick test. Normal driving position yields I am above the roll bar, with the seat slid super far forward and the back leaned as far as I can, I barely fit under. When I swap in a Corbeau Forza Seat I gain maybe 1/4" more headroom. This still has me barely a half inch below the top of the roll bar. Obviously more room is safer, but the SCCA time trial rules state "The top of the roll bar must be above the top of the driver’s helmet when the driver is in normal driving position."

My question is... am I in the clear with a half inch of clearance? I have already done a foamectomy, my race seat doesn't gain much more room, I would really like to avoid any permanent changes to the car as I don't know if I will every do this type of racing again. The pictures show normal seating position as well as seat slid forward as far as possible. I am only 5'10" which makes me wonder if something is amiss? Normally these threads deal with people who are over 6' tall. If there is a specific thread that has other ideas besides cutting seat mounts or custom brackets let me know, I would hate to buy a $1000 hardtop or a $400 new seat just to try out a single track event.

Thanks.
[IMG]http://i62.tinypic.com/xbxxl5.jpg[/IMG]
[IMG]https://www.miataturbo.net/attachmen...ine=1429628409[/IMG]

What kind of rollbar is that?

I am not positive.... I bought it with the car. Here are some pics for reference.
[IMG]https://www.miataturbo.net/attachmen...ine=1429630535[/IMG]
https://www.miataturbo.net/attachmen...ine=1429630535

How much clearance is there between the bar and the soft top? If there's extra space there then swapping roll bars is probably the best solution.

If it's as tall as can be done, then you need to lower the seat. If you've done a foamectomy and tried race seats, then the next step is to cut out the rear seat mounts, omit the sliders and bolt the seat to the floor. It sucks from the perspective of driver compatibility, but you'll gain a TON of room. I went from 1.5 inches above the roll bar (sitting on my stock seats) to 2 inches below by doing this.

--Ian

I was really hoping to avoid cutting mounts. Once you bolt the seat to the floor don't you lose the durability of the mounts? Aka, crash and your seat rips out of the floor. I assume I would need something to help support the load.

I will check clearance to soft top. Any input on SCCA regulations with the roll bar height?

Yes, if you bolt the seat to the floor then you need to reinforce the mounting points. I think this can be as simple as a backing plate on the underside of the floor, but I elected to take mine to a local race fabricator for the seat install. He made custom seat brackets for them too.

--Ian

This, the rear mounts and sliders obviously have to go, however I wouldn't go as far to say "a ton" of room is gained. It very much depends on what exact seat you have. A Sparco Sprint bolted directly to the floor will be the lowest possible, but [as in my case] a Sparco Rev touching the floor was barely low enough for my 5'9" and regular torso length to be underneath the broomstick with a Hard Dog roll-bar.

Yes, you'll need to sandwich the seat mount around the floor pan and create a hard-point to retain anything resembling safety. Of course, not a single vendor makes anything resembling plug-n-play mounts, which makes sense given how rare these cars are. =P I took AWR mounts and cut them up because they don't mount anything but a Sparco Sprint low enough. Don't even bother with the Kaze mounts, they mount everything higher than stock because they're forgot to engineer them after they made them look pretty.

more foamectomy. I have NB seats so it may be different, but I did a foamectomy, it wasn't enough, did more, seat actually got more comfortable and I got low enough Total drop from start to finish was about 1.5".

I am a little confused. You seem to be clearly passing the broomstick test there which means you're in the clear for HPDEs and unless you think you're going to roll the car your first time out on the track with street tires then you should be just fine. If you want to be lower than that it will likely involve permanent modifications to the car that you can commit to if you feel that tracking the car will become a much more common occurrence.

First picture he doesn't pass, his preferred seating position.
2nd picture he does pass, seat all the way forward, uncomfortable, not livable for the track.

He mentioned that if he swaps in a Corbeau Forza (fixed back seat) he still sits 1/4" below the roll bar. I assumed this seat would be used for the track anyway.

So to answer the question he asked, Yes. A quarter inch of clearance is within the rule set and you should be fine for the event. If you find yourself wanting to track more often and are uncomfortable with that amount of clearance as you get faster then you can change the seat or make permanent modifications to the floor pan to sit lower in the car.

Fair enough. I have Recaro Pole Positions, and I dropped my seating position by about 4 inches from stock doing this.

https://www.miataturbo.net/attachmen...ine=1429658343

--Ian

got it.

Good data point, thanks for sharing. Are your race-shop fabbed mounts in your build thread?

I'd love to be another 1/2" lower than what I ended up with; perhaps Recaro's are a better "low" buy than 1-piece Sparco's.

I tried this and got me a low as I could without cutting things up. I need to tilt it back a bit more though.ProCar Innovations Race Spec Seat Mount Version 2 | KazeSpec Engineering

Got me this far. https://www.miataturbo.net/attachmen...ine=1429673012

No, the mounts went in about 8 years ago, before I had any build threads. I haven't had cause to pull the seats out recently, but when I do I'll post photos.

I dunno if it's true of Recaros in general, or just of the specific Pole Position model. There was some kind of problem discovered with the PPs last year, and the FIA certification was pulled. I dunno why -- I've heard from a couple people that it's really a big deal over nothing, but you can't buy them right now. My certs were expired anyway (5 years for FIA), so it doesn't really matter to me. Supposedly Recaro is working on fixing whatever the issue is and new Pole Positions are expected in a month or two.

--Ian

Im not sure which version Kazespec mount Ryephile had but my Kazespec V2 seat mount with my Recaro replica(yes flame on) seat sits me with a good amount of clearance for the "broomstick test". Im 5'10" with a good amount of torso length. Your roll bar looks to be of a decent height so i would look into the mounts that your bucket seat is mounted too. If you have the coin, go with a custom mount if you really do like sitting in that Corbeau Forza seat.

Part of my confusion was even though I quoted that clearance rule from the time trial rule book, I was under the impression you needed a TWO INCH clearance below the roll bar. I guess I was not clear on that. I must have been confused from some other threads and some jargon in the rule book. So the definitive rule is "below" the roll bar. (I thought you needed two inches so in the event of a crash there is no way for you to contact the pavement)

I should then be just fine with the Forza seat and my 1/4-1/2" clearance. Time to sign up for HPDE :vash2:

While on this topic..... One other question, padding the roll bar. Must it be covered with an official brand or style of padding? Or are people able to slap something together to get through an event?

While I would highly suggest SFI padding I have seen multiple people at Sebring with absolutely no padding. You should really talk to people who attend your local events as each region is run slightly different.