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Kevin is right on about EGTs. important thing is CHTs in terms of engine life. EGTs are for reference only, absolute temps do not matter much except as giving info about the timing of the combustion event. Cool CHTs are supposed to translate to longer engne life, and more importantly if they are cool LOP. ROP operation is typically not as clean a combustion event, not to mention the much higher fuel flows. Empirical Data supporting this was shown at at the AP Seminar. But as Kevin mentioned in the APS thread, the worst place to operate an engine is typically in between ROP and LOP. Most of the engine manuals actually call for operation in this "red box" which actually makes for higher CHTs, and much higher internal combustion pressure (IPC), which shortens engine life. This is because as Kevin mentioned, factory injectors are so poor that the cylinders vary wildly in fuel flow. Hence a typical factory engine, without signifigant tinkering, swithcing of injectors etc, cannot be run LOP. Do the GAMIS make a difference? The AC I bought had them installed already so I can't say. One thing you notice with Gamis is as you lean, engine does not ever start missing cylinders. It just loses power and then all cylinders stop working at the same time. Best test i've had so far regarding fuel flow, is a 450 mile round trip at 7000-8000 ft. and engines averaged about 8.3 gals each at cruise, 2300 RPM, wide open throttle (21 In rear, 22 In front), 149-152 TAS. CHTs were 310-340, oil about 180 front, 195 rear. I was hoping to hear from other owners about their numbers. If you fly 200 hours a year and the GAMIs can save you 4 gals an hour, plus clean plugs, clean engine, potentially longer engine life due to cooler cleaner running, they may start to look more attractive. another thing i have never had a problem with is hot starts, and i wonder if the GAMIs have something to do with that too... Would like to hear more from other owners with monitors and Gamis...
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