Patrick,
I started work on two throttle bodies today and I found some
real interesting things. I was concerned about a dead spot off idle, and
was thinking about
re-clocking the TPS. I talked to one of my friends at Chrysler,
it turns out that re-clocking will not work. The ECM on startup looks
for the lowest voltage from
the TPS and sets the voltage as baseline (no adjustments). I did
flow one of the stock TB's at different throttle settings so I have a
baseline for my work. One
of the TB's will get 52MM plates (approx. 2.040 inch). The other
will use the stock throttle plates ( just under 2.00 inch). The stock
TB's are actually necked
down just above the plates ( this is actually there to shroud
the half of the plate(s) that swing up). Un-shrouding occurs at approx.
15 degrees throttle
movement. On the TB that will receive stock plates, I opened the
bore above the plates .040 inch, and then I took and additional .020
off the bore on the
back side (rear of the engine where the plates swing down). and
blended the work to the actual bore where the plates are positioned. On
the TB that gets the
big plates, I just bored the TB to match the plates. The next
step will be to place both TB's up in one the lathes (4 jaw chucks work
nice to center the bores)
and open up the air horn and remove the web between the bores.
The shafts will be the next (mill flats above and below the plates. I'm
hoping to finish both
tomorrow and then off to the flow bench. I'll give you the flow
numbers when I'm done. I do have your TB down at the shop. Tomorrow I'll
take the IAC, MAP,
and TPS off. It should be on its way to you either Monday or
Tuesday.
Frank
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