Yes - I'm the chump. Since I had a spare minute today, I was playing with
some numbers and this generated my puzzlement: I have an ex-IRL 4.0L engine
with certain "published" data - i.e. the GM Race Shop build manual. When I
model some of the numbers the results are quite bizarre. hence I'm wondering
what I'm doing wrong.
The build manual lists the following facts; 1) bore=3.661", stroke=2.85",
maximum RPM=10,500 (limited by rule). Therefore if I apply and old formula
(theoretical cfm = (displacement * (rpm/2) * VE) / 1728) or 243.54in3 [or
3.99L] x 10,500 / 2 * 1.00 / 1728 where VE = 1.00 or a perfect engine, I
should get the theoretical maximum air flow of the engine [pump] or
739.9cfm.
This is were I mention the last piece of published data -- the GM race shop
build manual puts the engine air capacity at 925cfm. Further, the hp specs
and dyno references by several sources fall in line with the 925cfm number
(more math). So if I go back to the formula above - VE would have to equal
1.25???? This does not compute... Is this possible. My head hearts.
John
Team Arrow / Team C5LSR
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