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[msemersky]

I decided to play with V-Tune for first time and it has been fun.  I highly recommend doing it as I feel like the bike is running better after 2 sessions.  Attached is a picture of my data after last one.  I'm missing a lot of data in the 60%-90% range as I'm riding.  I thought that percentage was throttle position but maybe I'm doing my riding wrong for data acquisition.  Any suggestions on how I should ride it during the data gathering to gather the proper the data in the higher percentage range?  Thanks!

[Unbalanced]

You may want to try and find open road that you can ride at higher RPM's lower gears, Steep hills are good too try using lower gears and bringing the rpm's up higher.   you can get to about 80kPa with auto tune, but I would recommend a dyno for the sweeps (60-100) that your trying to fill in.   Not saying you cant do it to 80, but its much easier on a dyno and would most likely be a lot safer. 

FWIW:   Some guys have mounted a video screen on their handlebars to see where they are filling in while they ride to try and help target specific areas, maybe one of them will chime in how they setup their screens to run.

[gabhart]

Anyone local to Northern Virginia with a laptop that has a good battery? I am itching to do this but my laptop battery is toast!

[msemersky]

As I'm riding should I be 100% throttle to get to the higher kPa?  I have no idea what what the kPa is, I thought it was throttle position  .

[Unbalanced]

Doesn't work like that.

[glens]

As I'm riding should I be 100% throttle to get to the higher kPa?  I have no idea what what the kPa is, I thought it was throttle position  .

In this case, "Pascal" is a unit of measure relating to pressure.  Standard atmospheric pressure is 101,325 Pa, or 101.325 kPa.

The area being measured is inside the intake manifold behind the throttle plate.  Once you hit ~100 kPa (or whatever the atmospheric pressure value in your location is; it'll be less at altitude) then opening the throttle any further will not let any more are into the engine.  That's to say that when you've reached atmospheric pressure behind your throttle plate, there's already as much air movement into the manifold as is possible without forcing it in with a turbo or supercharger.  This point is reached at some relatively small throttle positions at lower engine speeds, with greater throttle opening required at greater engine speeds.

Just throwing some made-up numbers out for the sake of discussion, you might find you've got ~100 kPa MAP (Manifold Absolute Pressure) at 40% throttle at 2000 RPM but to get that pressure at 5000 RPM might take 95% throttle.

Earlier ECM programming used RPM on the side of the table and throttle position across the top.  As you might figure now, 40% throttle can cover quite a range of manifold pressures at any given (especially lower) engine speed.  The fuel calculations the ECM uses are actually based on MAP so it's better to use that instead of throttle position, which the newer ECM calibrations do.  What's happened is that multiple pressures possible per table cell have been traded for multiple throttle positions possible per cell.  This is a good trade-off, but in my experience it makes it somewhat more difficult to v-tune well out on the road with no computer monitor available while doing it.  It was a bit easier to "blindly" v-tune with TPS/RPM VE tables than it is the MAP/RPM VE tables.

It looks like you're off to a fine start in your efforts, and if you really have trouble purposely hitting some areas of the VE tables for v-tuning: how often do you think you'll be running in those areas under "normal" operation, so how important is it really to spend time and effort to get them (v-)tuned?

[msemersky]

Thanks, great explanation and good point.  I'll ride again when I have some time and try to hit a few more but not be too concerned if I can't get much more.  For anyone that hasn't tried it you should.  Bike runs a little crisper and it is a lot easier to do than I thought it would be.