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Plural of Lotus is Lotus
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Did you buy it yet? I installed this BWR Harness Bar 2.0 mainly because no cutting required and anti-rotation bar is removable for daily use, easily bolted on for track day.
 

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If you look at the how the belt actually pulls on the bar, it rotates forwards, so the anti rotation types don't do jack. If the mounting bolts were such that the belt pulls above them, then it would, but they don't. You're best way to counteract any rotation is too tighten the snot out of the bolt so there's as much friction as possible between the bar flange and the roll bar boss. That all being said, there's a chance that some initial bar rotation forward could actually act as a shock absorber, but I won't volunteer to find out. Make sure to wrap the belts so that they are on top of the bar, too, to minimize twist since this puts the line of action closer to the center of rotation.
 

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I actually just installed mine and it was very easy. I found a you tube video that explained (and also noted to watch/save the washer under mount bolt.)
I ended up using a washer on one side and not the other as there was a tiny gap and I thought better to not stress the gap.

1261839
 

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Did you buy it yet? I installed this BWR Harness Bar 2.0 mainly because no cutting required and anti-rotation bar is removable for daily use, easily bolted on for track day.
I did the same for the same reason. The anti-rotation bars won't clear the subwoofer sitting on my rear parcel shelf, so having it removable made it work. And the anti-rotation bars are pretty much just marketing anyway.
 

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Question for you guys installing these with the stock seats. Are you swapping seats when you use the harness? I thought that it was a big no no to run a harness on a seat with integrated head rest and no shoulder belt holes?
 

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My SSC harness bar fits well, anchors to the factory harness bar mount points behind the roll hoop, cannot rotate and also enables the standard belt to be retained. The bar clears the speakers and only requires small slots to be cut in the trim panel. Easy to install:

 

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Question for you guys installing these with the stock seats. Are you swapping seats when you use the harness? I thought that it was a big no no to run a harness on a seat with integrated head rest and no shoulder belt holes?
My car has the Exige-style seats with integrated harness cutouts.
 

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Question for you guys installing these with the stock seats. Are you swapping seats when you use the harness? I thought that it was a big no no to run a harness on a seat with integrated head rest and no shoulder belt holes?
It is a question mark and compromise for me. I am on path and am racing in SCCA Solo AStreet, which allows a harness bar, but does not allow seat changes. So this is what I will try (No autocross track use yet).
 

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Question for you guys installing these with the stock seats. Are you swapping seats when you use the harness? I thought that it was a big no no to run a harness on a seat with integrated head rest and no shoulder belt holes?
It also depends heavily on your build. If you're positioned such that the harness does not touch the seat when you're buckled in, absolutely not a problem. If it IS resting on the seat in any way, I wish I could show you the computer modeling I've done that shows how badly that can go.
 

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Plural of Lotus is Lotus
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I purchased seat grommets from Inokinetic to cut shoulder and anti-sub holes. It's not a difficult project as there is really only 1 good location for shoulder points. You just have to get over cutting into an otherwise perfectly good seat.......Oh yeah, use the dremel outside. Gonna kick up a lot of fiberglass dust :)
 

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It also depends heavily on your build. If you're positioned such that the harness does not touch the seat when you're buckled in, absolutely not a problem. If it IS resting on the seat in any way, I wish I could show you the computer modeling I've done that shows how badly that can go.
Gotcha...and in all honesty, my knowledge on this is very lacking and I was strictly basing it off manufacturing info I had read. When I was looking at installing a harness many years ago, reading over the different manufacture install instructions (Schroth and Takata for example) they all said to never do that or cut holes into existing seats. At the time, I too was looking at cutting up my existing seats and using the then Sector 111 grommets but never went forward with it due to those warnings. I did end up eventually replacing the seats to support them but never pulled the trigger on a harness set.
 

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Gotcha...and in all honesty, my knowledge on this is very lacking and I was strictly basing it off manufacturing info I had read. When I was looking at installing a harness many years ago, reading over the different manufacture install instructions (Schroth and Takata for example) they all said to never do that or cut holes into existing seats. At the time, I too was looking at cutting up my existing seats and using the then Sector 111 grommets but never went forward with it due to those warnings. I did end up eventually replacing the seats to support them but never pulled the trigger on a harness set.
I don't want my previous post to imply that cutting shoulder harness holes in a stock Elise seat is okay. It will compromise the seat's ability to support the head when hit from the behind or when going backwards into an object, and there is not a lot of material left after you cut the slots. It is a different story for the sub belts though since the hole for them is (probably) reinforced very well by the seat frame.
 

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Plural of Lotus is Lotus
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Shinoo, care to comment here about retro-fit of grommets into stock seats?
 

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Shinoo, care to comment here about retro-fit of grommets into stock seats?
If you measure the ratio of the blue distance relative to teh orange distance, that'll give you a pretty good apprixmation of how much you weakened the head restraint. Let's say the blue line is 60% the orange line. Let's also assume the seat was designed to be safe with a heavy man whose head touched high (more bending leverage). Let's assume they designed it to be twice as safe as it needs to be for that guy. With the cutouts, that 2x safety becomes 1.2 - still safe but oh so barely. Now, if you are anything shorter and/or lighter than that guy they designed for, you already had more margin of safety. It also gets worse the sharper you cut your cutouts.

Here's where the numbers get real though - neither you nor I know what original margin they designed for or what crash loads or what occupant. We also don't know the "stress concentration factor" that increases stress when you cut into something. They may have used a standard 50th percentile male instead of an 80th. Too many unknowns for me.

1261966
 
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