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I know that guy.

I don't really post on forums much anymore. Engagement is minimal compared to what that type of platform used to be in years past. IG is just easier for me and takes up way less time than formatting a decent build thread.

You can always view all the IG content through a browser as the account is public.
 

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I don't really post on forums much anymore. Engagement is minimal compared to what that type of platform used to be in years past. IG is just easier for me and takes up way less time than formatting a decent build thread.

You can always view all the IG content through a browser as the account is public.
I assume that your account is tesla_bimmer
One issue with Instagram - like other similar services - is that it is just a pile of unorganized images (with attached comments in the case of Instagram). I didn't see any details of the subframe in the couple of screens of random images which I scrolled through, and I don't know of any reasonable way to look for it (given that there doesn't seem to be a "subframe" or similar tag), but that's what Eric was interested in. Are there other images or any description of this structure?
 

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Discussion Starter #6
I know that guy.

I don't really post on forums much anymore. Engagement is minimal compared to what that type of platform used to be in years past. IG is just easier for me and takes up way less time than formatting a decent build thread.

You can always view all the IG content through a browser as the account is public.
Jon, i already found you on the r3vlimited forum :)
 

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These are all the images with the subframe from the other forum.
Thanks. You probably understand what you're seeing, but for those who don't, and just as an analysis exercise for me to work through it...

The stock BMW design of this era has a T-shaped subframe: the "top" of the T is the beam that runs across the car, carrying the suspension arms; and the bar of the T is formed by the combination of a rearward branch down the centre line to the final drive housing, and the final drive housing itself. Three mounting points of the subframe to body are needed to prevent rotation in any direction due to suspension, drive, and braking forces - they are located at the ends of the top of the T (each side of the car ahead of the wheels), and at the bottom of the bar (the back of the final drive housing).


Front of the drive unit

This first bracket shown replaces the final drive housing and its mounting bracket, acting as the vertical bar of the T. It is much shorter than the original, but does not take drive torque directly so that might be okay. It goes to a point on the vehicle which does not normally have anything mounted to it... so if you do this, watch for adequate structure. It appears to be at a step in the floorpan which should be strong, but the bracket attaches to only the floor rear of the step, not to the near-vertical part of the floor.


This second bracket shown provides a front mount for the drive unit. This means that the first bracket does take part of the drive reaction, restraining the front drive unit against moving up in reaction to forward drive torque and being pulled down in reaction to reverse drive and regenerative braking torque. It is also supporting part of the drive unit's substantial weight.

These images show the brackets as installed, from each side:


Both of these brackets at the front appear to use existing mounting holes (which were for the final drive housing) in the unmodified original subframe; that's nicely done. :) Other BMW conversions that I have seen in this forum hack off this part of the subframe, and I can see why as the front of the differential housing portion of the Tesla drive unit is a tight fit into this space.


Rear and side of the drive unit


These two remaining images show two more brackets.

One is on the left side, and holds the single side bracket which keeps the drive unit from rocking side-to-side, and holds some of the drive unit weight because the unit is left-side heavy (because that's the motor side). It does not correspond to any part of the original BMW subframe, or any other original bracket. It goes to a part of the body which normally doesn't have any bracket attached, but it is the integral frame rail so it a structurally suitable location.

The remaining bracket - the only one clearly visible in the video at the beginning of this thread - supports the back of the drive unit. This supports a substantial part of the drive unit weight, plus is pulled down in reaction to forward drive torque, and pushed up in reaction to reverse drive or regenerative braking torque. The corresponding original bracket would be at the back of the final drive housing, but that's much further forward. Due to the lack of a structurally suitable point on the body at this location, this bracket bridges between the frame rails.
 

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Owner Jon Volk. He swapped in a Tesla powertrain and now it's an instant-burnout machine
Welcome to DIY Electric Car :)

I'm just curious - did you read anything other than the title before responding with what everyone already knew from the first post? These forums are supposed to work as a discussion: you listen to what others say, then add your contribution.
 
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