BMW M3 (E30 M3 | E36 M3 | E46 M3 | E92 M3 | F80/X)

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-   -   DIY: 6 point harness + bucket seat -- fully reversible (

SYT_Shadow Sun, May-15-2016 04:24:57 AM

6 point harness + bucket seat -- fully reversible
For the longest time I've wanted to install 6 point harnesses for track use while maintaining street-legality and without welding anything to the car.

This turned out to be quite the project so I decided to document it. This will not be as thorough as other DIY's as it isn't as complex.

Even though I did this to my E92, the instructions are universal

I am sure many will be horrified by the thought of fixed back seats and no roll protection. To them, I say that Scroth's documentation makes it very clear that 6 points are safer than 3 points in every situation other than the roof crashing down on you.

Before this modification I was running Scroth QFP with my stock cloth, manual seats. Needless to say, there is a massive difference in how stable my body is at the track.

Disclaimer: this is meant to showcase what I did. Race setups should be installed by licensed shops even if used for the street. I am not liable for any damage you cause to yourself, others or your car as a result of these modifications

Here is the hardware used:

2 Sparco Ergo seats. These have removable halos for street use and are reputed to be quite comfortable.

1 Brey-Krause harness bar. This was a key component of the mix as it's tested to meet DOT crash test standards.

2 Recaro sliders as I double-track the car and it makes ingress/egress much easier (no removable steering wheel either...)

Floor, sub, side and 'hybrid' seatbelt mounts from Match Schnell.
These hybrid mounts are supposed to allow you to run the 3 point and the 6 point together.
This was a complete fiasco. I don't understand how a reputable company like MS can make what can only be described as useless garbage.
I contacted their tech support and got some of the most asinine answers I've ever heard. They actually told me the same part that is described on their site as 'allows 3 points and 6 points at the same time' could have one OR the other. Upon pointing out what their website said all communication stopped.
EAS and Bimmerworld, you should stop selling this garbage.

Sub belt

Side mounts

Floor mounts

And the falsely advertised hybrid lap belt mounts

BK bar install
This comes with pretty clear directions and is easy to install. Once install you will lose access to your rear seats.

I removed the rear seats and backrests as they no longer serve a purpose

On the left, you install one bracket

You do the same thing on the other side and then can attach the rear points of the bar

And the other side

Now you have to mount the front points of the bar. It mounts to the stock seatbelt position on the floor of the car behind the front seats
Once you remove the OEM bolt, you can slide the black metal rod out with a twisting motion. See the pics below
This is also what you'll use to route the 3 point belt through the seat
You add the BK floor support as well as the exterior lap belt attachment

The BK bar has two front bars which bolt into the floor supports
This is what you're trying to achieve

Finished! It is incredibly solid!

Now lets move onto seat mounting
These are the parts you need

You want to build a sandwich in this order

The speaker grills must be removed. I left the actual speakers as I like the front subwoofers but they can be removed for a more hardcore build. Apparently they weigh 5lb each and the sound system will keep working without them once removed.
This is what it looks like once you've removed the front seat

The grill is removed with a phillips screwdriver

To remove the front seat, slide it backwards, remove the front bolts, then slide it forward and remove the rear two bolts

You will need to disconnect a large wiring harness under the seat

Remove the stock seat

Remove the stock 3 point receptacle from the stock seat. You'll reuse this on your race seats

To do this you'll need to open up the wiring harness and remove a couple cables which are connected to the 3 point

Put the floor mounts onto the car and install the sub belt mounting point.
It screws onto the bottom of the floor mounts

Once the floor mounts and sub belts are in place, you can bolt them down securely and attach the sub belts

Attach the sub belts to the bottom mounts and sub belt bracket

Here is a closeup of the subbelt bracket and the floor mount installed

Now, install the side mounts to your race seat. I used the second most inclined position possible as I have to drive to the track and sometimes that's 10h away.

I used some regular washers to space the sidemount out a bit

I also used washers on the outside bolts to help distribute force in case of an accident

Next, you'll install a bolt through the slider (first you 'open' the slider up) and sandwich the 3 point/6 point holder in there. There's a bolt welded to the side mount which allows this

The 3 point gets screwed onto the 'hybrid' MS part which is supposed to allow both the 3 point and a lap belt attachment.
As this is false advertising. In the end I bought a BK lap belt attachment for the E46M and cut it, then sandwiched it along with the 3 point
For additional security, I added a nut to the outside even though the mount is threaded

After screwing in the front and the rear of the slider, this is the result

Now it's a matter of placing the seats on the floor mounts and looking for holes which are accessible on both sides of the front or rear, whatever you want first

Finally, you route the 3 point belt through the seat and voila! You are finished

Final pics

Note that now you will have the airbag lights on. There are no seatbelt chimes because the car detects the seat belt is 'missing' and leaves you alone other than a lot of warning lights.
I bought a OC3 emulator but decided to just code them all out. I especially appreciate having removed the 'seatbelt butlers', as when using the 6-pts they would frequently interfere with the stock seatbelts and just be a nuisance.

SYT_Shadow Sun, May-15-2016 04:25:32 AM

Re: 6 point harness + bucket seat -- fully reversible
The MS people say this mount works for both the 3 points and a lap belt attachment point. That is NOT the case.

Here are some closeup pics of how the E92 stock 3 point receptable blocks almost 100% of the second hole which is supposed to be used for this.

Their tech support was worse than useless and blamed the issue on me even though their advertising is very clear

SYT_Shadow Sun, May-15-2016 04:25:57 AM

Re: 6 point harness + bucket seat -- fully reversible
Fast forward a year and I'm putting seats in the E90 now as the E92 is going back to the stock seats.

As the seat mounting was a major issue for me in the E92 and only Brey Krause had a good product, I went to them when it was time to do this to the E90. They build a harness bar for the E90 as well!
I asked them whether they had anything for the seat mounting as I heard rumors that they were developing a race seat mount that reused the OEM sliders. It turns out they have!

OEM sliders are way better than aftermarket sliders, even the Recaro mounts I used on the E92. With the Recaro mounts you could 'move' the seat side to side quite easily with your hands. I always thought that was 'how they all are' until I got into the car after it had the BK system that reuses OEM sliders, it is a night and day difference!

Additionally, the BK seat mounts gives you a few more advantages:
The sliders is actually designed by BMW to have the 3 point seat belt attached to it. This is a big difference from the Recaro mounts which are not.
It's WAY more solid than aftermarket sliders
It's cheaper as you already have the OEM sliders on your BMW seat
If your current seat has power sliders (mine do not), that functionality is retained with the race seats! How awesome is that?

Da Jemster Mon, May-16-2016 07:00:13 PM

Re: 6 point harness + bucket seat -- fully reversible

SYT_Shadow Mon, May-22-2017 07:28:59 PM

Re: 6 point harness + bucket seat -- fully reversible
Updated post #3!

pat-b Thu, Jul-06-2017 02:53:22 AM

Re: 6 point harness + bucket seat -- fully reversible
def in depth how to. thanks for sharing

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