MPG Help

Reply Subscribe

Thread Tools

Search this Thread

Mar 21, 2012 | 01:09 PM

#71

iclick

Extreme HDF Member

Joined: Sep 2005

Posts: 11,615

Likes: 50

From: Baton Rouge, LA

Quote:

Originally Posted by Spur56

IClick - could you explain this a little more. The FM map I have has a lot of negative values in the cruiseing range already. So if you are already below zero, you should not adjust? Some are like -16.

First, be careful with fuel adjustment, as you can go too far with it if not careful. When I suggested reducing fuel values in the cruise range it applies only to FM's standard map, not the one that has already been tweaked for mileage, often referred to as their "mileage map." I've gone further with the reductions on my own bike with success, but I would suggest caution. You can usually tell you've gone too far if you get hesitation, flat spots, detonation, or surging when it wasn't there before. Keep your old maps and give them a unique, identifiable filename, as that way you can go back to it if the tweak is unsuccessful.

I'm surprised you are seeing values like -16 and would like to look at your map(s) if you'll email me what you have.

Quote:

Also when you say 5-7%, does that mean reduce a cell reading from 10 to 9 (5% of 10 is .5) or reduce the 10 to 5. Thanks

Good question and I should've clarified that. If you see a value "10" in your Fuel Adj. tables it means the PCV will add 10% more fuel than the ECM dictates in that location. So, if you reduce the fuel in the cruise range by 5% you would subtract 5 from the values that are there. You can do this by selecting the range that you want (drag left mouse button making the area dark gray), usually 0-20% TP and 2000-3000 rpm, and hitting the pg-down key five times. That'll reduce all values by five.

Also, I wouldn't change any value above about 80% TP or 3000 rpm, as you want to keep the power that is part of the map you have installed available when you need it. If you spend most of your time in the cruise range like most of us you should see a mileage improvement by altering only the cruise range. In my maps I usually tapered the values at 40-60% TP so the transition isn't so radical, though, but that's optional. Unless you do that you may feel a four-barrel-carb effect when you roll-on the throttle and get into the richer part of the map. Tapering the values may smooth it a bit.

Last edited by iclick; Mar 21, 2012 at 01:18 PM.

Apr 7, 2012 | 07:41 PM

#72

Ozark Jim

Novice

Joined: May 2009

Posts: 22

Likes: 0

Thanks everyone

I have a used PCV that I picked up from a guy for 125 bucks and I am excited to use it.....but also want to keep my mpg up. He bought it thru fuelmotousa but I don't expect any support from them because it was bought used.

Great questions and excellent answers and explanations. I am sure once I get the PCV and software this will all make more sense.

This thread will give me something to refer back to if I start have mpg issues.

Thanks all.

Apr 7, 2012 | 08:19 PM

#73

iceman5218

Road Captain

Joined: May 2009

Posts: 545

Likes: 1

From: Jonesboro, AR

Quote:

Originally Posted by HD Jim

Would there be any advantage to adding octane booster to gas with 10% ethanol or any ethanol for that matter?

The money spend on booster will negate any increase in mileage.

Apr 7, 2012 | 08:26 PM

#74

iclick

Extreme HDF Member

Joined: Sep 2005

Posts: 11,615

Likes: 50

From: Baton Rouge, LA

Quote:

Originally Posted by Ozark Jim

They'll help. Just give them a call. Having the original invoice number would help if you have it.

Apr 7, 2012 | 08:56 PM

#75

RK Joy

Outstanding HDF Member

Joined: Mar 2012

Posts: 2,242

Likes: 3

From: Upstate NY

Just beginning life anew on my Road King, not really knowing what to expect for MPG (and not really caring that much I guess). H-D says 42 MPG overall. So I guess that could mean something like 36 city / 48 highway? Who knows. My first refill was done earlier today. I filled right to the bottom of the cup in the filler neck but doubt that it was quite that full by the dealer when I picked the bike up. Anyway, first tank would be 38 MPG assuming equal starting points. I will keep track over the life of the bike, or the rider, whichever comes first. :-)

2002 Deuce averaged 50.6 (TC88b) Stage 1, V&H Big Shots. Don't anticipate being anywhere near that but somewhere in the 40's would be nice.