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LainfordExpress
LainfordExpress Reader
4/11/13 6:13 p.m.

So I'm building an STF car that I'll have to drive to events only (won't have to daily drive). I've heard all kinds of horror stories about how unsafe it is to mix race seats with stock seat belts... but it seems a little extreme. I want to take as much weight out of the seats as possible, as per the rules, and the seats are one of the best opportunities to drop a few lbs.

Thoughts?

aussiesmg
aussiesmg UltimaDork
4/11/13 6:20 p.m.

What seats? What mounts? Are they adjustable? Do they slide?

Are you using factory mounts?

Do you have air bags?

EvanB
EvanB PowerDork
4/11/13 6:23 p.m.

I use a fixed race seat (not FIA cert) with stock belts on a semi-daily driver with no airbags. I don't see how it could be any less safe than the stock setup.

JoeyM
JoeyM UltimaDork
4/11/13 6:31 p.m.
EvanB wrote: I use a fixed race seat (not FIA cert) with stock belts on a semi-daily driver with no airbags. I don't see how it could be any less safe than the stock setup.

This is the basic argument against mixing street and race safety gear:
http://www.thetruthaboutcars.com/2010/05/five-point-belts-will-paralyze-you-and-other-fun-safety-facts/

I have no idea if that argument is legitimate or not.

spritedriver28
spritedriver28 New Reader
4/11/13 6:34 p.m.

I've got a set of Momo Nascar (carbon) seats in my daughter's Miata with G-force 5 point camlocks. I think it's probably safer than the stock seats/belts as there is at least some side impact protection. As far as comfort, they are liveable for an 8 hour drive, but 3-4 hours at a time is much more reasonable. I put tube frame Corbeau's in my Bugeye and with the seat heaters they are as comfortable as my Lexus.

LainfordExpress
LainfordExpress Reader
4/11/13 6:40 p.m.
aussiesmg wrote: What seats? What mounts? Are they adjustable? Do they slide? Are you using factory mounts? Do you have air bags?

Buddy Club Racing Spec Seats

Buddy Club Super Low-Down Rails (sliding)

Factory Mounting Locations

Cannot remove airbags per SCCA rules, but I can probably disable them.

EvanB
EvanB PowerDork
4/11/13 6:43 p.m.
JoeyM wrote:
EvanB wrote: I use a fixed race seat (not FIA cert) with stock belts on a semi-daily driver with no airbags. I don't see how it could be any less safe than the stock setup.

This is the basic argument against mixing street and race safety gear:
http://www.thetruthaboutcars.com/2010/05/five-point-belts-will-paralyze-you-and-other-fun-safety-facts/

I have no idea if that argument is legitimate or not.

The points in that article don't really seem to say anything about a race seat and stock belts, just the danger of 5-point belts and a roll cage on the street (which I agree with). I don't see the danger of adding a race seat with stock belts other than it doesn't allow you to move side-to-side as much (which doesn't seem to be a problem to me).

JoeyM
JoeyM UltimaDork
4/11/13 6:44 p.m.

You are correct. It doesn't say much about it. I've seen some people elaborate on that before (could not find the link, though) and the related paragraphs are:

What happens in a street car? Well, the roof collapses. There’s some roll reinforcement in most factory cars, but it’s not what you get in a race car. When the roof collapses, it’s okay, because a three-point belt allows your head and torso to move forward, away from the collapsing roof.

[...]

There’s a race-car safety system, and it consists of a full cage, five-point harnesses, helmet, and full race suit. There’s a street-car safety system, and it consists of three-point inertia belts, airbags, and soft interior surfaces. Don’t mix the two. The results are never good.

my understanding is that people who think it is unsafe think that having a seat that cannot break at a hinge and recline back think you're keeping your head in the crumple zone during some types of roll overs.

Again, I'm not advocating this view....I have no idea if it is correct.

LainfordExpress
LainfordExpress Reader
4/11/13 6:48 p.m.

I think the roof collapsing argument is... dated. I've seen industry full vehicle crash testing and seat testing first hand. I think it would take a truly hellacious accident/falling grand piano to smash a car like they're describing.

I think a more realistic worry is: severe back injury from seat back breaking/deforming in an accident. The seats tests are pretty severe, and lot of time is spent on occupant retention and preventing penetration to the H-point. I'm probably worrying to much, but I'm an engineer, it is my job to worry.

Jaynen
Jaynen Dork
4/11/13 6:49 p.m.

The seats are fine, most of the time just by removing the lap belt bolt on the stock belts and feeding it through the new seat you can safely use race seats and stock belts when not on the track and use the harnesses when you need them.

I don't think there is a safety issue at all with stock belts and race seats as long as you make sure the belts feed properly through the openings.

Apexcarver
Apexcarver PowerDork
4/11/13 6:50 p.m.

If its only seats, I would not be concerned.

As long as the seat does not interfere with the seatbelt (high sided ones holding belt off of you) you are pretty safe.

100% certain that its just as safe? Well, no.. without crash testing noone can tell you that.

The biggest concern I see is if you are using harnesses without a rollbar as the 3-pt belts allow you to not be held up while the roof collapses.

Secondary concerns are security of the mounting of the seat (how you install it) Use good hardware (grade 5 is good, no cadnium plated taffy!) to the existing holes if possible, if not you need to reenforce the new mounting points so it doesn't just tear through the sheet metal.

