As far as open loop goes that is just because you are moving the calibration around. It's like a torque wrench. If I calibrate 15ft lbs to 16ft lbs, every time I adjust the thing to 15ft lbs it is going to torque bolts to 16ft lbs. At least this is my understanding of it all.

 

LOL...I feel your pain. I burned an entire tank of gas getting the rear cylinder timing in line. My last run last night reached ZERO, YEAH!. I'll keep logging for a while to check it but I'm either dialed in or very close!

 

And what the heck every happened to swapping out the jets and advancing the distributor anyhow? Don't like the timing curve, change the springs and weights...

 

Jamie,

I just received the WB O2 sensors and AT module, so your post was very timely... Just so I'm clear... You're suggesting we reinstall the NB O2 sensors just so we can run in closed loop mode... because with the AT module and WB sensors we can only run in open loop mode...is that correct? Thanks!

Art

 

It was explained to me this way... Your engine has a finite displacement...96cu in, or 103, or whatever.... But it isnt going to actually move its entire displacement every cycle...The VE table is a representation of how much of the total displacement the engine is actually moving. So if each cylinder were to actually pump 48c.i.(for a 96 inch engine) it's VE table would show 1 at that particular RPM and pressure.

So, for any given speed and pressure, the ECM reads the VE table and says.."well, it's going to pump .86 x 48 (for example) inches at this particular point, so I need "x" amount of fuel for that amount of volume". If you alter your VE table, and put in a bigger number, that tells the ECM that more air is being drawn into the engine, so more fuel is needed to maintain the correct AFR. The engine isn't REALLY drawing in more air...but the ECM believes the table, and adds the fuel anyway, and the mix gets richer as a result.

 

Good explanation. This is the way I understand it as well. The ECM still tries to hit the AFR values in the AFR table, but adjusting the VE table basically tricks the ECM into thinking it needs more/less fuel than it really does to get the pre-defined AFR values.

I can see where this would be helpful, especially tuning in the closed-loop areas since any value lower than 14.6 in the AFR table will send the bike out of closed-loop into open-loop thus taking the NB O2 sensors out of operation. I guess you can only go so rich using the closed-loop Bias settings? Maybe thats why the VE tables are used to add fuel too in certain circumstances.

 

I think your understanding is correct but you are looking at it from the wrong angle. Its not tricking anything, the VE is the VE. You are in calibration or not. You may take it out of calibration to achieve a certain objective but you not tricking it, you are just running out of calibration intentionally to achieve some end goal.

 

That is why I am a little confused, The stock bike was said to be very lean so when you change pipes, Air cleaner it would allow better flow or more air volume into the motor and out of the motor. So it would be leaner yet!

So when I do my logs and it suggests that the cells be changed to a lower reading than the stock settings it confused me.

I put on a SE air cleaner, Changed header pipe to S & S power Duals and the Mufflers are the S & S SPO Mufflers.

So of course I would think that I would be higher. When I do a Delta between the Map that Dynojet suggested to use and after several Tunes I have cells that have as much as 18 difference.

Thanks again for all the help.

 

You are trying to look at volumetric efficiency as a tunable item. It is a constant at a given load and engine speed. It is not tunable. The VE tables are telling the rest of the map how your bike breaths (volumetric Efficiency) at a given load and engine speed.

 

Has anyone else noticed their motor pinging but have no knock retard show up in the datalogs?? Some of my logs show no knock retard when I have definitely heard a pinging. Some logs do show the ping. It is kinda odd... So unless there is something out there that sounds EXACTLY like pinging that isn't actual ping, then the ECM/PV/or Plugs aren't picking it up.

Anyone else notice this?