5 point harness with stock seats?
10-23-2002, 07:54 PM
#16
I purchased a Deist 5-point (that is actually a 6-point) harness set; but I only use 4-points (i.e., over both shoulders and across my lap), with my Porsche sport seats WITH NO PROBLEMS AT ALL!
With factory seats, the "6-point" (or "sub" belt) is not effective for anti-sub movement (unless you modify the seat and run the bottom belt up from the floor through a slot in the middle of the seat cushion), but can be useful in one important respect, namely keeping the cam ("quick release" where the belts click in) in the vicinity of your navel, so it doesn't "ride up" your chest. The "male" portion of the "5th" belt is at the top of an inverted "V", the two bottom parts of the "V" are fastened under your seat rails.
As indicted above, I do not use (and haven't insatlled) the 5th point in my car. I have a Brey-Krause harness bar which keeps my shoulder harnesses from sliding left & right (as you know, there are guides on that bar that the shoulder belts go through on their way to the front seat). After a dozen+ DE events I have NEVER experienced either shoulder harness slipping off my shoulders. Nor, have I had the cam slide up my chest (although it does travel 3 or 4 inches above my navel).
What I do, and it seems to work for me at least, is I plug everything into the cam. I then begin tightening the lap belts first. Then I tighten the shoulder harnesses. I continue the process, tightening the lap belts again, then the shoulders. A good rule of thumb is to tighten the belts until it feels like you can't tighten any more, take a deep breath AND THEN TIGHTEN AGAIN!
In any event, the 4-point set-up has kept me firmly plugged into my sport seat (e.g., I don't feel like I'm holding onto the steering wheel to stay put), and I guess if you add the bottom belt to the equation, just to keep the cam around your navel, you'll do fine with your stock seats.
Eventully, I may go with "track" seats, but I certainly don't feel compelled to do so for DE. Racing, as mentioned by Bill G., is a different story, and some organizational rules may require the "anti-sub" belt. Plus, with a racing seat you can utilize a HANS unit to protect against breaking your neck, which isn't feasible with stock seats.
Good luck & have much fun.
Richard
'87 Carrera-3.6L
With factory seats, the "6-point" (or "sub" belt) is not effective for anti-sub movement (unless you modify the seat and run the bottom belt up from the floor through a slot in the middle of the seat cushion), but can be useful in one important respect, namely keeping the cam ("quick release" where the belts click in) in the vicinity of your navel, so it doesn't "ride up" your chest. The "male" portion of the "5th" belt is at the top of an inverted "V", the two bottom parts of the "V" are fastened under your seat rails.
As indicted above, I do not use (and haven't insatlled) the 5th point in my car. I have a Brey-Krause harness bar which keeps my shoulder harnesses from sliding left & right (as you know, there are guides on that bar that the shoulder belts go through on their way to the front seat). After a dozen+ DE events I have NEVER experienced either shoulder harness slipping off my shoulders. Nor, have I had the cam slide up my chest (although it does travel 3 or 4 inches above my navel).
What I do, and it seems to work for me at least, is I plug everything into the cam. I then begin tightening the lap belts first. Then I tighten the shoulder harnesses. I continue the process, tightening the lap belts again, then the shoulders. A good rule of thumb is to tighten the belts until it feels like you can't tighten any more, take a deep breath AND THEN TIGHTEN AGAIN!
In any event, the 4-point set-up has kept me firmly plugged into my sport seat (e.g., I don't feel like I'm holding onto the steering wheel to stay put), and I guess if you add the bottom belt to the equation, just to keep the cam around your navel, you'll do fine with your stock seats.
Eventully, I may go with "track" seats, but I certainly don't feel compelled to do so for DE. Racing, as mentioned by Bill G., is a different story, and some organizational rules may require the "anti-sub" belt. Plus, with a racing seat you can utilize a HANS unit to protect against breaking your neck, which isn't feasible with stock seats.
Good luck & have much fun.
