Diff between theory and practice

[jon hanson]

hopefully someone can explain the following deviation from theory to me
The engine is a 1985 USA spec Toyota 4age 16 valve twin cam.
the factory engine management system has been removed and replaced with
a programmable system (controls fuel and ignition timing). The Toyota TVIS
flaps have been removed from the intake manifold (the new ecu cannot control
them). The O2 sensor is removed and the system is always open loop.
the system uses a MAP sensor and a TPS.
Peak torque occurs at 4800 rpm acc to spec. I recently had the car on a dyno
and was adjusting the fuel myself. At 4800 rpm I had a WOT fuel no of 155 to 
achieve a CO reading of 3.5%, at 6000 rpm I had a fuel no of 170 to get a 
CO of 3.5%. Accoarding to my limited knowledge peak volumetric efficiency
coincides with peak torque. I would have expected to have the highest fuel no
at around 4800 rpm and then seen them drop slightly as revs got higher
but the opposite happened. I'm a great believer in doing something and 
seeing the results for yourself. Can anyone explain why this is so, I'm
curious to know.

Jon Hanson
Johannesburg
South Africa.