needmoregarage

Just got my 2009 Z06 which I'm outfitting for track days.

Bought some race seats which will bolt onto the OEM rails which allows me to retain electronic adjustment of the seats and steering wheel.

Having trouble finding an anti-submarine bar that works with the OEM rails AND complies with Schroth (6 pt harness) installation recommendations.

Schroth wants the anti-submarine belts to feed through the seat slot and terminate 0 - 20 degrees beneath/behind the slot.

The ONLY anti-sub bar I've found is from Hardbar and it installs at the back end of the seat rails. It bolts onto the rails and has eyelets that allow the anti-sub belts to snap on, and also eyelets for the lap portion of the 6 pt to snap in.

The problem is - this places the termination of the anti-sub belts BEHIND where the manufacturer recommends. It could somewhat affect their function. It's possible I could be rejected from a DE event because my installation is not in accordance with Schroth (if there is a rigorous tech inspection - unlikely I think, but still....)

The only solution seems to be to drill through the floor pan and use backing plates to "sandwich" a bar at the right position beneath the seat so there is a reinforced plate for the termination of the anti-sub belts.

I wanted to avoid drilling holes if possible.

Anyone have a suggestion that might work with my OEM seat rails, and provide a reasonable solution?

(I have searched but not found the answer on the forum. If it's here please point me in the right direction).

RacePro Engineering

Either use the Hardbar piece - it will be fine in any tech inspection on earth - or, simply bolt the sub attachments through the floor with large backing, or fender washers on the outside.

Ed

needmoregarage

Thanks Ed.

trackboss

Get yourself a teamtech jet pilot harness. It it only needs 4 points and is a 6 point belt. Best harness I've ever used.

needmoregarage

Looked at it on Hardbar's site. Wasn't sure about a harness custom made to measurements.

Then hubby would need one for his measurements, and since he sometimes drives (not as much as me but we share) we'd have to snap the belts in/out.

And then...what to do for passenger? since both sides must offer equal restraint. I instruct and sometimes give people rides...

It seemed like a great idea but better if it's for someone who doesn't share the driving. Maybe I miss-judged....

It would be a good solution to the dilemma and I hadn't considered that. Thanks!

RacePro Engineering

Well, as ridiculous as it might sound, NOW we are getting close to things that Tech Inspectors and Scrutineers pay close attention to - not so much for autocross or DE - NOT YET - but certainly for high-speed competition. Unless this jet pilot harness has SFI or FIA approval and dating, or some other sort of official homologation, it will not be allowed for racing, and probably not for time trials.

Please be assured, I do not know anything about these restraints. But, the other factor to consider is ability to use with a HANS, when and if that becomes mandatory for DEs.

Ed

fatbillybob

Unfortunately passing tech does not mean you got a safe set-up. some tech guys are not worth very much. The reason for the scroth recs are because of how a sub belt works. a sub belt controls the action of the lapbelts thus providing an anti-submarine effect. The sub belt does not act directly to prevent submarining. If you use the attachments at the rear you are depending on the seat hole to be a defacto anchor/pivot point to control the lapbelt. That is wrong. The floor of the C5 and C6 I think is fiberglass balsa sandwich and not much better than "thin tin" found in most metal streetcars. If you would not lift your car from this point with your floor jack I would not use it as a sub anchor point. 50g's is a 45mph deltaV crash. That's about 10,000lbs for many average males or 1666lbs per strap, more on some less on others. If you do a simple engineering safety factor of 3 that's 5000lbs per anchor point. Vette is 3200lbs wet so yes jacking from the balsa or tin floor with zero buckling is the beginning of a reasonable place to start for non-engineers. I think you will find this will fail. What I would do instead is build a steel frame that you can sandwich at the 4 seat anchor points that places the sub anchor points in the proper position. If you fail to properly install your substraps bad things can happen. Really a good seat has 2 to 3 submarine holes. How all the hot FIA legal carbon sparcos, omps, etc get a way with one hole is beyond me. At least the hole would be cut trapazoidal to guide belt paths.
When done wrong....
http://www.sciencedirect.com/science...72346106002236

