Will someone explain the AFR numbers
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Intermediate
Joined: May 2011
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From: WETUMPKA AL
Will someone explain the AFR numbers
since I am not that technical on this. I have a 103 with t-555 cams so where should my afr be and is the higher the number more fuel or less fuel.
Road Warrior
Joined: Jun 2009
Posts: 1,347
Likes: 2
From: Michigan
HD runs a system that despite many critics actuall IMHO does a pretty good job bearing in mind the requirements placed on it by EPA.
Closed loop runs 14.6 : 1 which means by volume 14.6 parts air to 1 part fuel. This is excellent for economy as its about where therotically all the fuel is burnt.
For more performance, under load, and at start up it requires a richer mixture, i.e. less air to fuel. So 14.5 : 1 and down is richer and 14.7 : 1 and up is leaner.
Our air cooled engines run quite hot as compared to a water cooled engine, as the cooling system is less efficient. Running a richer mixture will to some degree make things run cooler but at the expense of mpg. As someone once said, "There is no such thing as a free lunch"
I run a pretty much stock 96" RK with AN BS air filter and free flowing pipes. I want good mpg over performance so run closed loop pretty much as HD designed it but have adjusted the CLB tables to help the heat just a little. I run about 14.5 : 1 in closed loop. Outside closed loop I have slightly altered some AFR settings and timing to eliminate knock, and improve power delivery.
I have adjusted the VE (volumetric efficiency) tables using the SERT software to cater for the modestly increased gas flow through my engine due to my modifications.
My bike runs good, and I am about to remove the stock headers for the Jackpot 2-1-2 stainless system, which I think will bring the heat down further.
I doubt I have helped much but at least I bumped the thread for you.
WB
Last edited by WildBill2566; Oct 2, 2011 at 12:59 PM.
You are not going to like this, because there is no easy answer. But i will give you my take on it, and there are many who know more than I about this subject.
HD runs a system that despite many critics actuall IMHO does a pretty good job bearing in mind the requirements placed on it by EPA.
Closed loop runs 14.7 : 1 which means by volume 14.7 parts air to 1 part fuel. This is excellent for economy as its about where therotically all the fuel is burnt.
For more performance, under load, and at start up it requires a richer mixture, i.e. less air to fuel. So 14.6 : 1 and down is richer and 14.8 : 1 and up is leaner.
Our air cooled engines run quite hot as compared to a water cooled engine, as the cooling system is less efficient. Running a richer mixture will to some degree make things run cooler but at the expense of mpg. As someone once said, "There is no such thing as a free lunch"
I run a pretty much stock 96" RK with AN BS air filter and free flowing pipes. I want good mpg over performance so run closed loop pretty much as HD designed it but have adjusted the CLB tables to help the heat just a little. I
run about 14.5 : 1 in closed loop. Outside closed loop I have slightly altered some AFR settings and timing to eliminate knock, and improve power delivery.
I have adjusted the VE (volumetric efficiency) tables using the SERT software to cater for the modestly increased gas flow through my engine due to my modifications.
My bike runs good, and I am about to remove the stock headers for the Jackpot 2-1-2 stainless system, which I think will bring the heat down further.
I doubt I have helped much but at least I bumped the thread for you.
WB
HD runs a system that despite many critics actuall IMHO does a pretty good job bearing in mind the requirements placed on it by EPA.
Closed loop runs 14.7 : 1 which means by volume 14.7 parts air to 1 part fuel. This is excellent for economy as its about where therotically all the fuel is burnt.
For more performance, under load, and at start up it requires a richer mixture, i.e. less air to fuel. So 14.6 : 1 and down is richer and 14.8 : 1 and up is leaner.
Our air cooled engines run quite hot as compared to a water cooled engine, as the cooling system is less efficient. Running a richer mixture will to some degree make things run cooler but at the expense of mpg. As someone once said, "There is no such thing as a free lunch"
I run a pretty much stock 96" RK with AN BS air filter and free flowing pipes. I want good mpg over performance so run closed loop pretty much as HD designed it but have adjusted the CLB tables to help the heat just a little. I
run about 14.5 : 1 in closed loop. Outside closed loop I have slightly altered some AFR settings and timing to eliminate knock, and improve power delivery.
I have adjusted the VE (volumetric efficiency) tables using the SERT software to cater for the modestly increased gas flow through my engine due to my modifications.
My bike runs good, and I am about to remove the stock headers for the Jackpot 2-1-2 stainless system, which I think will bring the heat down further.
I doubt I have helped much but at least I bumped the thread for you.
WB
Outstanding HDF Member
Joined: Jan 2010
Posts: 2,916
Likes: 31
From: earth
Do you have some type of tuning device? You ask where should my AFR be, do you have the ability to see where it is now or do you want a recommendation of what target AFR to tune to? As mentioned before not a simple answer. The beauty of EFI is you're not limited to one fixed AFR, but rather it transitions across the map. 14.7 in cruise range and enriched for power acceleration above the cruise range. A proper tune will provide power and economy, there is no benefit to tuning your street machine as rich as a drag racing bike across the entire map, and most will disagree with this unless they actually do their own tuning and know what's up.
Road Warrior
Joined: Jun 2009
Posts: 1,943
Likes: 3
From: NYC
so where should my afr be
and is the higher the number more fuel or less fuel.
So, 14.7:1 is a hot running engine with less power potential and lower emissions which consumes less fuel
AND 13.5:1 is a cooler running engine with more power potential and higher emissions which consumes more fuel
Last edited by speakerfritz; Oct 2, 2011 at 01:59 PM.
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Intermediate
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From: WETUMPKA AL
Thanks for all the great info guys.I do have a TTS tuner ,stage 2, no cat, t555tq cams and jackpot slipons.It has been dynoed and the afr runs about 13 to 13.5 but this weekend I started having major pinging and was just wondering if it was afr but apparently not.It also stalled a few times for no reason and a few hiccups back from the air cleaner and temp was below 220.I am now curious about CKP since I have had no problems previously and it pings at all temps and thru all gears .So any thoughts guys ?
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Thanks for all the great info guys.I do have a TTS tuner ,stage 2, no cat, t555tq cams and jackpot slipons.It has been dynoed and the afr runs about 13 to 13.5 but this weekend I started having major pinging and was just wondering if it was afr but apparently not.It also stalled a few times for no reason and a few hiccups back from the air cleaner and temp was below 220.I am now curious about CKP since I have had no problems previously and it pings at all temps and thru all gears .So any thoughts guys ?