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      03-21-2022, 11:27 PM   #1
lafuerza
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Z4MC Recommended Seat Mounts and Occupancy Mat

Got a set of Recaro Sportster GT seats in black leather and carbon weave to match my carbon weave dash and replace my electric/heated oem seats for more aggressive driving. Seems I graduated past the grip of the oem seats as I spent too much time in the passenger seat on high g turns.

I will be using recaro sliders unless there is a better option.

Looking for best fitting floor mount for the Z4MC to center the seat properly. I am okay with oem height for my driving position.

Also looking for options for passenger occupancy mat. US oem comes with foam for $617 which does not interest me. I do want to have oem functionality still like to take weekend fun runs not on the track.

Thanks in advance.
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      03-22-2022, 08:45 AM   #2
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I had ordered my occupancy mat from a dealer that had them listed in texas from their parts center when searching for it online. When I looked a couple years ago at my local dealer I was told the mat by itself had been discontinued and if I wanted to get one now it'd be getting the whole bottom portion of the seat
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      03-22-2022, 11:01 PM   #3
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The VAC Motorsports floor mount adapters are great for getting the seat into the exact position you want it. They add ~3/4" stack height to whatever brackets you use, but then they give you plenty of fore/aft and side to side flexibility in where you mount the seat.
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      03-30-2022, 10:56 AM   #4
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If you're okay with the stock seat height, you should get the Brey Krause mounts. They reuse the OE BMW sliders, which are stronger, cheaper (you already own them), have more travel, don't get noisy over time, and mount belts above them-- so the belts stay properly located to the seat, regardless of the position of the slider.

https://www.bkauto.com/R_9246_Bottom...4_p/r-9246.htm
https://www.bkauto.com/R_9247_Bottom...4_p/r-9247.htm

I would just code the occupancy sensor off. Its only function is to make the passenger airbag not deploy in an airbag if there is nobody in the seat, to make crashes cheaper.
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      04-03-2022, 01:39 PM   #5
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Quote:
Originally Posted by lafuerza View Post
Got a set of Recaro Sportster GT seats in black leather and carbon weave to match my carbon weave dash and replace my electric/heated oem seats for more aggressive driving. Seems I graduated past the grip of the oem seats as I spent too much time in the passenger seat on high g turns.
Do you have a picture of these seats? I have been considering this setup as well, stock drivers seat is big for a svelte person like me and the bottom foam is worn out.
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      04-08-2022, 02:31 AM   #6
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PLANTED do a z4m specific seat bracket that comes with the seat belt and seat buckle mounts pre welded, as much as i love the VAC and similar options but the price point is insane for those pieces imo, plus you need all sorts of accessories to get the stock seat belt to work plus the reciprocal. your talking a $1000 easily.

i hope these brackets workout as they are really nice pieces and the price point is fantastic, ive got a set to fit my carbon fibre tillet seats , using tillet slider and a slight taller mount.
my mounts are sat in my workshop ready to install when the weather improves here in the UK and they seem solid quality.

https://www.plantedtechnology.com/pl...ger-right.html
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      04-08-2022, 08:23 AM   #7
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Originally Posted by Beedub View Post
i hope these brackets workout as they are really nice pieces and the price point is fantastic, ive got a set to fit my carbon fibre tillet seats , using tillet slider and a slight taller mount.
my mounts are sat in my workshop ready to install when the weather improves here in the UK and they seem solid quality.

https://www.plantedtechnology.com/pl...ger-right.html
Planted mounts are held in high regard within the Miata and other communities, let us know how they pan out.
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      04-11-2022, 12:14 AM   #8
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I have had great experience with the Brey Krause seat slider base mounts for my Recaro, great build quality and under $240 per mount.
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      04-12-2022, 11:56 AM   #9
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Quote:
Originally Posted by 86Zed View Post
Planted mounts are held in high regard within the Miata and other communities, let us know how they pan out.
this is great news, i will try and get these installed within the next 3-4 weeks , ill record it for you YT channel where ill be doing a proper 4 episode piece on the car.

