Truth in dyno
Road Master
Joined: Jul 2007
Posts: 792
Likes: 0
From: Niagara Falls, NY
In my area, especially, I would not trust the abilities of the tuners here. A lot of them want to look at numbers and afr at wot. When I suggest I am more intrested in tuning for cruising I was looked down upon. That is when I got the twin tec and started my own tuning. I wish I had someone of your talent around me, so I can get some pulls and get advice. I'm not after peak numbers but rideability at cruise.
Road Warrior
Joined: Jan 2006
Posts: 1,808
Likes: 0
From: Waynesville, NC
Good post and some good tips. My question here would be is, where is the balance between horsepower and fuel mileage? Does this rest in having the correct AFR?? Does a nice straight AFR line of 13.2 give you the best of both worlds?? The reason I ask is I have had a bad tune and a good tune. Bad tune = 4 more horsepower w/bad fuel mileage, and the good tune = 4 less horsepower but a lot better fuel mileage. Personally I could care less what my HP and TQ numbers are, I just want the bike to run well. That is if I need to pass someone on the highway, I want the power, but if I am crusing, then I want the fuel mileage.
Can someone answer this ?
Thanks
Can someone answer this ?
Thanks
Last edited by HD Renegade; Apr 2, 2009 at 11:52 AM.
Road Captain
Joined: Sep 2007
Posts: 714
Likes: 0
From: Western,NC
Thanks for the helpful post harleytuner. I added the HD 103 stage II with 255 cams and no CR recently. I've read in some posts here that adding a little more fuel at startup with a SERT can cure hard starts when the bike is hot. In your experience is that true?
Tourer
Joined: Aug 2007
Posts: 466
Likes: 0
so what your saying is an afr of 13.2 is a good way to go for those of us that use an autune like the thundermax which is an auto tune unit and by default they set the auto tune to 13.0 ? also if i may ask this is on a different subject it has to do with rpm's what is a good rpm for the 96 to cruise at for example i can run 55mph in 4th gear at 2900rpm or 55mph in 5th gear at say 2300 rpm which is best on the motor both feel fine no lugging as far as i can tell so in your opinion what is a good rpm to cruise on these 96.(flat ground cruising) any info would be greatly appreciated.
Last edited by poppa cooter; Apr 2, 2009 at 12:05 PM.
Cruiser
Joined: Sep 2006
Posts: 237
Likes: 0
From: San Antonio, TX.
[QUOTE=harleytuner;4803093]Being a dyno tuner it troubles me to see some of your The other thing that bugs me is some of the A/F lines I see, or lack of. Bottom line is, if they can't read your A/F then they CANNOT perform a full tune, if they don't have a 250 dyno, they CANNOT perform a full tune. If they give you a "full tune" and don't show you the A/F calibration then they are hiding something. If you do have the A/F on your printout, it should be relatively a straight line, at around 13.2 : 1. Anything below that line is rich and anything above it is lean. That's NOT where your bike is running, (when you get it back) that is just where it is calibrated. Your Dyno lines should be smooth, when they get real wavy, usually at higher RPM's then your timing is probably off.
What exactly is the A/F line? What does it stand for?
What exactly is the A/F line? What does it stand for?
Road Warrior
Joined: Jan 2006
Posts: 1,808
Likes: 0
From: Waynesville, NC
[QUOTE=ATC2;4805415]
AFR = Air Fuel Ratio
Being a dyno tuner it troubles me to see some of your The other thing that bugs me is some of the A/F lines I see, or lack of. Bottom line is, if they can't read your A/F then they CANNOT perform a full tune, if they don't have a 250 dyno, they CANNOT perform a full tune. If they give you a "full tune" and don't show you the A/F calibration then they are hiding something. If you do have the A/F on your printout, it should be relatively a straight line, at around 13.2 : 1. Anything below that line is rich and anything above it is lean. That's NOT where your bike is running, (when you get it back) that is just where it is calibrated. Your Dyno lines should be smooth, when they get real wavy, usually at higher RPM's then your timing is probably off.
What exactly is the A/F line? What does it stand for?
What exactly is the A/F line? What does it stand for?
AFR = Air Fuel Ratio
"Heat soak" is a big debatable topic with me and the other techs I work with. When you take an engine (in our case) that is composed of many different types of materials, i.e. aluminum, steel, cast metal, etc. they all expand and contract differently to temperature. So if you are running your bike hard and it's hot and you just shut it off and it sits, the engine components will shrink at different rates, that means looser tolerances, that equals not good. Unfortunately there is not a lot we can do about it, at least until Harley comes out with more liquid cooled option which we all have opinions about. I for one, when I am running my bike hard, I try to "cruise" it around a little before just shutting it off, if I do shut it off immediately after a hard run, I try to let it cool off COMPLETELY before restarting it, to help make sure that all components of the engine are at room temp. As far as the Mustang VS> Dynojet, I can't really comment without being biased, I only have experience with the Dynojet, I have read up some on Mustang and they seem to be fine, but I can only talk about what I have experience with.
Good post and some good tips. My question here would be is, where is the balance between horsepower and fuel mileage? Does this rest in having the correct AFR?? Does a nice straight AFR line of 13.2 give you the best of both worlds?? The reason I ask is I have had a bad tune and a good tune. Bad tune = 4 more horsepower w/bad fuel mileage, and the good tune = 4 less horsepower but a lot better fuel mileage. Personally I could care less what my HP and TQ numbers are, I just want the bike to run well. That is if I need to pass someone on the highway, I want the power, but if I am crusing, then I want the fuel mileage.
Can someone answer this ?
Thanks
Can someone answer this ?
Thanks
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Advanced
Joined: Sep 2007
Posts: 50
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So while on the subject. Does anyone know or can confirm a good tuner in the Milwaukee area? I can't ask questions to dealers or people because I know VERY little about the subject myself. So you can see the trouble i'm having on which EFI tuner to pick and who i can use to do the tuning.
In some cases adding fuel at startup can help with hot starts. But with a 103" you shouldn't be having that hard a time to begin with. What compression pistons are you running? Do you have ACR? and is it turned on?