I wrote this once but it got lost i guess. I am close to getting 1000 miles on my new 09 Ultra and will be having a dyno tune with the SE pro super tuner and Rinehart slip ons and SE A/c and would like to have the best AFR set at that time. The dealer said they set them at 14/0 but would set it where ever i wanted it. I was thinking 13/8 . What do you guys know about this. Thanks for the help. I get so much info off of the site that helps me make good choices.

 

Wow! I have not heard anything like that since carburetors where in fashion.

It's done a little differently now,,,,

 

Look at what I posted in your original thread. BTW, your air/fuel ratio will be measured by whatever number of units of air : 1 unit of fuel.



Dennis

 

I guess i don't understand. The AFR is set with the ECM now and not jets but you still have to manage it some how don't you. I just had my last bike, a 05 Heritage with woods gear dirve cams dynoed and it ran 13/2 all the way across the dyno sheet.

 

You really want afrs around 14.1/14.3 in crusing range and lower at WOT. 13.2 is too low for a realtivly stk bike. I have my afr set at 14.2 and I have 15.5:1 compression.

 

What is causing your confusion is the way you are stating the a/f ratio. Your Heritage was not set at 13/2. I am guessing it was 13.2 / 1 or 13.2:1 or 13.2 to 1 However you want to say it. Meaning 13.2 units of air for every one unit of fuel. 13/2 would be the same as 6.5:1.

Look at the a/f ratios on my dyno sheet that I posted on your original thread on this subject. It will show you in a green line where it was from the factory and the red and blue lines will show front and rear cyclinders how it is set now.

Dennis

 

Dennis! Do you have a link to that tread? Thx!

 

https://www.hdforums.com/forum/touri...uel-ratio.html

 

"[B]est AFR" for what--cruise on flat road, partial acceleration, WOT, etc.????? "Best" for fuel mileage??? "Best" for lower engine temps????
I ask because AFR varies for all of those parameters and, with regard to acceleration and load, there is no single AFR that is "BEST."

 

I'm not under the impression that SEST can tune richer than 14.2:1 in the cruise range due to the limitations of the narrow-band O2 sensors, but maybe it can go lower. I hope he's not suggesting that you tune WOT to 13.8 or 14.0! That would be too lean for optimum performance. In the cruise range 14.2:1 would be rich enough for me, but some like it closer to 13.8:1 to maximize cooling at the expense of gas mileage. AFR's of 12.8-13.2 are ideal for WOT and I would strive for that. If you have an oil cooler and run synthetic oil you can probably go as high as 14.5 or even 14.6:1 in the cruise range to optimize gas mileage, and that's easily in the range of the stock O2 sensors. I've been running 14.7:1 in the cruise range with a PCIII and now PCV-AT and am having no issues with heat.

In summer I will be able to switch to a richer map on the fly with the PCV, which allows me to run leaner mixtures most of the time for better mileage, then switch to a richer map when the going gets hot in summer traffic. You can't do this with SEST or TTS (AFAIK) so you'll need to find the best compromise for your type of riding.

If I were you I would tell them to tune it no richer than 14.2:1 (even leaner with an oil cooler) in the cruise range (5-20% TP) and 13:1 at WOT across the board, tapering the AFR's as TP's increase. Then if you are unhappy with the heat you can have them richen it. If you run leaner than 14.2:1 in the cruise range I would install an oil-temp gauge and monitor oil temps closely in summer. It wouldn't hurt to have one even with a cooler and/or running richer AFR's. Keep in mind that in stock form the O2 sensors keep AFR's at 14.6 from idle to about 50% TP.