Performance Upgrade while Head's Off

[Bruce Bell]

How about 7.4:1

As I recall the 7A has a 46 cc combustion chamber, add to that the 16.1
cc in the piston & gasket then divide by the displacement of one
cylinder  62.1/461.2 = 7.426

The 16.1 can be derived from the total combustion volume of a cylinder
in the NG of 46.12 - 30 cc chamber volume.

Bruce

-----Original Message-----
From: quattro-admin at audifans.com [mailto:quattro-admin at audifans.com] On
Behalf Of Jim Green
Sent: Wednesday, October 01, 2003 9:41 AM
To: Todd Phenneger; Alan Pritchard; 'tihol tiholov';
quattro at audifans.com
Subject: RE: Performance Upgrade while Head's Off


--- Todd Phenneger <tquattroguy at yahoo.com> wrote:
> Hmmm,
>  Id be curious to know exactly what the CR would be.
>  Can anyone
> that knows the Volume of the head COmbustion
> chambers calculate
> it.
>   Javad?!?!
> l8r
>   Todd
>
> --- Alan Pritchard <apritchard at seaeye.com> wrote:
> > Rumour has it that it does, although no one has
> ever properly
> > confirmed it.
> > But what you will end up with is a ridiculously
> low
> > compression ratio, like
> > 6:1 so any performance gains from the multivalve
> head will be
> > lost by the
> > cr...

We've been through this before, I think it actually
works out to ~8.5:1 or something.  Whatever it was, I
remember that it was pretty good for a turbo motor.
That 6:1 CR is what you'd get with a 20vt head on an
MC block.  Good if you want to run 30 psi of boost....

=====
Jim Green
'89 90tq 034EFI Stage II
http://www.mswanson.com/~jgreen/car_home.html