Richard
'87 Carrera-3.6L
10-23-2002, 09:05 PM
#17
Instructor
Thread Starter
Wil (or others),
If I understand correctly, you are running stock seats with 5 point harnesses (or 6?). Where is your sub belt(s) mounted? Do you have a picture of your setup?
There is clearly a wide variety of opinions on the topic.
Thanks,
If I understand correctly, you are running stock seats with 5 point harnesses (or 6?). Where is your sub belt(s) mounted? Do you have a picture of your setup?
There is clearly a wide variety of opinions on the topic.
Thanks,
10-24-2002, 12:14 PM
#18
Technical Specialist
Rennlist
Lifetime Member
Rennlist
Lifetime Member
First, I'll say that I'm co-safety track chair in our PCA region. I feel strongly about track safety. Forget about the cars, we're talking people - you!
I'd suggest that some are fooling themselves to think that harnesses with stock seats (with a harness or roll bar with guides), or using a 4 point harness, will adequately protect them in a major collision or rollover at the track. There's a reason why PCA Club Racing rules say: "All cars are required to have a dedicated race seat with routing for straps" as well as "Five or six point 3" competition harnesses (with 2" sub belt), properly mounted, are required".
A harness with stock seat will keep you in place better than the 3-way belts, however, on some people, the straps can slip on the shoulder while driving, and in a rollover harness straps sliding up the seat is a real safety concern.
If you want to use harnesses, you should expect to make, at a minimum, the investment for the proper seats to support them. As an aside, you then have the ability to install cloth seats, that go a long way to help hold you in place. There are also some fine leather seats availble too.
FWIW, when I first put harnesses/seat in, I also put a rollbar in, figuring that the harness/seat combination would allow me to get closer to both the 911's and my 'edge of the envelope', making any collision or rollover more intense (thankfully I haven't tested that assumption).
I'd suggest that some are fooling themselves to think that harnesses with stock seats (with a harness or roll bar with guides), or using a 4 point harness, will adequately protect them in a major collision or rollover at the track. There's a reason why PCA Club Racing rules say: "All cars are required to have a dedicated race seat with routing for straps" as well as "Five or six point 3" competition harnesses (with 2" sub belt), properly mounted, are required".
A harness with stock seat will keep you in place better than the 3-way belts, however, on some people, the straps can slip on the shoulder while driving, and in a rollover harness straps sliding up the seat is a real safety concern.
If you want to use harnesses, you should expect to make, at a minimum, the investment for the proper seats to support them. As an aside, you then have the ability to install cloth seats, that go a long way to help hold you in place. There are also some fine leather seats availble too.
FWIW, when I first put harnesses/seat in, I also put a rollbar in, figuring that the harness/seat combination would allow me to get closer to both the 911's and my 'edge of the envelope', making any collision or rollover more intense (thankfully I haven't tested that assumption).
10-25-2002, 03:15 AM
#19
<a href="http://www.corner-carvers.com/wiki/index.php?Notes%20on%20Race%20Car%20Harnesses" target="_blank">Note on race car harnesses</a>
Check out the above
There is a pretty extensive discussion currently on the 993 forum re: someone wanting to modify the stock seats to use race harnesses. The above URL has convinced me to either keep the stock belts/seats or upgrade to harnesses/race seats, and not make a halfway compromise on safety...my $0.02
Check out the above
There is a pretty extensive discussion currently on the 993 forum re: someone wanting to modify the stock seats to use race harnesses. The above URL has convinced me to either keep the stock belts/seats or upgrade to harnesses/race seats, and not make a halfway compromise on safety...my $0.02
10-25-2002, 12:29 PM
#20
Hi:
Some answers to questions since my last post.
