What an interesting weekend at Maxton. Suprisingly it was'nt as hot as
that part of NC can get this time of year. Getting into a firesuit at
Bonneville isn't as bad as getting into one when you have the same heat and
90% humity to boot.
Anyway as Keith said we met Gary Eaker who spent some time answering
aerodynamic questions. This guy really knows his stuff, but when he starts
taling things like Renolds numbers I get lost. Perfect timing for us since
we were trying to evaluate the aero numbers on the Chevette with yarn. You
can't get a CD number this way, but basicly the yarn taped to the side can
tell you more than you might think. (Found out that you need to use yarn,
not mylar tape, as the way it tatters is important). The results are that
we have some very good airflow over the car with some typical trouble
spots, like wheel wells and any sharp edges. Got to have a video tape at
speed too. When I played mine back it really looks cool to watch the yarn
in those turbulant spots. Even at 180 MPH the yarn is moveing around.
As for the fuel injection. Well we had some trouble with the data
logging
at first (operator error). But after we got that sorted out we learned a
bunch more. This thing is a great data acqusition sysem (which may be worth
the price of admission by itself) and will tell you about A/F ratio, water
temp, air temp, RPM, throttle position (the driver can't lie now), manifold
apsolute pressure and more. It's also neet when you can change your whole
timing curve (or fuel curve for that mater) with a few key strokes. In our
case the fuel table was reasonably close out of the box, and we ultimatly
ran 179 MPH with out any changes. Still need to tweek it a bit, but we can
do that at Bonneville...have to correct for all that altitude
anyway...bigest problem now is getting the idle fuel circuits
adjusted...had it idling at 1000 RPM at one time but I changed things
around and forgot where my original setting were. Man I need to write
everything down now a days.
This little Lionel Williams built 258" is strong. Plenty of torque to
twist the car sideways if you get on it to hard. Wasn't sure what to expect
with only a 2.5" stroke, but with the injection this engine feels as strong
as the 304 we ran last year. Hope it does as the 225 MPH E/FCC record isn't
going to be easy.
John Beckett
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