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To boost or not??
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1,916 Posts
Discussion Starter · #1 ·
Alright I've got a few quick questions. I'm currently running RJ's map for my bike with Amsoil Filter, Topless, and V modded pipes. Gas mileage has gone down the toilet. To the point where I took an 164 mile trip this past weekend and had to fill up once on the way down and again on the way back, the first fill up as at about just about 1/4 and the other was just below 1/4. Cruising at about 75-80 and a steady head wind not bad enough to cause any of the wind wobble with solid wheels. So I decided to check the elevation difference between the two maps. RJ is sitting about 660ft and I'm sitting at 1442 which is about double. So how can I go about leaning out the map some with out making it to a Dyno... don't have the funds right now to make it to one....can anyone help me out here?

PS Right now I'm sitting at dead even between full and 3/4 and have 26miles right now so my city driving doesn't seem to be hurting to bad normally cruising at 40 in second or third gear. So about 3 to 3.5rpms.
 

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"A" is the only way
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3,349 Posts
I thought only carb. motors had to be adjusted for altitude, your difference from rj isn't that much it's when you get up in the mt and air is thinner that you start having problems.
 

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The Hawk
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3,920 Posts
You need to get definite numbers on your gas mileage to make any valid comparison. How many miles and how many gallons? The stock ecm has the capability of adjusting for both temp and pressure so it does self adjust for elevation. With the PCIII the easiest way to make overall adjustments is to use the buttons and lights on the front of the PCIII and adjust the whole area a couple of percentages and see what it does, if you don't like the results it is easy to return it back where it was.

Mike
 

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Friend of Max.
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21,719 Posts
The issue is your cruise speed. The map I have has a more lean AFR at 4000 rpm's. Running at 75-80 puts you at about 5000 rpm. It gets significantly rich in that range.

The IAT *should* compensate for elevation.
 

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To boost or not??
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1,916 Posts
Discussion Starter · #5 ·
Okay that would explain in then. Well I remember stopping at the gas station and it was 2.117 gallons and sitting at 78.2 miles which roughly gives me 36mpg. But with what RJ said makes since because I could watch the gauge drop as my wife and I were cruising between 75-80 but when I would take lead and bump it up to 85+ it seemed like the needle slowed down. I personally thought I was seeing shit from the 90+ heat and the highway but RJ's explanation of the running rich at 5000rpms makes sense. Well this just looks like an excuse for me to get a bigger tank LOL
 
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