1.) I still stand behind my strong vote for 5 or 6 point ( vs 4 point) belts. Richard Glickel properly says the purpose of the 5th or 6th strap is to locate the lap belts near your naval ( I like to say near your "natural pivot point"...your hip), and then curiously admits that the lap belts ride up 3-4 inches "above" ( my emphasis) his naval... when all is snugged-up. Let me tell you ...crash forces are UNBELIEVABLE compared to what is "snug" keeping you from flopping around in spirited driving. If you use shoulder harnesses, you MUST use some way to keep the lap belts from riding up and possibly damageing soft-tissue organs in an accident. God..I can't believe that this point is even being debated !!! Other points have "some" room for discusion, but this.. ???
2.) As to how to mount a 5th belt for a compromise factory seat...I mounted mine one of two ways on various cars. I had a 1.5" x 1" x 1/8 ( or 3/16?") angle fabricated, located between the front two seat mounting bolts, and had some theoretical load tests applied that predicted it would take over 1000 lbs of centrally-applied force to start bending the angle..and over 6000-8000 lbs force required to bend it fully one inch upwards...the limit I set for myself in keeping the low lap belt in place. ( FYI...normal lap belts require pull-through tests of, I believe, 3000-5000 lbs). Used a loop attachment hardware...this for a 5th belt. Alternatively, the 84-85 Carrera's ( but oddly not the 87 or possibly later Carrera's) have a stout , inverted "C" cross member under the seat that holds the power seat motors in place. ( The 87+ look weaker). Similar attachment as for the angle iron , and has the added benefit of constant belt length ( after adjustment) if you move the seat back and forth. Some people sell a flat stock bar that mounts the same way across the seat between the front two seat mounting bolts, but the thickness is in the wrong direction ( horizontal) for strength.
Although I'm not as strongly against a factory seat as Bill Gregory is...as a minimum, I would REQUIRE the use of welded-in belt loops on the roll bar's cross bar...and the use of a roll bar ( DAS) when using 5 or 6 point. Cris-crossing the shoulder belts behind the seat would also not be a bad idea...
--Wil Ferch
Some answers to questions since my last post.
1.) I still stand behind my strong vote for 5 or 6 point ( vs 4 point) belts. Richard Glickel properly says the purpose of the 5th or 6th strap is to locate the lap belts near your naval ( I like to say near your "natural pivot point"...your hip), and then curiously admits that the lap belts ride up 3-4 inches "above" ( my emphasis) his naval... when all is snugged-up. Let me tell you ...crash forces are UNBELIEVABLE compared to what is "snug" keeping you from flopping around in spirited driving. If you use shoulder harnesses, you MUST use some way to keep the lap belts from riding up and possibly damageing soft-tissue organs in an accident. God..I can't believe that this point is even being debated !!! Other points have "some" room for discusion, but this.. ???
2.) As to how to mount a 5th belt for a compromise factory seat...I mounted mine one of two ways on various cars. I had a 1.5" x 1" x 1/8 ( or 3/16?") angle fabricated, located between the front two seat mounting bolts, and had some theoretical load tests applied that predicted it would take over 1000 lbs of centrally-applied force to start bending the angle..and over 6000-8000 lbs force required to bend it fully one inch upwards...the limit I set for myself in keeping the low lap belt in place. ( FYI...normal lap belts require pull-through tests of, I believe, 3000-5000 lbs). Used a loop attachment hardware...this for a 5th belt. Alternatively, the 84-85 Carrera's ( but oddly not the 87 or possibly later Carrera's) have a stout , inverted "C" cross member under the seat that holds the power seat motors in place. ( The 87+ look weaker). Similar attachment as for the angle iron , and has the added benefit of constant belt length ( after adjustment) if you move the seat back and forth. Some people sell a flat stock bar that mounts the same way across the seat between the front two seat mounting bolts, but the thickness is in the wrong direction ( horizontal) for strength.
Although I'm not as strongly against a factory seat as Bill Gregory is...as a minimum, I would REQUIRE the use of welded-in belt loops on the roll bar's cross bar...and the use of a roll bar ( DAS) when using 5 or 6 point. Cris-crossing the shoulder belts behind the seat would also not be a bad idea...
