I posted a video a few weeks ago exploring this a bit.
Last week we went up again after a customer posted an observation that fuel flows would be close to the same at the same power setting ROP. His theory was that the lower fuel burns were primarily the result of the lower power LOP.
We set out to examine that theory.
The procedure was to go LOP at WOT, observing % power on the Garmin, then go ROP to the same % power by throttling the engine slightly. Did the tests at 10,500 and 12,500 feet as before.
You can see the results here: https://youtu.be/lWxDt2Sd9uA
On another note of interest, we compared the barometric pressure from the SDS ECU with what the Garmin was seeing for MAP when WOT. This installation uses the Show Planes induction system and we were seeing about 1 more inch MAP than what the barometric pressure was at altitude. You can see this in the video as well.
This engine has the SDS EM-5 EFI/EI on it with our 80mm billet throttle body. At anything over about 2/3rds throttle running 2450 rpm, there is no change in MAP, so this offers no measurable restriction to the induction air.
Thanks again to Les Kearney for getting me out of the shop for a while. We had a beautiful glass smooth day again for running these tests.
Unfortunately the wideband O2 sensor wasn't working again. We hoped to gather some data on EGT vs. AFR on this flight. Maybe next time.
Last week we went up again after a customer posted an observation that fuel flows would be close to the same at the same power setting ROP. His theory was that the lower fuel burns were primarily the result of the lower power LOP.
We set out to examine that theory.
The procedure was to go LOP at WOT, observing % power on the Garmin, then go ROP to the same % power by throttling the engine slightly. Did the tests at 10,500 and 12,500 feet as before.
You can see the results here: https://youtu.be/lWxDt2Sd9uA
On another note of interest, we compared the barometric pressure from the SDS ECU with what the Garmin was seeing for MAP when WOT. This installation uses the Show Planes induction system and we were seeing about 1 more inch MAP than what the barometric pressure was at altitude. You can see this in the video as well.
This engine has the SDS EM-5 EFI/EI on it with our 80mm billet throttle body. At anything over about 2/3rds throttle running 2450 rpm, there is no change in MAP, so this offers no measurable restriction to the induction air.
Thanks again to Les Kearney for getting me out of the shop for a while. We had a beautiful glass smooth day again for running these tests.
Unfortunately the wideband O2 sensor wasn't working again. We hoped to gather some data on EGT vs. AFR on this flight. Maybe next time.