Continental TSIO-520-R Fuel Flow questions
 

Hello,

In the Turbo Centurion checklist, the recommended climb power settings are:

• 30 MAP
• 2500RPM
• FF Lean to 120lbs/hr

On a side note, I see that on hot weather the FF may not reach 120lbs/hr with a full rich mixture, therefore you have to turn on the fuel pump to increase FF, then lean to 120lbs/hr.
Why is the temperature affecting FF in this case?

I know that TCM continuous flow system simply delivers a certain amount of fuel given the throttle position. No MAP or other parameters are taken into account.

Is it correct to state that with a TSIO-520-R, the FF will stay constant during a climb and no mixture change is virtually needed with altitude change (given the same MAP/RPM settings) since the turbo will keep the air pressure constant throughout the climb?

Thanks! :-)

It's been a few years since I was flying a turbo 210 (or a C340, essentially the same engine x2), but, offhand, 120lbs/hr seems too lean for climb, though maybe not for 30". In general, you're right, the mixture should not have to be adjusted during climb. Temperature-wise, I do recall having to have the mechanics tweak fuel flow with seasonal temperature change, as in, winter setting would not be just right once warmer summer temps came on, and vice-versa.
I believe the entire setup procedure is in this (very extensive!) service directive from Continental, SID 97-3G. A google search will turn up pdf files for this bulletin.
Not sure any of this will help, as I said, it's been a few years for me.

Thanks! Your answer is really appreciated and it shed some lights on my questions.

You should watch the CHTs during climb. If they remain constant, your fuel flow is good, if they rise, you need more FF.