--Wil Ferch
10-25-2002, 07:12 PM
#21
Instructor
Thread Starter
Well, I have to agree that a "compromise" appears to be a potentially dangerous option. I am now shopping for a pair of SRD's with shoulder openings and sub-belt opening. They look good, are reasonably comfortable, and will work well for track and street. I plan to retain my stock belts for the street. If anyone can recommend a good source, or has some for sale, please let me know.
Thanks for all your input.
Thanks for all your input.
10-25-2002, 07:29 PM
#22
Technical Specialist
Rennlist
Lifetime Member
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[quote]<strong>I am now shopping for a pair of SRD's with shoulder openings and sub-belt opening. </strong><hr></blockquote>
I've had SRD's in both my 911SC and my C2. For my bod, they are quite comfortable for daily driving and long distance, excellent support at the track, and, of course, have the optional sub belt hole.
Unless you want black with a white RECARO logo, most places have to order them for you. There's no extra charge for their basic fabrics and logo stitching in the color you want. My 911SC had beige seats and beige RECARO logo. On my C2, I have navy seats with a navy logo. I know someone else with a red 944 black interior that's ordering black seats with a red logo. So you can do some customization to fit your tastes, and it doesn't cost any more! The sub belt hole does, however, cost like $50.
Definitely call around and check prices. One place here in the Northeast that sells alot of Recaro seats charges around $625+ for the seat with sub hole. I found another place nearby that sells them, with sub hole, for around $540. I'd tell you to contact them, but they are limited to selling regionally, which doesn't help you in Atlanta. For anyone in the Northeast, they are Greenfield Imported Car Parts in Greenfield, Mass. 413-774-2819 (no 800 #). They advertise in Excellence. Good people, no personal affiliation.
I've had SRD's in both my 911SC and my C2. For my bod, they are quite comfortable for daily driving and long distance, excellent support at the track, and, of course, have the optional sub belt hole.
Unless you want black with a white RECARO logo, most places have to order them for you. There's no extra charge for their basic fabrics and logo stitching in the color you want. My 911SC had beige seats and beige RECARO logo. On my C2, I have navy seats with a navy logo. I know someone else with a red 944 black interior that's ordering black seats with a red logo. So you can do some customization to fit your tastes, and it doesn't cost any more! The sub belt hole does, however, cost like $50.
Definitely call around and check prices. One place here in the Northeast that sells alot of Recaro seats charges around $625+ for the seat with sub hole. I found another place nearby that sells them, with sub hole, for around $540. I'd tell you to contact them, but they are limited to selling regionally, which doesn't help you in Atlanta. For anyone in the Northeast, they are Greenfield Imported Car Parts in Greenfield, Mass. 413-774-2819 (no 800 #). They advertise in Excellence. Good people, no personal affiliation.
10-28-2002, 10:20 AM
#23
There are number of unbelievably dangerous misconceptions running though this thread and a couple good comments that weren't taken far enough. The Voices of Reason here seem to be Wil Ferch and Bill Gregory.
Seat belts or harnesses are big rubber bands used to slow the body in a somewhat controlled manner while the car they are attached to has already stopped moving. We are talking about making G loadings over 50 Gs survivable. (the smaller you are the more Gs you can take) 50 Gs works out to 10,000 pounds on a 200 lb person. Under these kinds of loads your belts will stretch over a foot.
The first big misconception that will put you in a hospital in a low speed crash is... "The sub strap is there to keep you from submarining the lap belt." It is there to keep the lapbelt in position over your pelvic bone while the shoulder belts try to pull them upward. Look at a stock belt. It never will ride up over the top "points" of your pelvic bone. That is where it can grab your lower bodies weight and decelerate it. If the belt slides even slightly over the pelvic bone, your body will use your kidneys as a cushion for the belt. This will put you in the hospital at an unbelievably low speed.
