Spica Air Intake Temps

["Dean W. Cains" <dwc@domain.elided>]

Hi Group:

I had a digital thermometer with a remote probe sitting in a drawer, so I 
took some temperature measurements of the air intake on my '74 Spica 
Spider.  For those not familiar with the architecture of the old Spider, 
there is an air intake scoop under the right front bumper, in a separate 
compartment from the radiator.  That scoop attaches to a flexible plastic 
hose, maybe 3" in diameter, that leads into the front end of the stock 
Spica air cleaner, which in turn feeds air to the four throttles.

I took a measurement of the ambient outside air temp, which was 91 - 92 
degrees F, and remained constant throughout the testing.  (Don't even ask 
about the humidity in S. Florida this time of year.)  Next, I installed the 
temp probe into one of the throttle openings.  The probe is very small, 
maybe only 2mm across, and I hung it so it touched no metal on the throttle 
body.  While driving the car, mostly at 40 - 60 mph on back roads, the 
intake temp measured from 93 - 96 F, with the Spica air cleaner 
installed.  Pretty good, I thought, but I did see a peak of 108 while 
stopped at a red light for a few minutes.

Next, I removed the Spica air cleaner and its flexible air supply hose, and 
took measurements driving the same route as before, with the probe still 
installed in the throttle body.  This time, the temperatures varied from 
138 - 142 while driving, and I saw a peak of 154 while stopped at that same 
red light.

I'll leave the discussion of these data points to those more knowledgeable 
on the effects of air intake temp on horsepower, 
pre-ignition/knocking/pinging, mileage and the like.  To the seat of my 
pants, I can't feel any difference in performance, although I was just 
cruising and not pushing the car.  I do happen to prefer the car with the 
stock air cleaner, though, as opposed to the Shankle Quadra-flow for 
example, mostly because the stock setup is very quiet and the Shankle 
isn't.  I'll also leave that discussion to others, regarding which air 
cleaner flows better, etc.


Regards,

Dean W. Cains
dwc@domain.elided

'74 Spider Veloce
Lutz, FL
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