fuel management needed?
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Cruiser
Joined: Feb 2009
Posts: 198
Likes: 42
From: South Jersey
fuel management needed?
While on a trip recently I read an article in American Iron magazine regarding changing pipes and A/C. The author wrote that with the EFI found on the newer bikes a fuel management system is not needed if changing pipes and A/C as the system will adjust itself. I have read on this forum many times that if you change one or the other a fuel management add on is not needed but if you change both one will be needed. What is the straight story? Thanks for any replies.
Tourer
Joined: Jan 2010
Posts: 343
Likes: 1
From: Phoenix, Arizona
I asked this same question based on the same AIM article over on one of the more visited forums (Touring). Was basically told that I must be pretty dumb to ask the question and then got 25 "expert" opinions on what is or is not needed. Problem is, how do you know who the real experts are and who are expressing opinions with no real knowledge? The consensus seems to be that all current production Harley's run lean from the factory and even a stock Harley can be improved by enriching the air/fuel mixture.
Road Captain
Joined: Sep 2006
Posts: 749
Likes: 2
I won't defend a self-proclaimed expert (which many here may come across as). I'm a shade tree mechanic. I'm no expert on HD, but what I do know is mostly from trial and error. You'll often find the answer to questions on this forum in the form of "opinions" vice fact. Which is also the case for a lot of HD shops these days. That's why we have these forums.
To me, I'd be thinking if I run these pipes/breather without remapping will it hurt the motor? Answer is no, sort of... You'll know the map is off if the motor pings, backfires, or plugs burn white, motor temp goes up, etc. If you have any of these symptoms they will be mild and won't damage the motor as long as you know to back off the throttle, ease on the gas, etc.
But, if you aren't familiar with these symptoms... you could do damage.
As the previous post states HD run very lean to start with and almost all will run better and cooler with remapping. So, you'd never be wrong if you add a PowerCommander or similar device and remap the bike.
To me, I'd be thinking if I run these pipes/breather without remapping will it hurt the motor? Answer is no, sort of... You'll know the map is off if the motor pings, backfires, or plugs burn white, motor temp goes up, etc. If you have any of these symptoms they will be mild and won't damage the motor as long as you know to back off the throttle, ease on the gas, etc.
But, if you aren't familiar with these symptoms... you could do damage.
As the previous post states HD run very lean to start with and almost all will run better and cooler with remapping. So, you'd never be wrong if you add a PowerCommander or similar device and remap the bike.
Road Warrior
Joined: Nov 2007
Posts: 1,984
Likes: 7
From what I have read, and this thinking is what I use for my bike tuning, the, O2 sensors HD and almost every other manufactur uses, autos includes, are really switches. They turn on and off so to speak. they have a range of +- 0.50 percent. Cost about 45-50 dollors each. Real wide band cost maybe 10 times that.
What I understand happens, is to maintain 14.6 AFR, which is set at the factory in the ECM, the ECM has about a 1/2 percent range, more or less, to adjust itself.
The engine sees more air flow, in actual fact, and to keep the AFR it is looking for it can adjust some all by itself up to a point. The map cells that are set at 14.6 will adjust and keep 14.6. The problem is the cells that are not set at 14.6. These are open loop and don't change. These are set at a AFR number given it, and the ECM just uses that number to calculate with and the result is what it "thinks" the AFR should be. So these areas can be really lean with a stock program. These areas today are in the low RPM range and real high RPM range, I think above 70 % throddle position, open loop areas. Places that need help already, now really do.
Tuning devices go from there and can change things, especially the areas where things are open loop. But you still have the same O2 sensor. You just work with it, which really works pretty well really. Some tunners do this really well for the whole thing. The 14.6, though left at 14.6 in the program, can be adjusted on another place in the progran, to give actually around 14.2 AFR for closed loop running. And the open loop areas gets new numbers to work with.
Something like that.
What I understand happens, is to maintain 14.6 AFR, which is set at the factory in the ECM, the ECM has about a 1/2 percent range, more or less, to adjust itself.
