fans, etc. and hp

[JHertzman@domain.elided]

In AD7-868 Scott Fisher says lotsa interesting things.

On electric fans, he writes "And third, of course, is the reduction in 
parasitic losses caused by the engine-driven fan.  I've heard figures as high 
as 6 or 7 bhp quoted as the power consumed by the engine fan at 6000 RPM, and 
I see that on the tach as many times a day as I can."

In the Vandenberg Papers the advantage was 1 hp @ 3000 and 3500 rpm, 4 hp @ 
4000 rpm, and 6 hp @ 4500, 5000, & 5500 rpm, so it seems to be a much broader 
advantage than that.

Fourth and fifth advantages which Scott did not mention are (4) lots less 
damage when the absent engine-driven fan doesn't throw a blade or blades, and 
(5) (assuming he runs the 'lectrick in front of the radiator) lots more room 
in the engine bay when you leave off the shroud.

Scott also mentions the Shankle Quadraflow and the claim of as much as a 
7-bhp increase, and asks "Has anybody used these?  Better still, has anybody 
performed before-and-after tests with these, or tested them on a flow bench 
with the stock Spica unit to see whether they improve flow, and at what flow 
rate?" Vandenberg's results on a '76 two-liter Spica engine compared the 
Shankle with a stock '74 airbox, same without a filter, and no airbox. No 
airbox was three to five hp less than the stock '74 setup. The stock '74 box 
without filter was same as with filter through 4500 rpm, and one to two hp 
less than with filter at 5000 and 5500 respectively. The Shankle airbox was 2 
hp less than the stock at 3000, 1hp less at 3500, identical at 4000m, 2hp up 
at 4500, and 3hp up at 5000 and 5500.

One of the other interesting comparisons was Shankle headers against stock 
cast-iron exhaust manifolds. Vandenberg tested the Shankle Alfetta header 
against the '76 and '79 stock Alfetta manifolds, and the Shankle '74 headers 
against the '74 stock manifolds. The '76 iron manifold was miserable (not 
surprisingly), down as much as 9 hp from the others. The stock '79 iron 
manifold was 1 hp ahead of the Shankle headers at three points (3500, 4000, 
and 5500 rpm) and identical at all other checked speeds. On the '74, the 
stock manifold was one to two hp better than Shankle at midrange and spot-on 
in the higher ranges. Those results are on a baseline (stock) engine and 
might not hold on all modified engines, but they do serve to make the point 
that Alfa's engineers and tuners were not as easy to improve upon as some of 
us might think.

One respondent asked if the article on The Vandenberg Papers could be posted 
to the digest. Not by me, no. If some webmaster wants to handle the charts, 
that might be possible. The information is nineteen years old, and doesn't 
get into Bosch systems or into electronic ignitions; most of it is fiddling 
with Spicas, and Wes Ingram (and others) would be more useful today for that 
end. The only other point (than those above) of general interest that I see 
is in Vandenberg's Spica vs Weber comparisons, where the Spica has a strong 
edge at the upper end.

Cheers,

John H.
Raleigh, N.C.

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