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After looking at the pictures in post 9 that 9and3 referenced, I suspect the extra holes are for the Competition Seat mounting brackets, not for the eyebolts.
The 'extra' holes you see is for RHD cars.

Remember that the Elise seats are not mounted symmetrically in the car.

The driver gets more room and his seat is more to the center of the car. The passenger seat is moved towards the side chassis beam. Both seats are also angled on their mounts..

On an RHD car the seats are 'shifted' the other way.

As the chassis' are not 'handed' (there is only one type for both LHD and RHD) there are multiple holes in the chassis in this case to accomodate both LHD and RHD seat positioning.

What people sometimes do with competition seats though is to fix the driver's seat frame (usually a fixed frame) to the car using BOTH holes to get an extra secure fit of the seat frame to the car.

Bye, Arno.
 

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Discussion Starter · #22 ·
Thanks Conan...and thanks for unknowingly providing the pic!
 

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I'd like to point out, and get some feedback on, this thread:
http://www.elisetalk.com/forums/showthread.php?p=804756#post804756
which has some interesting pics.

One item in the thread is a factory install which is very unusual, both in the choice of eyebolt locations and treatment of the fasteners "below decks," with a lot of exposed bolt length.

But there is also, in post 17, some pages from a Lotus manual describing the installation of mounting points in a Cup car. One point is the orientation of the strap nuts:
Lotus6PointHarness_Page_4.jpg

^^^Note that after locating the nut on the bottom skin, they specify drilling a big ol' 16mm hole so that the nut plate may be installed flipped over, with the nut on top. This would be a lot cleaner underneath, but it seems intuitively weaker to me. I've seen a few LT member pics with the nuts "down"; has anyone tried it like this, with the plates flipped over? (See paragraph 6 in the photo above).

Here is the reason I brought this up, though:
Lotus6PointHarness_Page_5.jpg

^^^This page describes an inboard mounting point right into the console (gear lever cover), through the rear gearshift assembly. You must cut a notch in the cover to clear the eyebolt. This is for Cup rails; is there a possibility of making this work with stock rails, or perhaps aftermarket fixed rails?

One last point. This procedure specifies installing the eyebolts hand-tight with no threadlock. Maybe this is to allow the eye to "self adjust" as the belt moves around under load? I suppose unscrewing isn't too likely, as the heavy belt would have to be carried around and around several times. Still... makes me leery. Obviously, you'd want to check it every time the harness was used.
 

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^^^Note that after locating the nut on the bottom skin, they specify drilling a big ol' 16mm hole so that the nut plate may be installed flipped over, with the nut on top. This would be a lot cleaner underneath, but it seems intuitively weaker to me. I've seen a few LT member pics with the nuts "down"; has anyone tried it like this, with the plates flipped over? (See paragraph 6 in the photo above).
The nut plates Lotus uses seem to have the nuts welded into the the plate. Most aftermarket ones have a nut (spot)welded on top, so that's a difference.

But the main reason that Lotus uses this method is most likely because there is free space/air between the alu sheet that forms the floor of the car and the extrusion that gets drilled through. (the extrusion is hollow)

By mounting it with the nut sticking 'upward' it most likely sits flush against the inside of the (hollow) extrusion and any force is directly transferred to the extrusion.

If you were to mount a plate with the nut 'down' you would really want to put some shims/washers between the plate and the extrusion, so any force would not first deform/buckle the alu floor sheet before taking the load on the extrusion.

Bye, Arno.
 

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hi guys doing a lot of searching has any one measured the distance? from some point for both the lab belts? and i also plan to eye bolt the shoulder straps to the chassis. any thoughts on those holes? theres nothing i can break under there?

rob
 

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so kinda did best guess with this. came out ok i think lap belts fit nice and shoulders straps are snug, put the seats back on before realizing i did not do the sub belts. thats next week i guess.
 

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Discussion Starter · #27 ·
Glad it came out alright. I should have put the driver's side inboard eye more outboard. Not sure if it's worth drilling another hole, though.
 

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Glad it came out alright. I should have put the driver's side inboard eye more outboard. Not sure if it's worth drilling another hole, though.
:thwack:
you shouldn't have any trouble with the outboard driver's side hole location. i think i moved the inboard hole outboard about a 1/4", and wish i had done it perhaps 1/2".

the sliding seat mechanism likes to interfere with the lap belt clips. visualize the range of motion on the belt clips attached to the eye bolts BEFORE you mark for drilling...
:D

congrats on getting it done. my "solution" for the problem is to remove the driver's lap belts and only install them when i'm at the track.
 