The engine sees more air flow, in actual fact, and to keep the AFR it is looking for it can adjust some all by itself up to a point. The map cells that are set at 14.6 will adjust and keep 14.6. The problem is the cells that are not set at 14.6. These are open loop and don't change. These are set at a AFR number given it, and the ECM just uses that number to calculate with and the result is what it "thinks" the AFR should be. So these areas can be really lean with a stock program. These areas today are in the low RPM range and real high RPM range, I think above 70 % throddle position, open loop areas. Places that need help already, now really do.
Tuning devices go from there and can change things, especially the areas where things are open loop. But you still have the same O2 sensor. You just work with it, which really works pretty well really. Some tunners do this really well for the whole thing. The 14.6, though left at 14.6 in the program, can be adjusted on another place in the progran, to give actually around 14.2 AFR for closed loop running. And the open loop areas gets new numbers to work with.
Something like that.
Last edited by Old Gunny; Apr 23, 2010 at 10:47 AM.
Thread Starter
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Cruiser
Joined: Feb 2009
Posts: 198
Likes: 42
From: South Jersey
Thanks for the replies. I think I will start off with a new A/c, then later change pipes and go from there, see how it runs without a fuel management system and if I see any of the changes mentioned then go for a power commander.
Outstanding HDF Member
Joined: May 2008
Posts: 2,543
Likes: 19
From: Ashland Ohio
My take, IMHO, is this: If you were to change ONE item, like exhaust OR air cleaner, you would be no WORSE than stock (which isn't great to begin with). The reasoning I use is the engine IS a great big air pump, OK?
If the intake is choked down from stock air cleaner assembly, it really doesn't matter too awful much how free flowing the exhaust is... AC has it choked. Same thing in reverse and one changes the AC.
But............ when one changes BOTH??? All bets are off. Now, your 'air pump' actually pumps more air, and the stock 'tune' still outputs the same fuel as before. MORE air and SAME fuel on an already EPA lean engine means even a LEANER engine.
There is simply a point each of us has to reach to come to the realization that a 'tuner' of some point will simply HAVE to be purchased and utilized.
So... what is YOUR point?
If anybody actually said you were 'dumb' for asking a legitimate question... I would strongly question ANY input from them. ALL of us are dumb from time-to-time, and the ONLY actual dumb question is the one not asked. Do NOT take internet idiots to heart, OK?
If the intake is choked down from stock air cleaner assembly, it really doesn't matter too awful much how free flowing the exhaust is... AC has it choked. Same thing in reverse and one changes the AC.
But............ when one changes BOTH??? All bets are off. Now, your 'air pump' actually pumps more air, and the stock 'tune' still outputs the same fuel as before. MORE air and SAME fuel on an already EPA lean engine means even a LEANER engine.
There is simply a point each of us has to reach to come to the realization that a 'tuner' of some point will simply HAVE to be purchased and utilized.
So... what is YOUR point?
If anybody actually said you were 'dumb' for asking a legitimate question... I would strongly question ANY input from them. ALL of us are dumb from time-to-time, and the ONLY actual dumb question is the one not asked. Do NOT take internet idiots to heart, OK?
Last edited by wurk_truk; Apr 24, 2010 at 07:05 PM.
Thread Starter
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Cruiser
Joined: Feb 2009
Posts: 198
Likes: 42
From: South Jersey
Thanks for the reply, I was in the dealer today ( had an electrical problem ) and the service manager gave a similar explanation, of course he also recommended staying away from a power commander or other fuel management system and getting the race tuner from Harley at about $450.00 followed by three hours of dyna at $75.00 per hour. He did recommend however changing both pipes and A/C at the same time .Thanks again for the advice, makes sense.
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Joined: Feb 2010
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If you do the pipes, A/C and tuner at the same time then you will have a stage 1 setup. It will be good for a 10 to 15% increse in TQ and HP. You will have a cooler running and a bigger smile.
Reserch, compare and choose your parts wisely
Check out (dobeckperformance.com) for tuners. Read all the information they have on tuners and how they compare to the others.
Reserch, compare and choose your parts wisely
Check out (dobeckperformance.com) for tuners. Read all the information they have on tuners and how they compare to the others.
