[RV8R999]

In my continuing effort to eliminate variables in troubleshooting my high CHTs during climb I'm wondering if you guys notice a difference in fuel flow during T/O and initial climb with the facet pump on and when it is off?

So far all my T/O's have been with the pump off and I noticed my FF in the mid 14 GPH range, which is a lot lower than I remember when this engine was installed in my other plane. I thought I recalled FF in the 18-19 GPH range. The other plane was a high wing and didn't have a boost pump.

Of course it is entirely possible I don't have the K-factor correct (I could no longer read it off the sensor and was going by memory but I think I'm close).

If my FF is too low I may be too lean for a sea level full power climb which would explain higher CHTs especially in a climb when the fuel really has to climb uphill. I'm grasping at straws here...

Weather sucks so I cannot go out to test it.

 

[Walt]

A 180 hp engine should be around 18 gph at TO. The engine driven pump has plenty of capacity to supply this FF on it's own, the facet is just there as a back up and to help prevent vapor lock in the hot FWF section. Lean condition at full power will definately cause high EGT's and CHT's.

 

[Ironflight]

In addition to what Walt said, yes - I see a good 1.0 - 1.5 gph increase in fuel flow indications when the boost pump is on Ken. I only use the pump for T/O and Ldg, or it would mess up my fuel totals. My experience is that this is fairly common with the standard mounting locations of the sensor just downstream of the boost pump.

Paul