The Lotus Cars Community banner
  • Hi there! Why not register as a user to enjoy all of the benefits of the site? You may register here. When you register, please pick a username that is non-commercial. If you use a name that appears on any search engine commercially, you must pick another name, whether it applies to you or not. Commercial usernames are for supporting vendor use only. If you want to become a supporting vendor and grow your business, please follow this link. Thanks!

Slotting seat for anti-sub belt

30K views 57 replies 20 participants last post by  LotusCC 
#1 ·
I'm going to slot the bottom of my OE Elise seat so I can properly install an an anti-submarine belt. Does any one know where I can find a grommet to trim out the hole when I cut it. I need something similar to Sector 111's grommets for use when slotting the seat back for a harness (Elise Seat Grommets).
 
#3 ·
I don't think it needs a grommet... I cut a slot in the bottom of the composite seat directly in front of the metal crossmember that runs underneath the seat... about 11" from the vertex of the seat back and seat bottom as per Schroth's guidelines (10-12" from the vertex). I then had an automotive upholstery shop sew in a leather sleeve instead of a grommet.
 

Attachments

#4 · (Edited)
I then had an automotive upholstery shop sew in a leather sleeve instead of a grommet.
Yes, that seems like it would work (and the pictures prove it!). But, if I can get a grommet, I won't need to make the trip to the upholstery shop. Thanks for the idea, though. If the grommet thing doesn't work out, I now know what to do.

And how did you anchor your sub belts? No doubt you drilled through the floor, but did you use anything other than a very stout backing plate as a reinforcement for the anchor bolt? And how thick was your backing plate?
 
#8 ·
apk, does the track pack bar bolt into the stock mounting points for the OE 3-point harnesses? Are there any additional bracing or mounting points used? From the pictures, it looks like the bar is bolted to the OE harness attachment points and that there are no additional bracing or mounting points, but it's hard to tell.
 
#17 ·
Can someone please post a picture(s) of the Corbeau grommets installed for the stock Elise seats - did you use 1 or 2 grommets per seat? I am installing the Schroth 6pt Enduro harness. It seems they should be forward of the seat rail to be 10-12" from the sys.6.pack pinch plate location and the sub belts are supposed to remain 4" apart - I assume this is measured from the center of each 2" belt leaving 2" between the belts from edge to edge?

Also if you have a close up photo and/or description of how exactly to attach the sub belts to the Sector sys.6.pack pinch plate properly as I can't find this in Sector or Schroth's install info. - Thanks.
 
#26 ·
I wish I had taken a picture of the sub slot in my Exige seats... the slot is immediately in front of the steel crossmember... in fact, the leather sleeve that is sewn into the seat is glued directly to the crossmember, so it would be the crossmember that would take the stress of the belt, not the seat slot.
 
#28 ·
Eric Walter: Thats what I bought for $11/each + shipping. (phone 801 255-3737) I am still hoping to see photos of someone else's install of these on the Elise (Probax) seat...
 
#29 ·
Thats what I bought for $11/each + shipping. (phone 801 255-3737) I am still hoping to see photos of someone else's install of these on the Elise (Probax) seat...
I'm also looking for someone to pioneer my seat surgery.

PLEASE send pictures.

Thanks......Phil
 
#31 ·
This weekend, I finished the harness install in my Opel Speedster. The sub straps are mounted using the Sector111 sys.6.pack. I'm slim, so I placed the cut out in the seat behind the cross brace. The cut out is large enough so I can reach the adjusters for the sub straps. Also, this way I can tuck away the straps when I'm using the std 3 point belt for daily driving.







More pictures:

http://www.flickr.com/photos/ericwalter175...57615678396427/
 
#32 ·
Eric,
its good to see that you are thinking about safety.
the bad news is that IMO, and likely the manufacturer of your harness, you have destroyed an inconnet pair of stock lotus seats by cutting them.


Installation- and Operating Instructions

see page #31 section called "seats."

in the first warning it clearly states that one should never modify factory seats by cutting slots in them.

even though a certain vendor sells these items, it is contradictory to what this website says about modifying any seat.

if you are truley concernd about your own safety, and that of your passenger, get a proper seat made for a harness.
remember, just because someone sells an item, doesnt mean its been tested, or is an improvement on safety.

at the race track i keep seeing safety gear getting tested out lately, and there is no way i would put myself in one of those set-ups pictured and feel "safe".


the stock set up is better than what i see pictured (IMO of course).
just my .02(again)
 
#33 ·
fishguy,

I am, of course, aware of your concerns. And I do take them seriously. Differing from the Elise, the Opel Speedster / Vauxhall VX220 do have crash structures mounted to the roll bar that are designed to "catch" the seat in rear impact. You can see them in the pictures I posted. With the drivers seat in a far back position, they stop a seat flexing backwards way before anything's gonna break. Actually, as a tall driver, in a rear impact I'd be mostly worried about the very hard foam covering the top part of these crash structures.
 
