I have been tuning my fuel injected bikes for quite some time and have used most of the currently available tuners. Before EFI, I tuned my bikes with Carbs as well. Many of the current tuners allow the rider to do a pretty decent job of tuning themselves. You can start with a base tune and use some sort of self tuning functions to "dial it in" for your bike. Different tuners handle it differently but the gist is that you start by setting the VE table to match the air flow characteristics of your bike. This is affected by the exhausts and air cleaner you have installed and varies bike to bike. These late model bikes use the O2 sensor loop to help with this adjustment. You can even use wideband sensors with some tuners. This self tuning allows you to tweak a canned tune to match your bike and good results can be obtained. Many of the tuners also allow you to change other characteristics of the tune as well - based on your knowledge.
As I said, I have used most of them and have really enjoyed tuning my bikes. I have learned quite a bit about tuning. Another feature of these late model bikes is their ability to "adapt" based on the feedback from the O2 sensor loops. That is why some folks say that your bike will learn if you just change an air cleaner or exhausts and should be able to adjust. That is true to some extent but you still end up with a very lean running (14.7 AFR) map in most areas.
So to the reason for the post - I have always tuned by adjusting the VEs (by self tuning with narrow or wideband sensors) to match the airflow of the individual bike and then adjust other areas of the map to get the tune I wanted. Normally, I ended up moving to an open loop map or at least have areas of the map where I set the AFR to something richer than the 14.7 used by closed loop. These maps perform well and I think we all agree that our bikes need to be a little richer than the EPA mandated 14.7. I have seen other tune by adjusting the VE values instead of the AFR table. If you tell the ECM more air is flowing by adjusting the VE table, the ECM would calculate that more fuel is needed and would end up in a richer running bike. My concern with adjusting the VE table is that we are fooling the ECM into an erroneous calculation instead of setting the AFR where we want it. Make sense so far?
I began thinking about that and realized that if you tuned by VE to make the mixture richer and left closed loop and the adaptive feature enable, the bike would in effect "detune" itself over time as the closed loop/adaptive feature tried to get back to 14.7 as measured by the O2 sensors. I posed that question to Jamie at FuelMoto to see if I was right. He confirmed my thinking and gave me permission to post his response so for those who are interested, here is what he said...
" Hello Dennis, I'll break it down a bit and feel free to share this with the forum if you would like. There are essentially two sides the ECM uses for fuel delivery on closed loop application: modeling (or predicting) and correction. The main lookup table for fuel delivery is VE which is a representation of the airflow model (prediction), the AF/Lambda table is used as a reference table. If an engine is correctly tuned the actual measured air/fuel mixture should match the AF table, essentially the VE is developed/synced to this AF. This is especially important on closed loop applications as this is the specific AF to be maintained (corrected) with O2 control. Closed loop targets a specific O2 switching voltage in the range of 450mv (some ECM's apply a voltage offset as well), the ECM then uses the Integrator to adjust the injector signal in real time as a short term fuel trim, there are various tables tied together and if the ECM sees that a given area continually requires specific fuel correction it builds a long term fuel trim AFF/AFV as well. That brings up a few questions: One key aspect to note is that AFF block learn is not the same resolution as the VE table, it affects a somewhat large cluster of cells. The second is that ECM correction always wins, for example if you have a closed loop bike with a cruise range target of say .980 Lambda (14.4 AFR) and would go into the VE table and richen it 15%, closed loop would work its way right back to .980 lambda using ST/LT fuel trim. On an open loop map (or open loop portion of the calibration) that is not a problem, however the key on a closed loop bike is to getting everything in place so the ECM has to do the least amount of math and correction. If it is open loop you can generally adjust VE independently from the AF/Lambda target, however there are still tables tied together such as PE, DE that still require AF accuracy in this respect. Hope this info helps... "
For those of you that tune your bikes, hope this is helpful. If not just ignore my post.
As I said, I have used most of them and have really enjoyed tuning my bikes. I have learned quite a bit about tuning. Another feature of these late model bikes is their ability to "adapt" based on the feedback from the O2 sensor loops. That is why some folks say that your bike will learn if you just change an air cleaner or exhausts and should be able to adjust. That is true to some extent but you still end up with a very lean running (14.7 AFR) map in most areas.
So to the reason for the post - I have always tuned by adjusting the VEs (by self tuning with narrow or wideband sensors) to match the airflow of the individual bike and then adjust other areas of the map to get the tune I wanted. Normally, I ended up moving to an open loop map or at least have areas of the map where I set the AFR to something richer than the 14.7 used by closed loop. These maps perform well and I think we all agree that our bikes need to be a little richer than the EPA mandated 14.7. I have seen other tune by adjusting the VE values instead of the AFR table. If you tell the ECM more air is flowing by adjusting the VE table, the ECM would calculate that more fuel is needed and would end up in a richer running bike. My concern with adjusting the VE table is that we are fooling the ECM into an erroneous calculation instead of setting the AFR where we want it. Make sense so far?
I began thinking about that and realized that if you tuned by VE to make the mixture richer and left closed loop and the adaptive feature enable, the bike would in effect "detune" itself over time as the closed loop/adaptive feature tried to get back to 14.7 as measured by the O2 sensors. I posed that question to Jamie at FuelMoto to see if I was right. He confirmed my thinking and gave me permission to post his response so for those who are interested, here is what he said...
" Hello Dennis, I'll break it down a bit and feel free to share this with the forum if you would like. There are essentially two sides the ECM uses for fuel delivery on closed loop application: modeling (or predicting) and correction. The main lookup table for fuel delivery is VE which is a representation of the airflow model (prediction), the AF/Lambda table is used as a reference table. If an engine is correctly tuned the actual measured air/fuel mixture should match the AF table, essentially the VE is developed/synced to this AF. This is especially important on closed loop applications as this is the specific AF to be maintained (corrected) with O2 control. Closed loop targets a specific O2 switching voltage in the range of 450mv (some ECM's apply a voltage offset as well), the ECM then uses the Integrator to adjust the injector signal in real time as a short term fuel trim, there are various tables tied together and if the ECM sees that a given area continually requires specific fuel correction it builds a long term fuel trim AFF/AFV as well. That brings up a few questions: One key aspect to note is that AFF block learn is not the same resolution as the VE table, it affects a somewhat large cluster of cells. The second is that ECM correction always wins, for example if you have a closed loop bike with a cruise range target of say .980 Lambda (14.4 AFR) and would go into the VE table and richen it 15%, closed loop would work its way right back to .980 lambda using ST/LT fuel trim. On an open loop map (or open loop portion of the calibration) that is not a problem, however the key on a closed loop bike is to getting everything in place so the ECM has to do the least amount of math and correction. If it is open loop you can generally adjust VE independently from the AF/Lambda target, however there are still tables tied together such as PE, DE that still require AF accuracy in this respect. Hope this info helps... "
For those of you that tune your bikes, hope this is helpful. If not just ignore my post.
