Been running a PCIII since April '06. My mileage also decreased until I had the bike dyno tuned. After that I could always manage 47-50 mpg if I kept my speed down (60-70 freeway) and I still had the power gains I was looking for. The motor is now 95", 10:5/1, 100+hp/100+tq and I regularly get 45+ mpg if I take it easy, 38 mpg riding hard and fast. Anyone that sells a PCIII or PC V before getting a good tune is throwing money in the toilet. The canned maps most always need tweaking to get the best results.

 

Seahag and others have it right, IMO, that the excellence of the results depends on the tuner, not the tuning hardware. The PCIII, PCV, SEST, and all the others basically do the same thing, which is to meter fuel based on the specification given by the tuner. You have good tunes and bad tunes, tunes that give good performance and cooling and those that optimize gas mileage.

I will disagree a bit with Leftcoaster that all canned maps need tweaking, as there is at least one exception, and that is the maps coming from Fuel Moto. In 2½ years I've found their maps to be spot on, and in the latest cases with the PCV Auto Tune the trims I've seen when running with Jamie's base map and target AFR's have shown almost no changes at all. That means that a tune done on an '07 RK in WI is accurate on my '07 SG in S. LA. Some say hardware varies from bike to bike, but Jamie says he's seen little variation between like-equipped bikes, and I side with him on this argument based on my experience.


OTOH, even though Fuel Moto's maps are written for the lowest common denominator for a reason, they tend to be a bit on the rich side for my taste. I think of their maps as being a good starting point, good maps to use for cooling and performance, or if mileage isn't your priority a great map to use at all times. He also has a "mileage map" that is better but IMO still doesn't go far enough (for me). With an on-off switch the PCV (or even PCIII with hub) you can toggle between two maps on the fly, and I use his original map for cooling but have leaned the cruise range in the second map for most of my riding. So, when the going gets hot in summer traffic I'll switch to the cooling map, then back when needed. When I said "lowest common denominator" above I mean as an example a bike without an oil cooler that is run in very hot conditions. I have a cooler and can bump the leanness in the cruise range more than most, and that helps me to get excellent mileage.

There is no reason why gas mileage with any EFI controller can't be equal to stock when properly tuned, as like so many things it is a compromise, mostly cooling verses mileage. Keep in mind that in stock form heat is an issue with many riders and this is a part of the compromise. I have been getting up to 50mpg before changing cams last week, and haven't given the bike a good mileage check since, although first indications are it is about the same. The new cams are not quite as tolerant of lean mixtures as before, but it is close, so I expect maybe 1 MPG or so lower than before since I've lowered AFR's from 14.7:1 to 14.5:1 in the cruise range. BTW, I have not altered any target AFR's above 40% TP, as I want the performance when I twist the throttle.

 

I just finished a 400 mile ride on mostly two-lane state highways with my newly installed PCV and averaged 45.2 mpg through two tanks of gas. This is with the FuelMoto map as installed for my configuration:

'08 Road Glide
103" Big Bore Kit (stock cams)
SE Intake
HD download
Monster Ovals on stock headers

 

Lost approx. 5 mpg, but well worth it!

 

About what I lost 3-5 MPG but totally agree well worth it ...

 

subscribed..

 

StreetGlider,
Did the autotune increase your mileage? Did you find it tuned the PCV to give you more response to the way you ride?

 

My bike ('09 Road Glide) with just an A/C and the stock tune never got better than 40.6 MPG. (usually between 38 and 40) At 2,000 miles I switched to Mobil 1 and the gas mileage jumped to 46.34 MPG (Yikes!!) The next day my PC V arrived and I installed it...the gas mileage dropped a little down to 43.48 but still better than stock. I always top off at the same pump with the bike sitting at the same angle to reduce the chance of getting bad numbers. I've only run one tank through it with the PC V and I'm curious to see if I can improve on the previous tanks numbers. So far I'm very pleased with the results. Oh yeah, I'm still debating on getting the Jackpots or not. (still have the stock mufflers) I kinda like being able to (easily) hear the radio.

 

Ordered my PC III last week from Fuel Moto just waiting for it to arrive......Can't wait to test on mine to see the difference.....Hope fuel mileage is not effected too much!! and BTW I will be selling my XiED's after my PCIII arrives....

 

I haven't checked it "officially" but I can tell my MPG is down since adding the PC-V. But MPG was and is not my primary concern anyway. The bike runs better, stronger and cooler and "cooler" was my primary concern. I don't commute on my bike, I ride to enjoy my bike and even though I may tack on lots of miles, I am not overly concerned about miles per gallon. Certainly, by doing Stage 1 mods, you twist the throttle a little more now too, accounting for some of the lost MPG.