Ok, Here's the story. I've got a 2007 Ultra (CVO of course) with a K&N breather, SERT w/custom map and installed the large volume SE mufflers. The map was for the original engine with aforementioned setup. (I'm on my third engine now) The SERT was mapped to be on the rich side to keep the engine cooled down and then leaned out at 3k for cruising. I was getting approx 43-45 mpg with the original engine/map. The map is on this site somewhere, if I remember it showed 96 hp with 108 torque.
Moving forward, now I'm getting at best 38 mpg on the freeway on this third engine. I checked this out on three tanks of gas in California using cruise control for the most part, no wind or adverse conditions. Ok, finally to my question: I've take the original SE mufflers, took the cores out and replace with the Fullsac 2" Cores. My thought is with the new cores and exhaust flow, this should lean me out close to where I was at on the first engine. Am I totally nuts with this thought, or does the theory have some merit? I'll track the mpg and I'm guessing if it stays on the underside of 50 mpg, I'm good and should not be too lean. If I'm all wet, let me know. I have my big boy pants on and can take it.
(I'm guessing I should fork out the $$$ for a remap. . ) Thanks, UglyJohn
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Topic: Replacing Exhaust, Do I really need to remap???? (Read 1189 times)