How lean can you go?

[HarleyFranco]

With the TTS Mastertune, how lean can you safely run a big twin engine.  Thinking that at low map low rpm you could maybe go to 15.1 AFR.  Is this thinking wrong?  At that range, cruise at low load, would you safely be able to run with that AFR?  Or would the heat be too much?

All thoughts welcome, all encouraged to respond.

Frank

[Doc 1]

With the TTS Mastertune, how lean can you safely run a big twin engine.  Thinking that at low map low rpm you could maybe go to 15.1 AFR.  Is this thinking wrong?  At that range, cruise at low load, would you safely be able to run with that AFR?  Or would the heat be too much?

All thoughts welcome, all encouraged to respond.

Frank

Frank
At 15.1 cruising you're getting into a place of meltdown....the TTS has limits built into the system that will not allow you to go to a meltdown, the Closed Loop Bais table will only let you go to 117mv which is 14.8 I believe, however, if a guy fudged the VE tables values to a smaller value meltdown could be reached.
I would say you're leaving a safe AFR cruising (low load) area at 14.68....even at this the bike will run good but it will be running hot.
Doc

[FLTRI]

Without fail the most heard complaint with these new, closed loop bikes is excessive heat. This is because 14.68 is where these bikes are set to run at for emissions regulations. If heat isn't an issue, as Doc1 said, 14.68 is safe....but hot. If you are looking for good mileage get it tuned by a qualified, experienced tuner for best mileage @ cruise.
HTH,
Bob

[HarleyFranco]

Thank You Bob and Doc,

Yes trying to get the best gas milage possible, but I don't want to go into meltdown.  The stock motor from Harley has the timing so far retarded that running that lean produces a lot of heat, I'm lowering the VE in the 3% to 20% throttle between 2000 and 3000 rpm, and feeling the engine as I ride for excessive heat.  I have raised the timing numbers to give some more power and the bike is running pretty good.  If it feels too hot I'll richen it up some and try again.

Thanks
Frank

[HarleyFranco]

Just an update.

Rode the bike two days going to work, it was cool in the morning and hot in the pm coming home.  Engine felt a little hot, but not anything worse than stock.
Took the bike for a nice long ride on Saturday, almost 500 miles, rode through cool areas and hot, not as hot as I would have liked, but the bike felt real good.
Was riding on Saturday two up, and averaged only 42 mpg, so maybe I'm not as lean as I thought I was.  The timing changes I made have really made a difference, bike feels completely different.  When you roll on the throttle in 6th gear the bike actually goes now, not like before where it fell flat.

After the fuel adaptive cells filled themselves in the heat didn't feel that bad at all, I have an Ultra Classic and I had the vents on the lowers open, but I had the vents up on the fairing closed all day.  Not sure how those adaptive fuel cells work, but after they fill in and do thier adjustment the bike runs cooler.

Bob, Steve, Herko, Doc,
Any explanation of what these adaptive fuel cells actually do?

Frank

[Doc 1]

Just an update.

Rode the bike two days going to work, it was cool in the morning and hot in the pm coming home.  Engine felt a little hot, but not anything worse than stock.
Took the bike for a nice long ride on Saturday, almost 500 miles, rode through cool areas and hot, not as hot as I would have liked, but the bike felt real good.
Was riding on Saturday two up, and averaged only 42 mpg, so maybe I'm not as lean as I thought I was.  The timing changes I made have really made a difference, bike feels completely different.  When you roll on the throttle in 6th gear the bike actually goes now, not like before where it fell flat.

After the fuel adaptive cells filled themselves in the heat didn't feel that bad at all, I have an Ultra Classic and I had the vents on the lowers open, but I had the vents up on the fairing closed all day.  Not sure how those adaptive fuel cells work, but after they fill in and do thier adjustment the bike runs cooler.

Bob, Steve, Herko, Doc,
Any explanation of what these adaptive fuel cells actually do?

Frank

Frank
The Adaptive Fuel Cells are the cells that actually learn and adjust to the request of the ECM, there are only a few (25 or so) learning cells through out the map, Steve Cole has placed those Learning cells in his calibrations to where he feels they will do the best job. When these cells learn they interpolate through the rest of the map in closed and open loop. Isn't it great......! TTS maps work so much better than other tuner maps just because of the time and effort Steve Cole put in to using all the learning cells plus placing them where they do the best job....this and several more fixes in the calibrations set TTS alone in the market today as the best tuner avalible.

[HarleyFranco]

Doc,

Thank you for the explanation, and I agree that the Mastertune is a very good product.  I have no experience using the race tuner so nothing to compare Mastertune to. 

Frank