How to: Vader-e36 seat install

[Toms73NovaSS]

before i get into it, question.. what type of steel are the brackets made from? i would assume mild steel? this is more of a curiosity than anything.

Yes they are made from 1/8 mild steel.

[AndrewBird]

I have never understood why people are scared about a seat moving or breaking in a frontal collision. In a frontal collision, the only stress your body puts on a seat is from the weight of your body down on it, no more. Inertia causes your body to move forward and forward only. Not down or back or up or any other direction. Your seat belt is the only thing that holds you back.

Now, that isn't to say force isn't applied in a roll over or rear end collision, but rear end collisions usually aren't nearly as bad as frontals and roll overs are going to be bad regardless of how your seat is mounted.

Also, as far as welding the seatbelt bar, as long as the weld is done properly, the welded section of bar will actually be stronger then the rest of the bar. And, with the shape of the bar, even if it did break at the weld, it would have to fold over itself before the seatbelt would come off.

[chris4891]

ive got to admit when i first saw this, i really wasnt sure that i was ok with it. but i think ive managed to rationalize it. before i get into it, question.. what type of steel are the brackets made from? i would assume mild steel? this is more of a curiosity than anything.

also, im not familiar with the e36 seat, but i assume the bent rod behind the seat is there to attach one side of the seat belt. i think that particular feature is the key thing that makes me ok with this.

lets assume in the case of a front end collision theres no one in the seat. id imagine those brackets are strong enough to resist the inertia of the seat from wanting to keep moving forward. but if you were to put a person in the seat, things change a bit. now you have this rather large mass that you need to slow down.

for the original e30 seat, in the case of a front end collision, where your body weight is thrown forward, that loading is transmitted into the seat belt, then into the seat frame, and ultimately back into the main structure of the car.

In your case, and seemingly that style e36 seat in general, the load path is a bit different. instead of the forces in the seat belt being supported by just the seat frame on either side, now on one side youre tied directly into the structure of the car through that seat belt bracket. thats a much better design, imo. in this fashion, i would think that a much smaller percentage of the loading would be transmitted through your offset mounting brackets than if you were to applied this same concept to a regular e30 seat.

just a note though. while i've rationalized the design, i probably still wouldnt put it in my car without running a simulation in my finite element software at work, mostly for piece of mind.

regarding what golde30 said about connecting the mounts front to back on each side... you've pretty much already done that once youve attached the seat. that rail is pretty stiff. its geometry makes it quite a bit stiffer than if you were to just have a piece of 1/8 flat sheet connected front to back.

if you were going to beef up anything, do so on the set of inside brackets (towards tunnel). that inside rail, which is presumably where the seat belt attaches, is whats going to carry a percentage of the load from the seat belt.

A little background on myself.. im a mechanical engineer and do structural analysis most days. doesnt mean im infallible though.. if anyone sees anything wrong with my logic, speak up.

very clean install, btw

[Toms73NovaSS]

At the moment no. I have so many things going on I don't have time to finish the things I have started.

[Tsweers89]

willing to make these brackets for me. i'd be willing to pay. i ndont have access to a cnc machine or anyhting along the lines of what i would need to make them

[golde30]

or just connect the 2 mounts on each side so that you have to bars running one on each side of the seat. this would prevent any movement of the mounts. the way you did the bolts to mount to the seat down is exactly what i have been telling every1 who asks how to install vaders to do, just with 2 large brackets instead of 4...

[e30serg]

Oh. Nice write-up though. What about adding another hole to each bracket to prevent rotation?

[e30serg]

I know welds are strong but cutting and welding the lower seat belt rod scares me....

[Toms73NovaSS]

I do know what you mean. I tried to stop the swivel effect particularly with the rear plate near the door. there is a long flat edge that would bear it self along the inner rocker area. Also the seat slider mechanism is right near the inside of the rocker and it would prevent the seat from going very far at all.

However, use the design at your own risk. The seat and belt areas are an important restraint areas in an accident. I am not a certified engineer and have not crash tested this design!

[george graves]

Nice drawings - but the mounts are going to "swivel" in an accident.

With that said - I won't even pretend to say how much or even if it is dangerous. I guess you'd need a crash test dummy and the NTSB to find that out. Know what I mean?

[Toms73NovaSS]

damn, I didn't know we had another local. why weren't you at the bimmer meet a few months ago? are you on nyspeed?

btw I have a mint set of manual non heated black leather vaders for sale if anyone wants them.

Was not aware of the meet..

Have account on nyspeed, but rarely visit, too much adolescent drama.

I am also on dubsinthebuff as vw to bimmer. ( in fact my sig picture I took off the picture of the day thread from there, picture taken at meet late summer at Shamus' house) Also, I believe Chris D. knows you, he was telling me about a guy that is selling his touring...

[Nicademus]

damn, I didn't know we had another local. why weren't you at the bimmer meet a few months ago? are you on nyspeed?

btw I have a mint set of manual non heated black leather vaders for sale if anyone wants them.

I'd want them but I'm sure they're too expensive, especially after shipping.

[ColdAccord]

damn, I didn't know we had another local. why weren't you at the bimmer meet a few months ago? are you on nyspeed?

btw I have a mint set of manual non heated black leather vaders for sale if anyone wants them.

[Toms73NovaSS]

damn that looks good.

R the measurements in mm?

Yes, it's stated in the write up.

[Hartge_H27]

damn that looks good.

R the measurements in mm?