Fixed back seats cert

[elias 253]

Anyone here successfully managed to get aftermarket fixed back seats carted in an e90/e82 chassis? My main question is around what is required to pass cert in relation to seat base and seat belt buckle anchorage, since it is originally mounted to the seat.

Any help is much appreciated,

cheers

[Harper 547]

In a coupe you will almost certainly have to get it certed without the rear seat. 

The problems you run into is that the gap between the bucket seat and the B pillar has to be more than 300mm which it almost never is. My pole position ABE's on factory sedan sliders with Brey Krause brackets are barely 300mm if you are generous with the measurement. I don't know of a single aftermarket slider that has anywhere close to the same amount of travel as the factory sliders. 

The other issue is that even if you meet all those requirements if there is a seatbelt pass through as there is on pole positions, then the seatbelt obstructs the entrance to the back seat and would likely be deemed unreasonably difficult to get in and out.

In addition to that you need to have a way to release the seats from the back seats which would need to be made custom, most sliders/brackets don't have that functionality.

I think it might be possible to get it certed with the right seat (perhaps cobra nogaros since they don't have a seatbelt passthrough) on the right brackets such that there is a sufficient gap but when I talked to NZTA they pretty much told me it would come down the discretion of the certifier even then as to whether it was unreasonably difficult to get in or out of the backseat in an emergency. 

I was prepared to run the bucket seats with no cert in my E46 but my car actually had a pre-existing cert for bucket seats that were legal but doesn't specify so it still passes WOFs. 

[elias 253]

Sorry should have added, the car will not have any rear seats, its getting a half cage fitted before cert, seats won't be on sliders. Main concern is what bases can I use that will pass NZ cert. My bad should've worded my question more clearly, appreciate the response none the less.

cheers 

[M3AN 4016]

No rear seat makes a huge difference to the ease with which you can do this. Different chassis but same considerations, I researched this for my e36 M3 coupe, and @sweetm3 did get an e36 coupe certed with aftermarket fronts and sliders, and a rear seat.

No rear seat (rear seat and seatbelts must be removed and I believe the vehicle needs to be re-registered as a 2 seater) means no access/egress requirements so that's good, I know NZKW and VAC Motorsport mounts can be certed in NZ, I'm sure other brand name mounts, like Recaro would also be fine. I can't recall what brand @sweetm3 used but they're obviously also fine. Or at least was all true a few years back, always talk to your cert guy before spending the money.

Then the seatbelt receptical fixing point needs to be OE or a new, reinforced mounting point, you can't use a non-OE mounting point on an aftermarket seat base (or slider) to the best of my knowledge. This is normally on the transmission tunnel and there are documented NZTA/LVVC standards for this with all of the necessary measurements.

Did you find this: https://www.lvvta.org.nz/documents/standards/LVVTA_STD_Seatbelts_& Seatbelt_Anchorages.pdf

 

[elias 253]

On 1/21/2023 at 3:50 PM, M3AN said:

No rear seat makes a huge difference to the ease with which you can do this. Different chassis but same considerations, I researched this for my e36 M3 coupe, and @sweetm3 did get an e36 coupe certed with aftermarket fronts and sliders, and a rear seat.

No rear seat (rear seat and seatbelts must be removed and I believe the vehicle needs to be re-registered as a 2 seater) means no access/egress requirements so that's good, I know NZKW and VAC Motorsport mounts can be certed in NZ, I'm sure other brand name mounts, like Recaro would also be fine. I can't recall what brand @sweetm3 used but they're obviously also fine. Or at least was all true a few years back, always talk to your cert guy before spending the money.

Then the seatbelt receptical fixing point needs to be OE or a new, reinforced mounting point, you can't use a non-OE mounting point on an aftermarket seat base (or slider) to the best of my knowledge. This is normally on the transmission tunnel and there are documented NZTA/LVVC standards for this with all of the necessary measurements.

Did you find this: https://www.lvvta.org.nz/documents/standards/LVVTA_STD_Seatbelts_& Seatbelt_Anchorages.pdf

 

sweet thanks a lot for the info, much appreciated. From talking to a certifier ive come to the conclusion that the most straightforward method is to use nzkw bases and mount the receptacle to the transmission tunnel to NZTA/LVVC standards. I won't be using sliders as I don't need rear seat access and im the only driver of the car so that keeps things simple too. I will be using Sparco Rev art seats, and will get matching FIA spec side brackets to make sure all the parts are of a reasonable quality to ensure safety. Then should just be a matter of coding the airbags. The other end of the seat belt shouldnt be a problem?

Cheers,

[M3AN 4016]

15 minutes ago, elias said:

sweet thanks a lot for the info, much appreciated. From talking to a certifier ive come to the conclusion that the most straightforward method is to use nzkw bases and mount the receptacle to the transmission tunnel to NZTA/LVVC standards. I won't be using sliders as I don't need rear seat access and im the only driver of the car so that keeps things simple too. I will be using Sparco Rev art seats, and will get matching FIA spec side brackets to make sure all the parts are of a reasonable quality to ensure safety. Then should just be a matter of coding the airbags. The other end of the seat belt shouldnt be a problem?

Cheers,

All good and that sounds like a great plan. Other end of (stock) seatbelt will certainly not be an issue, if it's OE it's already approved.

All said and done, since you're putting in a half cage and proper seats, why not install a 3 or 4 point harness? That will probably cost you less than adapting the lap/sash and provide a more secure human/seat interface...

Edited January 24, 2023 by M3AN

[elias 253]

1 minute ago, M3AN said:

All good and that sounds like a great plan. Other end of (stock) seatbelt will certainly not be an issue, if it's OE it's already approved.

All said and done, since you're putting in a half cage and proper seats, why not install a 3 or 4 point harness? That will probably cost you less than adapting the lap/sash and provide a more secure human/seat interface...

From what I understand harnesses are only street legal with a full cage, complete airbag removal and motorsport authority card but I may have misinterpreted the rules.

Will be getting a harness bar as a part of the half cage to keep the option for track use etc.