Think about it this way. Take a baseball bat and give it to someone and have them take a swing at your middle. If the bat connects with your pelvic bones on each side what is the outcome? As the bat connects, the force of the blow is distributed to the surrounding body by the bone's solid structure. The soft tissue in the middle is protected from being crushed by the bones of the pelvis on each side. It will hurt really bad and if the blow is really hard you might break your pelvis. Now imagine that the bat is hitting you a couple inches higher, above your pelvis. As the bat swings into the soft tissue in your middle, the only way the organs can absorb energy is by moving out of the way. The abdominal muscles will take some of the blow but not much. The only solid structure inside you at this point is your spine and it is headed in that direction. Small problem though, your kidneys are the first semi solid structures behind the abdominal muscles. The kidneys are solid because they are full of uncompressible fluid but its surface is stiff, unlike a flexible water balloon. They will absorb a little bit of energy as they burst. These are just the highlights. There are lots of other things in there that don't like to be smacked. I would be amazed if you didn't end up on a dialysis machine if you were in a 25mph head-on collision with your belts pulled up around you middle.
If you are driving around with a 4-point harness you are living in a safety fantasy. There is no safety organization that will allow this. No car manufacturer will allow this. A stock 3-point harness is MUCH safer. Lets see what you have. You have your body strapped to the seat so that you are well supported against cornering loads, which is great. If you don't have to support your body position by holding onto the steering wheel you can be much more sensitive in your steering inputs. You have nice big cool belts to show your friends, which is fun, but it does nothing for the car. You also have a lapbelt that won't stay down, hooked over your pelvis. Even if the belt starts out in the right place the shoulder harnesses will be pulling up with considerable force and the lapbelt WILL end up around your middle. Under a "light" 5 G hit, a 200 pound man will find his lapbelt pulled upwards with over 250 pounds of force. (assuming that at least 1/4 of the force is absorbed by the shoulder harnesses). To the people that say "I've been running this for years and it works fine." I would like to point out that you haven't tried this while running into a wall a 30 miles an hour. This is the difference between getting out and cussing (if your belts are correctly installed and adjusted) or waiting for an ambulance to come pick you up and possibly dying.
If you wear a 5-point harness look at where your lapbelt rides on you. If your sub strap doesn't pull the belt down into the correct position then it is too loose or the sub-strap is misplaced. You could enjoy all the comforts listed for the 4-point harness. The sub-strap should be positioned so it is in a direct line with your body angle. If you run a yardstick down your stomach, where the yardstick hits the floor is where the sub-strap should attach.
A 6-point harness as mentioned by Alan Herod is to keep someone driving in a reclining position from actually "submarining" the belts. They are intended for formula cars but if you want to go through the hassle they will work fine, but mounting them correctly is a problem. If you run them through the single bottom hole of a normal race seat they act as a single strap and should be attached like a 5-point's sub-strap. They are actually designed so that they should be mounted so that each strap goes on each side of "the naughty bits" so it will rest at the juncture of your hamstrings tendon and the pelvic bone. They are then mounted rearward so they act like a "hammock" to distribute the loads of the lower body that the seat cushion would take in a normal car. Once again its biggest job is to pull the lapbelt down.
A little note on H style shoulder belts. They are designed to be used with racing seats only. A stock seat has a very real possibility of coming apart under the loads of a rear end collision. If it folds backwards, which is what it wants to do, the H strap will stop your rearward movement as it catches on your neck and breaks it. The H strap is only there to keep the belts neat.
Think safety, then speed...
Wayne
Seat belts or harnesses are big rubber bands used to slow the body in a somewhat controlled manner while the car they are attached to has already stopped moving. We are talking about making G loadings over 50 Gs survivable. (the smaller you are the more Gs you can take) 50 Gs works out to 10,000 pounds on a 200 lb person. Under these kinds of loads your belts will stretch over a foot.