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Discussion Starter · #29 ·
After all the warnings...I know.

Actually, the problem was that I had the driver's seat lined up with the wrong set of holes when I was laying it out. I assumed the seat was supposed to capture the shifter bracket like on the passenger side (had the console out to reinforce the bracket).

Forgot to mention...instead of grinding the backing plates to fit on the flat portion of the undertray, I put very large washers between the backing plate and undertray. The plates were then flat when clamped against the washers and the raised portions of the undertray. That allowed to me to keep the plates at their full 4". I had to grind the washers a bit and grind down some of the excess chassis adhesive, but it was way less grinding than if I had ground the plates.
 

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purist, i noticed in your op, you only have listed lap belt locations. did you also bolt your shoulder belts to the floor? and what do you mean the "I assumed the seat was supposed to capture the shifter bracket like on the passenger side (had the console out to reinforce the bracket)."?both of my seats tag the shifter matrix...

as my backing plate i used 3 inch flat stock aluminum and drilled and set it so it fit square with the under part of the car. ... what a pain in the ass.
 

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Discussion Starter · #31 ·
Shoulder belts are just going around the v-force bar. Subs are going to the stock belt mounts on the seat.

On the driver's side, if I put the rear inboard bolt through the hole in the shifter bracket, the seat interfered with the bracket. I moved it out to the other set of holes and it cleared. The side of the rail still sort of captures the tab on the bracket, but is not clamping through it.

Did I use the wrong holes? That would be great news. If that's the case, I'll try again...maybe the bracket was out of position when I originally put the seat in.

Can anyone confirm?
 

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...did you also bolt your shoulder belts to the floor?...
you've written about this several times. i just cannot understand what you've done... aren't you using a harness bar?
 

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ill take a pic. what led me to this set up is the og racing rep i was talking to. he said the proper way is to use the harness bar as a guild, rout the shoulder belts through the guild slots then straight down to the eye bolts in the floor.... he said many clubs do not allow you to run if your shoulder straps are only secured to the bar.
 

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Discussion Starter · #34 ·
I've never understood that. By having the harness go over the bar and down to the floor, you're increasing the force on the bar by 41%. Sure, the harness will still be attached to the floor, but if the bar comes free they'll be too loose to do you any good.
 

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Discussion Starter · #35 ·
first is inboard side of drivers seat, second out side drivers seat, third, bolts through the floor and backing plate
Huh?

Edit: Never mind...pics weren't loaded.
 

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I've never understood that. By having the harness go over the bar and down to the floor, you're increasing the force on the bar by 41%. Sure, the harness will still be attached to the floor, but if the bar comes free they'll be too loose to do you any good.
i held a mods weekend, i was really hoping some one was coming that had done it before... nope.. so i was left with LTs posts on the subject, what og racing rep told me, and a conversation i had with a lotus tech a few weeks ago.

i did what i thought was best based on all sources. :shrug:
 

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I've never understood that. By having the harness go over the bar and down to the floor, you're increasing the force on the bar by 41%. Sure, the harness will still be attached to the floor, but if the bar comes free they'll be too loose to do you any good.
You also allow more stretch by a HUGE margin -- meaning in the event of a front-end collision, you'll become very loose in the seat after the intial impact. The belts are intended to stretch up to 10% (or more) on impact. The longer the distance between the harness ends, the more stretching distance will occur.
 

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i suppose its easy enough to do both set ups. just re wrap the belts. im open to other thoughts on this. does every one just have it wrapped around the bar? maybe ill set up a poll.
 

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i suppose its easy enough to do both set ups. just re wrap the belts. im open to other thoughts on this. does every one just have it wrapped around the bar? maybe ill set up a poll.
honestly, i can't think of one good reason to extend the belts to the floor. you're still relying on the bar to provide the "whoa" in an impact, and you've increased the length and possible failure points on the belts and perhaps my biggest fear is that there could be a tangle behind the seat whereby the belt is jammed or pinched somewhere just enough to allow you to cinch her up (and think it's all tight), but have actual slack in an impact when the pinch releases the rest of the belt.

$0.02
 
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