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- Sep 16, 2019
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I installed the Surefly EIS on my left mag in May- IO540 K1G5 PA32-300- mainly because my left mag broke and wanted to get rid of the impulse coupler AD. Flew with standard fixed timing until August when STC allowed variable timing for the PA32. A few thoughts:
- Surefly- easier starting, 2 blades max hot or cold.
-Fixed timing. Was running about 100deg ROP. Getting 145-150 TAS at 8k - max MAP. 15.7 GPH with CHT 320-330 (350 on #6 gasket probe). Could do LOP but would lose about 8kt TAS to get 12.5 GPH or so.
-Variable timing. All CHT now higher by about 30deg. #6 now pushing 400 and #2 (2nd hottest, bayonet probe) 360 whereas before was about 330. Have to keep fuel flow up to 16-17GPH to keep CHT <400. No gain in performance speed wise. However, LOP appears much more consistent. CHT 315-340 across the board at 12.5GPH but lose TAS, now about 135 (total 8-10kt TAS loss).
Another interesting thing I noted- Carbon Monoxide levels are minimal/0 on my cockpit monitor LOP but creep up to 40-50ppm at ROP operations.
From my reading, advanced timing appears to have the most benefit in LOP operations and mininal benefit in ROP. In my personal experience, it appears to be a hindrance in ROP but makes LOP easier. I have linked a few articles below that describe this phenomenon as well. Not sure if I will keep the variable timing, based on my current eval, may go back to fixed as I tend to fly max TAS, ROP most of the time.
https://gami.com/paulferraris_leanofpeaksaga.pdf
https://www.danhorton.net/Misc/Nigel Speedy - Ignition Advance .pdf
- Surefly- easier starting, 2 blades max hot or cold.
-Fixed timing. Was running about 100deg ROP. Getting 145-150 TAS at 8k - max MAP. 15.7 GPH with CHT 320-330 (350 on #6 gasket probe). Could do LOP but would lose about 8kt TAS to get 12.5 GPH or so.
-Variable timing. All CHT now higher by about 30deg. #6 now pushing 400 and #2 (2nd hottest, bayonet probe) 360 whereas before was about 330. Have to keep fuel flow up to 16-17GPH to keep CHT <400. No gain in performance speed wise. However, LOP appears much more consistent. CHT 315-340 across the board at 12.5GPH but lose TAS, now about 135 (total 8-10kt TAS loss).
Another interesting thing I noted- Carbon Monoxide levels are minimal/0 on my cockpit monitor LOP but creep up to 40-50ppm at ROP operations.
From my reading, advanced timing appears to have the most benefit in LOP operations and mininal benefit in ROP. In my personal experience, it appears to be a hindrance in ROP but makes LOP easier. I have linked a few articles below that describe this phenomenon as well. Not sure if I will keep the variable timing, based on my current eval, may go back to fixed as I tend to fly max TAS, ROP most of the time.
https://gami.com/paulferraris_leanofpeaksaga.pdf
https://www.danhorton.net/Misc/Nigel Speedy - Ignition Advance .pdf