The first big misconception that will put you in a hospital in a low speed crash is... "The sub strap is there to keep you from submarining the lap belt." It is there to keep the lapbelt in position over your pelvic bone while the shoulder belts try to pull them upward. Look at a stock belt. It never will ride up over the top "points" of your pelvic bone. That is where it can grab your lower bodies weight and decelerate it. If the belt slides even slightly over the pelvic bone, your body will use your kidneys as a cushion for the belt. This will put you in the hospital at an unbelievably low speed.
Think about it this way. Take a baseball bat and give it to someone and have them take a swing at your middle. If the bat connects with your pelvic bones on each side what is the outcome? As the bat connects, the force of the blow is distributed to the surrounding body by the bone's solid structure. The soft tissue in the middle is protected from being crushed by the bones of the pelvis on each side. It will hurt really bad and if the blow is really hard you might break your pelvis. Now imagine that the bat is hitting you a couple inches higher, above your pelvis. As the bat swings into the soft tissue in your middle, the only way the organs can absorb energy is by moving out of the way. The abdominal muscles will take some of the blow but not much. The only solid structure inside you at this point is your spine and it is headed in that direction. Small problem though, your kidneys are the first semi solid structures behind the abdominal muscles. The kidneys are solid because they are full of uncompressible fluid but its surface is stiff, unlike a flexible water balloon. They will absorb a little bit of energy as they burst. These are just the highlights. There are lots of other things in there that don't like to be smacked. I would be amazed if you didn't end up on a dialysis machine if you were in a 25mph head-on collision with your belts pulled up around you middle.
If you are driving around with a 4-point harness you are living in a safety fantasy. There is no safety organization that will allow this. No car manufacturer will allow this. A stock 3-point harness is MUCH safer. Lets see what you have. You have your body strapped to the seat so that you are well supported against cornering loads, which is great. If you don't have to support your body position by holding onto the steering wheel you can be much more sensitive in your steering inputs. You have nice big cool belts to show your friends, which is fun, but it does nothing for the car. You also have a lapbelt that won't stay down, hooked over your pelvis. Even if the belt starts out in the right place the shoulder harnesses will be pulling up with considerable force and the lapbelt WILL end up around your middle. Under a "light" 5 G hit, a 200 pound man will find his lapbelt pulled upwards with over 250 pounds of force. (assuming that at least 1/4 of the force is absorbed by the shoulder harnesses). To the people that say "I've been running this for years and it works fine." I would like to point out that you haven't tried this while running into a wall a 30 miles an hour. This is the difference between getting out and cussing (if your belts are correctly installed and adjusted) or waiting for an ambulance to come pick you up and possibly dying.
If you wear a 5-point harness look at where your lapbelt rides on you. If your sub strap doesn't pull the belt down into the correct position then it is too loose or the sub-strap is misplaced. You could enjoy all the comforts listed for the 4-point harness. The sub-strap should be positioned so it is in a direct line with your body angle. If you run a yardstick down your stomach, where the yardstick hits the floor is where the sub-strap should attach.
A 6-point harness as mentioned by Alan Herod is to keep someone driving in a reclining position from actually "submarining" the belts. They are intended for formula cars but if you want to go through the hassle they will work fine, but mounting them correctly is a problem. If you run them through the single bottom hole of a normal race seat they act as a single strap and should be attached like a 5-point's sub-strap. They are actually designed so that they should be mounted so that each strap goes on each side of "the naughty bits" so it will rest at the juncture of your hamstrings tendon and the pelvic bone. They are then mounted rearward so they act like a "hammock" to distribute the loads of the lower body that the seat cushion would take in a normal car. Once again its biggest job is to pull the lapbelt down.
A little note on H style shoulder belts. They are designed to be used with racing seats only. A stock seat has a very real possibility of coming apart under the loads of a rear end collision. If it folds backwards, which is what it wants to do, the H strap will stop your rearward movement as it catches on your neck and breaks it. The H strap is only there to keep the belts neat.
Think safety, then speed...
Wayne
10-28-2002, 07:39 PM
#24
Hmmm, I think I will have that 5th belt installed before next year's DE season (we're done here until the Sping).
