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914World.com _ 914World Garage _ 5-point belt without cage?
Posted by: mbseto Jul 27 2017, 07:40 AM
So I'm not planning to race the car I'm working on, but was thinking about the seatbelts. Would it make any sense to put 5-pt belts in it to increase safety? Would it help to make up for lack of air bags? Does it even make sense without a roll cage?
Posted by: jd74914 Jul 27 2017, 07:42 AM
I don't have anything meaningful to add on the safety aspects, but if you're going to put a harness in, do yourself a favor buy a DOT one and only buy it from Schroth. 
Posted by: tygaboy Jul 27 2017, 07:51 AM
I'm assuming you've thought about this same thing:
For me it was weighing safety and convenience. In the end, I'll have both:
I'm going to street drive with a 3 point retractables BUT, I'm having them made with snap hook connectors.
I'm also adding installation points for the harness set up.
Headed to the track? No problem! Snap, snap, click, click! All set.
"Re-streeting" is 4 clicks away!
Posted by: McMark Jul 27 2017, 07:51 AM
Racecar safety is not the same as street car safety, IMHO.
Use three point belts.
Posted by: GeorgeRud Jul 27 2017, 09:07 AM
Agreed!
Posted by: Dave_Darling Jul 27 2017, 09:12 AM
Yup, what McMark said!
Try belting yourself in properly with five-point belts (that means TIGHT!) and then try looking back so you can back up. Not gonna happen. Turning the radio on or off? Only if you have a remote control for it. Unlocking or opening the passenger door? Nope. Passenger window? I hope you have electric windows. Change for a toll-booth?
All of those normal things you wind up doing while driving need a little bit of give, and properly fastened race belts have none. And if you're not wearing them correctly, they can be more dangerous than the three-point belts.
--DD
Posted by: mepstein Jul 27 2017, 09:26 AM
I hate driving our customer cars with 5 point belts.
Posted by: 914forme Jul 27 2017, 09:50 AM
I plan on racing my car, and I have 3 points in for street, and a 6 point in for the track.
Used to run 5 points and things get old quick. At that point it was a race only car, that saw street duty to get to and from the event. I was to dumb to toss it up on a trailer and ride in comfort with A/C Heat, and well a radio.
Plenty of good 3 points, out there, IF you go 5 points go with https://www.schrothracing.com/technology BTW DOT approved belts I think are only made in a 4 point configuration or 3 point, which requires a normal car cabin to hook up.
You will also need upper mounts, and reinforcing plates, I did both front and back on my car. Under floor, and for the 6 point setup I am running 2 under the drivers seat. https://www.schrothracing.com/docs/Competition_Instructions.pdf.
You will also like to stick with 2" belts for the shoulders as 3" get a bit awkward, or a 3" / 2" Hybrid belt.
So after all of that, I think I would go with a 3 point with new webbing. Seat Belt Planet has some both early and later style that will work.
Posted by: 914forme Jul 27 2017, 09:59 AM
Oh and there are lots of belt manufactures out there, I only trust my life with Schroth belts. I can go with lots of others, and lots of big names. That being said, I am willing to pay a bit extra upfront to reduce the downside. Downside in the case could be death, or disability. Neither sound like a road I want to take because I saved a few $100 dollars.
Death is in all of our cards, so thats not a choice, but it is a choice if I buy an Ebay special and test it with a sudden unplanned deceleration maneuver and knock on death's door. I'll get there soon enough with out my CSOBitist causing me to be there before it was planned.
Posted by: falcor75 Jul 27 2017, 11:49 AM
A car without a roll cage can get unsafer from 4 or 5 point belts.
With the stock 3 point belt you can twist towards the middle of the car incase of a rollover that starts to compromise the cabin height. With a 5 point harness you are stuck upright and have no cage to help keep the cabin height intact.
Posted by: 90quattrocoupe Jul 27 2017, 12:52 PM
A car without a roll cage can get unsafer from 4 or 5 point belts.
With the stock 3 point belt you can twist towards the middle of the car incase of a rollover that starts to compromise the cabin height. With a 5 point harness you are stuck upright and have no cage to help keep the cabin height intact.
I am sorry, but in a rollover and centrifugal force working against you, I don't believe you could twist toward the center of the car. You might be able to do it rolling left, but definitely not right.
I have rolled 3 cars and was not able to do anything during the rollover, besides hanging onto the steering wheel.
Greg W/
Posted by: Elliot Cannon Jul 27 2017, 06:58 PM
Inertia reel seat belts are krap! Some of the new ones will tighten up when one or more of the airbags is deployed which is a good thing. Older inertia reels will pay out a slight amount before they stop. Inertia reels were developed because people didn't like getting their clothes wrinkled. 
