CAI & Octane

["Paul Elliott" <pelliott@xxxxxxx>]

William,

>I have been told that it's useless to get a CAI without having the
OBD-II reprogrammed.  Because no matter what type of filter you get, if the
mass
air sensor has not been changed from its factory settings, the cars
performance will remain the same.<

Simply not true.  Even if it were, you dont account for the fact that CAIs
generally grab not just MOre air, but Cooler air...There is an IAT (Intake
Air Temperature) sensor, which uses the temp of the intake charge to
allocate fuel dispersal....But back to quantity...The purpose of your MAF
or HFM as its often called is to measure the quantity (Mass) of air injected
into your system.  Based on this Mass, the DME has tables which are
consulted.  ie, for X amount of intake air, Y amount of fuel will be
injected.  What OBDII does is to 'move' this window, in an effort to
maintain a stoichiometric (sp) mix.  Put another way, it will strive to
maintain a 14.7 ratio of air to fuel.  But, its NOT absolute.  Remember,
the purpose of the HFM technology is to measure a Range of air mass.  Its
really  quite simple:  The more air, the more fuel that's injected.
Otherwise, if
fuel were static, more intake air would lead to an unsafe lean condition
in short order.

Hence, a CAI that pumps more air delivers more power...Its just that
simple...And complicated!  If you still dont believe it, there are dyno
graphs around which generally show an increase of approx 10 - 15 Hp gain
with no other change than the intro of a CAI!  Check either the ECIS web
site, or Jim Conforti's ...They both show similar results.
_____________________________
Paul Elliott
'99 Alpine White M3; <20000 mi; Forged M dbl-spokes; Rotex pads; Dinan Stage
II Supercharger; Stygar Short Shift Kit and clutch stop; Skaags pedals

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