More hot air

[graham.hilder@domain.elided (Graham Hilder)]

No no, only kidding with the Subject..... no hot air on this digest eh!!!
Anyway, what I meant was Hot and Cold Air.  I'm a bit behind in my Digest =
reading, and have just seen some of the early posts about feeding cold =
rather than hot air to your engine. It certainly stands to reason that =
there should be some benefit, as numerous posters pointed out, but what =
I'm wondering is how much, for your average Alfa engine?  Back in Digest =
864, 7 July, Rich wrote "All of Alfa's 2 liter engines produce different =
amounts of power...... but let's say your car produces 129 HP.... on a =
standard day (72 degrees F), breathing outside air.  Now let's say we =
reroute the intake so that it's breathing air from the engine compartment, =
and let's say that the air in there is 110 degrees F.  Breathing that air, =
the engine will make about 114HP". =20

Most interesting, as we're talking about a loss or gain of more than 10 =
per cent here, which seems a very significant amount for this simple =
change. I wonder Rich, were these figures merely by way of general =
example, or might that order of change be really expected in practice on a =
2L Alfa motor?    If so, perhaps I should do something about my Alfetta =
GTV 2L intake...... a good swag of quick & easy extra HP may there for the =
taking!  Cold intake trunking is cheap.  But 10 per cent and more seems a =
bit much to expect from so little effort.    I wonder if Rich or anyone =
out there has any test results as such.

The other typical Alfa engines in our stable are of course our Alfasud =
boxers, in our case the twin dual choke Webered versions. These are built =
with a thermostatic air intake valve, which at cold temperatures collect =
warm air from a heater box around the exhaust pipe, and when warm, switch =
across to collect exclusively cold air rammed in via a big duct from an =
air entry hole on the front grille.  Admirable idea.  However the =
thermostatic intake valves invariably fail after a few years, and jam in =
the position which feeds permanent hot air to your engine (and not rammed =
either,  to add insult to injury). This is the state all my Suds have been =
in when I bought them (second-hand). Naturally I've tried restoring the =
rammed cold air input to the engines, but can't say I've ever notoiced a =
lot of improvement..... well to be really honest, can't say I've notoiced =
any..!!    Maybe one needs a dyno test to tell...... but I was hoping for =
something more significant.  By the way all these Alfasud boxer examples =
are sharp well-performing motors, not clapped-out old dungers which =
wouldn't care what they were breathing. =20

Anyway, I'd be interested to know if anyone does have any actual test =
results for the hot-to-cold change on a standard or near-standard Alfa =
motor, be it classic DOHC Alfa or Alfa Sud boxer.      Sorry if it's =
already appeared in a Digest later than those I've read yet.

Regards to all,
Graham Hilder,
N.Z.
(Various Alfas, Nord and Sud)

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