4 replies to this topic

[jim v]

Last year, I modifed my VFR a bit, a '99 catless header (jethot coated), micron exhaust and a PC3, (dialed in by a local shop, can't remember the name right now), etc. I was happy with the results, it ran and sounded better. Riding around town or at a track day, the bike responded more precisely to the throttle - even if I was in the wrong gear coming out of a turn. note that this was in Albuquerque - 5000ft above sea level, very dry

Now I'm in Boston - sea level, pretty humid. I thought the PC3 would need a bit of adjustment, but the bike seems to be running pretty well. Its still responds to the throttle smoothly, even at low rpm's. I haven't done a track day this year (and there are fewer places to let the VFR rip in Boston than there were in ABQ) so I don't have lots of feel for whats going on at high rpm.

now I'm not sure what I should do

• leave well enough alone
• make a small fueling adjustment (maybe 3% across all rpm's?)
• make a big fueling adjustment (maybe 8% across all rpm's?)
• something else?

any advice/info would be great. Also, if I do make an adjustment, the procedure is - remove PC3 from bike, plug into my laptop, multiply all entries by 1.05 (to make a 5% increase), save and the return it to the bike. or did I leave something out?

what does vfrd think?

jim

edit - 02 vfr with catless header and micron exhaust

Edited by jim v, 11 August 2012 - 09:14 PM.

[CharlesW]

Last year, I modifed my VFR a bit, a '99 catless header (jethot coated), micron exhaust and a PC3, (dialed in by a local shop, can't remember the name right now), etc. I was happy with the results, it ran and sounded better. Riding around town or at a track day, the bike responded more precisely to the throttle - even if I was in the wrong gear coming out of a turn. note that this was in Albuquerque - 5000ft above sea level, very dry

Now I'm in Boston - sea level, pretty humid. I thought the PC3 would need a bit of adjustment, but the bike seems to be running pretty well. Its still responds to the throttle smoothly, even at low rpm's. I haven't done a track day this year (and there are fewer places to let the VFR rip in Boston than there were in ABQ) so I don't have lots of feel for whats going on at high rpm.

now I'm not sure what I should do

• leave well enough alone
• make a small fueling adjustment (maybe 3% across all rpm's?)
• make a big fueling adjustment (maybe 8% across all rpm's?)
• something else?

any advice/info would be great. Also, if I do make an adjustment, the procedure is - remove PC3 from bike, plug into my laptop, multiply all entries by 1.05 (to make a 5% increase), save and the return it to the bike. or did I leave something out?

what does vfrd think?

jim

edit - 02 vfr with catless header and micron exhaust

You need verification from someone more knowledgeable than me, but I think the values shown in the cells is the percentge of change from the stock ECU values.
If it has a 5 then 5% more fuel is added at that point.
-5 would mean 5% less fuel is supplied than the stock fuel setting.

[kaldek]

There is no need to make any adjustments to the Powercommander for changes in altitude except for wide open throttle - say 60% and above.

The reason for this is below this throttle position, the ECU uses Manifold Absolute Pressure (MAP), air temperature and engine speed to determine engine load and therefore decide how much fuel is required. Since air pressure changes with altitude and the bike is already measuring this change, it is *already* adjusting fuel for you based on your altitude, except for really wide throttle positions.

In summary this means you do NOT need to tweak the Power commander to suit different altitudes except for large throttle openings. That's when the VFR ECU switches from Speed-density (rpm/MAP) to Alpha-N (Throttle position/rpm) to determine required fuel.

You could use a Powercommander V and an Autotune with nice & accurate AFR values that match what creates the most power. You can leave the cruise cells alone (small throttle/low rpm) and focus on the high rpm ranges. That way whenever you change altitude the autotune will do the tuning alterations for you.

[jim v]

There is no need to make any adjustments to the Powercommander for changes in altitude except for wide open throttle - say 60% and above.

The reason for this is below this throttle position, the ECU uses Manifold Absolute Pressure (MAP), air temperature and engine speed to determine engine load and therefore decide how much fuel is required. Since air pressure changes with altitude and the bike is already measuring this change, it is *already* adjusting fuel for you based on your altitude, except for really wide throttle positions.

In summary this means you do NOT need to tweak the Power commander to suit different altitudes except for large throttle openings. That's when the VFR ECU switches from Speed-density (rpm/MAP) to Alpha-N (Throttle position/rpm) to determine required fuel.

You could use a Powercommander V and an Autotune with nice & accurate AFR values that match what creates the most power. You can leave the cruise cells alone (small throttle/low rpm) and focus on the high rpm ranges. That way whenever you change altitude the autotune will do the tuning alterations for you.

kaldek, thanks for the info - I'll leave things alone for now and think about a making adjustments to large throttle openings, or taking the plunge and getting a PC V with AutoTune

jim

[johnmark101]

Remember you can save your current map on a computer. That way you can always reload it in the event you make changes that do not suit you in the end.