Re: alfa-digest V8 #476 1970's hp

[Scott Fisher <sfisher71@domain.elided>]

--- Anne O <marinefuel@domain.elided> wrote:
> So much catching up to do, New York is not having a
> winter this 
> year. With temperatures in the 50's F it is more
> compelling to drive the Alfa rather than read
> about Alfas.

Whereas I've been hit with a double-whammy -- a rainy
Northwest February, coupled with a clerical error that
left my Alfa uninsured for the past week or two --
we're taking care of that tomorrow (and fortunately
saving several hundred dollars in the process, which
is a nice silver lining).

> I have a published horsepower claim for a 70's Alfa-
> the owners manual for my former 1973 lists 129 SAE 
> net for the Berlina,GTV and Spider, with the 
> caution "This is a new horsepower rating
> measured with a new procedure which should not be
> compared with previous power ratings.". 

Ah-ha!  Thank you -- interestingly enough, this does
correspond exactly to the "horsepower measured at the
calculator" in my rain-induced hallucinations of the
past week or so.

> You can't use a percentage formula to compare pre 
> 1973 SAE hp to any other standard.

I see -- it's not so much a different metric (as in
converting between KW and HP or meters to feet, for
example) as a change in methodologies.  It would seem
that if a 1972 vehicle with the SAE gross power figure
was identical in every way -- cam lift and timing,
compression, ignition settings, displacement, etc. --
to a 1973 vehicle, it would be plausible to make a
guess about *that* vehicle's gross/net relationship. 
But I can believe that, say, Alfa and Chevrolet might
have radically different proportions between their
1972 and 1973 figures for mechanically identical
engines, due to the different loads imposed by the
ancillaries of the two carmakers.

> KW is killowatts, a standard onto itself. KW x
> 1.341= HP. KW net horsepower is with all 
> accessories.

One of the published sources I found listed a European
Alfa 2L at 112 KW gross/95 KW net -- figures that,
using your 1.341:1 ratio, correspond to 150 bhp
gross/127 bhp net.  

I, for one, am now convinced that -- notwithstanding a
preference for carburetors on other merits -- there is
no measurable gain to be had by converting from a
'72-'74 Spica-equipped U.S. 2L to its European
equivalent.  Fred's wonderfully succinct admonition to
use the Euro cams with Webers -- coupled with the
slight change in lift and timing -- suggests to me
that at least some of the changes might have been made
to provide improved vacuum to the carburetor, giving
more lift (vacuum) earlier in the cycle.  

I am if anything *more* impressed with the original
engineers at Alfa in the early Seventies -- managing
to meet increasingly stringent U.S. pollution
requirements while keeping power output comparable
between the European and U.S. versions of the cars. 
Meanwhile, I think I'm going to look at the SCCA Solo
II rulebook (as I *do* care about it) and see what
they say about removing the engine-driven cooling
fan...

> Happy comparing.

Tomorrow about 1 PM we get the new policy on the
Spider (and also on the 356, though it'll take a while
for me to finish putting the new clutch cable back in
it).  I hope to be experiencing Alfas as something
other than a gedankenexperiment by this time
tomorrow...

Thanks again,

--Scott Fisher
  Tualatin, Oregon

.
Yahoo! Sports - Coverage of the 2002 Olympic Games
http://sports.yahoo.com

--
to be removed from alfa, see /bin/digest-subs.cgi
or email "unsubscribe alfa" to majordomo@domain.elided