A simple adapter to allow you to mount a 76mm/3" intake/filter onto a Bosch flapper/vane-type airflow sensor with an ~82x37mm bolt pattern, as found in many late 80s to 90s cars such as BMW E30/E36, VW Golf Mk2/Mk3, Mazda MX5/Miata (NA/NB) and 323/Familia (BG), Peugeot 405 Mi16, and various Toyotas (Celica, Supra, Soarer, Camry).

Print from PLA only if using to test fitment, if you are going to actually use this for more than a few minutes please make sure you print it from ABS, ASA, PETG or other similar high-temperature filaments (minimum glass transition temp of 80C). If you do not, you risk having your engine ingest unfiltered air when the adapter collapses at best, or chunks of plastic at the worst.

Print with thicker walls and bottom/top than normal and higher infill to ensure good strength (I printed with 1.2mm wall/bottom/top thickness and 40% infill), remember this adapter needs to support the weight of the filter attached to the end of it. No supports or rafts required.