MEFI 1 to MEFI 3
#2
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Join Date: Oct 2009
Location: Dallas, TX
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I am trying to understand this also. What is the difference between MEFI 1, 2, 3, 4, 4A, and 4B? Can you upgrade - answer seems to be 'you must upgrade both ecm and harness'. Is that right? Can they all be reflashed? I assume the newer versions have more configuration options. Finally, what is the difference between the MSD, Delco, and Mercury 'MEFI' units?
#3
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Join Date: Mar 2009
Location: Beaverton Or
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#4
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I am trying to understand this also. What is the difference between MEFI 1, 2, 3, 4, 4A, and 4B? Can you upgrade - answer seems to be 'you must upgrade both ecm and harness'. Is that right? Can they all be reflashed? I assume the newer versions have more configuration options. Finally, what is the difference between the MSD, Delco, and Mercury 'MEFI' units?
Everyone pretty much uses 4's now because of availability. The 3's are getting hard to come by and are getting expensive because of that. The 4 is pretty cheap at about $450. Some of the 3's from Merc. are over $1000. MSD and Painless both use a 4b. Merc. never used the 4 in a production engine. There isn't much difference in the 4a and 4B. However, the cals are not directly interchangable. You have to convert the files to use one in another.
In new engines, I strictly use a 4B. It is the latest and greatest of the Mefi's and has the greatest tunability. It is a very advanced ecm. I can tune and have used them all, but I prefer the 4B on a new build, especially supercharged.(but I do use them on NA engines as well) Hope this helps explain it some.
Eddie
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Eddie - would like to talk to you about a 4b and harness. I'm currently using a MEFI 1 with a boost-ref fuel regulator. Will you be available for a quick phone call sometime next week?