The discussion on the mechanical fan/electrical fan is an excellent example
of some very, very intelligent and knowledgeable folks trying to find a
"correct" answer to a complex problem.
When I was in school I was diametrically opposed to math. And in a lot of
ways, I still am. Just not very good at it. I have an awful lot of
respect for people who can keep all that stuff straight. I never went
beyond, well, algebra in school and there's very little of that I can
remember. (or care to!!) But the great thing about math is it's inherant
OBJECTIVITY. And that's the great thing about this discussion...
objectivity. This way, relatively stupid guys like myself can reach a
logical and reasonable conclusion ON OUR OWN independent of others'
opinions and hunches. As usual, we find that in this case there are pros
and cons to either style fan, and for a car that is a street driver the
benefits are not GENERALLY going to be realized in the form of POWER.
After hearing Brian's anecdote about the plastic fan shattering, I think
maybe I oughtta switch to an electric fan just for that reason alone! Last
I knew, the red plastic fans were unavailable new, and probably damned hard
to find used, so I'd hate to lose mine!
My hat's off to you guys! Thanks much for an VERY enlightening discussion.
BTW, since part of the discussion was trying to arrive at some real-world
numbers for how much power finds its way to the rear wheels, I recall some
figures like this in an article in the Brooklands Books "Triumph TR6
Collection No. 1." The article beings on page 59 and is entitled "Triumph
On The Dyno." They put the car on a chassis dyno and then made slight
modifications to the needles and to the distributor to "supertune" this
particular car.
The pertinent paragraph reads as follows:
"When it was decided that enough was trimmed, we ran it on the dyno. The
gains all the way up were more than significant. While only 18 horses
showed at 2000 rpm, there were 31 at 2500. At 3500 rpm, the meter
indicated that we were getting 54 hp at the wheels or four more than we had
gotten at peak. This time the peak at 5000 rpm showed 67 hp and it fell to
62 at the redline speed of 5500 revs. The upper end still showed a slight
tendency to be lean so the needle tips were touched up a little further.
This time the meter indicated that 71 horses were at work at peak and 65
were will working at the redline 5500 rpm."
After the tuning they did I think it's reasonable to think that AT THE
FLYWHEEL, this motor would probably produce more power than the stock 104
hp. But probably not a WHOLE BUNCH more... let's say 110 hp? If that was
the case, using their peak number at the wheels of 71 hp, that works out to
about 64% of the engine's power getting through to the rear wheels.
Pete Chadwell
1973 TR6
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