excuse the massive pics but heres the seats!! 4kg each! alot of saving up to make these happen!
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      04-13-2022, 01:05 PM   #10
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Love the tillet seats. My buddy has a set and sat in them. I was looking at them very closely until a local recaro deal popped up. Looks like the race shop is recommending the VAC mounts with recaro sliders for my build. will see how it goes. They do a lot of BMW track builds.
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      04-13-2022, 01:28 PM   #11
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VAC everything is garbage. Don't do it.
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      04-13-2022, 02:35 PM   #12
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Quote:
Originally Posted by Obioban View Post
VAC everything is garbage. Don't do it.
I've used the VAC seat mounts in my E30 M3 for more than a decade. I've found that they are excellent. I have also sourced them for my Z4, and the pieces are again excellent quality.

My Z4 came with the Planted mounts, and they leave some things to be desired. While they seem decently constructed, the mounting tabs to the floor are pretty thin, and the mounts could be lower. Additionally, the inner floor mounting tabs (near trans tunnel) are under the main structure making them essentially impossible to properly tighten the fasteners (factory fasteners are 28ft-lb + 90deg).

I would choose the VAC mounts every day of the week.
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      04-13-2022, 03:18 PM   #13
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Quote:
Originally Posted by lelandr View Post
I've used the VAC seat mounts in my E30 M3 for more than a decade. I've found that they are excellent. I have also sourced them for my Z4, and the pieces are again excellent quality.

My Z4 came with the Planted mounts, and they leave some things to be desired. While they seem decently constructed, the mounting tabs to the floor are pretty thin, and the mounts could be lower. Additionally, the inner floor mounting tabs (near trans tunnel) are under the main structure making them essentially impossible to properly tighten the fasteners (factory fasteners are 28ft-lb + 90deg).

I would choose the VAC mounts every day of the week.
I did a fairly lengthy write up on seat mounting. Most mounts on the market aren't great. Belt only correctly located in one seat position, crappy sliders, etc. VACs are, IMO, particularly bad-- a friend of mine had them fail in a crash (as in, the slots the bolts go through to attach the seat to the car failed). I would rather stick with the stock seats than use VAC mounts and/or slides.

Things I value in aftermarket seat mounts detailed here:
https://nam3forum.com/forums/forum/m...ck-bucket-seat

Semi related: I am a seat engineer (albeit for commercial and military vehicles, primarily).
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      04-13-2022, 09:32 PM   #14
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Quote:
Originally Posted by Obioban View Post
I did a fairly lengthy write up on seat mounting. Most mounts on the market aren't great. Belt only correctly located in one seat position, crappy sliders, etc. VACs are, IMO, particularly bad-- a friend of mine had them fail in a crash (as in, the slots the bolts go through to attach the seat to the car failed). I would rather stick with the stock seats than use VAC mounts and/or slides.

Things I value in aftermarket seat mounts detailed here:
https://nam3forum.com/forums/forum/m...ck-bucket-seat

Semi related: I am a seat engineer (albeit for commercial and military vehicles, primarily).
That was a very interesting post, and I agree with much of it for the mixed use seat which you are seeking.

For my E30 M3, I used the factory sliders with Lee Vuong's brackets bolted to Recaro SRD seats. For track use, I used a Recaro SPG Vario Halo with Recaro angle brackets bolted directly to the VAC floor mounts (these things) (my plan for the Z4 is the same with the addition of Sparco sliders). My Z4 currently has whatever the newest Sparco fat guy seats on Sparco sliders to the Planted mounts. My M3 currently uses the VAC mounts with Recaro sliders directly to the SRDs as I wanted to sit lower. While the SRD has room for the 3-point receiver, the factory one is too long so as you mentioned with the fixed back seats, the lap belt isn't as tight.

I'm confused about what failed on your friend's mounts? The floor mounts are bored and tapped with multiple rows of holes for mounting flexibility of either brackets or sliders. Are you saying that the material between adjacent holes tore through? As the bolt sandwiches the Recaro seat bracket (or a slider) to the floor mount, I would think that the bolt under the washer in single shear would be the weak link here (assuming that the crash load is truly in the shear plane, which seems unlikely). The bolt will apply a normal force into the seat mount, but this is distributed over a comparatively greater area (I think that I use 25mm bolts which go all the way through).

