e46 M3 Community-designed CAD files Master List

[Obioban]

A little project I've been working on for the last little while is an adapter to help the Bosch 0261230101 MAP sensor fit better to the CSL air rail. For those who don't have the background, the original MAP sensor for the CSL is NLA. a few years ago NZ_M3 identified that the 0261230101 sensor was a good replacement option given it's characteristics are very similar to the original.

The key difference in it is the physical packaging - the original sensor had two mounting points, whereas the '101 sensor only has one:



Now it's a pretty close fit, but not ideal for the following reasons:

1: The nose of the sensor is a few mm too long.
2: The o-ring OD is too small.
3: It obviously only has 1 mounting point rather than two.
4: The mounting holes are deeper and therefore the OE bolts are not long enough.
5: The distance from the centre of the nose to the centre of the mounting hole is slightly less than the distance from the centre of the hole to the centre of the mounting thread on the CSL secondary air rail.

In general I believe others have used a craft knife to cut a little bit off the nose to make it fit, but I wanted to do a bit better.

So I made this 3D printable adapter plate.

The adapter solves for #1 and #3 above, #2 is addressed via a replacement o-ring, #4 is addressed via replacement bolts and #5 is addressed partly by the adapter and partly by modifying the sensor.

The adapter looks like this:



and here it is in printed form:



And here's photos of it installed:






Below are the details you need to know if you want to use this for your own install:

CAD File: The STL for the adapter is here E46_M3_MAP_Sensor_Adapter_v1_3.stl
Material: I printed mine in PETG-CF30 which is sufficiently heat resistant and hard wearing for the application.
Finishing: I printed mine with extra solid layers and ironing turned on to give a good surface which I then carefully wet-sanded to produce a very nice finish.
Affixing to the sensor: Once I was happy after test fitting I used plastic adhesive to glue the two pieces together.
Fitment: I used a carbide burr on my Dremel tool to thin out the metal insert in the sensor mounting hole to increase the wiggle room when mounting (hopefully it goes without saying to keep the sensor pointed down so you don't get bits inside it). Mine did JUST fit without, but I wanted to ensure the sensor was centered correctly and not being pulled to one side as well as prove the procedure out for others.
O-Ring: The correct size of o-ring to use is 14mm OD x 8mm ID x 3mm H Viton.
Mounting Bolts: If you wish to replicate the look of the original mounting bolts they are DIN7984 bolts (M6 x 18mm), I chose to get mine in stainless steel rather than zinc plated like the OE items.


A big shout out as well to davidinnyc who acted as guinea pig to try the adapter out before I did my install. He found on his rail that the fitment was too tight to get both bolts in, so it's a pretty close thing without grinding/filing of the sensor mounting hole, unfortunately this isn't something the design of the adapter can fix, given it's the sensor itself that is slightly wrong dimensionally for this application.


Hope this is of use to people - enjoy :-)

This seems like a great 3D print solution.

Why not slide the adapter on from the front, instead of having it go under, so the second mount hole can apply even clamping force on both sides?

[karter16]

This seems like a great 3D print solution.

Why not slide the adapter on from the front, instead of having it go under, so the second mount hole can apply even clamping force on both sides?

That would certainly have been an option - in practice it seems that this approach allows for more than enough clamping force to hold it in place. The second mounting point is as much cosmetic as it is functional as the sensor is held down pretty well even with just the one mounting point.