James wrote:Folks,
After a dozen messages about the K&N air filters I
just have to put my 2 cents in. If your Tiger can stand to
have an Air filter stack assembly exactly 2 1/2 inches high
using the original Tiger AC filter mounting assembly, then
use any of the following air filters:
(All must be distorted from round to oval).
STP SAF-50A
AC A355C
FRAM CA324A
FRAM CA5033
Motorcraft FA612R
Puro AFP83-1
Problem is that it cost you $3 to $5 each and you can only
find them at almost every discount auto store in the world.
They also fit a very rare car called a Mustang.
As these filters are taller than the original Tiger
filter one should be able to get more CFM into the carb
with less restriction to the flow. I use them on my 351C.
James Barrett Tiger II 351C and others
James and Listers,
This is where dynos come in handy. Back in 1991 we were able to try
different versions of airfilters to determine whether different paper
elements would work better or is the K&N the way to go. We were checking
because we had suspicions about the airflow through an oiled surface. We
were running a highly modified 355 cu in chevy and a 3" K&N with the
standard diameter ...about 14"... In tuning the engine at that time we found
that the 3" tall K&N was sufficient to provide No restriction in power over
no airfilter at all as a matter of fact the run produced around 1-2 HP more
with the filter assembly ?.!? go figure!! must have had something to do with
the Morroso Filter assembly (The actual K&N Filter was the one we had run
all the previous season). We then tried the Brand new paper elements and
found that ALL of the paper elements decreased HP by an average of 7-8 HP.
The best of the paper elements was the Motorcraft filter as it only dropped
4HP (We tried 3 in total Motorcraft, AC, and a generic). When we stacked the
Paper airfilters so that they were 6" high we got similar results to the K&N
indicating that it was an air restiction issue and that the paper elements
were not as free flowing as the K&N. One other note is that we then tried
the K&N stubstack (a molded plastic piece that fits into the Holley
4-barrel) This combination allowed us to go 1 jet size larger and in fact
was worth a measurable 10HP. Based on our dyno guys interpretation he saw it
all the time and said that the stub stack "corrected" the airflow into the
poorly designed choke area and actually increased the volume of air that
could enter the carb. This increased airflow slightly leaned out the engine
and allowed us to fatten up the jetting slightly resulting in........more
power! (This is where we found the 10HP) (Final HP 620 with 580 ft lbs of
torque and the lotus files that this is all stored on BOB are still
somewhere with my old Amiga computer stuff...I will dig it out someday)
Since those tests I have found little to change my mind about using K&N. It
was the very first thing bought for my Tiger when i purchased it 3 months
ago. (After plugs, points, cap, rotor, and condensor) The stubstack won't
work on the Tiger as you need at least 3" of Filter assembly so i guess the
only option is a Barry Grant Sports Claw.
I guess HP costs money and the K&N was/is 10 times more money than the paper
elements so depending on your situation you may choose to use the paper
elements. It may also be that the level of efficiency and air demand in a
350" racing engine is substantially different than a stock 260" engine.
Regards,
Tim ronak
B382000680
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