Hi,

How many seconds after reaching T/O MP do you get Max T/O FF on your carburated O-470 engine?

Mine, an O-470R,
JPI graph shows to have a FF of 9.3GPH when reaching T/O power at sea level, some 20 sec. later stabilized at 21 GPH
As you will see on the graph, EGT’s reach almost 1500F and then as FF increases drop some 70F.
CHT’s are below 350 during T/O and initial climb.
Would like to compare to other carburated O-470’s
Thx.

Interesting! I wonder if this has anything to do with the CS prop? I’d imagine it wouldn’t be that big of a difference if any though. Maybe latency in the gauge? Smoothing in the signal?

Man that seems like a very long lag period for it to get to full flow. Granted I'm running a IO-520, but when I firewall it and look down a couple seconds later after I'm off the ground I'm getting 28ish, it's pretty immediate. The carb may take a bit longer, but 20 seconds is a long time...

I will check mine the next time I am up, I think that is a instrument lag issue. How fast does the fuel flow change when you are pulling power? DENNY

Thx for the interest.

The IO 520 graph coming also from a JPI and believe the same fuel flow sensor shows the MP and FF lines going up almost overlapping each other.
They reach their maximum at the same time and EGT's don't go up and then down like with the carburated 470.

Believe what we see on the graph for the 470 is quite true.
I would be very interested to compare, guess they will be similar but would really like to see how much.

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I checked this morning and the O-470R in my carbureted ‘56 Skywagon peaks at between 22.5 and 23.1 GPH around 5 seconds after liftoff as measured by a JPI FS-450 fuel flow/totalizer gauge.

Thx, any idea how long from full throttle in to lift off?

I envy your 23Gls/hr FF.

.

I would estimate 5-6 seconds from full throttle to liftoff. Cool air, slight headwind.

I would estimate 5-6 seconds from full throttle to liftoff. Cool air, slight headwind.

Makes me envy your carb. even more.

Have had the intention to see how it reacts going back on the throttle Denny but so far forgotten...
Thx for the comment.