Gaining head room for a tall person: Recaro SPG XL, BK R-9773, PEP hardware, & weldin

[oly]

I'm 6'5” and wanted to be able to wear a helmet so I've been evaluating how to get more head room in a 911 since at least a year before I bought my car. My goals were to maximize headroom, keep at least the original level of support and safety in the seat and seat belt mount, and have minimal permanent impact to the car. There were many ways to do this but this is the combination that worked best for me:

Seats: Recaro SPG XL – Racing shells so they get me very low and are tall enough to support the back of my head to well above my ears. And they are street legal. I tried many other seats and the only other option that fit my criteria were Kirkey Road Race seats. But the Kirkey's also require a cage which I'm not ready to do yet. I got the SPGs from HMS Motorsport.

Seat Mounting Brackets: Brey Krause R-9773 – I lucked out and got the only set of these that exist so far. The owner of BK had them developed for his SC with the goals of using the factory seat mounts (no sliders), maximizing head room, and maximizing leg room. They position the seat so that the lowest part of the seat is behind and below the aft end of the seat mounts. The owner used the brackets with Recaro SPG XLs for some time but then sold the SC so he did not need them anymore. So they put on new powder coating and sold them to me. I don't know why but BK decided not to produce more of them.

Relocated Seat Belt Receptacles: Original receptacles from REAR seats, miscellaneous fastener hardware from Professionally Engineered Products (PEP), and welded in doubler plates - Because the original receptacles are mounted to the stock seats it was necessary to develop a new seat belt anchor method. The three main mount goals were: 1. solid mounting for all seat belt attachment points 2. get the receptacles low enough so that the seat belt could go through the seat belt slots in the seat, and 3. not damage or create any interference with fuel lines or control cables in the tunnel.

Installation:
The first step was to install the receptacle doubler plates. To prepare for the doubler plates I used a hole cutter to make Ύ inch holes in the tunnel where the seat belt bolts would go. The Ύ inch hole was just big enough to allow for a nut welded to the doubler plate to recess into the tunnel. This picture shows the nut and hole in the vertical part of the tunnel at the front end of the access hatch on the driver side.



Eurotech here in Burlington VT made the doubler plates and did the welding. They fabricated the doublers from 1/8 inch steel and welded nuts (from the PEP KT109-3-NON-901 kits) to their back sides. This picture shows the back side of the doubler plate (the side that will get welded to the tunnel) with the nut on it.



Then they welded the doublers to the tunnel. This was a very slow process because I asked them not to damage the undercoating, insulation, and any of the interior. So they welded a small section then let that section air cool. They gave up trying to cool the area more quickly with a water soaked rag. The reason was that the water messed up the weld preparation work so that additional welding attempts would not work without re-prepping the surfaces. They finished the job by sealing the weld seams and painting the area. Start to finish, Eurotech's work took 11 hours. Obviously this was an expensive part of the task but Eurotech's work was excellent. The result was a very solid pair of mounts with no burns in the insulation or undercoat, no burning through the thin (~1/16 inch) tunnel, and no interior damage. This is a picture of the doubler on the passenger side.



The nut threads are partially visible in the back of the hole.

I attached the rear seat belt receptacles instead of the front seat belt receptacles to the new mount locations. The first advantage of using the rears is that they are shorter than the fronts by about 0.6 inches. This pictures shows the difference in length (rear receptacle on top and front receptacle on bottom).




The second advantage of the rears is that they are flexible and will make the slight “dog leg” bend around the seat brackets to be in the correct orientation for connecting to the male pieces.

I made two changes to the rear receptacles. One change was to rotate the plastic protectors for the webbing around the long axis of the web by 180 degrees. This allowed the protectors to prevent the webbing from rubbing directly on the tunnel. Rotating the protectors is like trying to switch arms in a straight jacket. But doing it at about 70 deg F worked without cracking the protectors. These are before (ignore the bolt and washer) and after shots:






The other change was to use a combination of PEP attachment hardware with the original front and rear attachment hardware. The combination mounts the bottom receptacle fitting slightly away from the tunnel and allows it to pivot but still hold a set position. This picture shows the sequence of attachment hardware.




From left(tunnel side) to right(bolt head side) the parts are:
1.spacer (from the PEP KT109-3-NON-901 kits),
2.plastic washer from original rear mount,
3.original rear receptacle,
4.original conical washer from front seat receptacle,
5.original spacer from rear receptacle, and
6.bolt, 1 3/16” version of the bolts from the PEP KT109-3-NON-901 kits (the 1” version of this bolt that came with the kit is the one in this picture but it was too short so I'm using the 1 3/16” version).

Side Note 1: I looked into other options to solve the seat belt receptacle mounting and height problems including multiple e-mails and conversations with Trampas Costello at PEP. He was VERY helpful, but in the end it made more sense for me to use only some of PEP's fastener hardware. In case someone else is interested though, PEP has a least two possible kits that came close to meeting my goals. One is the non retractable kit (KT109-3-NON-901). I ordered and did a trial fit of this kit but it did not work. Specifically, this kit was meant for mount locations on older 911s. This caused several problems including having to locate an uncomfortable metal length adjustment fitting between the sitters hip and the seat. The other possible option is the retractable kit (KT101XR & KT101XL). But these were time consuming to install and even their shortest (customer) receptacle height was about 1” too high. Also, the retractable kits would have replaced much of the perfectly adequate original seatbelt parts.

Side Note 2: Another possible idea for minimizing the height of the seat belt receptacle was to use the rear seat belt receptacle and mount fitting with a shorter length of webbing connecting these two parts. I talked with Denise at Snake Oyl about this. But the shortest length that they could make was 1.25” longer than the stock length.

