BMW Rallying Forum

We have to put harness fixing points in the sills of our compact.
The Blue book obviously prefers the threaded fixing plates to be on the underside/farside of the panel, obviously to help resist tension forces - i'm not sure if this is obligatory.
On the compact we just have a deep sill, is it ok to weld the standard fia mounting plate to the internal face of the sill, obviously with the threaded nut on the underside (in a hole).

Or are we missing a trick?
Cheers
John

This is one of those awkward ones, 99% of the time this is fine, however all it takes is one scutineer to not be happy with it and kick up a fuss and you're out.
If it was me, i would weld an angular 3mm plate into the corner where the sill meats the floor, then drill a hole in the floor side and put the fia plate underneath. This way you reinforce the floor which is quite thin in the compact and brace it to the sill for rigidity

martin, are you saying put the plate under the floor.
if theres an option i dont really want to drill the floor as i'd like a smooth underbelly on this car. i'd like it in the vertical face of the sill ideally.
If the floor was a bit higher than the bottom edge of the sill (like the e30) i wouldnt mind.
Do i make sense

Don't have my car to hand and I can't remember How Lee's done it, but I'm pretty sure we used the standard (type approved) threaded mountings in the sill on the red car.

is-si wrote:martin, are you saying put the plate under the floor.
if theres an option i dont really want to drill the floor as i'd like a smooth underbelly on this car. i'd like it in the vertical face of the sill ideally.
If the floor was a bit higher than the bottom edge of the sill (like the e30) i wouldnt mind.
Do i make sense

Understand, I would weld the fia plate behind a larger 3 mm spreader plate and then seam it to the inside of the sill. Although the standard pounts would suffice, they are often in the wrong place especially if you have shifted your seating position back

Thanks Martin we'll proceed on that basis