fatbillybob

I believe you are implying anchoring at 4 points but a 6 pt harness "parachute style". While this works from a submarining standpoint it is the weakest way to control submarining and weakest way to control a harness in a rollover when compared to proper 6 pt and 5pt systems. We used to do this for casual trackday cars with stock seats. It is an OK way to start learning about the sport but not a good way for the long haul. One day you will wish you had something else. I never intended to loose a car on track but 4 helmets later (20 years) I've had 2 big crashes. I think its not if but when.

RacePro Engineering

Bob, one needs to consider the very low angle of the bottom of the seat, to the mounting point on the floor IN A CORVETTE. This makes the anti-sub belt attachments mount IN SHEAR, because any pulling force will be more horizontal than vertical. In a sedan or GT, the primary function of the anti-sub belts is to hold down on the pelvis the lap restraints. By design, the lap and shoulder belts are going to see the vast majority of those forces, and that is why most are a 3" web. Even if one gets up-side-down, the shoulder belts do the work, and the anti-subs hold the laps in place.

That having been said, we all do everything reasonable to ensure that NOTHING surrounding the driver comes loose in a crash.

Ed

trackboss

In the last 16 years I have strapped into a variety of harnesses. The jet pilot is by far the most comfortable and secure harness I have tried in my opinion. It is also the only harness I have actually tested in a crash. Furthermore, the 3-2-3 version I have works extremely well with my hans. It would be hard to convince me there is a safer harness. In my corvette I have it mounted to my hardbar rails and I have to say it, as well as the seat (kirkey road race deluxe), are rock solid. If I were building a race car then I would build my own attachment points for the seat rails as fatbillybob has done.
Also, in my case I use snap in attachments so when I I am not at the track I completely remove the lower portion of the harness and tuck away the shoulder harnesses behind the seat so I can use my factory belts. For those sharing it is a very simple swap to have their own lower snap in belts sized properly if there is big diffference in body size and one belt will not work.

Choose whatever works for you. Here is a link to the jet pilot if you want to look it over:

http://www.teamtechmotorsports.com/r.../jetpilot.html

fatbillybob

In principal the science is known about which harness styles are "safer" but in reality drivers have to think safety system not this harness or that harness. I would much rather be in an OEM corvette 3 pt belted system than a poorly executed 6pt harness. It is extremely difficult to out perform and OEM systems for a casual dual use trackcar eventhough you might pass tech for your organization with one's makeshift safety attempts. This is a very hard topic to wrap one's head around and I commend the OP for asking the hard questions.

Bill Dearborn

I use a stock C5 Manual seat track for my passenger side Ultrashield aluminum race seat. I had a local guy (who Ed probably knows from his Porsche days) weld a sub belt bar between the two sides of the track. It is solid and works as intended. The sub bar impacts the floor so I use a couple of spacing washers on the rear seat bolts to lift the bar off the floor.. I also had some lap belt mounts welded to the rear of the tracks where the seat bolts pass through the track. The seat and track are out in my cold shed for the winter but if you would like I can go out and get some pictures showing how it was done.

A couple of things to to think about. The angle of the sub belt to its mounting point and its length change with seat position and the body type (skinny as a rail to so heavy the 17 inch wide seat sides are bulging) of the person sitting in the seat also affects the length of the belt. So if you have multiple drivers/passengers adjusting the seat differently you may not get an optimal set up for everybody. Only one setting will be correct for a specific person. You can't do anything about the angle changing and it is a real PIA to adjust the strap length since the only way to get your hands on the adjusters is to pull the seat out.

My Ultrashield driver's seat is fixed into position on a set of Hardbar rails and after some trial and error I got the sub belt length adjusted for me and I never touch it.

Bill

needmoregarage

Thank you all.

