LOP Observations in a Saratoga II TC


I own a 2005 Saratoga II TC, and I am not affiliated with Advanced Pilots Seminars, or the manufactures of GAMI injectors (ie., this is an unbiased report...).

In hopes of prolonging engine life, extending range and better engine monitoring, I recently installed GAMI injectors, and a JPI EDM-700 (so I could monitor EGT's). Total cost, with labor about $10,000.

I also paid $395 for the Advanced Pilot on-line seminar.

Finally, the San Diego Piper dealer has taken interest in this experiment and has offered to inspect the engine for free after several flights to see for himself if there are any adverse effects.

Test #1:

Friday, May 11, KCRQ - KSDL

Cruise at 11,500. I should have recorded the OAT, but let's just say it was a hot day over the Arizona desert.

ROP Settings, for "Performance Cruise":
MP 33
RPM 2440
TIT 1500 (about 150 deg ROP)
GPH 25
TAS 170

Trip Computer predicted:

1:23 Time to Destination
39.7 gal fuel remaining upon landing.

Once in LOP (which took about 2 minutes to establish the first time, about 100 deg LOP)

MP 33
RPM 2440
TIT 1590
GPH 14
TAS 150

Trip Navigator predicted:

1:32 Time to Destination
51.5 gal fuel left


About a 12% reduction in airspeed / increase in remaining trip time
About a 36% reduction in fuel consumption.

Engine running smooth.

Several minutes later I recorded a second reading:

At about 100 deg LOP,

TIT 1600
#2 CHT 402 (this is by far always the highest CHT)
#1 EGT 1485 (seems abnormally low)
#2 EGT 1555
#3 EGT 1538
#4 EGT 1525
#5 EGT 1529
#6 EGT 1535

On the way back I figured out how to use the EDM LOP Lean Assist. It finds the first EGT to peak (when enriching from the LOP side), I then leaned until the #2 CHT was at 400. This put me at about 75 deg LOP.

As I approached San Diego, and the OAT began to drop, the TIT/CHT/EGT's all dropped as well. This allowed my to adjust closer to 50 deg LOP, with the expected increase in airspeed.

The limiting factor (at least on a hot day) seems to be the #2 CHT. Can baffling improve this situation?

I have already posed the question to Walter as to why the TIT reads higher. Perhaps someone else knows why.

On Monday I fly again, this time I will fly in Piper recommended "Long Range Economy Cruise" (24/2300), and other modes to compare.

I am not planning on increasing the MP above 33 during cruise.

I am still climbing full rich.

Eric Johnson


  • Walter,

    How did you fix the baffling in the Bonanza?

    True that the TIT reads higher than the EGT's, but why is the TIT higher for LOP operation?

  • If you run ROP, particularly toward best power (performance cruise) settings, the chances of incomplete combustion are higher. This can result in uncombusted fuel in the exhaust that can subsequently burn in the exhaust manifold. This can result in high TIT indications.
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