How is the M3 GTS running both the three point OEM belt and a race harness?

[warp10]

As quoted above. Thinking about getting a race seat as I am doing multiple track days a month but still daily drive. Wanting to keep the three point but want to have the availability of the six point for safety at the track. Please advise vendors and all.

[w00tw00t]

subscribed!

[kaiv]

Not sure what your question is but yes you can have both the stock 3pt belt and an aftermarket harness installed.

You'll need an OE style seat belt receptacle mounted on the aftermarket seat mounts.

Example on my old car:

[Richard@M-World]

Yup as Kevin says some racing seat mounts offer attachment for the OEM seat belt receptacle. You can utilize the factory 3-pt system this way.

As for a 6-pt system, the only safe and proper way of installing them is to attach the shoulder belts to the roll cage/roll bar, and the anti-sub and lap straps to the chassis of the car with proper, welded reinforcement plates. Don't let anyone convince you otherwise.

Here are some pictures from the GT4 as they came from BMW. Courtesy of CheckCaptain.


Left lap strap (left side of seat)


Right lap strap (right side of seat)


Anti-sub straps (under the seat)

[warp10]

Originally Posted by Richard@M-World

Yup as Kevin says some racing seat mounts offer attachment for the OEM seat belt receptacle. You can utilize the factory 3-pt system this way.

As for a 6-pt system, the only safe and proper way of installing them is to attach the shoulder belts to the roll cage/roll bar, and the anti-sub and lap straps to the chassis of the car with proper, welded reinforcement plates. Don't let anyone convince you otherwise.

Here are some pictures from the GT4 as they came from BMW. Courtesy of CheckCaptain.

Attachment 814212
Left lap strap (left side of seat)

Attachment 814213
Right lap strap (right side of seat)

Attachment 814214
Anti-sub straps (under the seat)

Great info thanks which floor mounts would fit this need. I it matters I am looking at OMP and recaro seats.

Thanks

[bigjae1976]

VAC makes some universal mounts for hte E9X.

[paradocs98]

Originally Posted by Richard@M-World

As for a 6-pt system, the only safe and proper way of installing them is to attach the shoulder belts to the roll cage/roll bar, and the anti-sub and lap straps to the chassis of the car with proper, welded reinforcement plates. Don't let anyone convince you otherwise.

A really important point, because some vendors would have you believe (incorrectly) that you can safely attach the lap belt mounts and ASM belt mounts to the aftermarket seat mounts, and not directly to the floorpan.

[bigjae1976]

Originally Posted by paradocs98

A really important point, because some vendors would have you believe (incorrectly) that you can safely attach the lap belt mounts and ASM belt mounts to the aftermarket seat mounts, and not directly to the floorpan.

So VAC's sub strab bar which bolts on to their FMAs are a no-no?

[paradocs98]

Originally Posted by bigjae1976

So VAC's sub strab bar which bolts on to their FMAs are a no-no?

I did a lot of research on this a year ago because I was really interested in doing a Recaro or RaceTech fixed bucket/VAC floor mount combo for my sedan. I wanted to do this for keeping more planted in the seat on the track and for safety considerations. I wanted to run a real 5- or 6-point harness with it, which would mean having the lap belts attached to the brackets on the VAC floor mounts, as well as the ASM straps attached to a bracket on the VAC mount. Since I have a sedan and not a coupe, I'd have to use a harness bar instead of a roll bar or half-cage for mounting the shoulder straps.

My reading indicated that this would be a half-assed solution at best, and potentially less safe than just running the stock 3-point belt. The harness bar can break free from its mounts and fly around the car during an impact, and by attaching the lap belts and ASM belts to the VAC floor mounts, the force of the impact is transmitted to the four floor mount bolts that secure the floor mount to the floor, potentially allowing the whole seat and harness assembly to break free. I think you could end up like a monkey on a test sled bouncing around the interior of the car.

I'm pretty certain most sanctioning bodies and club racing groups require that the shoulder harness straps be mounted to a fixed roll bar or cage, and that the lap belts and ASM belts be secured to the floor pan/chassis, with a welded plate on the other side of the floor pan.

[Checkcaptain]

GTS also has welded brackets for the 6 point belt, plus rollbar.