I was re-reading the W20 training PDF and found two nipples on the exhaust manifold in the sketch, pp. 37. The description pp. 38 calls them "Connections, secondary air system (only US)". This looks like an exhaust gas tap but there is no description of its operation or what it feeds.
I looked at the engine sketch, pp. 36, and it shows two tubes identified as "Turbulence lines" going from the exhaust manifold to the intake manifold. They are described as:
- . . . The turbulence lines generate a swirling effect as a result of the air flow upstream from the intake valve during the mixture preparation. The combustion becomes more efficient as a result. The function primarily has an effect in the partial load range as with a small throttle opening in the vacuum in the intake pipe is greatest and thus a higher volumetric flow is achieved in the turbulence lines.
The only problem is the system overview, pp. 34, shows the "turbulence lines" in blue, cold, coming from the engine block, not the exhaust nipples. What it doesn't explain is where the positive air pressure comes for these "turbulence lines." It shows the positive crankcase valve line feeding the same intake assembly. So the "turbulence lines" remain a puzzle.
On the gas tank capacity:
- 9 liters / 2.38 gallons, pp. 45
- 2 liters / .5 gallons reserve, pp 45
- > 0.8 liter ( 0.21 gal) pp. 61 - minimum fuel level for Rex operation
So I'm wondering if we could code the tank for 10 liters and get a full fill?