Gents,
Has anyone successfully modified the 993 sport seats to properly accomadate the shoulder straps of a 4 point harness?

As RECARO is the manufacturer, I would suspect there is provisions internally (structual) for the shoulder harness.

Of course the modification would have to be asthetically pleasing and only be done if structually possible. i.e. An upostery shop could properly cut out the area & add the plastic openings as in the SRD seats for example.

Any feed back would be appreciated.

Thanks!

 

i use five point harnesses with the sport seats just fine without modificatoin. The only thing you need is a harness bar and you shouldn't have any problem with it.

 

I use six point harnesses with a harness guide bar. I agree that it would be nice to be able to put the shoulder harnesses through the seat backs, but an equally if not more important issue is the anti-sub belt, which really should go through the seat cushion.

Richard

 

Stuttgart:
Please elaborate--how do you keep the harnesses in the right position across the shoulders? Do you, for example, make an X (left rear belt to right front latch) with the belts?

I think Brey Krause makes a seat frame add-on that permits the mounting of the sub belt?? I know one exists of the 996 seats. Anyone have other options?

 

I think the thing that helps is the fact that the sabelt harness has a 1 ft peice of webing that attaches the two shoulder belts right behind the seat.

I guess you could make the same thing by getting some webbing and buckles.

I think the sub-belt is important too. We attached ours to the bar underneith the seat(993TT). The sub belt keeps the shoulder straps tight.
Obviously by using it this way it does not actually keep you from "submarining", but i don't think this is a real issue as long as the seat back is relatively straight up and down, and the lap belt is tight. Some say that attaching to the bar under the seat is not strong enough, but in a wreck it isn't goin to have much force on it. (unless you flip )

 

Stuttgart,
You are making a lot of assumptions that could really put you endanger in a serious accident. I see you live in Atlanta so my guess is you go to Road Atlanta. You could be up to 150mph or more and over 100 in several places with very hard concrete walls nearby. If I ran there primarily I would be very concerned about what restraint system I had in my car.

IMO, and this has been discussed many times before you should either, stay with the stock set up (3pts, stock seats, airbags, etc) or go to a full race set up (roll bar or cage, proper seats, 6 pt harnesses, etc) Anything in between and you are IMO less than safe.

I guess my real problem with what you have said is that you profess that what you have done is ok safety wise. If you want to run that set up that is great just don't pretend that it is fine.

 

this is my opinion, in no may do i believe i'm an expert. I apologize if it came across that way
Also i didn't really expain the set up very well.

I do believe this is safer than stock, although not as safe as a true six point through the seat.

what specifically do you believe is not safe b/c i am interested.

I guess you are refering to the sub belt. But i don't,with all due respect, see how this is less safe than stock. the 5 point with tight lap belts and tight shoulder belts does the same as the stock three point, and the sub belt keeps the lap belt from being pulled upward in a wreck.

I do on the other hand agree that a four point harness is less than safe, b/c if you get in a wreck the lap belt is pulled upwardby the shoulder belts allowing you to submarine, where as stock three point cinches the lap belt tight in a wreck.

again a disclaimer: my opinion

 

[quote]Originally posted by Stuttgart:
<strong>this is my opinion, in no may do i believe i'm an expert. I apologize if it came across that way
Also i didn't really expain the set up very well.

I do believe this is safer than stock, although not as safe as a true six point through the seat.

what specifically do you believe is not safe b/c i am interested.

I guess you are refering to the sub belt. But i don't,with all due respect, see how this is less safe than stock. the 5 point with tight lap belts and tight shoulder belts does the same as the stock three point, and the sub belt keeps the lap belt from being pulled upward in a wreck.

I do on the other hand agree that a four point harness is less than safe, b/c if you get in a wreck the lap belt is pulled upwardby the shoulder belts allowing you to submarine, where as stock three point cinches the lap belt tight in a wreck.

again a disclaimer: my opinion</strong><hr></blockquote>

I think that Greg's point is that if you use 3 point belts and roll over and the roof collapses, then you can still maneuver out the side.

If you have a 6 point belt and a harness bar and rollover, you head will be holding up the car ( most likely, although very badly. )

If you have a roll cage and 6 point belts, then the roof won't collapse so you can safely stay buckled in your seats.

Jeff

 

Stuttgart,
My post wasn't meant to be a flame, I hope you didn't take it that way.

I hope you have your shoulder belts mounted to the rear seat belt mounting points and not wrapped around the harness bar. If you have a harness truss (better since it shortens the belts) then that is fine.

You have the cross strap that helps keep the belts from sliding off your shoulders, that is good. I guess the sub strap is the thing I have the biggest issue with. In a serious accident you will slide forward and if the sub belt mount fails and maybe even if it doesn't the lap belt may ride up and hit you in the soft mid section vs. the hard pelvic bone. Results would be serious, possible fatal injuries.

Mark had a link to a story/study a very educated guy did regarding sub belt placement, etc. If he would re-post that it would be great.

My reasoning as to why your stock seats, belts etc are better than an in between set up is that your stock set up has been tested and designed in some of the best engineering facilities in the world.
Your five point with harness bar and stock seat, were they ever tested?
I can attest having been in two DE accidents (neither while driving only instructing/riding) that your set up will work in a side impact into a relatively soft tire wall at 30-40 mph. How would it have faired in a straight ahead frontal impact? I have no clue, glad I didn't find out.

