Harness Install & My solution to headrest problem.

[JMon]

I can not stand driving a car on a track with a 3 point belt.
Since Schroth doesn't have a "quick fit" solution for the F80, I decided to figure out a solution.

I used the Schroth E90 quick fit pro kit with Anit-Submarining.
Only thing different I had to do was add a longer bolt for the main seat belt.

Installation took about 30 mins and was pretty easy.

Now to the problem with the headrest not having a belt pass through:
The harness naturally seems to come up at the exact right spot (When using a HANS device)
I additionally had a custom strap made to ensure the belt can not slide down between the seat sides. (Function the poles in the E90 headrest did)

I'm not sure this is safe, but it is the solution I'm using and the best I could come up with.

[JMon]

pictures:

[Acree]

Wow... nicely done.


TrakBch

[MasterP]

Nah. Not for me.

5/6 points for fixed backs.

Stock for Stock seats.

[Dweezil]

so you are using the shoulder pads to pad the belt against the seat? Shoulder pads are not used anyway I guess when using hans...Give me details on the custom strap please

[M3 Number 86]

Is the custom strap behind the headrest or under your neck?

[redpriest]

I hope Schroth makes a solution soon for the F8X M3/M4.

[afadeev]

[QUOTE=JMon;19496136]

Originally Posted by redpriest

I hope Schroth makes a solution soon for the F8X M3/M4.

They do, they just don't advertise it.

I've just test fitted my 08 Mini Schroth ASM quick-fit harness, and it fits and works perfectly.
Pics to follow.

Originally Posted by JMon

I can not stand driving a car on a track with a 3 point belt. [...] I'm not sure this is safe, but it is the solution I'm using and the best I could come up with.

I have no doubts that it's safe.
But for folks who don't understand Schroth ASM technology and testing results - no, it's definitely not for you.

Originally Posted by TrakBch

Nah. Not for me.
5/6 points for fixed backs.

This is actually a 4-point Schroth harness.
Either way, if you want proper 5/6 point harness, fixed-back seat is not enough. You really need a proper roll cage to go with all that!

a

[redpriest]

[QUOTE=afadeev;19526629]

Originally Posted by JMon

They do, they just don't advertise it.

I've just test fitted my 08 Mini Schroth ASM quick-fit harness, and it fits and works perfectly.
Pics to follow.




I have no doubts that it's safe.
But for folks who don't understand Schroth ASM technology and testing results - no, it's definitely not for you.



This is actually a 4-point Schroth harness.
Either way, if you want proper 5/6 point harness, fixed-back seat is not enough. You really need a proper roll cage to go with all that!

a

Pics of fitment?

[SYT_Shadow]

Looks pretty good! However it would not work with the PCA clubs I run with in the Northeast. Some instructors have freaked out when they see the appropriate QFP belts on the E92M and only relax when I show them the label which specifies it was made for that model.

This was a large screwup on BMW's side. The M3 is the king of dual purpose cars and the stupid fixed headrest with no belt holes screws this up.

When I get my F80 it'll get a harness bar (BK), seats and 6 points

[M4ymb]

Very nice try, good thinking!

But this won't pass any track tech inspections. The angle of the belts are more than 30 degrees at the attach points on the rear seat. You'll need a harness bar to attach there. The cross over behind the seat is a pinch point (at least it looks like in photo) that can cause the belt to fail.

Changes that need to be made - Make a harness holder for the top part of the seat. Something out of Alu or metal wrapped in a soft material. That can be bolted to the frame of seat. Again a harness bar usually has this type of belt holders.

Also needed to use the stock seat is a Sternum Strap for your belts, All harness companies offer belts with them.

Simple changes I think. Attach points look ok, but this current setup will compress you back in any type of crash.

As far as these seats go, they are fine IMO. They are great daily seats and have a design in the backrest that allows for proper Harness Belts on the chest.

The image is only an example of how to guide the belts through and the straps needed on chest.

[adc]

Originally Posted by M4ymb

Very nice try, good thinking!

