DB9 Air Box Delete, The DB9 airbox is restrictive at high rpm and large throttle openings if the engine is modified at all (e.g. remap, removing secondary cats, etc.) and particularly if using the DBS inlet manifold which flows much better at high rpm, as the only inlet to the airbox is though the restrictive cold air feed from the front grille area.
On the DBS, Vantage V12 and the S versions of the Vantage V8, there was an extra flap or valve on the side of the airbox, controlled by vacuum and a solenoid to allow extra air in at high rpm. This was done to allow extra air to flow when needed but keep the drive by noise to a reasonable volume.
I decided to bypass the airbox completely, the Air filters are under the wing in an area sealed off from the engine, and has a cold air feed so it won’t be sucking hot air from around the engine but the better cooler more dense air from the grille area. As well as extra performance at the top end this modification adds a nice induction sound to the engine.
I used the Redpants airbox delete adaptor, this is a 3D printed part designed for the Vantage V8 but will work on a DB9. The existing mounting does not line up on a DB9 so i drilled 2 new holes in the adaptor to fit to the DB9 mounting bracket.
Links
DB9 Volante anti roll bar upgrade