I do know that since then I don't wear harnesses unless it is a proper set up and I do check mounting points etc before I hop in anyones car.

A 100mph+ accident is a life threating event. Thankfully it doesn't happen very often but if you are pushing your car and yourself you owe it to your family to do your homework on safety equipment and set up.

 

[quote]Originally posted by Jeff 993TT:
<strong>

I think that Greg's point is that if you use 3 point belts and roll over and the roof collapses, then you can still maneuver out the side.

If you have a 6 point belt and a harness bar and rollover, you head will be holding up the car ( most likely, although very badly. )

If you have a roll cage and 6 point belts, then the roof won't collapse so you can safely stay buckled in your seats.

Jeff</strong><hr></blockquote>

Jeff,
That is definetly part of it. My bigger concern personally is having a loss of brakes or a mechanical failure that sends me straight off the track and into something solid.
Not that I have never seen a roll over at a DE or Club Race but compared to other shunts it is fairly rare.

 

I can't find that link, but here are some comments concerns:

First off, I don't buy into the deal about not using 5/6 points without a roll bar. I have had many folks claim that is dangerous yet no one has ever cited an injury from such an accident. It is not the best set up, but you have to decide if the risk of adding to rollover injury exceeds the other safety of the 5/6 points.

The real point is that 5/6 points were developed for racing and the data and testing is with racing seats and cages. Anything less than that and you are gambling that it will work.

In any heavy frontal crash, the sub belt will take some serious forces. In an upright seating position, it mostly serves to keep the lap belt in the right position. In a lay down car, it keeps you from sliding under the belts (Hence my nickname for such cars is "Cup Cars".) Mounting is critical and you should never cut corners on the angles or hardware used. The slightest error can twist a belt in an impact and dump it (we all know what that is after Dale E's death).

Stuttgart, I am not sure what bar you are talking about using under the seat, but if the sub straps are not firmly attached either to the seat bolts or through the floorboard with big washers to spread the load, I think you are at risk. The seat bolts are engineered to take the forces if you are in an accident and are strong. Other parts are not designed to take such loads.

In regard to the H style belts - I agree that those should keep things in place IF the H is close enough to the seat back. There is some debate about what usually happens with the shoulder harnesses in a hit. Some people have been using sternum straps to keep the belts from separating, but I have seen some recent studies that indicate what really happens is that your arms fly forward and actually help keep the shoulder belts together. There have been some neck injuries associated with sternum straps.

Bottom line is that WE are the crash test dummies when it comes to anything that is not stock. There is no way to do enough testing in every config to provide the same kind of data that street cars have or certain race cars.

My choice for the track:
Full cage
Full Nomex Suit
Fire system
Arm restraints
HANS

 

Thanks to EJ for finding the article that Mark and I were referring to.

<a href="http://www.corner-carvers.com/wiki/index.php?Notes%20on%20Race%20Car%20Harnesses" target="_blank">Notes on Race Harnesses</a>

If you don't read the whole thing here is a good paragraph.

"The submarining happened because there was little to stop it. Crotch straps are there for two reasons. Not only do they have a direct effect in preventing sliding underneath the lap belt, they also stabilize the whole system. Unlike the tree-point belts in a passenger car, the buckle of a race harness is in the center. This means as soon as the shoulder belts are loaded, they pull the lap belt upwards and the lower part of the body tries to shoot underneath.

This killed Jochen Rindt, who told me in 1969 that although he had come to accept a harness in the Lotus, he would never wear crotch straps. In his crash at Monza his lap belt ended up near his neck, rupturing his liver on the way. Australian child car seats, which also have central buckles, have crotch straps for exactly the same reason."

 

Greg Fishman is right on the mark. One thing you should also know about is what the belts actually do during a crash. They do NOT act like steel cables, keeping you firmly planted against the seat. They actually stretch a LOT. Several inches, and I recall seeing test footage where it looked more like 4-6 inches plus, but the memory is vague.

They are supposed to do that. The point is that no matter how tight the lap belt is across your hips when you get in the car, it will stretch a lot on impact, and you can and will slide under, doing the nasty things like crushing your mid section.

If I were you, I'd go look at some of the sport seats that have sliders and reclining mechanisms that have been mentioned on this board recently. Sparco makes a nice one. Better bolsters for track driveing, still have easy access to the back seat, and yet has holes and slots for a proper harness installation. One other bonus is that you can put your factory seats in storage, maintaing their pristine condition.

Here is one that I am considering purchasing, though I can't tell from the picture if it has a slot in the cushion for a sub belt:
<a href="http://www.sparcousa.com/pseats_street.asp?id=95" target="_blank">http://www.sparcousa.com/pseats_street.asp?id=95</a>

 

Here is a DYI install for Recaro SRD seats.

<a href="http://www.gagme.com/greg/911/hacks/seats.html" target="_blank">http://www.gagme.com/greg/911/hacks/seats.html</a>

 

[quote]Originally posted by Craig W:
<strong>They actually stretch a LOT. Several inches, and I recall seeing test footage where it looked more like 4-6 inches plus</strong><hr></blockquote>

Someone who used to drive the Subaru factory rally car said that in an ~80 mph crash into a tree, his shoulder belts stretched ~14 inches.