Listers,
Steve W. asked the following question:
"While everything that I have read about K&N filters claims HP gains
of small to significant, I would like to raise the question of filtration.
How well does a K&N filter dirt out of an engine?"
I helped build, race and prep 3 different Class 7S Toyota 2WD pick-ups for
the SCORE and HDRA dessert racing series' during the 1980's. All three
trucks were fitted with K&N oiled air filter elements. I dont know exactly
how someone would measure the effectiveness of an air filter in a
laboratory environment but I can attest to the ability of these filters to
remove any harmful dirt and dust particles from the engine intake system
while blasting through a silt bed in southern Nevada or Mexico. Through 5
seasons of dessert racing we never experienced an engine failure
atributable to the ingestion of dirt or dust. Furthermore there was never
any evidence of dirt or any contamination inside the intake tract at any
time during the numerous post-race engine top-end teardowns neccessary in
the class we were running in.
An example of the type of dirt, dust and silt that we regularly came in
contact with can be illustrated by the following story:
During one particularly silty race in Nevada we had the misfortune of
breaking a limiting strap on the left rear of the truck and subsequently
pulling the two left rear shocks apart, This resulted in Pat (my friend and
driver at the time) loosing control and rolling the truck onto its
passenger side in a ditch. Pat liked to smoke cigarettes and always carried
a pack with him for occasions such as this. Before each race he would take
great care in wrapping up these smokes and a lighter to ensure that they
would be dry and ready to go if we broke the truck. Well, to get on with
this story, we unstrap and climb out of the truck and while I'm pulling the
High-Lift jack off the truck to get back on all fours, Pat is unwrapping
his "fix". I've just about got the jack in place when Pat comes over and
taps me on the shoulder and says "check this out". He has just opened his
brand new pack of cigarettes and there is a 1/4" of silt in the bottom of
the pack. He upends the pack and out comes the little stream of silt into
his other hand. We just shake our heads and continue the righting
operation. It appears that the silt was of such small grain size that it
infiltrated Pats ziplock and tape job as well as the factory packaging on
his smokes. It did not however infiltrate the intake system of the engine,
thanks to the K&N.
I realize this is an incredibly long-winded way to illustrate the
effectivness of a K&N filter but if a K&N can keep particles small enough
to infiltrate Pats cigarette stash from entering our engine in the dessert
racing environment, they will obviously do the job on the street.
I have one in my Tiger.
Mike
|