New seat harness rules

Good:
http://media.photobucket.com/image/harn … odM2M1.jpg

Bad:
http://www.aeu86.org/download/ae86/id/7433.jpg

+1 Good info in this tread.

While the shoulder belt angle is good (and that's the point you were illustrating), the belts should be wrapped around the harness bar, rather than routed down to the floor. Two reasons: The vertical member of that bar is only meant to stability the bar and keep it from rotating on the side anchors, not to take the full force of the shoulder harnesses. And also because of the extreme amount of stretch, especially with 2" belts.

The purpose of the lap belts is much less to hold you down (that matters only in an upside-down rollover impact, but to hold you back in a front impact (much more common). That's why the laps must be super tight and positioned below your illiac crest (lump you can feel in your hip bone). The purpose of the anti-sub belts is just to counteract the upward pull of the shoulder harnesses, which raises the lap belt and can cause your lower torso to slip under the lap belt, killing your squishy belly bits.

When the shoulder belts are too low or high, the spine is compressed unnecessarily when your upper torso rotates forward.

The new rule doesn't say whether it applies to the belts at the top of the shoulder grommet hole, bottom of the hole, or actual shoulders of driver. This makes quite a bit of difference, especially when the anchor point is close to the seat (as it should be). I'm guessing they will be lenient and accept either. Care should be taken that with the tallest driver that the belts don't go through the shoulder grommet and sharply up to the shoulders. Wearing a HANS makes this even more imporant, because the HANS adds about 3/4" of height to your shoulders.

Some more pictures.

Good:
http://www.downunderteam.com/images/belt1.jpg

The closer the belt fastens to the race car or rollcage the better. It's better to fasten it to the rollcage than let it fold over the cage to the floor.

Bad:
http://www.downunderteam.com/images/belt2.jpg

The belts are attached to upright eyelets. If the eyelets were aimed forward there is less chance the eyelets will break.

True, but they appear to go down too sharply. They should go straight back, or down at at most (EDIT: my bad: 15) 15 degrees. Competition seats are not rated for a down load on the seat back.

There is also some slack in the webbing at the buckle -- this will pull through before the belt goes tight, creating slack.

Bad wrap, too. The 3-bar buckle is distant from the anchor. It will slide back about 2", creating about 4" of slack. A wrap would be better here.

Also that bar looks mighty thin -- maybe it's just the picture. Eyebolts must be grade 8 (sold by harness companies); those look like regular hardware store items. Eye Bolts

And last, I wouldn't put tape on harnesses. You simply don't know what is in the adhesive.

# 3.5: Five- or Six-Point Harnesses: Five- or six-point harnesses mandatory, including fifth or fifth/sixth "anti-submarine" belt. All harnesses must be SFI or FIA approved; dated within four years of the race; and properly mounted.

o 3.5.1: Harness Mounting: Grade 8 or better hardware and 3-inch or larger load washers are required when mounting to sheetmetal. Shoulder harnesses should be within 15 degrees of horizontal from load point to seat entry.
         
o 3.5.2: Anti-submarine belt(s) should be mounted vertically. If this requires cutting a hole in the seat squab, don't route the belt(s) in a way that allows them to fray on a seat spring. If vertical mounting is impractical, the mounting point should be located behind, not ahead of, the belt buckle.

I don't know that the harness rule has really changed.  It has just been inspected and enforced more in recent races.

Aside from the angle of the harness bars, their proximity to the seat has also been a problem.

I have seen a lot where the harness bar is so close to the seat the buckle loop things are not behind the seat and they failed tech. 

So the bar needs to be at the right angle and as well as a proper length from the
seat.

On the 240Z, I think we kinda got lucky.  With the driver in the seat our shoulder straps don't usually touch the seat or barely touch the seat.

The driver's shoulder height in relation to the cut outs in the seat is what it is and some guys fit better than others too.

A solution to this situation is to weld plates to the top of the bar, pointing straight back. Call them "tabs" if you prefer. Drill a hole in them and bolt a buckle/anchor (not clip-in) to it (grade 8). Put a washer under the anchor to keep the webbing from getting pinched.

This is a particularly easy solution when someone else on your team has the welder, drill press, and cut-off saw. Drink beer and watch.

Yes, the buckle must not bind on the seat grommet