But this won't pass any track tech inspections. The angle of the belts are more than 30 degrees at the attach points on the rear seat. You'll need a harness bar to attach there. The cross over behind the seat is a pinch point (at least it looks like in photo) that can cause the belt to fail.

Changes that need to be made - Make a harness holder for the top part of the seat. Something out of Alu or metal wrapped in a soft material. That can be bolted to the frame of seat. Again a harness bar usually has this type of belt holders.

Also needed to use the stock seat is a Sternum Strap for your belts, All harness companies offer belts with them.

Simple changes I think. Attach points look ok, but this current setup will compress you back in any type of crash.

As far as these seats go, they are fine IMO. They are great daily seats and have a design in the backrest that allows for proper Harness Belts on the chest.

The image is only an example of how to guide the belts through and the straps needed on chest.

The Schroth Quick Fit is designed to attach to the rear bench seatbelt points. It was made to work with this angle. The angle is very similar between E90 and F80, if anything the F80 has a smaller angle due to the longer wheelbase.

[afadeev]

Originally Posted by JMon

Facts first:
1). Harness in question is Schroth QuickFit 4-point harness with ASM (Anti-SubMarining). I am not going to debate the pro's and con's of 4-point ASM Schroth harnesses. But here is what they are, with an explanation of how they work:
https://www.hmsmotorsport.com/produc...kfit-harnesses
2). Schroth QuickFit ASM harness is DOT approved, and street legal. Therefore, it is approved and legal for all DE's. By definition, they will pass tech inspection (though your assurance of point #2 may be requested).
3). There is NO requirement to have the shoulder belts to be mounted parallel with the top of the seat. Anchoring them to the top of the rear shelf is one of the options, but so is mounting them to the BMW factory seat belt anchors at the base of the rear seats:
https://www.hmsmotorsport.com/docs/B...structions.pdf

They are legal, and I've personally been cleared with them for multiple DEs with multiple cars over the years (E36M3, MCS, F80M3).

Originally Posted by M4ymb

Simple changes I think. Attach points look ok, but this current setup will compress you back in any type of crash.

Not true.
Observe Schroth test video:

Originally Posted by adc

The Schroth Quick Fit is designed to attach to the rear bench seatbelt points. It was made to work with this angle. The angle is very similar between E90 and F80, if anything the F80 has a smaller angle due to the longer wheelbase.

Exactly!

Frankly, I'm far more comfortable attaching them at the two rear seat belt anchor points, then I would have been at the flimsier rear shelf.


The QuickFit allows me to leave 2 outboard attachment points permanently installed in the car. I just clip the harness on before the event, and remove it afterwards to restore full use of the rear seat.

YMMV,
a

[M4ymb]

Solid points both ways but It's your safety. I personally don't like what I saw in the video mainly because your asking the OEM seat to perform a task it was never designed to do. No OEM belts guide through the seat any longer because the loads on the seat are to great. That video and that seat can be crushed like a can if enough force is applied to the center like that. Installing a harness bar allows for the bar to perform the energy transfer not the seat. Look at the OEM belts in the car now. At no point does it rely on the seat to do anything besides keep you upright.

[M3 Esq]

It's your safety and your car, so if you're comfortable with it that's up to you. But the stock seats airbags and belts are a safety system engineered by professionals to work together to keep you safe. That system was extensively crash tested. The schroth belts obviously were not designed to work with your application and your setup has never been crash tested. I hope for your sake you don't need to test it. Out of concern for your own safety you really ought to rethink that setup. I've seen a lot of shit happen at the track and people get hurt without proper safety. Call HMS Motorsport and talk to Joe Marko. He knows more about race car safety than anyone I've ever met. Maybe they have a proper solution for you.

[afadeev]

Originally Posted by M3 Esq

It's your safety and your car, so if you're comfortable with it that's up to you. But the stock seats airbags and belts are a safety system engineered by professionals to work together to keep you safe. That system was extensively crash tested. The schroth belts obviously were not designed to work with your application and your setup has never been crash tested.

