Hi everyone,
I am new to DML (although I've been reading the archives for a couple of
weeks now) and would like to introduce myself. I am the proud new owner of
a '99 Blk CC SLT 4x4 w/ 318 auto. I live in the Wichita KS area and am a
Field Service Eng. w/ Raytheon Aircraft.
Now that you know me, I would like add my thoughts to the thread on ram air
hoods. I seem to recall an article that stated an aircraft turbine engine
regained atmospheric pressure at the intake at around 80 kts (don't quote
me, I can't find the article to back it up, will keep looking) but has an
enormous frontal area with very efficient intake. Modern sportbikes also
use ram air scoops fairly effectively and Sport Rider magazine had a very
good article recently (Oct. '99) on this issue. Taken roughly from that
article:
Pressure (force divided by an area} = 1/2 x density (mass divided by
volume) x velocity squared. The resulting maximum theoretical pressure
would be about 27 Millibar (approx. .4psi) at 150 mph.
I feel this may be true on an intake hung out in a perfect airflow, but
remember, most automotive scoops are close to the body line of the vehicle
very close to the stagnant boundary layer of slower moving air next to the
hood further reducing effectiveness. Remember that this pressure still has
to fight it's way through the air cleaner, intake tract, TB, intake
runners, past intake valves and against the positive and negative pressure
pulses working their way back up through the intake as the engine gulps in
air. This can leave you with as much as 70% pressure loss in a good system,
even greater loss in a bad system. The greatest benefit from a ram air hood
will be the added benefit of a colder intake charge as stated in previous
replies.
Even more important than all this in my opinion is, the Fun Factor, which
is = Personal Enjoyment (how good does it make your Dak look) divided by
P.F. (personal funds, can you afford it) or in other words, if you like it,
that's what matters.
Now my question. What's all this about low throttle position sensor output
voltages on reworked T.B's. I just ordered one from Quick D. Was this a
mistake? I am adding it to a Gibson Cat-Back, Hypertech PTM, 180 deg.
thermo and K&N Gen II (all still on order). Any thoughts are appreciated.
The truck only has about 2,500 miles on it but since I'm going through a
divorce I am treating myself to as many mods as I can afford, and then
some. My motto is "Spend it before she gets it!". Sorry about being
long-winded on my first post to the group, I'll try to keep it shorter in
the future.
Mike Gibbons
gibbons@fn.net
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