With a carb no less. The carb is causing 5 to 8 inches of
Hg loss in manifold pressure due to venturis and butterfly
plates despite the fact it is a 58 mm carb. 58 mm is 2.3 inches
in diameter. At full throttle we were still seeing 10 inches Hg
vacuum or an absolute manifold pressure of around 20 inches of Hg.
A fuel injection system would eliminate most of this loss.

We ran out of time tuning Tracy's fuel injection  sys so Dave suggesting
getting some numbers using the carb. Dave and the folks knocked out a
carb intake manifold in one day. I need to depart for the
Paris air show on Friday morning. Will be gone for a week.
I will visit Francois and Mistral in Geneva and try and talk
him into a P-port :)

Much thanks to Dave Lemon and all the guys at
Mazdatrix that helped out. Half a dozen jet changes and we were
up and running. These guys really know their Webers.

These are the pictures and numbers for the 28 inch runner
version. This would make a good engine for the 2.17:1 gear box.
Note the torque peak is 5600 to 5700 RPM which would make a
good cruise setting.

Paul Lamar


<Weber58-28inch-runner-dyno-curve.jpg><28-inch-runners.jpg>

The number are wonderful considering the length of the runners.  They
validate what we pretty much knew already.  I am sure you will be able
to determine experimentally a runner length that develops max power at
7500 rpm.   Any feeling for the idle rpm with the carb set up?    Jerry

Hang on Jerry. It is the next message.

Paul Lamar