A properly equiped dyno will be able to read temperature, humidity and barometric pressure. These are NOT adjustable by the tuner so I guess your answer would be NO, the tuner cannot manipulate your numbers this way.

 

I appreciate that and I am glad you're getting something out of all of this.

 

Harleytuner,
If you recall I just had 211 cams and dual dressers put on my 2006 Ultra. As a result of these being put on, I had the bike retuned (SERT). My mileage went down from about 39 to40 mpg to 33 mpg. My tuner agreed to retune the bike without any charge. So during my 20,000 service, I had him return it on the dyno. Here is the new dyno chart. What do you think? I haven't had it long enough to check the mpg yet.

 

I can't really tell what he was targeting in the airfule line. If the red dash line is set at 12:1 then you are still running a little rich. If it's at 13:1 you are pretty close in the higher RPM's but just a hit too lean. It's hard to tell what your bike will be doing for fuel mileage, this printout is just for the 100% (full throttle) run and on just 1 cylinder. I would need to know what your bike is doing at cruising ranges (15% to 25%) throttle around 2000 to 2500 RPM. You have to realize that your are only looking at the A/F for 1 of the cylinders. It is possible to have 1 cylinder running rich and the other running lean. It just depends on how it is tuned.

 

Great topic... Thanks Chad and all who have contribute to make this a very informative thread.
I 've been saving up for a tune for a while, bike is getting done as I write. I now feel better informed on what to look for and questions to ask.

 

I stressed to him that I wanted better gas mileage. I showed him some of your posts and he understood what you are saying. He said he tries to do what you are suggesting. He tries to balance out mileage with making sure the engine doesn't run to hot. Since I stressed the mileage thing I think he was willing to go not as rich and try to get me better gas mileage. I think he said the line is 13.2. And I think he said he set my AFR at 14.1 in the cruising range. Does that sound good?

 

Yeah, that's not too bad then if he targeted 13.2:1 like he should have. He could have went leaner with the A/F in cruising though, up tp 14.6:1, I like to set mine at 14.4 in cruising and 13.6 to 14.2 at the higher percentages and 13 at 80 and 100%. But he definately has you in a pretty safe area, you should do pretty good on eceomony where he has you.

 

good stuff...just came up on this thread. Thanks H-tuner!

 

The straight AFR line showing a nice 13.2 on a dyno chart tells you nothing about gas mileage, except at WOT. There can be a balance between mileage and performance without one detracting significantly from the other. If you have a means of changing the AFR's using an EFI controller--e.g. PCV, SEST, etc.--you can tune the cruise range for mileage and those areas outside your normal part-throttle mode for performance. There have been quite a few discussions on this here, mostly on PCV threads, and I've spent quite a bit of time perfecting this concept on my SG.

 

iclick is exactly right, you can tune performance and fuel effeciency seprate from each other. A tuner can tune the higher RPM and throttle position ranges for performance and tune the cruising ranges (7% throttle and 1500 to 3000 RPM range) for economy. Since the average rider spends over 90% of his/her time in cruising range and very little time in performance range your mileage should be good. Let's face it, when you twist the grip and are unning 80% or WOT the furthest thing from your mind is economy. I tuned a bike for a friend, 113" making 130+ Hp and he can average 44 MPG no problem when he's just cruising around.