May 19th 2006.
my customers are using these K&N add-on air filters.
They're supposed to give you more horsepower by
allowing more air into the engine. Allowing
the engine to breathe more freely. This may be OK for ten
laps in a club race, but for long term use on the highway?
NOT a good
the messy job of cleaning then, these filters actually
let more fine particles of dirt through into the engine.
is that the inlet manifold, known as a throttle
body in technical terms, needs cleaning at least three
times more often
| Oiled Gauze
|Dust holding capacity
|Load up characteristic
The Desert Research Institute
DoD #0200 WMTC BMWRA DIOC
Reno, Nevada (702) 673-7380
What this table shows is
that in order for the K&N filter to allow more air flow, it needs
to also allow more fine particles to
the engine as well. Which is OK for a racing car, which
will have an oil change every 150 kilometres or so, anyway.
Motors technical service bulletin (04-07-30-013A0),
issued in January 2005 says as follows:
of an excessively/over oiled aftermarket, reusable
air filter may result in:
Engine Soon (SES) light on;
Transmission shift concerns,
slipping and damaged clutch(es) or bands.);
Engine driveability concerns,
poor acceleration from a stop, limited engine r.p.m.
that is used on these air filter elements may be transferred
on to the Mass Air Flow sensor, causing contamination
As a result,
the grams per second signal from the MAF may be
low and any or all of the concerns listed may occur.
goes on to say:
of an aftermarket reusable air filter does not
void the vehicle's warranty."
rest assured that any damage caused by the use of an
improperly oiled aftermarket air filter will void the
filter that fails to filter out fine particles as it
should may result in MAF sensor contamination, which will
to those caused by an over-oiled air filter.
people who have modified their motorcycle fuel and
exhaust systems to use K&N filters, with good results.
they have modified their bikes to cancel out the lean
running conditions normally required to meet emission
filter is part of the package of opening restrictive
intake and exhaust systems and increasing fuel flow
of added air flow. The filter is not a stand-alone
fix. A fuel-injected car engine that's finely tuned by
an on-board engine
system cannot be easily modified.
an aftermarket oiled air filter isn't worth the risk
of driveability issues that may result.
serious doubts in my mind about the claims of increased
power and fuel economy gained solely through the use
to admit they got taken when they've bought an expensive
product like this?
MUST be working. Right?