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 Post subject: Re: Seat Mounting Rules
PostPosted: Sun Dec 29, 2019 8:28 am 
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Joined: Tue Dec 31, 2013 10:40 am
Posts: 406
Location: Huntsville, AL
I picked up the Viper Racetech seat from a customer and its STOUT. Ractech told me in order for Chrysler to use it in the Viper LeMans program they crashed one and the seat survived a 45G impact. Good enough for me.

I have installed a few of these seats for customers.
https://racetech-usa.com/shop/RT4119-motorsport-seats

They are painfully expensive, but extremely nice and the back mounting makes them very strong. Racetech claims you can "stiffen the chassis" with these seats.

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Brett W
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 Post subject: Re: Seat Mounting Rules
PostPosted: Sun Dec 29, 2019 8:54 am 
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Joined: Thu Feb 28, 2019 5:57 am
Posts: 74
loopracing wrote:
I'm also interested in the reasons the engineers had for saying the backrest mount was dangerous.

My discussions with them (as I recall, it was Momo and Sparco that led the charge) were along the lines of their seat's design purpose. They are designed to be firmly mounted at the bottom but are designed with flex at the upper part to absorb shock loads. If the back of the seat were firmly attached such that there was no flex, then the occupant would have to take the full brunt of the loads; the body would load against the seat, then internal organs would load against the body. The seat is designed to be a shock absorber (so to speak).

They were further horrified (that word was used specifically) that people were randomly modifying and mounting things into their composite seats that it was not designed for; fears of seat breakage during a crash and/or subjecting the back to impact of these devices. As I recall, RaceTech acquiesced on the first-generation of MX-5 Cup cars, shipping specially-designed inserts for their mandated seat in which to attach a back brace fo rthe SCCA's required regs. They didn't like it, but they did it and it was at least consistent.

Keep in mind the original purpose for these braces was not to stop the seat from moving, but to stop the seat from breaking. They originated from several Showroom Stock crashes where the OEM tilt-able seats - you may recall, required by the regs at the time - were breaking at or near the pivot points. We tried first to require a horizontal bar in the rollcage behind the driver to catch these seat failures, but it was Jay Wright's crippling near-fatal crash at the 1993(?) Runoffs that sealed the deal on the need for getting rid of factory seats. In fact, Jay's crash resulted in not only the requirement for (initially optional) race seats in Showroom Stock but also larger rollcage tubing mandates and the requirement to extend that seat-catching horizontal bar all the way across to the passenger side of the main hoop (the diagonal bar in Jay's car came out of the plane of the main hoop, compromising the integrity of the main hoop, which subsequently collapsed on him.)

As we moved forward from the race seats requirement, we found that many were not being mounted well, and some "race seat" designs were not very well-designed (not all were subjected to certification requirements) and could bend/break in a crash. Further, some seats were being mounted on factory sliders which, although have to meet a NHTSA standard, may not always meet the requirements for racing. So, to address these failures we started requiring seat back races. Kinda like a Band-Aid on a cut that needs stitches...

(There was a brief moment in time not too long ago where Touring Corvettes were mounting their race seats to factory sliders, and those sliders are, to be honest, shit. We were grabbing the seats and you could easily move them around. It then that we added a ban on the use of factory sliders.)

Once the seatback brace requirement happened, I noted that FIA-cert seats are not designed for a back brace. I started contacting manufacturers for their opinions, and with their assistance drove the allowance for no seatback braces when using FIA-certified seats that are properly mounted to the manufacturer's specifications. Soon after that we got into the 5-year FIA cert argument, then the subsequent removal of the 5-year requirement, then soon after discussions about killing children. It got so bad that one interpretation in one region was causing people to get excluded from events when they went to another region, so SCCA just gave up and left seast designs and mounting to the discretion of the competitors and scrutineers.

And here we are today. I have not personally heard of any negative feedback on the current process; I think most people are reasonable and truly want their cars to be as safe as reasonably possible without getting into rules arguments.

I use higher-end carbon/composite race seats in my cars; Racetech tends to be my go-to. And we mount them firmly to the floor (the cage would actually be better) but with no back braces. And I do make a point of physically checking all seat mounts for every annual and logbook I do, strongly encouraging improvements where needed.

