"Blow, or Hardly Blown," or "My life under a Flow bench" by Monica L. & Size DOES Matter by I.M. Anonymous

[mlp]

In the absence of any known performance "benchmarks" (at least to me, if
anyone has more, better or other information on the Audi 20 valve heads, I'd
love to see it),  against which progress, if any, can be said to be made, I
offer the following data point to the various 20 valve lists (accompanied of
course by the  general & usual "YMMV" caveats.)

FWIW, and in with the hope that those who find this of any help can provide
me with like information, if you are doing, or considering having head work
done on a car and find your self wonder just where it was that you might
have been coming from vis-à-vis what the factory originally delivered, more
or less, out of the box:

"Early AAN Head Stock Bench Flow Baseline"
INTAKE - measured in Inches (") of lift / cfm
Lift	  Cyl1    Cyl2	Cyl3	  Cyl4	Cyl5
.050	   39.9    39.9	 41.5	   40.7	 37.6
.100	   74.0    72.2	 75.5	   74.5	 72.2
.150	  100.2   102.4	103.3	  100.3	 99.2
.200	  132.6   128.9	130.9	  131.6	132.0
.250	  159	    155.1	161	  158.4	157.5
.300	  177.2   175.5	178.8	  178.4	175.3
.350	  185.8   185.7	188.8	  190	 	184
.400	  188.2   190.3	193.6	  194.4	188.2

Total 1,056.9 1,050.0 1,073.4 1,068.3   1,046.0

EXHAUST - measured in Inches (") of lift / cfm
Lift	  Cyl1    Cyl2	Cyl3	  Cyl4	Cyl5
.050	   31.8    32.9	 33.1	   31.8	 31.7
.100	   61.2    61.2	 62.5	   61.4	 60.4
.150	   85.5    84.8	 85.9	   84.1	 84.8
.200	  109.1   111.3	110.6	  108.9	108
.250	  120.3   123	123.5	  120.9	119.8
.300	  126.5   128.4	129.5	  127.3	125.2
.350	  129.5   132	132.7	  129.7	128.2
.400	  131.4   133.7	134.8	  131.4	129.5

Total   795.3   807.3   812.6   795.5     787.6

- The flow figures were generated using a test pressure of 25" of H20,
"normalized" I believe to reflect 25" at sea level.

- This is a "Stock" Head, never been run in, with stock port & valve setup,
i.e. a head presumably as it came/comes from the factory.

Also offered for those who wonder about such things, are
- www.turboford.org/faq/ta.htm and
- www.merkurencylopedia.com/motor/esslinger%20head.html
- a bunch of stuff at http://www.pumaracing.co.uk/

If anyone's got other suggested links &/or datum on Audi/Vw 20 valve head
work and flow information, please let me know.

Last, I offer for free beer conversation the following hypothesis regarding
heads, valves & "pressurized" operations thrown at me by one porting maven
confronted by the question, "Well, if all that polishing and grinding you
are doing isn't generating a number better than anything above, what the
hell are you doing?"

Bleary eyed hypothesis/theory/defense (??), "Well, A**H**, it don' make no
difference in a pressurized car.  Pressurized {editorial clarification here,
i.e. super & turbocharged applications) cars don't need to worry about all
that flow bench B*S* (s/he'd had more than a few beers, and I believe
his/her SO had recently tossed them out of the house, or something like
that.)  If'n its pressurized, all you want to be go'n fur is SIZE!  S/he
told me "SIZE matters.""

So do the listers have any facts, opinions or ??? to add?

Cheers
mlp



-  Stock valve job (see Bentley,