I run my mustang with rebadged cobra monaco's with the stock belts and no rollbar and I am not overly concerned.

Disabling airbags.. no shop will do it for you as it violates federal statutes, but diy is up to you and your state.

Seats don't have airbags in them, do they?

LainfordExpress
LainfordExpress Reader
4/11/13 6:52 p.m.

OE seats have airbags.

I thought thought the law was that the airbags had to be able to be deactivated... maybe just the passenger seat?

Apexcarver
Apexcarver PowerDork
4/11/13 6:52 p.m.
JoeyM wrote: my understanding is that people who think it is unsafe think that having a seat that cannot break at a hinge and recline back think you're keeping your head in the crumple zone during some types of roll overs.

Fallancy..

If the seat were to break in this type of incident, they would also break in a heavy rear-end collision which would be much more dangerous.

LainfordExpress
LainfordExpress Reader
4/11/13 6:55 p.m.

Yeah, the seat retention and cargo retention tests I did when I co-oped with a different manufacturer convince me that the hinge mechanism is pretty robust.

Slippery
Slippery Reader
4/11/13 6:55 p.m.

The only thing I want to add, is that with my fixed back Recaro Pole Positions ... the lap part of the belt will not work as intended due to the high lower bolsters.

J

LainfordExpress
LainfordExpress Reader
4/11/13 6:57 p.m.
Slippery wrote: The only thing I want to add, is that with my fixed back Recaro Pole Positions ... the lap part of the belt will not work as intended due to the high lower bolsters. J

Agree on the bolster issue. I'm thinking of getting a lap belt, like a race style, and just use both.

Apexcarver
Apexcarver PowerDork
4/11/13 6:57 p.m.
LainfordExpress wrote: OE seats have airbags. I thought thought the law was that the airbags had to be able to be deactivated... maybe just the passenger seat?

newer than sept 1st 2006 has advanced airbags that limit deployment if someone under a certain weight are in the seats. (theres other stuff, but thats the gist)

Shops have to be registered with the government to install non-original deactivation switches. Even then, they can only do it for handicapped people. Now, this only applies if you are doing it as a business, if you DIY your not in any trouble.

Removing airbags? yeah, it makes it less safe, but if your comfortable with that compromise for the weight reduction, nothing is stopping you. Its not an instant death, its just more susceptible to being injured.

Your probably not going to be able to shut off the airbag warning light on the dash though and it may disable the whole system.

mazdeuce
mazdeuce Dork
4/11/13 7:44 p.m.

If you have seat mounted airbags then that changes the game a bit. Unless you know that you can disable the one bag without messing up the deployment of the rest of them then I probably wouldn't do it. The steering wheel bag is a pretty important part of the system that keeps you safe with a three point belt. I'm not sure about your car, but on my 2 there is also a seat position sensor that tells the computer how close you are and changes how the airbags fire.
I think we're entering an era or keep it stock or go all the way to a cage.

wbjones
wbjones UberDork
4/11/13 8:01 p.m.

I drive my Kirkey seated CRX to and from events ( not very comfortable) ... has 6 pt harness ..but I use the OEM 3 pt while driving to and from .... the only concerns I have is that the seat back doesn't reach high enough to keep my head from bouncing off the roll bar in the event of a crash ... working on a solution

yamaha
yamaha UltraDork
4/11/13 8:31 p.m.

The ti has generic sparcos iirc, with the amount of things removed from that car(it'll get a cage after its challenge days are over) I will be safer with a 5 point harness and no rollbar than I would be with the stock seats and belts....airbags were removed(along with about everything else) prior to my purchase. Oddly enough, I remember the fixed back seats being rather comfortable before.

mazdeuce
mazdeuce Dork
4/11/13 8:42 p.m.

Edit: Double post an hour apart. Weird.

codrus
codrus Reader
4/11/13 10:11 p.m.
Slippery wrote: The only thing I want to add, is that with my fixed back Recaro Pole Positions ... the lap part of the belt will not work as intended due to the high lower bolsters. J

FWIW, the Recaro Pole Positions that I have in my Miata work fine with the stock lap part of the belt running over the bolster.

motomoron
motomoron Dork
4/12/13 1:27 a.m.

I'm using Cobra Suzuka GTs w/ Schroth Profi II HANS 6 point beltsn and a back half cage in the e36 M3. I'm using it because it's safer if I ever have "The Big One", like getting something really wrong near the top of the climbing esses at VIR, or a bad, bad crash in T4 or T10 at Summit.

The bar is a foot behind the top of the seats, which are fixed mounted on VAC brackets.

I've sat in 'em for a truly hateful 7 hour plus drive home to DC from NJMP and I was genuinely uncomfortable, but if you're stout of back and knee, it's livable.

Claff
Claff Reader
4/12/13 2:40 a.m.

I know I'm spoiled by Miata simplicity but I can have the stock seat out and the Kirkey in in about three minutes. It's a no-brainer to put the stocker in for during-the-week duty. Something to consider for this STF car being discussed?

kanaric
kanaric New Reader
4/12/13 6:50 a.m.

I know someone who had their face broken by airbags because he sat too close to the steering wheel in a minor accident, lol. Idk where your racing seat position is set but I would turn them off regardless if you are not sitting reclined.

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