Looking at an sample problem of the wanna-be sport car called Mazda Miata:
The Miata Cowl Induction Project is developing an inexpensive, effective
method for increasing high-speed acceleration in Miatas.
THE PROBLEM
Stock Miatas draw engine intake air from a warm, low pressure area above the
driver's side fender. Hot air is less dense than cold air, and thus contains
less power-nourishing
oxygen per cubic centimeter than cold air. Low pressure also lowers the
density of air.
THE SOLUTION
Engine performance can be improved by putting cold, high pressure air into
the engine by simply changing the location of the air intake to a zone of
higher pressure and lower
temperature. The area at the base of the windshield (the cowl) is ideal for
this--that's why car manufacturers put the intake for passenger ventilation
there. It's also quite close to
the intake on the standard airbox housing the air filter.
The other nice feature of cowl induction is the fact that the faster the car
goes, the higher the pressure is at the engine intake.
So, our project is to make a duct which will direct air from a rectangular
hole in the firewall directly above the clutch cylinder (in front of the
driver) to the inlet of the standard air
box. Our test '95 Miata has a K&N drop-in filter installed to allow high
flow at the intake to continue on into the engine intake manifold. We'll
test the performance of the duct in
a variety of ways after installation.
THE APPROACH
Techniques used in aerospace for manufacturing composite air ducting were
adapted to this project. We built a 3D foam pattern of the inside mold line
of the ram air duct and
used this to make a three-part fiberglass/epoxy casting mold. We will cast a
mandrel in this mold, then lay up carbon/epoxy over the mandrel and cure
under a vacuum bag.
The vacuum bag provides perfectly distributed compaction force to squeeze
out excess resin and air, giving a dense, high quality laminate. Molding
over an internal mandrel
makes the prototyping easier and will insure smooth internal walls for
airflow. Carbon fiber gives a duct which is much stiffer and lighter than it
needs to be, but it also looks
cool.
Is the same problem with our current Dakota?
----------------------------------
Steven St.Laurent
Test Engineer
Test Branch, GSD, MCTSSA
MARCORSYSCOM, USMC
Tel: (760) 725-2296
stlaurents@mctssa.usmc.mil
mailto:Saint1958@home.com
-----Original Message-----
From: Bernd D. Ratsch [mailto:bernd@texas.net]
Sent: Thursday, April 13, 2000 12:17 PM
To: dakota-truck@buffnet.net
Subject: RE: DML: NEED HELP PLEASE!
If you bring up a vehicle that has a RamAir system, don't forget to mention
that it's also built into the aerodynamics of the vehicle. Notice where
the scoops are as compared to where they are on a truck. BIG
difference. The system is mainly a "Cold Air Induction" system which most
vehicles could use for better performance anyway.
The other item is also the "RamAir" system isn't functional until after
approximately 100mph...at maybe .1 boost. Top Fuel race vehicles use the
RamAir effect and are capable of close to 1psi boost...but they're also
achieving this well above 300mph.
We've all been through this several times already.....
$0.02
- Bernd
At 11:52 AM 04/13/2000 -0700, you wrote:
>First time for a Dakota. If it works on a WS-6 Trans AM it has to improve
>the air flow for the Dakota.
>
>----------------------------------
>Steven St.Laurent
>Test Engineer
>Test Branch, GSD, MCTSSA
>MARCORSYSCOM, USMC
>Tel: (760) 725-2296
>stlaurents@mctssa.usmc.mil
>mailto:Saint1958@home.com
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