No surefly, but do have EI in my 10. I feel that I am saving close to one GPH at cruise by having more than 25* of advance, along with balanced injectors. I flew back from Iowa yesterday and at 7K' was getting 165Ktas at 10.5 GPH. At 14K' I get 165 around 9 GPH.
My system is variable via my choosing, not just a fixed advance table. I do have multiple tables for ROP/LOP as well as a knob to increment/decrement from those tables. I run 23* at 29" and this goes up as the MAP decreases. That said, I need to run lower advances if I am climbing ROP. MAP decreases as you climb and therefore a stock adv table will keep advancing eventhough you are ROP and it is raising CHTs with no performance benefit. In these cases, CHTs can climb 30-40* or more beyond a lower advance. If I am climbing LOP, then the advance is beneficial and have no CHT issues.
I am a true believer in the benefits of advance for LOP cruise, but not so much with those systems that have unchangeable advance schedules. I would recommend the SDS system, as it allows you to build tables that truly work and gives you a manual switch to go between tables you build for LOP and ROP operations. This is a HUGE benefit IMHO.
Lean mixtures like more advance & rich mixtures do not. Gross simplification and you can search here for more details.
When the advance is matched to the conditions, you WILL NOT have CHT issues. If you can't properly match the advance to the conditions, you likely will see elevated CHTs, when ROP, compared to 25* fixed mags in the climb phase-especially above 6-8K'. A surefly with fixed 25* advance will behave exactly the same as your mag.
N64LR - RV-6A / IO-320, Flying as of 8/2015
N11LR - RV-10, Flying as of 12/2019
Last edited by lr172 : 05-20-2022 at 08:04 AM.