I don't like that much slack weather I'm rolling over or slamming into a power pole. (An experience I would rather avoid by the way). 
Posted by: Elliot Cannon Jul 27 2017, 07:00 PM
A car without a roll cage can get unsafer from 4 or 5 point belts.
With the stock 3 point belt you can twist towards the middle of the car incase of a rollover that starts to compromise the cabin height. With a 5 point harness you are stuck upright and have no cage to help keep the cabin height intact.
You're going to lean toward the middle of the car during a rollover??
Posted by: Racer Jul 27 2017, 07:16 PM
I would consider Shroth 4-pts. Other than that, inertia reels.
I have a '70 with OEM belts. Ugh. Like and hate em at the same time. My '76 had inertia reels for street and 5pts for the track. That was much better. As metnioned, looking back to back up, or reach across and open the passenger door or window etc is a pita with tightly worn fixed belts.
Posted by: falcor75 Jul 28 2017, 03:36 AM
A car without a roll cage can get unsafer from 4 or 5 point belts.
With the stock 3 point belt you can twist towards the middle of the car incase of a rollover that starts to compromise the cabin height. With a 5 point harness you are stuck upright and have no cage to help keep the cabin height intact.
You're going to lean toward the middle of the car during a rollover??
I wasnt talking about during the actual rollover, I meant afterwards if the passenger compartment is compromised. If you are stuck upright with a 4 point harness and the b-billars give in, the next thing to keep the roof up is your spine. The info is from a racer in Sweden who happens to work for Volvo evaluting crash performance so I think I'll trust his opinion over anyone else on this board unless their have a similar profession.
But then again, its your life and your choice, I was just trying to help.
Posted by: mbseto Jul 28 2017, 08:01 AM
OK, looks like 3-pt inertial belts it is. Thanks for all the information!
Posted by: Mark Garriott Jul 28 2017, 08:50 AM
I wasnt talking about during the actual rollover, I meant afterwards if the passenger compartment is compromised. If you are stuck upright with a 4 point harness and the b-billars give in, the next thing to keep the roof up is your spine. The info is from a racer in Sweden who happens to work for Volvo evaluting crash performance so I think I'll trust his opinion over anyone else on this board unless their have a similar profession.
But then again, its your life and your choice, I was just trying to help.
An off-roading fellow had this experience first hand. He rolled his pickup truck out in the desert, and he and his buddy were squished onto/into each other in the middle of the cab. He realized if he had 5 point harnesses, it would have been much worse.
Posted by: Elliot Cannon Jul 28 2017, 10:49 AM
This argument come up once every few years. I guess we're good for a few more years. I'm always happy to participate.
Posted by: Justinp71 Jul 28 2017, 11:55 AM
Have you guys noticed that the 914 inertia belts only work when you get on the brakes hard? But in a modern car they also work by pulling them very fast? Or do my 914 inertia belts need a rebuild?
Posted by: SirAndy Jul 28 2017, 12:05 PM
Have you guys noticed that the 914 inertia belts only work when you get on the brakes hard? But in a modern car they also work by pulling them very fast? Or do my 914 inertia belts need a rebuild?
Do you have the chrome bracket that redirects the belt so it still goes straight down from the reel?
If not, your belts will never work correctly.
Which is another reason why i prefer the non-retractable early style belts ...
Posted by: Keyser Sose Jul 28 2017, 12:33 PM
Using a three-point harness what exactly happens when you're t-boned on the passenger side of the car or slide into something passenger side first? From that angle of impact what exactly is restraining you?
Posted by: SirAndy Jul 28 2017, 12:55 PM
The lap belt ...
Posted by: arne Jul 28 2017, 01:03 PM
Mine will lock with a quick tug. If yours don't, something is wrong.
Posted by: Justinp71 Jul 28 2017, 01:51 PM
Mine will lock with a quick tug. If yours don't, something is wrong.
Thanks, my passenger side is the same way. I will look into that asap.
Posted by: Justinp71 Jul 28 2017, 01:52 PM
Have you guys noticed that the 914 inertia belts only work when you get on the brakes hard? But in a modern car they also work by pulling them very fast? Or do my 914 inertia belts need a rebuild?
Do you have the chrome bracket that redirects the belt so it still goes straight down from the reel?
If not, your belts will never work correctly.
Which is another reason why i prefer the non-retractable early style belts ...
Yes, mounted to the inside of the b-pillar, correct?
Posted by: Keyser Sose Jul 28 2017, 02:38 PM
The lap belt ...
So in a passenger side collision a three-point harness is the functional equivalent of a lap belt? Is that really acceptable? It isn't to me.
