RE: 5 valve heads

[Dave Eaton <Dave.Eaton@clear.net.nz>]

on the contrary, with big bore motors, high revving motors, you are faced 
with fundamentals such as valve mass.  5 valve heads (3 inlets usually) 
help here, as they have a smaller mass than 2 valves for the same surface 
area.

of course, nothing is ever as simple as it seems and the folks who set out 
down the 5v path for f1 mills revving over 16,000 (yamaha, ferrari) must 
have done a lot of math.  it sees that they were wrong.  20/20 and all 
that.

audi are not running 5v heads in the v8tt for the r8 due to "fuel 
considerations".  that this is an issue for an oversquare 3 litre v10 motor 
running over 18,000 revs has very little to do with normal engines one 
would suppose.

dave
'95 rs2
'90 ur-q

-----Original Message-----
From:	IRDdevelop@aol.com [SMTP:IRDdevelop@aol.com]
Sent:	Sunday, 31 January 1999 20:28
To:	mlcmlc@enter.net; Dave.Eaton@clear.net.nz
Cc:	quattro@coimbra.ans.net
Subject:	Re: 5 valve heads

also 5 valve heads do not have much of an advantage on big bore engines, 
vave
surface area isnt much greater than on a 4 valve. And being that most race
engines are using short stroke large bore motors so they can rev higher
(easiest way to get more power), then you see why 5 valves arent used in
racing.

Ned