explain why i need to remap
Tourer
Joined: May 2010
Posts: 348
Likes: 5
From: The mitten state
Just to be clear! There is FUEL ADDED! That is because there IS MORE AIR available with an open air cleaner. As I stated few really understand fuel injection! When you increase the VE ( expected MASS of Air) you do INCREASE the fuel at those throttle and MAP settings. That is the nature of speed density! What you DO NOT CHANGE is AIR FUEL RATIO!!
But if the airflow ( mass ) increases you must also add FUEL as well.
And anytime the air rate changes you can expect to also have small changes in ingnition timing to correspond to those areas of engine operation where the airflow is increases! So both fuel and spark maps should change slightly! Again an increase in fuel does not mean a change in A/F ratio! And yes the flash bumps the ERPM Redline limit slightly.
While VE is "volumetric efficiency" it is used in the ECM calculation for scheduling FUEL. When the difference between what the ECM "SCHEDULES" and what the O2 sensor detects vary the FUEL CONTROL then adds or subtract very small amounts of fuel "by CELLS"(adaptive fueling) until the correct A/F ratio is maintained.
When those adaptive cells add fuel in closed loop for a GIVEN CELL, that fueling during OPEN LOOP (in the same cell) can then also be added, during open loop operation. However, during OPEN LOOP a CELL may have more ENGINE OPERATION RANGE than during closed loop, so fuel can still be incorrect if the VE's for a given Speed and Load are incorrect!
And again just for clarification a BARO and MAP reading are used for fueling, as a MAP sensor can and does read BARO with engine off! And the BARO reading can actually be modified during engine run, under some speed and loads, so BARO as well as MAP are used for fueling. Those "VE" numbers are only one part of scheduled fuel, but they are the major table values changed when a reflash is done!
But if the airflow ( mass ) increases you must also add FUEL as well.
And anytime the air rate changes you can expect to also have small changes in ingnition timing to correspond to those areas of engine operation where the airflow is increases! So both fuel and spark maps should change slightly! Again an increase in fuel does not mean a change in A/F ratio! And yes the flash bumps the ERPM Redline limit slightly.
While VE is "volumetric efficiency" it is used in the ECM calculation for scheduling FUEL. When the difference between what the ECM "SCHEDULES" and what the O2 sensor detects vary the FUEL CONTROL then adds or subtract very small amounts of fuel "by CELLS"(adaptive fueling) until the correct A/F ratio is maintained.
When those adaptive cells add fuel in closed loop for a GIVEN CELL, that fueling during OPEN LOOP (in the same cell) can then also be added, during open loop operation. However, during OPEN LOOP a CELL may have more ENGINE OPERATION RANGE than during closed loop, so fuel can still be incorrect if the VE's for a given Speed and Load are incorrect!
And again just for clarification a BARO and MAP reading are used for fueling, as a MAP sensor can and does read BARO with engine off! And the BARO reading can actually be modified during engine run, under some speed and loads, so BARO as well as MAP are used for fueling. Those "VE" numbers are only one part of scheduled fuel, but they are the major table values changed when a reflash is done!
Last edited by FBRR; Feb 21, 2012 at 11:50 AM.
Seasoned HDF Member
Joined: Jul 2008
Posts: 9,282
Likes: 1,139
From: southeast PA
I've tried the XIED's and the Fuel Pak. Not happy with the results, which were minimal. Maybe it was just my particular bike. Then I installed the TMax, which uses wide band O2 sensors, and it made a huge difference in power, especially low end, and runs a lot cooler.
Like 8541hog said, I'm sorry I wasted my time and money with what are really partial solutions.
Like 8541hog said, I'm sorry I wasted my time and money with what are really partial solutions.
Outstanding HDF Member
Joined: Dec 2010
Posts: 2,036
Likes: 8
From: Temecula, CA
The addaptive fueling FBRR refers to is usually enough to compensate for your normal Stage 1 modifications. However, the factory fueling requirements are set pretty lean and doing a proper tune which adjusts your VE tables is generally considered a "best practice". I have a PowerVision with Autotune Pro and just a stage 1 on my bike (tuner overkill) but I did so in case I made future modifications. It's autotune basic worked very well in getting my tune spot on for my modifications.
Road Warrior
Joined: Apr 2010
Posts: 1,403
Likes: 72
From: North Dakota
When I said no fuel was added, what I meant was the AFR was maintained at the factory setting. I like FBRR's explanation, especially concerning the adaptive learning that most people don't realize carry into open loop.
FBBR, can you state where under most conditions, in your experience, "Open Loop" is entered. I understand it to be about 80% throttle or over roughly 4,000 RPMs. I have seen a lot of people believe it is anything other than cruising or idle.
FBBR, can you state where under most conditions, in your experience, "Open Loop" is entered. I understand it to be about 80% throttle or over roughly 4,000 RPMs. I have seen a lot of people believe it is anything other than cruising or idle.
Road Warrior
Joined: Apr 2010
Posts: 1,739
Likes: 10
From: Suffolk, England
When I said no fuel was added, what I meant was the AFR was maintained at the factory setting. I like FBRR's explanation, especially concerning the adaptive learning that most people don't realize carry into open loop.
FBBR, can you state where under most conditions, in your experience, "Open Loop" is entered. I understand it to be about 80% throttle or over roughly 4,000 RPMs. I have seen a lot of people believe it is anything other than cruising or idle.
FBBR, can you state where under most conditions, in your experience, "Open Loop" is entered. I understand it to be about 80% throttle or over roughly 4,000 RPMs. I have seen a lot of people believe it is anything other than cruising or idle.
Even the performance stage 2+ maps have it up to 80% throttle and 4000 rpm.
Cruiser
Joined: Jan 2012
Posts: 166
Likes: 2
From: Pa
Sure wish I could understand why t-max owners think that 13.2 to 13.5 fuel ratio at light throttle settings is good for the motor. Pouring extra fuel in a motor to try to cool it down is a great way to shorten engine life by up to 30%. A good dyno operater using a speed density(map sensor) system can tune a bike to proper a/f ratios for the kpa(load) that the motor is sensing, and not have over-heat problems.
Road Warrior
Joined: Apr 2010
Posts: 1,739
Likes: 10
From: Suffolk, England
Agreed. Much richer than about 14.2:1, except when pouring it on, is a waste of fuel and not doing any good. Down into the 13s when around town and when cruising is too rich.
Last edited by Foxster; Feb 21, 2012 at 10:54 PM.
Road Warrior
Joined: Dec 2010
Posts: 1,629
Likes: 46
From: East Hartford, CT
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Road Master
Joined: Nov 2006
Posts: 1,164
Likes: 401
From: Port Coquitlam B.C.
Sure wish I could understand why t-max owners think that 13.2 to 13.5 fuel ratio at light throttle settings is good for the motor. Pouring extra fuel in a motor to try to cool it down is a great way to shorten engine life by up to 30%. A good dyno operater using a speed density(map sensor) system can tune a bike to proper a/f ratios for the kpa(load) that the motor is sensing, and not have over-heat problems.
Thread Starter
|
Tourer
Joined: Jan 2011
Posts: 290
Likes: 2
From: wayland ny
Wow a lot of good info here and fbrr you deff. sound like you know what your talking about. But to be honest im a little confused. Is it the narrow band o2 sensors or the predetermined f/a ration of the map/throttle position sensor during open loop setting why the remap needs to be done?