Posted by: SirAndy Jul 28 2017, 02:43 PM
It's the same for every car you've ever driven. In fact, your 3-point won't do much beyond the lap belt in a driver side collision either.
Try yanking your top seat belt at an 90 degree angle right at the reel and see how well that works. They aren't designed for that unless you have some sort of bracket that redirects the pull of the belt.
And that's the same on any brand new car today as it is on a 914.
Posted by: Keyser Sose Jul 28 2017, 04:48 PM
It's the same for every car you've ever driven. In fact, your 3-point won't do much beyond the lap belt in a driver side collision either.
Try yanking your top seat belt at an 90 degree angle right at the reel and see how well that works. They aren't designed for that unless you have some sort of bracket that redirects the pull of the belt.
And that's the same on any brand new car today as it is on a 914.
Actually no, new cars today have air bags, 914's don't, and my 914 has 4-point belts. i've heard the negative opinions about four pointers on the street, and the convenience things Dave mentioned are certainly true, but there's no direct comparison I can think of where the performance in a collision of four point belts are inferior to three-pointer. Am I wrong about that? As you mentioned, in a passenger side collision the three-point harnesses are actually only lap belts... and lap belts were outlawed... when was it?
I know it's only opinion and I'm aware of the ongoing back and forth. It would be interesting to see some quantitative data, if it's available. Have you ever seen any?
Posted by: whitetwinturbo Aug 8 2017, 11:39 PM
.............a grim reminder to watch everyone around you and be ready for evasive action. 914's are hard to see due to their tiny size.
Interestingly, my 1997 Porsche belts tighten when accelerating hard then loosen when the throttle is off.....
Posted by: jd74914 Aug 9 2017, 05:59 AM
Actually no, new cars today have air bags, 914's don't, and my 914 has 4-point belts. i've heard the negative opinions about four pointers on the street, and the convenience things Dave mentioned are certainly true, but there's no direct comparison I can think of where the performance in a collision of four point belts are inferior to three-pointer. Am I wrong about that? As you mentioned, in a passenger side collision the three-point harnesses are actually only lap belts... and lap belts were outlawed... when was it?
I know it's only opinion and I'm aware of the ongoing back and forth. It would be interesting to see some quantitative data, if it's available. Have you ever seen any?
4-points are considered dangerous since you can submarine and your body can shift forward under the belt in case of accident (unless using the sweet Schroth belts) unlike 3-point belts which grab you and keep you from pulling forwards. Wearing a cheap 4-point is almost like not wearing a belt in a forward collision.
If I have time later I'll try to find the Schroth documentation on 4-pts showing the above.
Posted by: falcor75 Aug 9 2017, 06:06 AM
https://www.schrothracing.com/technology
Posted by: Keyser Sose Aug 9 2017, 08:11 AM
4-points are considered dangerous since you can submarine and your body can shift forward under the belt in case of accident (unless using the sweet Schroth belts) unlike 3-point belts which grab you and keep you from pulling forwards. Wearing a cheap 4-point is almost like not wearing a belt in a forward collision.
If I have time later I'll try to find the Schroth documentation on 4-pts showing the above.
I'd be curious to see that. The "ASM Anti Sub Marining Technology" section in that Schroth link just says it's "better" but doesn't explain how. They also limit their "safer" claims to frontal impacts only. I quite frankly can't see anything in a 914's three point harness that "grabs you" to keep you from pulling forwards, making it safer than any four-point, or anything at all in a three-point that restrains you if you're hit from either side. I've heard the anti-submarine claims before but have never seen substantiation, so I'm curious to see what that Schroth documentation has to say.
Posted by: jd74914 Aug 9 2017, 08:29 AM
There is a white paper on it that I'm not finding at the moment. For now here's a video:
https://www.youtube.com/watch?v=HR_FhuSEaU8
Basically, ASM uses straps of different "modulus" so one stretches more than the other causing you to get pulled somewhat similar to a 3 point harness so you get jammed by the lap belt vs. holding you evenly on both shoulders allowing you to slide. I'm not sure what the implications of this modification are in a side impact scenario.
Posted by: Keyser Sose Aug 9 2017, 09:43 AM
I can see that. The different modulus of elasticity would let one shoulder travel further forward, making the body bend slightly around the lap belt, thus reducing the submarine effect. Interesting. Or you could accomplish the same thing by leaving the inside shoulder belt on your standard four-point harness slightly loose. Or upgrade to a five-point harness.
But this question wasn't about the different technologies used in four-point harnesses, it's the about the comparative safety of a standard three-point retractable harness compared to a four or five point. It was said that the three point harness is safer and the four-point harness is unsafe. I doubt both of those points in all cases, but especially in a side collision, and would love to see something empirical, either way.
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