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Apr 11, 2011 | 04:04 PM

#21

JCleary

Outstanding HDF Member

Joined: Jun 2008

Posts: 2,132

Likes: 25

From: NorCal

I suspect your poor mileage is due to the canned map, plus the fact that with a PCV you're forced to run open loop all the time.

If you had the ability to run closed loop, you could set your target AFR to 14.2 and get your mileage back plus run cooler than stock.

Apr 11, 2011 | 05:02 PM

#22

smokindave

Road Warrior

Joined: Mar 2008

Posts: 1,783

Likes: 10

From: Oh

Just rode the bike yesterday (solo) a little over 200 mi. I have the same pipes as you but, run a SEPST and had mine dyno tuned. Checking my mileage I got 42.4 mpg and that is with a bike with only 1900 mi on it. I also like to twist the throttle. Like has been said, it's all about what tune you are after. Looking at my AFR on the tune, I have never seen such a straight line on a dyno sheet, looks to be about 13.6 all the way across. Ran really cool yesterday in over 80 degree temps.

Apr 11, 2011 | 05:30 PM

#23

iclick

Extreme HDF Member

Joined: Sep 2005

Posts: 11,615

Likes: 50

From: Baton Rouge, LA

Quote:

Originally Posted by JCleary

I suspect your poor mileage is due to the canned map, plus the fact that with a PCV you're forced to run open loop all the time.

I've run open-loop for two of the last four years, the other two with the PCV-AT. I'm currently running open-loop with the Power Vision and continue to get upper-40's for highway mileage, 48.5 mpg on a recent 200-miler on the backroads, all using E10 gas--a point or two higher with pure gas. Is this good enough? The NB O2 sensors used in the stock system and all flash-based, closed-loop aftermarket systems do nothing more than act as switches to keep the engine running at stoich at part-throttle. In this case closed-loop does little or nothing to improve gas mileage, and absolutely nothing to improve performance above 50% TP, assuming you have a good tune to begin with. These NB O2 sensors are in-place to meet EPA regulations, not as the tuning miracle I keep hearing about on some of these threads.

Also, if you don't like "canned maps," which are typically tuned for cooling over economy, you can tweak them to improve mileage. There are plenty of threads on this and other forums to explain how. Just because the tech who provides the map has elected to tune with an emphasis on cooling is not an indictment of the hardware tuner.

Quote:

If you had the ability to run closed loop, you could set your target AFR to 14.2 and get your mileage back plus run cooler than stock.

Sure, but 14.2 is your limit with the NB O2 sensors. In open-loop or with WB closed-loop systems you can reduce the AFR even more if desired. All the NB sensors do is keep it at 14.2 (up to around 15.0 if specified), which you could accomplish with open-loop given a tune that specifies 14.2 at that point. What few understand is that the MAP and other on-board sensors compensate very well for altitude and temperature changes, and these are working with a PCV in open-loop just as they do without.

Last edited by iclick; Apr 11, 2011 at 05:34 PM.