You are WAY over-complicating this.
4 point Schroth with ASM will turn into a 3-point stock-like seat-belt in case of an accident (the folded flap on the inboard shoulder belt will release and expand the length of the driver right shoulder strap). Therefore, anything that was tested to work with OEM 3-point belt (airbags, etc) will work as intended.

The benefit of the Schroth ASM is that in holds your butt in place to provide extra feedback, reduce fatigue, and avoid that crash in the first place.

But obviously, to each his own.

Originally Posted by M3 Esq

Call HMS Motorsport and talk to Joe Marko. He knows more about race car safety than anyone I've ever met. Maybe they have a proper solution for you.

No kidding - I bought my Schroth ASM belts from HSM.

If you have a specific safety issue you want to raise - please do so.
If you are fear mongering in general - OK then.

Originally Posted by M4ymb

I personally don't like what I saw in the video mainly because your asking the OEM seat to perform a task it was never designed to do. No OEM belts guide through the seat any longer because the loads on the seat are to great. That video and that seat can be crushed like a can if enough force is applied to the center like that. Installing a harness bar allows for the bar to perform the energy transfer not the seat. Look at the OEM belts in the car now. At no point does it rely on the seat to do anything besides keep you upright.

Now that is an interesting concern.
I never evaluated the probability of the back of the seat collapsing under the additional seat belt compression loads. I would imagine similar concerns would be present in rear-end collision cases where longitudinal loads are placed on the seat back:
https://www.facebook.com/SeatBackFailureAwareness/

Now I really want to know more about M3/4 seat back strength under normal driving conditions (forget the track and the Schroth debate)!

a

P.S.: On other hand, Schroth recommends this arrangement, and there must have been some engineering studies behind their recommendation to mount rear attachment points as described. Alas, that's less than perfectly comforting.
P.P.S.: AMG C63 and GTR's OEM seats do offer harness pass through the back of the front seats. Not sure how much stronger they are vs. M3/4 seat backs:
https://www.google.com/url?sa=i&rct=...61374039653491
https://endagtr.files.wordpress.com/...tion-seats.jpg

[afadeev]

[QUOTE=redpriest;19569693]

Originally Posted by afadeev

Pics of fitment?

Here are a few more from my car:

[M3 Esq]

Originally Posted by afadeev

You are WAY over-complicating this.
4 point Schroth with ASM will turn into a 3-point stock-like seat-belt in case of an accident (the folded flap on the inboard shoulder belt will release and expand the length of the driver right shoulder strap). Therefore, anything that was tested to work with OEM 3-point belt (airbags, etc) will work as intended.

The benefit of the Schroth ASM is that in holds your butt in place to provide extra feedback, reduce fatigue, and avoid that crash in the first place.

But obviously, to each his own.



No kidding - I bought my Schroth ASM belts from HSM.

If you have a specific safety issue you want to raise - please do so.
If you are fear mongering in general - OK then.



Now that is an interesting concern.
I never evaluated the probability of the back of the seat collapsing under the additional seat belt compression loads. I would imagine similar concerns would be present in rear-end collision cases where longitudinal loads are placed on the seat back:
https://www.facebook.com/SeatBackFailureAwareness/

Now I really want to know more about M3/4 seat back strength under normal driving conditions (forget the track and the Schroth debate)!

a

P.S.: On other hand, Schroth recommends this arrangement, and there must have been some engineering studies behind their recommendation to mount rear attachment points as described. Alas, that's less than perfectly comforting.
P.P.S.: AMG C63 and GTR's OEM seats do offer harness pass through the back of the front seats. Not sure how much stronger they are vs. M3/4 seat backs:
https://www.google.com/url?sa=i&rct=...61374039653491
https://endagtr.files.wordpress.com/...tion-seats.jpg

I'm not trying to start a flame war about 4 points, that's all been discussed at length in other threads. My comments were directed at OP, and I was reacting to the fact that OP is using E90 quick-fits on his F80, and fabricated a custom strap to make it fit. I am not an engineer and I don't profess to be an expert in racecar safety, but using a quick-fit belt designed for another car, and assuming its safe for your car based on the fact that it's been tested and determined safe for the car it was designed for makes no sense to me. I don't know what belts you are running.

