Aerovee Turbo High EGTs

[tps8903]

I made incremental changes and I'm happy to report the engine is running amazingly and in spec with temps. I ended up coming out about 1.5 turns from my initial setting. Also, the smiley vent for the oil sump is a perfect circle on my plane. I bought a plastic push in plug to block it. My oil temp only went up 3°F on average. So I'll leave that in for now. If the hot FL temp demands it I can pull it out during preflight.

Today I tried Lean of Peak and Rich of peak Cruise. The engine ran pretty well Lean of peak, however EGT 1 was way up at 1472 when the rest were in the 1300s. So I moved to Rich of Peak and they were much more balanced. I was burning about .75Gal more per hour by my calculations, but I was also traveling 7-8mph faster.

I'll likely run Rich of Peak going forward.

I did an extended run at 35" MAP. EGTs in 1300s, CHT at 370-375

[tps8903]

Alright I richened the aero injector another 1/4 turn and gave it another try. It actually seemed like everything was a little hotter than last time! I wonder if it's possible that I'm just still too lean and I was way lean before when I thought I was in the ballpark? Pulling the mixture out causes the EGTs to start rising right away, so I don't think I'm lean of peak even at full rich, but I am a little confused why it ran hotter today with the carb set richer.

Here are a few data points. I didn't get good stable CHT checks at 35" and 40" because they were just increasing and I didn't want to keep at it too long. I'm trying to keep them below 420 as much as I can...

Anyway this is all at 1500' MSL and mixture pushed all the way in the whole time:

30" MAP - 2900 rpm - 5.1 gph
EGTs: 1405 / 1350 / 1395 / 1350
CHTs: 381 / 386 / 408 / 390

35" MAP - 3150 rpm - 6.0 gph
EGTs: 1490 / 1425 / 1475 / 1425

40" MAP - 3300 rpm - 6.9 gph
EGTs: 1525 / 1465 / 1515 / 1465

Hi Chris,

I finally got mine tuned up nicely.

My fuel flow at
35" MAP is about 6.7 +/- 0.2 gph
EGT 1304-1317
CHT 352-370
30" MAP is about 5.5 +/- 0.2 gph
EGT 1270-1313
CHT 356-372

My fuel flow was calculated manually by flying for 30 minutes. I don't have a fuel flow transducer. So I'll have to do it a few more times to increase accuracy. Based on my total burn for the 2.5 hour flight I suspect they are very close.

That's leaned to Rich of peak. I lean until the hottest CHT is in the 370 range. EGTs end up in the 1300s

I ran lean of peak at 30" to see what savings I could get. My #1 EGT stayed very hot (1470), but my CHTs were all in the 350s. I calculated that I'm saving less than 1 gph, so for me it wasn't worth the risk when it's running so smooth Rich of Peak.

Based on where you are now with numbers, you will need at least another 1/4 turn, but likely 1/2. I'd do it in 2 steps so you don't blow by the sweet spot.

BTW, my TAS at 2000' DA on a 27°C day at 35" was 164 mph. She is screamin' fast. I don't suspect I'll have any issue getting factory numbers at altitude. I will however settle on 30" or 32.5" for my cruise settings. She sounds happy at those settings.