Quote:
Originally Posted by Jim Vander Wal
Check out the SecondStrike tech page. Mike has an aircleaner calculator that works well and shows a fair amount of info on different sizes. Seems to track my experience fairly well.
His carb sizing calculator is good too, albeit developed for drivability rather than peak performance. This one too tracks my experience.
Jim
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Dating back to some time in 2000 if memory serves me correctly (might be 2001, prior to 9/11).
427 center oiler, 10:2:1 compression, 650 holley DB (already dyno tuned) fairly mild street cam as a base for the test on a "chassis" (not engine) dyno. This was done as we were baselining a new chassis dyno at a friends shop and thought it would be interesting to be able to show his customers the difference of what something as simple as an air cleaner could make.
My notes are as follows:
no air cleaner: 322hp
then 14X2 "K&N" air cleaner: 314hp
then 14X4 "green" air cleaner with drop base:324hp
then Stelling and Heller air cleaner (stock filters as we did not have K&N or Green filters in stock at the time):302hp
All of the above were done one after the other. No tweaks or changes where done to the carb or engine timing. Strictly a demonstration for about 20 customers who were at the shop that Saturday. All HP above was measured at the rear wheels.
The car was ERA321, dark blue metallic, running a toploader 4spd and 3:31 rear gear ratio.
I can confirm those where actual results, less then a few minutes apart on a brand new Dynojet chassis dyno. Real world, real wheel HP data. Somewhere in my old files I may have the torque numbers to go along with this but have yet to find them.
As a side note, the numbers above where done before we had a K&N or Green Filter-14" filter top. The filter top would add a huge amount of airflow vs the chrome lid that was used at the time of the chassis dyno runs to the tune of an additional 500cfm, just for the filter top.
Bill S.
PS:
Formula wise:
Using the simple formula
A= effective filter area
CID=engine displacement
RPM=maximum RPM expected
Using the CFM formula of height X diameter x 6 x 3.14