We (husband and I) had a conversation about this today. With the mods to the seat and the harnesses - are we better off with the OEM 3 point belt rather than a less than optimally installed 6 point? We will only use the 6 pt in conjunction with HANS, and generally it will be me driving, and occasionally my husband (he's not as addicted as I am).

I went out of my way to find seats that would work on the OEM rails so I could retain the electronics, not really thinking about the difficulty of finding a proper termination for the anti-sub belts.

I'm thinking once the OEM seats are out of the car - maybe the shop I'm using (they are a performance shop and have extensive experience in this) can figure out a way to sandwich some plates on the floor (bolting through floor pan) or maybe a bracket that can be custom made beneath the seat. The complication may be all the electronics that are under the seat. Those may prevent an easy solution - in which case maybe I have to give up the electronics after all.

I would appreciate photos of your installation Bill Dearborn. No hurry - I'm still receiving parts and don't have an appt with the shop until mid-month. I appreciate the suggestions.

trackboss

You would be surprised how well a good seat holds you in place even with the factory belts. If doing that you need to make sure the lap portion of the belt goes across your lap and not the seat sides. Some race seats have really tall sides and if your legs are small diameter there will be a gap between thelap belt and your legs. With my kirkey the lap belt works great and the seat does not interfere with it in any way. I hate to say it, but I've tested that too.

Bill Dearborn

Will see if I can get some tomorrow or Saturday. Snow is supposed to be flying pretty well tonight so may wait a day.

I know a number of people have put holes in the floor boards with what seems like no issues. However, I wouldn't drill the floor board. It is balsa wood sandwiched between fiberglass or carbon fiber panels depending on whether you have base or Z06/ZR1. They are very strong and stiff as built. The strength of the panel comes from the honey comb structure of the balsa wood and the panels sandwiching the balsa wood protect it. If you put holes in them you break the seal and moisture/water can get inside. Balsa wood and water do not get along well.

Bill

hapnermw

Use the JetPilot and Hardbar bracket. I have two and they have fit every instructor from large guys to small women with no issue. Teamtech provides a wide range of adjustment around the base measurements. Tell them what you need and they will make it. There is no comparison between using this harness and the stock belts.

Bill Dearborn

If you do this, don't use the Hardbar harness bar. It rides too high. Use the Sharkbar instead.

Bill

needmoregarage

I found what I think is Sharkbar for a 5 pt harness, and one for lap belt attachment, but I don't see anything for a 6 point harness.
Both found here:
http://speeddirect.com/index.aspx?nodeID=127

Is this what you mean?
If so - looks like I'd have to use the 5 pt harness bar and modify it so I could attach both anti-sub belts.

Bill Dearborn

I was referring to the harness bar Vs the lap and sub attachments. The Hardbar harness bar mounts between the OEM shoulder belt mounts and is too high for proper mounting of the harness shoulder belts. Here is a link to the Sharkbar info:
http://www.vetteworksonline.com/ that web page you referenced is broken. Give them a call and talk to the owner. He customized the bar for my application and gave me a better deal than the price on the web page.

Here are a bunch of pictures I took this morning of my Ultrashield seat mounted on C5 (C6 is basically the same) Manual seat track.




















You can see the sub belt mount is very solid and right where it needs to be when the seat is all the way back.

The pictures of the lap belt mounts don't show how they wrap around the end of the track thus rounding into a partial cylindrical shape which makes them quite strong. The shoulder bolts used to fasten the lap belts to the mounts are from Porsche. The guy who did this modifies Porsche's for racing and track days.

Hope this helps. I can get better pictures in a couple of months when I pull the trailer out of the shed to get ready for my first track days at the end of April.

Bill

needmoregarage

Bill - THANK YOU!!

Very helpful - great pics! I appreciate your time and effort in the ^^^ post!

In the mean time I've been looking at the jetpilot harness which does seem to solve the problem. Wondering what folks with the jetpilot do for the passenger seat. Since they are made to measurement we are figuring we'll have one made for each of us (since they are so easy to switch back & forth) and our passenger must fit in order to ride.