Strong crosswinds and headwinds cause loud wind noises in many Model 3's. When we received our Model 3 in January we asked Tesla customer service about the windsield upper wind noise but service said it was normal. After owning several model S's we knew this was not normal for Tesla. We also noticed similar complaints on forums. So our investigation began.
We started with comparing the windshield and glass roof junction areas of our Model S and compared it to our Model 3 and we found a big difference. The gap or channel between the 2 glass pieces on the 3 has a deep area the spands the entire width of the windshield. With the help of John, a very smart engineer and RPM customer, we tested the Model 3 with a sound meter comparing it with and without our seal, and our theory was proven. Over a course of 3 days we drove the same roads and freeways with and without the seal and we found a 5 to 8 decible difference under windy conditions. The rough wind noise from the top of the windshield is now gone. When the seal is installed it eliminates this channel and stops the air from getting trapped between the 2 panels.
The Details: We tried different roads and different speeds. We ran repeate tests with and without the seal on the car, then on same road and then go try on a different road and different speed. We always tested in both directions to ensure we were comparing apples to apples as close as possible. THIS WAS CRITICAL.
There are videos on the forums show tests or Model S and Model 3's but never the same road at the same time with both vehicles. Also the sound tests show a meter on the arm rest, but we tested the top of the windshield where the sound comes from.
We believe what is happening is the channel (gap) acts as a resonant cavity for certain frequencies and if those frequencies fall in the spectrum that you are most sensitive to it will annoy you. If not, you will tune it out. John didn't have a spectrum analyzer, but that would have added an interesting dimension to the analysis. Also we found the wind noise to be louder near the corners of the windshield.
This installs in less than 5 minutes, no tools are needed, no gluing, no cutting, no mess. Just press it in, and once installed the open gap channels look better than new. The large gaps on the sides of the car and the front and back edges on the roof glass look perfect and are flush or below the glass line.