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Joined: Jun 2008
Posts: 4,109
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From: Connecticut
My take, IMHO, is this: If you were to change ONE item, like exhaust OR air cleaner, you would be no WORSE than stock (which isn't great to begin with). The reasoning I use is the engine IS a great big air pump, OK?
If the intake is choked down from stock air cleaner assembly, it really doesn't matter too awful much how free flowing the exhaust is... AC has it choked. Same thing in reverse and one changes the AC.
But............ when one changes BOTH??? All bets are off. Now, your 'air pump' actually pumps more air, and the stock 'tune' still outputs the same fuel as before. MORE air and SAME fuel on an already EPA lean engine means even a LEANER engine.
There is simply a point each of us has to reach to come to the realization that a 'tuner' of some point will simply HAVE to be purchased and utilized.
So... what is YOUR point?
If anybody actually said you were 'dumb' for asking a legitimate question... I would strongly question ANY input from them. ALL of us are dumb from time-to-time, and the ONLY actual dumb question is the one not asked. Do NOT take internet idiots to heart, OK?
If the intake is choked down from stock air cleaner assembly, it really doesn't matter too awful much how free flowing the exhaust is... AC has it choked. Same thing in reverse and one changes the AC.
But............ when one changes BOTH??? All bets are off. Now, your 'air pump' actually pumps more air, and the stock 'tune' still outputs the same fuel as before. MORE air and SAME fuel on an already EPA lean engine means even a LEANER engine.
There is simply a point each of us has to reach to come to the realization that a 'tuner' of some point will simply HAVE to be purchased and utilized.
So... what is YOUR point?
If anybody actually said you were 'dumb' for asking a legitimate question... I would strongly question ANY input from them. ALL of us are dumb from time-to-time, and the ONLY actual dumb question is the one not asked. Do NOT take internet idiots to heart, OK?
There is a lot of misimformation being put out about what you have to do or you will ruin the motor. Will it run better and cooler with fuel management? Yes it will, more after exaust and intake mods. Is it really needed? No. I would do it for the reason that the engine will run cooler and better. Have you ever riden one with mods done without fuel management? I have and I will say other than the engine temp there is very little change.
Road Warrior
Joined: Nov 2007
Posts: 1,984
Likes: 7
To correct my on self---Not 1/2 percent. Not real dumb just have AAAD. Age Activated Attention Disorder.
the ECM thru the O2 sensors, that are used from the factory, can be adjusted about 1/2 of a AFR number.
It can controll between 14.1-15-1. It is set at 14.6 and that is it's midpoint, but this is adjustable in the ECM.
The thing is, if yoy know the AFR at any time in the engine, then you can give those numbers to the ECM with the Tunners.
And to tell you something I have a SERT from Harley I would give away but it is locked to my ECM.
I replaced this with a TTS Mastertuner before the fix came in. Way much better. Lets you find out, using the O2 sensors, what the VE (volumetric efficency) is.
My bike is set where 95% of the time I am in closed loop. But with the TTS I know what the VE is outside closed loop and can give the engine what it needs when it ask for it. And be on the money.
Have been introduced all over again to this TTS becaused I but in a Woods TW400-6 over the Weekend.
the ECM thru the O2 sensors, that are used from the factory, can be adjusted about 1/2 of a AFR number.
It can controll between 14.1-15-1. It is set at 14.6 and that is it's midpoint, but this is adjustable in the ECM.
The thing is, if yoy know the AFR at any time in the engine, then you can give those numbers to the ECM with the Tunners.
And to tell you something I have a SERT from Harley I would give away but it is locked to my ECM.
I replaced this with a TTS Mastertuner before the fix came in. Way much better. Lets you find out, using the O2 sensors, what the VE (volumetric efficency) is.
My bike is set where 95% of the time I am in closed loop. But with the TTS I know what the VE is outside closed loop and can give the engine what it needs when it ask for it. And be on the money.
Have been introduced all over again to this TTS becaused I but in a Woods TW400-6 over the Weekend.
Last edited by Old Gunny; Apr 26, 2010 at 12:02 PM.