RE: FW: Head work - Porting, Polishing etc. & Bench Flow Tests,

["Michael Pederson" <mlped@concentric.net>]

Thanks Chad - its looking like I will have to get a side-by-side comparison
done if I want hard, i.e. test bench information.  Unless this charting or
tabulating of the changes / effects of porting & polishing is incredibly
difficult or expensive, it just strikes me as strange the shops that want to
sell the service either can't, don't or won't back it up with some kind of
documented claim or proof that you are in fact getting something for your
money other than bragging rights to a "Ported & Polished Head."  Sounds like
a bad Jay Leno Clinton joke.
BTW, who did you use in the Springs?  I've heard the name "SuperFlow" I
think mentioned / recommended as one of  the places to go for head work.
Do you know if your shop has had experience on Audi's 20 valve heads?

Michael Pederson
Colorado
quattro@audifans.com
-----Original Message-----
From: Sherry & Chuck Clark [mailto:clark@rmi.net]
Sent: Sunday, September 26, 1999 8:19 PM
To: quattro@audifans.com; MLP
Subject: Re: FW: Head work - Porting, Polishing etc. & Bench Flow Tests,

MLP wrote:

In a follow up to a post on the S-Car list re 20valve heads, and in further
search of relevant information or personal experiences,  I though I would
check to see if anyone on this list has had experience with, or information
to share about the porting, polishing & tweaking of Audi cylinder heads for
better performance.  By way of background and as a preface to the queries
below,

   Michael,
        When I had my total engine rebuild done, I decided among other
things to get the 10v head P&P'd. I already had the Dialynx e.m. with the
larger ports so the head ports were enlarged to match this. Also, the
intake manifold was match ported to the head. The critical factor here
is that you need an experienced shop/machinist to do the work as the
first head I had done, they hit a water jacket in the head. You instantly
have a 70 pound paperweight if this occurs as I sure wouldn't trust
any measures in welding to backstep this mistake. No, I don't know
stock numbers in reference to flow data nor did I ask to have them
done on the new P&P'd head but all I can say is that by seat of the
pants feel, the new motor felt stronger. This was probably also due to
the new motor and not just the head work. Also, I did install a 268*
Piper cam. Idle did not suffer and once again, pull to redline feels much
better.
  As you mentioned, the only way to really know if the gains are worth
the $$$, you should have an o.e.m. head and P&P'd bench flow tested
side by side. If the numbers are correct in the table you posted on an
8v VW motor, the cfm alone is a significant gain. Hope this helps,

Chad Clark '87 5k Tq-
Colorado Springs, CO