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-   -   Before and after engine data (http://www.powerflowsystems.com/forum/showthread.php?t=125)

nomocom 06-10-2014 07:44 PM

Before and after engine data
 
I've considered your exhaust for my Lycoming powered Cessna (0-360). A few years ago I fielded a phone call from one of your marketing guys, we had a nice chat about the sale going on, increased power, and a few other items. I didn't bite because there seemed to me to be a lack of data.

My sticking point has been and continues to be the apparent lack of gami spread information. Sure, more power is nice, but what I really want is cylinders running the same approximate fuel air mixture, so I have an engine that I can set the fuel flow on, and I get the desired results on each of the cylinders.
Right now with the Marvel carb and Elano exhaust, the engine monitor shows mixture disparity. If I want 250 deg ROP for climb out, I don't want one cylinder at 100 ROP and another at 300 ROP. Or, if I want to cruise at 35 LOP I want all cylinders in that region, not one at 100 ROP, and another at 70 LOP.

Given all the engineering and design Powerflow has put into these exhausts, would it not follow that the cylinders should breath more similarly since they are all on a tuned equal length exhaust pipe?

Various write ups discuss fuel savings and smoother running engine. Not clear why though. Is it because part of the cylinder to cylinder fuel air mixture disparity is cured by a tuned equal length exhaust system?

Not having data on this was fine 10 years ago, but given the numbers of airplanes with both fuel flow meters and engine monitors, I can't fathom a reasonable excuse for not having before and after gami data.... I mean guys... .help me out here, sell me an exhaust system! Or alternatively, if it doesn't help with mixture, I'll focus on making a switch to fuel injection.


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