The only deviation from that is in my historics 914: there's just not enough space to mount a good seat for my 6'1" frame. Instead, I'm forced to use an aluminum Butler seat that is directly mounted to the floorpan with bolts. Its back is mounted directly to the firewall with bolts and a small spacer to keep my head in front of the rollcage main hoop plane. I try to pad my body from the seat pan as best I can with Temper Foam. I'm not a big fan of that design at all...


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 Post subject: Re: Seat Mounting Rules
PostPosted: Sun Dec 29, 2019 10:35 am 
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Joined: Tue Dec 31, 2013 10:40 am
Posts: 406
Location: Huntsville, AL
Greg Amy wrote:
The only deviation from that is in my historics 914: there's just not enough space to mount a good seat for my 6'1" frame. Instead, I'm forced to use an aluminum Butler seat that is directly mounted to the floorpan with bolts. Its back is mounted directly to the firewall with bolts and a small spacer to keep my head in front of the rollcage main hoop plane. I try to pad my body from the seat pan as best I can with Temper Foam. I'm not a big fan of that design at all...



Do away with the traditional seat all together and build an aluminum containment structure that will allow you to sit on the floor directly with a poured foam insert. Treat the seating arrangement like a formula car.

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Brett W
Huntsville, AL


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 Post subject: Re: Seat Mounting Rules
PostPosted: Sun Dec 29, 2019 12:06 pm 
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Brett W wrote:
Do away with the traditional seat all together and build an aluminum containment structure that will allow you to sit on the floor directly with a poured foam insert. Treat the seating arrangement like a formula car.

That's a good idea. I'll have to look into how to do that.


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 Post subject: Re: Seat Mounting Rules
PostPosted: Sun Dec 29, 2019 1:56 pm 
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Joined: Tue Dec 31, 2013 10:40 am
Posts: 406
Location: Huntsville, AL
Greg Amy wrote:
Brett W wrote:
Do away with the traditional seat all together and build an aluminum containment structure that will allow you to sit on the floor directly with a poured foam insert. Treat the seating arrangement like a formula car.

That's a good idea. I'll have to look into how to do that.



One call and some car shipping gets it done. HAHA

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Brett W
Huntsville, AL


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 Post subject: Re: Seat Mounting Rules
PostPosted: Mon Dec 30, 2019 3:11 pm 
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Joined: Wed Jul 06, 2011 3:48 am
Posts: 658
Location: Florida
Been watching this for a while and thought it might be time to input a real world comment. We are running a pair of HP Bugeyes, and as you know they were made for 5 foot 90 pound drivers with little feet. I don't fit that but I manage to get in and out without falling on my face mask. We are using the Kirkey wrap around, 20 degree, reinforced aluminum seats. Both cars have roll bar mounted back rests as per the GCR. February, 2016 I put in head restraints on both seats. Thanksgiving of 2016 coming out of Sebring long course turn 16 I slid on oil and wound up on the other side of the rumble strip in the grass, still under control, shifted to third hard on the gas to keep the car straight, and tried to get back on the concrete surface. Did good until the right rear wheel hooked on the 2" drop off of the pavement and wound up in a 180 degree slide across the track into a humongus jersey barrier sideways, bounced off and did another 180 to wind up 10 feet from the barrier facing down track where I was supposed to be going. Found it hard to do with the left front A arm in the oil pan. I was 4,800 in third gear at the time so you can compute the speed. Camera showed it all and my total head movement to the left was visually calculated at 3 to 4 inches. With no sturdy back rest mount and no head side restraints I don't think I'd have survived that one. Moved the jersey barrier back four inches. Track has put a whole line of tires out there now just in response my wreck. Point of all this is if you trust a seat without hooking it up to the cage I'd make sure it's built to take something similar. Personally, I hope none of us has something as severe as we did.

