Thank you for your interest in the S&B Particle Separator. The Particle Separator will work when mounted directly behind a windshield. Just provide a 2" gap between the vortexes and the windshield and you will pull in plenty of air.
The only thing you lose by mounting it behind the windshield is RAM air, but unless you are racing, it is not necessary. You can learn more about the [Particle Separator on our website](https://www.sbfilters.com/particle-separator).