Still can't say that I'm considering switching to track seats yet, but if (when) I do, I will follow Bill Gregory's recommendation for cloth covered seats (less slipping than on leather).
Richard
'87 Carrera-3.6L
Still can't say that I'm considering switching to track seats yet, but if (when) I do, I will follow Bill Gregory's recommendation for cloth covered seats (less slipping than on leather).
Richard
'87 Carrera-3.6L
10-28-2002, 09:06 PM
#25
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Wow - In the few DEs I have done so far I have used the stock 3 point belt and seat. My new DE car has a harness bar and 5 point harness mounted as discussed above (shoulder belts through harness bar - with H strap - and crotch strap bolted to floor in front of seat). You all make me think if I am using the stock seat I should just stay with the 3 point belt and lose the harness bar and harness. How about using the 3 point belt in addition to the 5 point harness?
10-28-2002, 09:57 PM
#26
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ZCAT3:
Ultimately, the safety decision you make has to be mentally confortable for YOU ! However, you should make an informed decision, which is what this forum and thread are trying to do.
Another *don't do*...IMHO....
Don't run 5 point systems without a roll bar. You are now *SO* locked in-place , that although you feel better driving...you are at more risk ( compared to 3 points) should you now roll -over. 3 points at least allow the body some sideways movememt to avoid your head being crushed, ..5 points do not.
Have you even considerd the "H" metal clips that prevent the retractors form working in a 3 belt application? This allows the belts to be fully extended..and the "H" clips ( used mainly for baby seats?) will allow the belt to be fully tight without retractors in-play. Now you gain the benefit of tight seating, and the safety of a 3 belt if you roll over. Still the roof on the 911's can come down...altogether I'd vote for keeping the 5 points, and start adding the missing pieces like a DAS roll bar.
---Wil Ferch
Ultimately, the safety decision you make has to be mentally confortable for YOU ! However, you should make an informed decision, which is what this forum and thread are trying to do.
Another *don't do*...IMHO....
Don't run 5 point systems without a roll bar. You are now *SO* locked in-place , that although you feel better driving...you are at more risk ( compared to 3 points) should you now roll -over. 3 points at least allow the body some sideways movememt to avoid your head being crushed, ..5 points do not.
Have you even considerd the "H" metal clips that prevent the retractors form working in a 3 belt application? This allows the belts to be fully extended..and the "H" clips ( used mainly for baby seats?) will allow the belt to be fully tight without retractors in-play. Now you gain the benefit of tight seating, and the safety of a 3 belt if you roll over. Still the roof on the 911's can come down...altogether I'd vote for keeping the 5 points, and start adding the missing pieces like a DAS roll bar.
---Wil Ferch
10-28-2002, 10:40 PM
#27
Instructor
Thread Starter
Will,
I refer back to my earlier post. Is the need for a rollbar as important in a Targa? The targa has a "factory" rollbar in place that the coupe doesn't have. Therefore, is it safer in a rollover?
I know that the A-pillars may not hold up, but a rollbar wouldn't help that anyway. Just wondering.
I refer back to my earlier post. Is the need for a rollbar as important in a Targa? The targa has a "factory" rollbar in place that the coupe doesn't have. Therefore, is it safer in a rollover?
I know that the A-pillars may not hold up, but a rollbar wouldn't help that anyway. Just wondering.
10-29-2002, 05:26 PM
#28
Alright, I have carefully followed and reviewed this important post - and I'm more stumped than before. I am asking you all for your best opinion. 
Please forgive me if the answer already lies above.
I have a stock 86 cab w a DAS removable rollbar (no seat belt loops). I've done only 2-4 DE days in a year in the last 4 , but would like to do a few more next season (say maybe 5-7, tops). I of course run in the lower(est)groups, and currently have no desire to move much higher - for that, I feel this is the wrong car - and I want to keep it stock, and frankly don't see trading up as a current option or priority.
