why the dislike of the fuelpak
#151
01-25-2014, 08:04 AM
I think there's a chance they do so something for closed loop, but probably not enough after a short time.
What the fuelpak does is intercept the signal from the ECU to the injectors. It then changes the length of the pulses so that more or less fuel is added than the ECU is aiming for.
Which is OK so far. But the ECU reads this change in fuel via the O2 sensors and tries to correct it. So if it sets the injectors to achieve an AFR of, say, 14.6:1 but reads an AFR of 14.1:1 instead it will lean things out and drag the AFR back towards 14.6:1.
So there will be a push-pull in closed loop between the ECU and the fuelpak that will result in some indeterminate AFR actually being achieved.
Then there is the problem of AFV.
This is a system where on a stock setup if the ECU reads that it is having to make a long-term adjustment in closed loop, it will then apply those changes to open loop too. For instance, if you switch from gasoline to E10 then the ECU will adjust both closed and open loop to compensate based on the readings it takes in closed loop.
What happens with a fuelpak is that the ECU thinks the bike is running rich all the time and adjusts the closed loop as I said above but this also has a knock-on effect in open loop via AFV. So the changes the fuelpak is making to open loop get reduced too.
What this leads to is that immediately after fitting and adjusting of a fuelpak the bike could run well. However, by the time a few tanks of fuel have gone through, the tune will have drifted off to who knows where.
What the fuelpak does is intercept the signal from the ECU to the injectors. It then changes the length of the pulses so that more or less fuel is added than the ECU is aiming for.
Which is OK so far. But the ECU reads this change in fuel via the O2 sensors and tries to correct it. So if it sets the injectors to achieve an AFR of, say, 14.6:1 but reads an AFR of 14.1:1 instead it will lean things out and drag the AFR back towards 14.6:1.
So there will be a push-pull in closed loop between the ECU and the fuelpak that will result in some indeterminate AFR actually being achieved.
Then there is the problem of AFV.
This is a system where on a stock setup if the ECU reads that it is having to make a long-term adjustment in closed loop, it will then apply those changes to open loop too. For instance, if you switch from gasoline to E10 then the ECU will adjust both closed and open loop to compensate based on the readings it takes in closed loop.
What happens with a fuelpak is that the ECU thinks the bike is running rich all the time and adjusts the closed loop as I said above but this also has a knock-on effect in open loop via AFV. So the changes the fuelpak is making to open loop get reduced too.
What this leads to is that immediately after fitting and adjusting of a fuelpak the bike could run well. However, by the time a few tanks of fuel have gone through, the tune will have drifted off to who knows where.
#152
01-25-2014, 10:04 AM
Elite HDF Member
I think there's a chance they do so something for closed loop, but probably not enough after a short time.
What the fuelpak does is intercept the signal from the ECU to the injectors. It then changes the length of the pulses so that more or less fuel is added than the ECU is aiming for.
Which is OK so far. But the ECU reads this change in fuel via the O2 sensors and tries to correct it. So if it sets the injectors to achieve an AFR of, say, 14.6:1 but reads an AFR of 14.1:1 instead it will lean things out and drag the AFR back towards 14.6:1.
So there will be a push-pull in closed loop between the ECU and the fuelpak that will result in some indeterminate AFR actually being achieved.
Then there is the problem of AFV.
This is a system where on a stock setup if the ECU reads that it is having to make a long-term adjustment in closed loop, it will then apply those changes to open loop too. For instance, if you switch from gasoline to E10 then the ECU will adjust both closed and open loop to compensate based on the readings it takes in closed loop.
What happens with a fuelpak is that the ECU thinks the bike is running rich all the time and adjusts the closed loop as I said above but this also has a knock-on effect in open loop via AFV. So the changes the fuelpak is making to open loop get reduced too.
What this leads to is that immediately after fitting and adjusting of a fuelpak the bike could run well. However, by the time a few tanks of fuel have gone through, the tune will have drifted off to who knows where.
What the fuelpak does is intercept the signal from the ECU to the injectors. It then changes the length of the pulses so that more or less fuel is added than the ECU is aiming for.
Which is OK so far. But the ECU reads this change in fuel via the O2 sensors and tries to correct it. So if it sets the injectors to achieve an AFR of, say, 14.6:1 but reads an AFR of 14.1:1 instead it will lean things out and drag the AFR back towards 14.6:1.
So there will be a push-pull in closed loop between the ECU and the fuelpak that will result in some indeterminate AFR actually being achieved.
Then there is the problem of AFV.
This is a system where on a stock setup if the ECU reads that it is having to make a long-term adjustment in closed loop, it will then apply those changes to open loop too. For instance, if you switch from gasoline to E10 then the ECU will adjust both closed and open loop to compensate based on the readings it takes in closed loop.
What happens with a fuelpak is that the ECU thinks the bike is running rich all the time and adjusts the closed loop as I said above but this also has a knock-on effect in open loop via AFV. So the changes the fuelpak is making to open loop get reduced too.
What this leads to is that immediately after fitting and adjusting of a fuelpak the bike could run well. However, by the time a few tanks of fuel have gone through, the tune will have drifted off to who knows where.
That said, seems like plenty of folks have ran them for 10s of thousands of miles without issue.
See yall down the road on this. Enjoying my FuelPak so far.
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