On Thu, 3 Sep 2020 09:35:46 -0700 (PDT), Paul Murphy
wrote:

On Saturday, April 20, 2019 at 11:48:12 AM UTC-7, Oren wrote:
On Fri, 19 Apr 2019 14:59:42 -0700 (PDT), Z3 4eva
wrote:
Seems we have a wealth of morons here. Don't post with your f u c k i n g opinion, post with an ANSWER. Opinions are like a s s h o l e s. Everyone's got one, most all of them stink! Idiots...
Thanks for your opinion moron.

What was your answer, I must've missed it.
Another Moron here, I suppose. ... Although I do have a Aeronautical Engineering degree, this is not my specialty and was wondering... I only plan on keeping the car for another year (e60) and I am on my 3rd (and yes, the last one was with a new Behr motor at the same time). I did notice a good deal of carbon on the power lead and did clean that up before reinstall but it still failed again.

My Stupid Question: Is there a speed at which would limit the damage. My intuition says, "Run max so that no resistance is 'required,' but I'm probably missing something.

Thank you,
(signed)
Your Humble Moron.
Not missing anything. High speed removes the resistors from the
equation totally. I SUSPECT the problem is a poor connection to the
resistor block causing more heat that it was designed for - the
"carbon" on the connection re-enforces that opinion. Solder the
connector to the pin of the resistor. Alsocheck to make sure there is
nothing inside the duct blocking airflow to the resistor. I remember a
"fix" on some vehicle a few years back that involved making a sheet
metal "scoop" to redirect air across the resistor more effectively.
Another "fix" is to install a PWM variable speed controller - well
heat sinked, to control the speed instead of the resistor. Possible to
install multiple pre-set controllers to "mimic" the resistor and make
the stock control functional if you wanted to keep the car for a long
time - or to use the switch to switch calibration resistors to the
PWMinstead of switching load current.