For the most part, in my plan, I think that the either the sliders themselves or the M6 or M8 bolts clamping the parts together seem the weakest links.

Perhaps you are saying that the holes (mine are not slots) in the floor mounts where the M10 fasteners attach to the floor failed? I.e., that perhaps they are not thick enough at this point?

Thanks for your post.
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      04-14-2022, 08:25 AM   #15
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Slides are absolutely the greatest failure point. We use the same slide provider as Recaro, and have redundant fail safes to keep the seat attached to the car as they fail 100% of the time in pull testing (which, unless you're running a seat back support, is what you do any time you go into a wall backwards). We have tested the slide provider than Sparco uses, and they're significantly weaker. For my personal cars, I'd only use the slides that BMW provides (as they're designed to take belt loads or reverse crash loads), or bolt the seat directly to the floor (which lets you properly locate the belts, which you can't do for any position but one with slides).

VAC seat mounts:
Their underlying issue is being slotted front AND rear where the seat attaches (meaning only friction hold it in place, so it can built up inertia in a crash-- only one side should be slotted, so the seat can't move), and not enough material between slots. Every other seat mount maker I can think of only slots one end of the mount (which should be the front, as they take less load on average).

Using my best MS paint skills, first his seat failed at orange, then it failed at red:
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      04-14-2022, 03:31 PM   #16
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Quote:
Originally Posted by lelandr View Post
I've used the VAC seat mounts in my E30 M3 for more than a decade. I've found that they are excellent. I have also sourced them for my Z4, and the pieces are again excellent quality.

My Z4 came with the Planted mounts, and they leave some things to be desired. While they seem decently constructed, the mounting tabs to the floor are pretty thin, and the mounts could be lower. Additionally, the inner floor mounting tabs (near trans tunnel) are under the main structure making them essentially impossible to properly tighten the fasteners (factory fasteners are 28ft-lb + 90deg).

I would choose the VAC mounts every day of the week.
i did notice those inner bolt locations looked difficult to reach.... ive also read they are quite high, The tillet carbon shell seat is VERY low.... so this will be helpful in my case. Their must be a way i an access those inner bolts, even if i have to trash a tool to make it work.
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      04-15-2022, 06:36 AM   #17
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Quote:
Originally Posted by Beedub View Post
i did notice those inner bolt locations looked difficult to reach.... ive also read they are quite high, The tillet carbon shell seat is VERY low.... so this will be helpful in my case. Their must be a way i an access those inner bolts, even if i have to trash a tool to make it work.
Normally, I would recommend that you use a torque extender to get under there. However, the factory bolts require 35Nm (I think) and then a further 90deg (I'm sure) as these are the BMW micro-encapsulated screws. You could torque them and then put a mark and use a good 6-point box-end wrench to get as close to 90 as you can. I hope you work out.

I got around this by sourcing good-quality 10.9 flanged fasteners and simply torquing them to 35Nm which is what BMW does on pretty much every other car.
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      04-15-2022, 06:49 AM   #18
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Quote:
Originally Posted by Obioban View Post
Slides are absolutely the greatest failure point. We use the same slide provider as Recaro, and have redundant fail safes to keep the seat attached to the car as they fail 100% of the time in pull testing (which, unless you're running a seat back support, is what you do any time you go into a wall backwards). We have tested the slide provider than Sparco uses, and they're significantly weaker. For my personal cars, I'd only use the slides that BMW provides (as they're designed to take belt loads or reverse crash loads), or bolt the seat directly to the floor (which lets you properly locate the belts, which you can't do for any position but one with slides).

VAC seat mounts:
Their underlying issue is being slotted front AND rear where the seat attaches (meaning only friction hold it in place, so it can built up inertia in a crash-- only one side should be slotted, so the seat can't move), and not enough material between slots. Every other seat mount maker I can think of only slots one end of the mount (which should be the front, as they take less load on average).

Using my best MS paint skills, first his seat failed at orange, then it failed at red:
Another +content post.

