Re: The big AeroCarb/AeroInjector thread
Posted: Tue Oct 10, 2017 12:53 pm
lutorm wrote:If we interpret "peak lean" as peak EGT, this instruction is wildly inconsistent with any other sources I've found which say that "full rich" usually is 250F rich of peak and that the "red box" where the engine should not be operated extends to 200F ROP for powers over 80%.
I interpret the tuning instructions as saying that they want you to run the engine with the mixture knob pushed in to the full rich position. Then lean it out until the engine starts to run rough and check to make sure the peak EGT you see during that leaning operation is at least 90 degrees hotter than what you started with (at full rich mixture).
Basically, they want to make sure that your engine is running rich-enough at its richest setting, and 90-degrees of EGT difference is a minimum safe amount of "room" between full-rich and peak-EGT.
NOTE: An engine may not run rough until it gets past peak-EGT, so you want to look for the highest recorded value over that span; not necessarily the EGT you see at the leanest possible setting.
NOTE 2: EGT gauges don't respond totally instantaneously, so I'd do the mixture pull fairly slowly, to ensure that the gauges have a chance to record good values.
My $0.02,
--Noel
Sonex #1339