#37 ·
fishguy,

I am, of course, aware of your concerns. And I do take them seriously. Differing from the Elise, the Opel Speedster / Vauxhall VX220 do have crash structures mounted to the roll bar that are designed to "catch" the seat in rear impact.
so what is the plan to keep you in the seat when the slot you cut breaks apart and the harness goes flying off your shoulders?

maybe just push against the steering wheel really tight, and keep you body in place.

really, how much material is left on the outboard side of that slot, maybe 2 inches at the most.

I do firmly believe that the customers of that seat grommet cut out for the Elise stock seat are truely "crash-test dummies".

a few reasonable (rhetorical) questions to think about;

1)do you really think there was any safety testing done on that product?

2)do you think there should be some, or any for that matter, testing done on a product that may be called upon to withstand a great amount of force, with your personal well being on the line. .............people do wear seat belts for a reason.

3)do you think that schroth only put that warning i linked to earlier to scare people into buying expensive seats instead of a $25 seat grommet and cutting out thier own holes in a seat?

4)do you think there might be a reason, no racing group that i could ever think of would allow that set-up you have pictured to be used in an event....................ever?

5)Do you believe in darwinism when it comes to home done safety modifications?


I am not selling anything, i have no interest other than wanting to not see people putting themself at risk, when they think they are making safety improvements.

I saw an impact that was so huge last month that it ripped the harness bar right out of the car, harness still attached to the bar(which was now bent).

I still race my cars 1-2 times a month, but I also have respect for the physics and g-forces we are toying with, and therfor prepare myself properly with items that are well tested.

new (proper)seats are not that expensive when you really think about the big picture.
best wishes
 
#34 ·
:popcorn:
 
#38 ·
Everything is relative...

Fishguy and I have weighed on this issue before, and not always on the same side.

I'm one if the "crash dummies" he refers to (on a different thread) ;), but despite where I may fall on the evolutional scale, I have to acknowledge that what fishguy says is correct. Don't compromise safety.

I made a different decision based on his comments, and went to Exige seats instead of cutting grommet holes. It works for me, but is still not the "optimal" solution. Which brings me to my point...

I don't race anywhere near the class of car or event that fishguy does. I do the basic Autocross, where the biggest accident potential is crushing a few cones. Not exactly catastrophic g-force inducing impacts.

For the level of event I compete in, my set-up is fine. My airbags are still functional, I wear a helmet and I am tightly restrained. Not F1 grade safety gear, but reasonable for what I do.

If I go up in competitive levels, I will reconsider my safety choices. That said, I don't think every driving situation requires a full-scale safety set-up. If that was the case, Camry's would have roll cages and fire suppressant systems!

Regards,
Wayne
 
#39 · (Edited)
so what is the plan to keep you in the seat when the slot you cut breaks apart and the harness goes flying off your shoulders?
I cannot quite picture what direction of impact and forces working on the body and belt would result in such an event. But that does not rule out this could be a valid concern..

maybe just push against the steering wheel really tight, and keep you body in place.
Instead I'll give my airbag a hug and see this thread flashing by before my eyes in my last 10 milliseconds. :crazyeyes

do you really think there was any safety testing done on that product?
No, I don't. For that matter, the seat choices with factory cut outs that would fit my car are the Corbeau LE and the Tillet B5 or the Exige seat. Neither of which is FiA certified. Of these only the Exige seat would seem to properly work with leaving the 3 point belts in place. Did Lotus do any serious rear impact testing with their seat? I'm not really convinced about that...

do you think that schroth only put that warning i linked to earlier to scare people into buying expensive seats instead of a $25 seat grommet and cutting out thier own holes in a seat?
It seems that Schroth acted sensibly, generally disapproving modifications of seats they haven't seen. This does not rule out specific modifictions of this kind working properly.

do you think there might be a reason, no racing group that i could ever think of would allow that set-up you have pictured to be used in an event....................ever?
I am aware that a FIA approved seat on fixed rails and a roll cage with a harness bar that's not depending on bolts to hold it will be safer. It would seem unreasonable to me, if the regulations for the 800m autocross events I perform in would make such requirements..

I saw an impact that was so huge last month that it ripped the harness bar right out of the car, harness still attached to the bar(which was now bent).
I have little confidence in the standard 3-point restraint system saving my life in such circumstances. I know of one deadly incident in an Opel Speedster a year ago where the standard belt ripped.
 
#40 ·
Here is a picture of the back of an Elise & Exige seat. Notice how each share a similar spine? This is where the seat's strength comes from. Notice where Lotus has cut the grommets in the Exige seats? This area does not contribute to the integrity of the seat. This is where grommets on Elise seats should be placed. The Elise & Exige seats are otherwise the same in construction.

