10/15/2026
How much difference can a properly designed bellmouth make? Apparently quite a bit!
A while back, I designed and 3D printed a bellmouth for The Instigator. Recently, I decided to try that same bellmouth on a completely different setup, a stock 6.0L with a cam and a stock LSA blower.
The results were pretty impressive!
🔴 With bellmouth: 620.67 HP
🟢 Without bellmouth: 600.92 HP
Nearly 20 HP difference at peak and over 50 HP down low!
Here’s the interesting part. Both pulls were made on the EXACT same tune. We literally just removed the bellmouth and made another pull. Nothing else changed.
And what’s even crazier is that this bellmouth wasn’t designed for this throttle body or blower setup. It was designed for a completely different application!
I’d be willing to bet that a bellmouth designed specifically around this throttle body would produce even better results.
It’s pretty impressive what a little attention to inlet airflow can accomplish. Sometimes it’s not about adding more boost or throwing more parts at something. It’s about making what you already have work more efficiently.