[morgan302]

Why not run them to the rear "package tray" and the buckle point that is in middle of each rear seat?

[M4ymb]

Now that is an interesting concern.
I never evaluated the probability of the back of the seat collapsing under the additional seat belt compression loads. I would imagine similar concerns would be present in rear-end collision cases where longitudinal loads are placed on the seat back:
https://www.facebook.com/SeatBackFailureAwareness/

Now I really want to know more about M3/4 seat back strength under normal driving conditions (forget the track and the Schroth debate)!

a

P.S.: On other hand, Schroth recommends this arrangement, and there must have been some engineering studies behind their recommendation to mount rear attachment points as described. Alas, that's less than perfectly comforting.
P.P.S.: AMG C63 and GTR's OEM seats do offer harness pass through the back of the front seats. Not sure how much stronger they are vs. M3/4 seat backs:
https://www.google.com/url?sa=i&rct=...61374039653491
https://endagtr.files.wordpress.com/...tion-seats.jpg[/QUOTE]
__________________________________________________ __________________________________________________ ___________

I'm pretty sure the OEM seat design is adequate to NHTSA ratings which "I Think" is 45mph.

As for the AMG / GT-R racing buckets and the "pass thru" design. I'd hope they are designed for the loads.

What I do know is Porsche GT seats are designed to only work with the RS cage installed. They come with a safety instruction book that says to use the 3 point OEM belt if the RS Cage is not present.

[afadeev]

Originally Posted by M3 Esq

I am not an engineer and I don't profess to be an expert in racecar safety, but using a quick-fit belt designed for another car, and assuming its safe for your car based on the fact that it's been tested and determined safe for the car it was designed for makes no sense to me. I don't know what belts you are running.

Just for the record - HMS/Schroth (and other vendors) don't crash-test their harnesses with every single vehicle + seat permutation. That would be silly expensive.

The focus of their customization is making sure that the right length belts are available for each car's mounting points. In the case of quick-fit Schroth harnesses, they test that the seat buckles fit into a given car's seat belt system (yes, they all differ). It just so happens that E90, Mini, and F80 seat buckles and relative interior dimensions are similar to identical, making the same harness re-usable across all of the above. Nice.

Originally Posted by M3 Esq

My comments were directed at OP, and I was reacting to the fact that OP is using E90 quick-fits on his F80, and fabricated a custom strap to make it fit.

That's not what he did.
The strap is mostly cosmetic, and prevents the shoulder belts from slipping to the sides of the seat when not in use. The same as what the normal headrest would do if shoulder belts were routed between its posts.

I don't have that strap.
Mine do slip to the side, so I have to adjust them when I buckle in. It's a minor inconvenience for me. So minor, that I have no plans to do anything about it.

But if you were bothered by the belts not staying exactly in place to slide perfectly over your shoulder when you get into the seat, than a strap like OP's would fix it.

a

[YMB_M3]

Originally Posted by afadeev

Just for the record - HMS/Schroth (and other vendors) don't crash-test their harnesses with every single vehicle + seat permutation. That would be silly expensive.

The focus of their customization is making sure that the right length belts are available for each car's mounting points. In the case of quick-fit Schroth harnesses, they test that the seat buckles fit into a given car's seat belt system (yes, they all differ). It just so happens that E90, Mini, and F80 seat buckles and relative interior dimensions are similar to identical, making the same harness re-usable across all of the above. Nice.



That's not what he did.
The strap is mostly cosmetic, and prevents the shoulder belts from slipping to the sides of the seat when not in use. The same as what the normal headrest would do if shoulder belts were routed between its posts.

I don't have that strap.
Mine do slip to the side, so I have to adjust them when I buckle in. It's a minor inconvenience for me. So minor, that I have no plans to do anything about it.

But if you were bothered by the belts not staying exactly in place to slide perfectly over your shoulder when you get into the seat, than a strap like OP's would fix it.

a

I just called Schroth Racing and asked about the 4 point harness for our cars and they said they don't make one for the F80 M3. Also, when I asked him if we could use the E90 kit he said that would by "wildly unsafe." Just some food for thought