|
The Camshaft in the Ford Kent Crossflow engine is
located in the engine block. This makes it very time consuming and
demands lots of work to change the cam type.
With the
Natural Aspirated (N.A.) engine, it was almost
too much work to do cam tuning experiments.
Moving to Turbo tuning, this issue is gone as the
camshaft should go back to a non overlap cam and be as standard as
possible in all configurations. Overlap will result in blowing the
fuel mixture through the engine directly into the exhaust system.
Initially i did that with the result of having 2500ppm fuel in the
exhaust gas, some 10% higher fuel consumption and lower
torque/power.
With the fuel injection, I initially went for a
semi-sequential solution. I didn't spend the time to make a Cam
Sensor system to indicate TDC compression of cylinder no 1. I
have also heard that it wouldn't do any difference in performance, which
I later verified.
Aiming for higher and higher power, so far, five (5)
different turbo configurations have been tested. The highest output
level was 300HP, which required a lot of fuel. Bosch, green
0280150558, injectors at 440ml/min (42 lb/hr) was/are being used.
With those, the problem of stable fuel delivery arise
at idle and at low vacuum over the rpm range.
No getting round it, I had to develop a Cam Sensor unit,
and move to full sequential fuel injection. This will double the
injector on-time, as it runs the injection over two crank turns and
not for every turn. With double fuel injection time, the injector
minimum turn-on/off time (typical 1.6mS) is less important.
The Cam Sensor unit was made of an old Motorcraft
distributor unit. A steel wheel with a tooth notch was made and
mounted on the axle. A Hall-Effect sensor from Honeywell '2AV54' was
used. Everything was assembled, aligned and tested to give a perfect
trigger signal, that should have the rising edge be between 180 and
6 deg before TDC of the compression for the cylinder number one
cylinder.
With the full sequential set-up there are no problems
with the 440ml/hr injectors at idle or low vacuum (low MAP) over the
rpm range.
|
