Matt said:
The best would just be the OE airbox de-restricted, and a high flow filter such as K&N/Pipercross.
We've seen Pipercross Vipers fitted to a Vectra B that was loosing 15bhp because of the bend needed on the cold air feed.
Thas a massive loss just from a 90 degree bend :eh:
Ive got a K&N pannel filter and it seems alot better than the paper ones pluss you can cleen them 🙂
Standard air box has to be the best cold air induction for vectras as your limited for space, ive tryed a couple of different ideas but i cant better the air box 🙁
The only idea i had recently was to make a coller to fit the air box so you would get an 80/85mm outlet from the box then use a 45 degree reducer to the 70mm intake pipe dunno.. could be an improvement along with a 3-31/2 inch cold air intake :think:
For noise i just drilled a couple of holes in the air box where it sits against the wing. Its nice drool.gif