The only reason I was considering slides for my Recaro Halo seat is ingress and egress. The Z4 Coupe doesn't have a huge door & piling 195lbs of 6'1" dude in and out of the seat would be easier if it could slide. I suppose that for the race seat, i could go directly to the floor mounts and hope that I can see over the dash.

Interesting about your comment of the Recaro vs. Sparco sliders. When I bough the car, it came with Sparco, but I suppose that after your comment, I will source the Recaros. I don't have the original sliders as the car didn't come with them, and I wouldn't want the motorized stuff anyway.

I totally see why the VAC mounts failed. Quite frankly, I'm shocked that they would use slots front and back. The bolts there aren't that tight to start with--while I wouldn't want my finger to be subjected to that clamping force, it's not as if they are super tight. Normally, I would expect a fitted hole in the front and a slot in the back.

Anyway, I am not using that part as I have the Recaro Side mounts for the Recaro seat and the Sparco side mounts for the Sparco seat. What I have from VAC are the floor mounts at the base of the side mounts you marked only.
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      04-16-2022, 03:56 AM   #19
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I have original Recaro floor mounts and sliders specific to the Z4 (base frame 2014.071.2) enroute and will report how they are. I will be mounting my Recaro RS-W with Recaro sidemounts specific for them too i.e. Recaro everything top to bottom.

I ordered over 3 months ago so these took a long while, ETA is this coming week. My supplier also ordered the left-hand side (2014.071.1) if any one is looking for them. Cost approx US$380 to get them direct from Japan to Singapore via the authorised Recaro dealer here.
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      04-24-2022, 09:40 AM   #20
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Ok guys,

ive literally been sitting on these for months now ( pun intended ) ive finally got all the needed pieces together to make this happen. Its taken 6 months of research, researching the best seats, what i want from the new seat install, sourcing hardware from across the globe and trial and error. The install should be complete by next weekend. My seat bases have welded in tabs for the seat belt mount point Plus the the tensioner. Due to TOMK mentioning how low these TILLETS sit in the car , i went with the raised planted bases , the sliders add additional height , plus ive got the taller TB3 tillet side mounts. From my calculation even with all that additional height i'm still going to be lower that the stock seat at it lowest setting. The B5 seat has a big dip in the base and you simply don't realize how low they position you. All bolts are titanium and everything needed to be to an OEM level of finish. The custom seat pads have not arrive as yet. So far the seat project has cost around 4k so a significant investment, these seats will bring the car under 1400kg.

Heres some pics of things coming together, next weekend will see the install finally happen , ill be recording the install for my YT channel.

I need the car ready for two reasons, 1) got a BMW magazine shoot at my workshop , 2) i want to get on my first track day by the end of the month

putting this lot together is a total PITA and you need to expect that modding the hardware is going to have to happen. So far really pleased with the OEM type look of the bases and side mounts.
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      04-24-2022, 10:43 AM   #21
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So far, ( i hope i don't come to regret this ) but i don't see any reason why you wouldn't choose the Planted bases, excellent construction, lots of room for custom mounting to the top plate but the real deal killer is the seat belt and tensioner pre welded tabs. In my case I need the height they provide as i'm using a carbon shell seat that feels like your sitting way too low.

final install will be happening next week which ill be recording for my YT channel.
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      05-02-2022, 12:38 PM   #22
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Quote:
Originally Posted by Beedub View Post
So far, ( i hope i don't come to regret this ) but i don't see any reason why you wouldn't choose the Planted bases, excellent construction, lots of room for custom mounting to the top plate but the real deal killer is the seat belt and tensioner pre welded tabs. In my case I need the height they provide as i'm using a carbon shell seat that feels like your sitting way too low.

final install will be happening next week which ill be recording for my YT channel.
Do you want knocks against it?

-Long, unreinforced tabs that'll become straight in crash (aka, expect the seat to relocate and the belts to get looser in a crash)
-Limited slider options, and none of them great.
-The seat belt mount position is fixed, so only one slider position properly locates the lap belts do you body.
-their side mounts (doesn't apply to you) have HUGE slots (weak)
-weak and fixed position sub strap mount, that isn't properly located for most seat installs

Their side mounts especially sketch me out:

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