Open Element Air Cleaners: Some temperature measurements

From: svieth@ameritech.net
Date: Sun Jun 21 1998 - 18:57:22 EDT


This weekend I picked-up a very cool gadget from a local Radio
Shack. The Shack sells an "Auto/RV Thermometer" for $15. It
is about the size of a pack of gum and comes with a 6-foot
lead and termperature sensor.

The temp is displayed on an LCD display down to the tenth
of a degree. I mounted the thermometer on my driver side mirror
with the included adhesive (put her right on the glass, next to the
top of the mirror housing). I then snaked the temperature lead
under the hood and into my Mopar Performance open element
air cleaner.

Here is what I found:

Driving down the Interstate tonight, I found that when I was
cruising at 65 mph, the temperature of the air going into
the throttle body is 35 to 40 degrees HOTTER than the
ambient air measured at the mirror. Yes, cruising down the highway
gives a difference of 35 to 40 degress. The temp outside tonight
varied from 72 to 75 degrees as I cruised along the Interstate.
The temps in the air cleaner were around 110 to 115 F. <==< =:^0

When I got into town and went from stoplight to stoplight, it
got even worse. I was seeing air cleaner temps around 120F. <==<
YIKES!!!!!

These open element air cleaners are sucking tons of hot air from
under the hood.

I did notice once neat thing: I started the truck after it sat for a
while and drove off at a reasonable pace. The temp in the air
cleaner wasn't that much higher than outside air. I then
watched the coolant temp guage on the dash climb to
operating temp. Boom!!! The air cleaner temp started to climb
rapidly. It's not the engine block giving off all that heat, it's
the hot air coming from the radiator. We're sucking
in air that has been heated by the radiator. Ugh!

I even tested cruising as fast as 80mph on the Interstate. This
doesn't help the air temps in the air cleaner. In fact, it hurts.
At higher speeds, the temp is guaranteed to hang around 120F
when the outside temp is in the low 70s.

I challenge all Dak owners with to purchase the same "Auto/RV"
thermometer from a local Radio Shack and report their results.
Mount that baby on your mirror and guide the "measuring part"
under your hood. Post the results.

My next test will be to local the "measuring part" near where the
factory air box got its fresh air supply (near the front,
passenger-side corner of the engine compartment) before I removed it.

I am very suprised at these numbers. Especially at high speeds. I
think we're going to have to scrap the open element air cleaners.
Raising the air temp by 40 degrees *can't* be helping our
performance.

-Scott

p.s. If you kick on the A/C, that's good for another 8 degrees of
heat going into your open element A/C. Sigh... :^(



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