When I told my instuctor my plans, he suggested my next "upgrade' should be harnesses...so given stock seats, how would you all proceed?
My own thought was to get a 6 point harness such as the one just installed on my freind's boxster - from what I've read here, I would bolt the shoulders to the seat rails, and then double loop them over the harness...
I'm thinking,based on what I've seen at the track(s), that this can't be a unique query..
Thanks in advance for your help <img src="graemlins/xyxwave.gif" border="0" alt="[bigbye]" />
Fred L.
Please forgive me if the answer already lies above. I have a stock 86 cab w a DAS removable rollbar (no seat belt loops). I've done only 2-4 DE days in a year in the last 4 , but would like to do a few more next season (say maybe 5-7, tops). I of course run in the lower(est)groups, and currently have no desire to move much higher - for that, I feel this is the wrong car - and I want to keep it stock, and frankly don't see trading up as a current option or priority.
When I told my instuctor my plans, he suggested my next "upgrade' should be harnesses...so given stock seats, how would you all proceed?
My own thought was to get a 6 point harness such as the one just installed on my freind's boxster - from what I've read here, I would bolt the shoulders to the seat rails, and then double loop them over the harness...
I'm thinking,based on what I've seen at the track(s), that this can't be a unique query..
Thanks in advance for your help <img src="graemlins/xyxwave.gif" border="0" alt="[bigbye]" />
Fred L.
10-31-2002, 12:56 PM
#29
Hi:
I'll take a shot at this...others will undoubtedly have yet different opinions.
Hmm.. a cab with a DAS bar?....opens up another can of worms. How? Look at how the rear section of DAS mounts. It uses 2 8mmx30mm bolts to hold the rear of the bar in-place. UNLIKE a coupe, if you go on your head, say backwards...now you have these 2 dinky fasteners holding the rear of the bar...in SHEAR. Coupe mounts the same way but has a roof acting as a skid plate, so that the bar will be less likely to "Dig-in" when upside down. I would modify the mounting bracket to have ANOTHER pair of bolts added vertically...in TENSION/COMPRESSION.
- next. modify your DAS to include welded-in shoulder belt hoops. For added safety, criss-cross the shoulder belts behind the seat and don't use an "H" strap which can hurt as much as it can help.
- Get a 5th strap and mountit solidly to the bottom. If you don't have seat heaters on your stock seats, consider having a hole put into the seat bottom for the 5th strap to pass through. Otherwise, drape over the front and go through floor or mount as I described earlier.
--Wil Ferch
I'll take a shot at this...others will undoubtedly have yet different opinions.
Hmm.. a cab with a DAS bar?....opens up another can of worms. How? Look at how the rear section of DAS mounts. It uses 2 8mmx30mm bolts to hold the rear of the bar in-place. UNLIKE a coupe, if you go on your head, say backwards...now you have these 2 dinky fasteners holding the rear of the bar...in SHEAR. Coupe mounts the same way but has a roof acting as a skid plate, so that the bar will be less likely to "Dig-in" when upside down. I would modify the mounting bracket to have ANOTHER pair of bolts added vertically...in TENSION/COMPRESSION.
- next. modify your DAS to include welded-in shoulder belt hoops. For added safety, criss-cross the shoulder belts behind the seat and don't use an "H" strap which can hurt as much as it can help.
- Get a 5th strap and mountit solidly to the bottom. If you don't have seat heaters on your stock seats, consider having a hole put into the seat bottom for the 5th strap to pass through. Otherwise, drape over the front and go through floor or mount as I described earlier.
--Wil Ferch
10-31-2002, 05:33 PM
#30
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What's wrong with bolts in shear? I've calculated that Grade 8 seatbelt bolts will take about 13,000 lbs in shear. Two of them will thus take 26,000 lbs of force before breaking, which increases the strenth of the roof by about 10 G's. Are my calculations correct? Grade 8 bolts have about 150,000 psi tensile strength, and a percentage of that (can't remember the number) in shear.