I do agree with fishguy that a quality race seat is safer option.
 

Attachments

#41 ·
Shinoo - my Sector 111 wish list includes a sub belt grommet for 6 pt Schroth

I had to make a sub grommet by cutting and splicing 2 Corbeau 5pt grommets - the upholstery shops wanted $200+ per seat to sew in sleeves and said it required ungluing the center padding of the seat which I didn't want. - The sys.6.pack worked well - I also put some split tubing over the metal crossmember edges under the seats near the sub belt pathway.
 

Attachments

#44 ·
thruthfully, who cares about autocross and "safety" in those events. you are not going to hit anything are you?

as far as the cutouts, lets assume for a minute that schroth has no idea or experience with any safety stuff, and that they are completely wrong about thier warnings on never modifying seats by cutting slots in them.
this is just an assumption, as i do beileve they have tons of expertise and experience, and would follow the guidlines on their website no matter what people say.

that said, look at the size and angle of these elise seat grommets. even the exige seat slots are large. they are large so that different sized drivers can use these, and also so that when you are restrained by your harness it can stretch and move in the slots w/o putting pressure on the seats slots themselves. those sector 111 seat grommets are way to narrow and small to be safely used in an impact on a non modified seat( look at the design of racing seats slots, vs. theis design).
add to the equation that you have modified the seat and changed its integrity, and then load up that hole with lots of force from the belt moving under the force of holding the driver in place in a wreck, upwards most likely, and wanting to be flat, as opposed to twisted as the hole looks to me, and bingo, there is the a big problem with the untested design.

to me, the design from this vendor, looks like someone made huge compromises in everything to cram those grommets into the only space available to cut out. the seats are just too narrow.

i say this item is an epic failure, and those who use it are potential candidates for either the darwin award, or are just too cheap with $ too do safety things correctly, and actualy make themselves safe.
I would prefer the stock set-up with a CG lock over this any day.

perhaps its ignorance(not stupidity) and the users have no idea of what they are dealing with when they have a wreck.

those items( the sector 111 Elise seat gromments), if they are going to be contiuned to be sold should have a big disclaimer about only use for autocross, and only on a vehicle that is never going to be driven on the street again. not even driven on the street to the autocross event. IMO those seats are compromised to function with thier intended purpose.
also a reference to the schroth website where it says never to cut a seat.

selling these is a lawsuit waiting to happen.

the grommets and cutting out the Elise seats for a harness is an epic failure.

how much does a proper seat cost, and what is your own safety worth?:wallbang:

good luck
 
#45 ·
Joe from HMS (Schroth's US distributor) is the one who encouraged us to offer these grommets.

The integrity and strength of the Elise seat is not compromised as long as the 'spine' is not cut. The grommets themselves are stiffer and stronger than the pieces of fiberglass that are cut out. If this area contributed to the strength of the seat then the grommets would make it safer!

Running street cars on the racetrack is a risky proposition. Period. We should all accept the risk involved.
 
#46 ·
+1

The Elise and Exige seats Shinoo shows in his earlier post are my seats. I took those pictures to help understand what is actually the difference between the seat types when it comes to harness openings using grommets.

I believe that either seat would be equally safe. That DOESN'T mean they are the best option for a given type of racing or driving environment.

And about the comment : "truthfully, who cares about autocross and "safety" in those events. you are not going to hit anything are you?", I disagree.

It IS possible to hit something hard (like a light pole or other perimeter barrier) or another vehicle in AutoX. It can happen, so I want to be as safe as possible when I run in those events.

Regards,
Wayne
 
#55 ·
Every racing shell that I've seen has as hole cut in the seat for the harness to go through.

I've never seen one that had any metal reinforcement or rounded pivot point for the belt to go through.

Maybe I haven't seen them all. Maybe the ones that I've seen have a thick area that the crotch straps pass through.

ken
 
#57 ·
Sorry for bumping this old thread, but I had to consult it frequently in the past week.

I brought my seat to an auto upholstery shop nearby (after cutting the hole in the fiberglass shell myself) and they quoted me $250 per seat to cut through the padding and sew in a sleeve. They said there would be no way to do it without pulling out the center section so it would be labor intensive. I found another upholstery shop that would do it for $100 (though they also had to pull the center section).

The result is pretty good. The leather is sewn in at the top and then glued down underneath the seat which also provides a smooth path for the belt so it's not rubbing on the seat shell. Once the seat bracket is bolted onto the seat, it clamps down on the leather patch glued to the shell so it should hold pretty tight.



I did mine behind the plate because in front seemed like it would put the belt too far away from me in my normal seating position. Though I might do the passenger side one in front of the plate since most of my passengers are bigger than me.
 

Attachments

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top