Bob

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Bob Hess 165947
HP 13 '59 AH Sprite HP Hybrid
HP 49 '60 AH Sprite HP/Vintage


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 Post subject: Re: Seat Mounting Rules
PostPosted: Mon Dec 30, 2019 6:29 pm 
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Joined: Wed Jan 01, 2003 8:46 am
Posts: 200
Location: Howell, MI
I’ve had a similar situation as Bob. I ran a T2 car and got run off to the outside of the exit of the boot and got sucked into the foam barriers. I basically pancaked the whole right side of the car hard enough to break the fuel module off in the tank and break the front upright. I had a composite seat (not FIA) but “engineered” to bolt a seat brace with integrated bosses and webbing to support. The seat was attached to a set of MOMO mounts and sliders with welded in bosses to strengthen the floor pan. The seat ended up breaking apart on the bottom and snapped the seat back mount off at the roll bar. End result was the only thing left holding me was the belts but my right hand left the vehicle smacking the barrier. Thankfully only a nasty sprain. All my seat from then on have been firmly mounted to the cage if I can.

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Eric Vickerman
HP something


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 Post subject: Re: Seat Mounting Rules
PostPosted: Tue Dec 31, 2019 6:09 pm 
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Posts: 230
The question I have regarding the back support is concerning how that back support works in a rear end crash. Would a crushable mounting be feasible. Some design that addresses both direction impacts.

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Dick Gagliardi
Chicago region
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 Post subject: Re: Seat Mounting Rules
PostPosted: Wed Jan 01, 2020 5:03 am 
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Joined: Wed Jul 06, 2011 3:48 am
Posts: 658
Location: Florida
Good question. If you consider the difference between front and rear wheel drive there are all sorts of combinations of cages that you have to consider. Our primary HP Sprite with coil over rear suspension has roll cage tubing connecting the two top mounts. That coupled with the the rear end housing, links, driveshaft, etc. makes for a pretty sturdy bunch of metal to absorb a rear hit. The primary seat back support goes down to that tube with the two rear hoop supports on either side. In it's lifetime the car has survived two roll overs, a hard rear end hit and and a hard right side hit on a jersey barrier after hitting brake fluid from a blown out caliper on the car just ahead. Nothing on the cage moved at all. The front drive cars are a different animal and I'm sure someone out there has a design that will work to protect from rear end hits. Happy New Year!

Bob

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Bob Hess 165947
HP 13 '59 AH Sprite HP Hybrid
HP 49 '60 AH Sprite HP/Vintage


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 Post subject: Re: Seat Mounting Rules
PostPosted: Wed Jan 01, 2020 8:24 am 
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Joined: Tue Dec 31, 2013 10:40 am
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Location: Huntsville, AL
Its interesting the difference in the European seat mounting theory and the American seat mounting theory.

The Europeans want to see the seat bottom mounted and see the upper portion of the body move a little to absorb some of that energy from a crash.

The American seat theory is solid mounting the seat as much as possible and keep the body from moving at all. Much of that has come from the sled testing done through the NASCAR safety institute.

Racetech has obviously gotten a lot of their seats into many top level race cars because of the perceived strength of their mounting philosphy.
Quote:
What is the difference between the FIA 8855-1999 (old) and FIA 8862-2009 (new) seat standards?

The test method for the new 8862-2009 standard differs significantly from that of the older 8855-1999 standard. The old standard simulates three successive impacts; 20G rearwards, 15G laterally and another 10G rearwards by using a crash test dummy and rapidly decelerating a sled. The new standard is quasi-static, meaning the seat is fixed and the loads are applied by hydraulic rams to the head, shoulder and pelvis areas of the seat simultaneously. There is both lateral and rearwards tests where the seat must withstand;

Laterally: 7kN (Head), 11kN (Shoulder) and 14kN (Pelvis)
Rearward: 7kN (Head), 14kN (Shoulder) and 14kN (Pelvis)

It is difficult to compare the two standards accurately except to say that the newer 8862 standard is much more rigorous and simulates an impact of approximately 70G.

The other point to note is that seats meeting the new FIA standard are required to use stiff, energy absorbing foam in the head, shoulder and pelvis areas, improving safety for the occupant.


Its interesting the new FIA standard is far stronger than the older standard, yet most all of us race with 99 standard seats. I'm sure some of that is driven by costs.

Recaro https://www.recaro-automotive.com/us/ra ... quirements

Sparco has some 2009 seats and WOW!!!!. Gues we know why very few people use them:
https://www.sparcousa.com/vehicle-seats-competition

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Brett W
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