5-point belt without cage? Options

[mbseto]

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?

[Keyser Sose]

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?

[SirAndy]

From that angle of impact what exactly is restraining you?

The lap belt ...
(IMG:style_emoticons/default/shades.gif)

[Keyser Sose]

From that angle of impact what exactly is restraining you?

The lap belt ...
(IMG:style_emoticons/default/shades.gif)

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.

[SirAndy]

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.

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.
(IMG:style_emoticons/default/shades.gif)

[Keyser Sose]

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.

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.
(IMG:style_emoticons/default/shades.gif)

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?

[jd74914]

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. (IMG:style_emoticons/default/sad.gif)

If I have time later I'll try to find the Schroth documentation on 4-pts showing the above.

[Keyser Sose]

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. (IMG:style_emoticons/default/sad.gif)

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.