Oh man, you done went and confused me again!
I thought AFR had nothing to do with the VE table. In other words, the only reason to set them to 14.6 AFR in my case, is to enable closed loop. Once I calibrate the VE table, those VE values should be good no matter what I set my AFR to correct?
The way I read what you just wrote, you are telling me that if I calibrate my VE tables @ 14.6 AFR, then I change my AFR's to say 13.8 and below in open loop, my VE tables are not good any more?

If this is the case then PV is pointless for me. I will never be running anywhere near closed loop AFR's and I don't plan on welding up 18mm bungs to be able to tune lower AFR's. Unless that is the only way to make used out of the $600 I already shelled out.

 

Ahh now it is clear. Are the changes folks are making to the fuel tables just trial and error? Educated guesses?

 

I think what iclick is saying is you want your VE's dialed in first, this is the purpose of doing tuning logs, getting the VE values to match your particular engine. Then whatever AFR you set afterwards would mean that your set AFR would be correct (open or closed loop).

Changing the AFR makes no changes to the VE values, that my understanding anyway.

 

That's all correct. I'll answer Gelvis in a separate reply.

 

Don't feel bad, as it took me six months to get a grip on this concept. You've got five months and 28 days to be even with me.

Correct. The idea is to set AFR where you want it in the AFR table and tune the VE tables to match the true (measured) AFR. IOW at a given point (let's say for example 2500 rpm @ 50 KPA) when your set (AFR table) and measured (reading from O2 sensors) AFR's match, the VE value is correct. You can then change the Set AFR value as you like, within system limitations of course. You're limited when running closed loop to approx. 14.4-15.0:1 but in open-loop you can move higher (which nobody would want to do) or lower. I'm not sure what limitations we have in open-loop, but I've seen Set AFR values at 12.0-12.5 in stock tunes, so I know you can go that far, and I am running 13.0 at WOT with no issues.

When VE values are adjusted properly (Set AFR = Measured AFR) you don't change VE values again unless you make changes that alter airflow (cams, different mufflers, head work, etc.). Once VE is dialed in you can change your Set AFR values (within reason) and the ECM should do the math and give you that AFR.

To my utter amazement this actually works. My current open-loop tune is set anywhere from 13.0 at WOT to 14.5 in the cruise range, and I have VE's where they should be. I wanted to create a rich tune in case I ran into some really bad traffic and needed some extra cooling, so I simply changed all values in the AFR table to 13.0 and left everything else including the VE table alone. I monitor Lambda with the WB sensors and to my amazement it shows ~.89 (13.0) everywhere in the operating range when running this tune.

Remember that VE is "predicted airflow," which won't change with the AFR setting. Thus, once VE's are dialed in you don't change them unless you alter your configuration.

If you want to run closed-loop you must run within the limitations of the NB sensors, which is quite narrow. The WB sensors will not allow you to run closed-loop with a stock ECM (at this time anyway), and they are only good for tuning in open-loop. Right now I have WB sensors installed with the AT-100 and I both tune and run in open-loop.

Now that my tune is perfected I could switch to the stock sensors and run closed-loop quite easily since I'm running at 14.5:1 in the cruise range. Having an old AFR-based calibration I'd have to change the values to 14.6 where I want to run CL and set the Closed Loop Bias to achieve 14.5. On a newer Lambda-based bike I would change the Lambda values to .98 or .99 and I would be ready to roll.

But I really don't see the point in doing that. I watch Lambda while I ride and running open-loop I don't see much deviation, maybe ±2% with some random spikes beyond that, and my datalogs reflect a rather tight control on AFRs. My PV Tune deltas rarely go more the 2% one way or the other. Would closed-loop make this a more consistent and accurate tune? Maybe, but I wonder if the result would be measurable. I think not and believe the NB sensors are there to meet strict EPA regs, not as a means to make the bikes run any better. Just my 2¢.

Thus if you want to run outside the NB-sensor limitations (i.e. richer) I would run open-loop and forget it. With a stock ECM you really have no choice unless you opt for a PCV-AT, or go with Thundermax or EMS. The PCV-AT does not allow access to the ECM tables, T'Max has no knock-sensing feature, and EMS allows no user tuning at all beyond the closed-loop settings its shipped with. So nothing is perfect, but stay tuned. I have a suspicion that DJ will offer us a way to auto-tune with the stock ECM and WB sensors at some point in time, but I wouldn't hold my breath just yet. That'll mean another accessory to buy, but if we want bleeding edge we'll have to pay for it.

 

By "fuel tables" do you mean the VE tables? AFR table?

 

For all of you who are beta-testing the PV firmware, be advised that if you revert to a non-beta FW you should follow some guidelines. First, after reverting to non-beta FW go to and implement "Restore Original Tune" to get rid of any remnants of the beta FW on the tune. After doing that, re-flash your current tune to the ECM.

This is an advisory I got from DJ. I had to revert to a non-beta FW (1031) because of a major bug with 176 calibrations. If you have a 176 calibration you should beware that the VE tables may not be the same as the ones in the tune you used to flash. This has been reportedly fixed in a beta-FW to be released soon.

 

I have a tune from fuel moto, which I have been data logging and when I go to recalculate the ve tables it says that no changes will be made. Does this mean the ve tables are already spot on? My combo is a little differnt than what the tune was made for or am I missing somthing. The tune is for a 107 with 555 cams, I have a 106 with tman 625 cams every thing else is close to the same. The tune is just as it was sent to me no changes, It runs good no popping, pinging or missing. It just feels a little rich on the top end or like its not getting enough air? What should be my next step?
Any ideas?

 

AFR table.

 

If you are getting no changes made, mostly likely you are not logging all channels needed or are missing something in the procedure. Recheck everything and try again. Even if you are "spot on", you will still get minor changes every time you tune.The Tuning Basics link in my sig may help.