The next steps were bolting in the receptacles and seat brackets. I used button head cap screws to bolt the brackets to the mounts. The low profile button heads are necessary to avoid interfering with the seat in the low position. These pictures show before and after on the driver's side.





The second picture shows that I bolted the brackets in the most forward position. This means that the seats cannot be set to their lowest possible position. But so far the seating position is working well for me so I may just leave it there. Using the brackets in the most aft position requires drilling an additional mounting hole in each mounting rail to line up with the front hole in the brackets. I drilled these holes for the passenger side seat and mounted those brackets in the lowest most aft position. This gives me roughly 1/2” more head room on the passenger side than on the driver side. This picture shows the installed seat.

[oly]

Results:
1. Solid and correct location of the seat belt receptacles. This picture shows the receptacle and the passenger seat in its lowest mounting position.



2. Somewhere between 1 1/2” and 1 Ύ “ more head room from the original base model seats (not the sport seats). With the old seats my head lightly hit the roof liner. This picture shows the top of my fat and balding head on the driver side with the new seat set up.



If I remove the butt cushion in the SPG, I get about another 1/2” of head room. Not a good thing for long drives but maybe okay for DEs when I want the extra room for a helmet.

This is a picture of the bottom side of the passenger seat and shows the bottom of the seat below the top of the car mounting rails (shows the same concept as in the BK's CAD drawing below).



I've seen plenty of posts about how much racing shells improve the driving experience of the car. After a few hours of back road driving here in VT I strongly agree.

But the cons first:
1.Reduced backward visibility when you want to change lanes and when you are backing up. This is not a big problem but it requires more deliberate action.
2.Egress and Ingress challenge – like any racing shell.
3.Back seats are very difficult to access.

The benefits for me are:
1.Better visibility both up to the sides and up to the front (I can be first in line at a stop light and see the stop light without any contortionist moves.).
2.Better lateral support.
3.Better control of clutch, brakes, and gas because my body doesn't move backwards so much when I use the pedals.
4.Quite a bit of weight savings although I have not figured this out exactly yet. The original seats and sliders weighed 89 lbf. The new seats and sliders are probably less than half that.
The end result is a much more stable Go-Kart like feel to the car. I remember back to using the original standard seats and feel a bit motion sick just thinking about their lack of support. My conclusion is that Porsche NEVER should have offered a 911 with the baseline seats. Those seats were not quite as unstable as the ones in my parent's 1977 Ford Granada with the faux convertible roof done up in white naugahyde (gives the vehicle the status associated with the annihilation of an albino rhinoceros but without the guilt). But the Porsche and Ford seats are in the same ballpark!

Parts & Costs:
$1798 2 Recaro SPG XL seats
$358 2 pairs of BK R-9773 seat brackets
$442 fabricate and weld 2 anchor plates
$4 20 button head cap screws and washers
$3 2 seat belt receptacle bolts from PEP, 1 3/16" length
$1 2 grade 8 nuts from PEP
$1 2 aluminum spacers from PEP
$2607 total


xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxx


These are the Brey Krause R-9773 bracket pictures and information. You won't find them on the BK site because they don't have plans to produce more of them. But BK has done all the development work so you may be able to convince them to make more.

[BlueSideUp]

Thank you for the great write up!

Did you look into lowering your seat mounts as well? When I was looking at Carreras I specifically avoided the 1985 model year because Porsche raised the seat mounting rails by 3/4 of an inch for some reason.

I ended up with a non-sunroof early 911 that I hope to install some better seats into soon. If I can just get sponsored by TRE I'll be able to pick up their new fixed back seat.

[oly]

Jess,

You're welcome!

I looked into lowering the seat mounts as well but decided not to because of the difficulty of returning the car to its original configuration. My car only has about 36,000 miles on it, has been treated VERY well, and was completely original when I bought it (two years ago) except for an aftermarket stereo. Because of this, it took me a long time to justify, to myself, cutting the receptacle holes then having the welding done. But that will be a very easy modification to cover up with carpet if I ever want to.

Considering my need for headroom and my desire for a Carrera 3.2, it would have been better to have found a 1986 or later car. (From the measurements that I've made on 1984 and 1985 car mounts, there is no difference in height between them.) But as you know probably better than most people, finding a sunroof delete car is difficult. Finding my car took me seven months of serious hunting and then dealing with buying and getting the car from the other side of the country. If I had to do it again, I might buy a car that was not as well taken care of. That way I could do things like lower the seat mounts and not feel like I was a bit of a criminal.

What year is your car? Is the TRE seat aluminum?

Art

[jjwood]

Another tall guy thanks you for the post. Very useful info.

[BlueSideUp]

Art- I am 6'5" as well with a 36" inseam. My car is a 1970 911 so I don't have a center console either. The TRE seat is a fiberglass shell with steel reinforcement in the back. I looked at the seats at the Ventura Porsche show but I think they were the first set. Unfortunately they were on top of a table so I couldn't sit in the seats. The build quality looks really good, on par with what I'd expect to see in a 911.

Dave from TRE told me he has made lowering brackets to bring the sliders down below the level of the OE mounts. The outer mount on an early car is removable so you have a lot of width to work with unlike on the later cars. I'm unsure of the width of the sliders.

Hopefully Dave will have more made soon and I can try them out, I'm running about 225lbs these days with a 38" waist. My Recaro SRD was a nice fit but the seat ended up way too high in the car.

[oly]

Jess,

The TRE seats sound promising; it would be comforting to have some steel in my seats. I'm envious of your car having removable outer mounts; that allows for more lowering options.