Engine running high CHT. Saratoga II TC. Lycoming recommendations confusing.
Q I need advice. I own a 2008 Saratoga II TC. Seems to me that you should operate an engine according to the recommendations of the manufacturer. Yet, when I try to lean my engine according to Lycoming’s recommendations, I inevitably get to peak TIT, which Lycoming says is fine.
The problem is that my #2 cylinder will generate CHTs of 425+ degrees, which Lycoming also says is fine. Seems to me that I am cooking my engine at those temperatures. To get the #2 CHT down below 400 degrees, I have to run 20-23 GPH of fuel. How is everyone else running their engines? Does anyone get the 17 GPH numbers that Lycoming says are feasible at 75% power?”
A Have you tried running 50 degrees lean of peak? You’ll lose a little speed but this should get you down to 14.5-16 gph and no higher than 75%. I Installed a newer engine monitor and with LOP operations my CHTs are around 375 degrees. Make sure all the baffles are doing their job under the hood.
When my No. 2 was hotter than the rest, I found that my No. 2 exhaust gasket was leaking. Good thing for the monitor I was able to change only the gasket and not the entire cylinder.
A I also own a 2008 Saratoga II TC and have the GAMIs installed.
For me the same thing is true regarding cylinder No. 2. Total time is 460 hours. I don’t think I have any problems with an exhaust gasket already. And because my annual was done three weeks ago, they should have found anything in that area. In my case No. 2 is always the hottest. But I can manage to fly LOP with 14-15 gph at 31 inches 2400 rpm and get a TAS of roughly 155 knots at 12,000 feet. Anything more than 155-160 knots TAS is not achievable for me if I run LOP. There, I usually get temps around 380-400 degrees for the No. 2 cylinder and the rest is way below.
If I run rich of peak I totally agree to your findings. I have to have a fuel flow of more than 22 gph to keep the No. 2 cylinder below 400 degrees.
I think it is a general problem of the TIO-540 in the Saratoga that the No. 2 cylinder is pretty hot. What I find interesting, though, regarding the baffle seals is how do I know whether they are OK or not? I will have to take a picture and post it here.
What would be interesting though is, at what speeds and power settings you guys run the TIO-540. ROP and LOP would be interesting.