kevin lane wrote:
I am curious, when I look at other's installations it appears
there is
much
more room above the engine block than in my RV-8 w/20B, which is
basically
12" above crank centerline at the firewall to 8" at the front of
the
block.
What is the Mustang II clearances?
I am having to install my primary injectors on the underside
of the
intake runners for instance. I am finally getting to the
throttle
body.
Turrentine told me a 5.0L would work fine (2 3/8" dia) which is
a
long
ways
from a 4" (2.7 times the cap) which I heard recommended on this
list. I
did
notice that the throttle axle piece that holds the two 2" brass
plates
from
the stock carb could also hold a single 4" plate easily, so
fabricating
a 4"
might not be too difficult. I might even attempt to saw off the
bearings
and weld them to a piece of 4" pipe if I decide I need the
humongous
throttle.
It's exciting to see your progress. I hope to later turbo
my
engine
and
will be much interested in learning from your installation.
Kevin Lane Portland, OR
e-mail-> n3773@attbi.com
web-> http://home.attbi.com/~n3773
Keven a 2-3/8 throttle body is too small. There will be a loss of
manifold
pressure. It is nearly impossible to make one too big.
Are you using a step down in the intake manifold for the injectors
such as in this picture? This almost fits under the cowl of a Bill
Schertz's
Kis Cruiser so it should fit an RV8 no problem.
Paul Lamar
Keven,
Here is my start on a throttle body using the secondaries
butterfly
shaft from an old 13B throttle body and a 4" dia aluminum tube.
Just
need
to add a base plate and a couple of shaft stops/idle adjustment and
its
done. So it is certainly feasible. However, I have heard reports
that
large plage throttle bodies not infrequently have a problem with
sticking
butterfly plates when they are under manifold vacuuum. We'll find
out. The
smaller throttle body inthe first photo is a 5.0 1996 stock 70 mm
throttle
body - looks small beside the 4" tube.
Ed Anderson
Butterflies don't stick as the pressure is balanced about the shaft.
Slide throttle stick unless ball bearings are used.
Paul Lamar
Ed,
The LS1 throttle body is 754mm (approx. 3") and is very simple device
and
plentiful off ebay for around $50. Also, easy to modifyit to rest in
the open
position by replacing the return spring with a Mazda TB spring. After
buying
one off ebay, I figured that I should have a 4" TB, so I bought a 95mm
Holly
racing unit. Looks like it should do the trick.
Mark S.
Hi Mark,
Yes, I saw the Holley throttle body and drooled over it, but decided to
spend my money elsewhere. I'll check into the LS1 throttle body. But, I
might just continue to see how hard it is to make my own.
Thanks
Ed Anderson
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