Re: SPARCO sprint*
(Orginaly posted by Moti (blackbird) on miataforum.com)
Choosing a racing seat -
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First thing to check is crash rating.
Very simple, an FIA approved seat must withstand a 15g crash to get the approval.
15g is a bad joke pretty much, as any POS almost can withstand a 15g crash and AFAIK most track accidents are averaging 25-30g's.
Some companies will advertize the actual crash rating of a seat, like my Cobra that are rating my Evolution at 42g.
Sparco, for example, are on the other side of the map, just advertizing that their seats are FIA approved, which as I mentioned, is as good as nothing.
They do make good competition seats that are widely used in professional motorsports, but those are ~$2k a piece and made of CF, the common seats from Sparco that you see out there - Sprint (tubular steel), Rev (fiberglass) and Corsa (fiberglass too, CF version is used in WRC cars) aren't the competition ones...
Material choice is very important too -
The best seats are normally made of CF or Kevlar or both, those are the strongest ones and normally carry a higher price tag.
I specifically like Cobra because they make good Kevlar seats, adviertize the actual crash rating and have relatively good prices for them, my seat, which is a full competition seat made of Kevlar, was only ~$1050 with the side mount brackets (~$170 for the brackets).
Next in the chain comes fiberglass, which is not all bad, but known to crash - literally break in pieces, in medium to high G impacts.
Next would come the tubular steel seats, those are something I will not recommend to anyone who really care for their safety and intend to do any type of DE event in their life, that kind of seat barely passes the rules for FIA rating and well known to bend in an impact... dunno about you but I'd really hate steel tubes bending on me if anything happens, I consider it to be a no no.
Aluminum seats aren't FIA rated and I personally find it to be a problem when you can bend the seat yourself, doesn't even take a real impact ... I know a lot of miata guys use them but all the ones I ever set in were just really uncomfortable.. it is a no no in my book as well.
Next, you want to make sure you fit in the seat well -
Have a seat, try it out, move in it, if you can move side to side, the seat is to big for you, a racing seat should have a snug fit to your body.
Seat your butt all the way into the seat - do you have enough support for your thighs? is the cushion you're sitting on comfortable? most manufacturers do offer extra cushions for more support, though obviously, the less cushions you use and more comfortable you are the better it is, you'll get more feedback from your car through the seat.
For a seat with shoulder "wings" (which is highly recommend for those high G corners), how does your body fit between the wings? are your shoulders free to move around? is it tight? does it make you arch your shoulders and upper back?
Weird as it may sound, the correct fit is pretty tight, tight to the point that it makes youarch your shoulders and upper back, and why is that -
When you're turning the steering wheel, one of your arms stretches a bit forward as it moves away with the wheel, making your shoulder span a bit narrower, if the seat fits you fine when you're sitting with your arms straight forward, now your shoulders are actually becoming narrower and you start moving in your seat because of the lack of support for your narrower shoulders.
This is important since you're buying the racing seat to support your body, right?
Other side supports are obviously important too, thigh support is normally offered in a much better way than any stock seat offers, but make sure it isn't too wide or you start moving in your seat again.
head rest should be at least at the height of the middle of your head or taller, with helmet or without.
Harness slots are very important - where are they located in relationship to your body? are they at the height of your shoulders? slightly higher? this is good.
Are they slightly lower? the location of your harness bar will determine if the seat is useable for you or not - the harness should be as horizontal as possible, if the harness bar is considerably lower than your shoulders and the harness slots are considerably lower you're in an unsafe situation where your body will not be supported properly in case of an impact, it will actually move in the direction that your harnesses will "want" to stretch to.
If the harness slots are much lower than your shoulders the seat is not for you, period.
Reclining seats aren't racing seats, if anyone has one of those in mind go ahead and post it in the show car section.
Leather? well, it looks cool but as you said, it really isn't the best material for a racing seat... you don't see many leather seats in race cars do you ?
Alcantara looks good too and is much grippier, you do see those in racing seats sometimes.
Also note if there are any tough material patches in high wear areas, keep that seat looking good for longer time .
Last but definitely not least - are you comfortable?
Remember that a good racing seat, even though it should have a pretty snug fit should be comfortable.
Seat mounts -
The best mounts as far as safety goes are fixed side mounts, non adjustable, no sliders. You set the angle that you wish to sit in and bolt it to the floor (normally to secondary brackets and than to the floor).
This is also the best way to get those extra inches need for a broomstick test for the ones here that might be thinking about track driving.
Sliders are sometimes required for cars with multiple drivers with different dimensions.
I am not sure if bolting a side mount seat to sliders is even possible, you might be stuck with the normal mounts at the bottom in this case... I would suggest to avoid using sliders if possible.
No matter which one of the two methods you're using, make sure you're using high grade fasteners, I used for my seat 12.9 grade bolts to connect the seat itself to the side mounts and also to connect the side mounts to the steel brackets that are bolted to the floor (you'll make this brakcets to adapt between the side mounts and the stock mounting holes and also to set your position of driving), than I used the OEM bolts to connect the steel brackets to the original mounting holes.
The OEM bolts that hold the seat down are high grade and I recommend re-using them, the 12.9 grade bolts I used are probably a bit of an overkill, so I must have spent $4.00 more on buying them... call me a reckless spender , I would hate to snap bolts in an impact.
I would also recommend using the original mounting holes if possible, those are the strongest points that you can attach the seat to before doing a serious modification, if you must use the floor (say because you're really tall and need the seat all the way back while using side mounts) make sure you have some good size backing plates on the underside.
I may have forgotten a few more things so if someone jumps in a post them that'll be great, this covers the most of it though.
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The good and the bad -
Good racing seat don't carry $200-300 price tags, it just doesn't exist.
Since you don't have spare parts for yourself save the extra $200-300 and buy a good seat.
The good is that you'll be much safer and far more comfortable, well worth those couple hundreds extra.
post pics!
