Jamie, in your opinion, what approximate AFR does a CLB setting of 700mv normally give you on one of the FuelMoto tunes? I have heard so many different opinions I would like to know what your experience has shown.

Also, does the CLB table affect the open-loop areas of the map? I have heard that if you increase all CLB values within the CLB tables, it will increase fuel in all areas of the map, not just the closed-loop areas. Any truth to this? Thanks.

 

I would suspect that Closed Loop Bias only comes into play when operating in closed loop. I believe it just tweaks how the O2 sensor signals are interpreted.

 

Let's see...

"Closed Loop" bias. Nope! Don't see an "Open Loop" bias mentioned.

 

It just sets the switching voltage or "target" of the o2 sensors. If you have it set to 700 the ecm sees 701 as rich and 699 as lean. A target of 768 would ask for an afr (based on a fuel with a stoich of 14.68) of 14.5:1. If you are using the narrow bands to collect the data to calibrate your ve tables you would, in a perfect world, offset the afr values in the open loop area by .18 when resetting your afr table. The o2 sensors are really lambda sensors so when you set the bias to 768 you are asking for lambda .993 which is to the rich side, as stoich for any fuel has a lambda value of 1. This is why running closed loop allows your bike to adjust for different grades of fuel.

 

I just remembered reading somewhere that the offset created by setting the CLB values to other than 450mv was applied not only to the closed-loop portion of the map, but the open loop portion also (I think I may have read it in the TTS tuning manual). It makes sense to me that if the closed-loop portion of the map needs x amount of offset, the open-loop areas would need it too. I would still like to hear what Jamie has to say about this issue. Thanks for the replies.

 

While actual stoichiometry of gasoline varies, setting the O2 bias to 700mv will put you in the 14.4-14.5 range. Your second question is a bit more complex, a quick answer is yes if the ECM sees specific requirements in Closed loop they may be applied to open loop, it all depends on how far the O2 integrator is reaching out as well as other factors. What is most important to understand is that when the ECM builds these adaptive values they are not the same resolution as the VE tables. The adaptive trims are larger block learn areas and it may be adding/removing fuel less than optimally over a given area.

 

Thanks Jamie. Did you mean to say closed-loop twice in your second sentence? I would expect CLB and adaptive learn to be applied to the closed-loop portion of the map, but I am asking if the open-loop portion of the map can also be affected by the CLB settings and adaptive learn.

 

Thanks again. Finally got around to doing this. Got 4 very good quality cruise range tuning runs in based on your suggestions. Generally the VE changes were in the region of 3-4% less fuel on the front , one cell about 6.5%, and on the rear only 1-2% leaner with 2 cells at higher rpm/lower MAP slightly richer. These tuning runs were on a cooler day (55 deg. vs. 80 deg.) so I'm not too surprised. I'm going to do the follow-up as you suggested and check for knock and the AFF's. I have one additional question. Assuming I am happy with this new "MPG" map, would it make sense to copy the VE values from 2-3K through 60 MAP over to my Open Loop map (lambda 0.945)? Seems to make sense to me, but thought I would get some input. Thanks again.

TedMan

 

I'm not sure if the following advise is good for everyone but here's what I would do with the questions you've asked.

First I would try to make a few more runs with your closed loop map. Turn on the knock sensor. During these data logs I would find a safe straight run where you can make a really hard acceleration running high into the rpms. Maybe also find a highway on-ramp where you can do a real-world hard acceleration to merge onto a highway. Include some highway cruising in your closed loop region of the map.

Save this log and tune against the map by creating a PVV file for the FR/RR VEs, AFR and FR/RR Spark Advance. Use this PVV file and the data log from your run. Focus on 2 areas.

1) Copy the recommended VEs from the tune calculation (2000-3000rpms and 20-60Kpa) into both the front and rear cylinders VE tables of your closed loop map. Use "Save As" to give the map a slightly different name (V2, V3 etc) so you can always go back if you need to.

2) Now check the Spk Advance tables for both cylinders. If there's knock of more than 1 degree in a cell there's different approaches you can use to address it. Generally I add a slightly higher VE value to that cell using an approach of 1:1. 1% higher VE for each degree of knock. But if the knock is really high above 5, then I go to the map's Spk Adv table for that cell and lower the Adv. It takes abit of experimenting to find the right combination but generally small changes are best and then ride, log and repeat (which is fun in itself).

Make sure to keep the graduations smooth in the VE tables in any region you make changes. Generally I try to keep the VE table values increasing from left to right and top to bottom, but there are definite exceptions such as the very left of the table, 750-1500 rpms and the very bottom right corner of the VE table. The same thinking should apply to changes you make in the spk advance tables. try to keep the graduations from one cell to the next proportional and smooth.

Since I started with a very good map I have not had the need to lower the spk adv with a few very minor exceptions out at 4000rpms and 90-100Kpa. And I only had to lower the spk in this region because I had maxed out the VE in a couple of cells.

I think you'll find that more tuning logs will really smooth out the performance in the closed loop region of the map and really improve the fuel economy. Getting rid of significant knock in the open loop range of the map will significantly improve top end and aggressive performance of the bike. My personal goal is to get the knock down to no higher than around 1 degree anywhere on the fr/rr spk advance tables and then turn the knock sensor off.

Personally, I would NOT transfer the Closed Loop VE values to your fully open loop map if the Open Loop map is already running well. I would however transfer any changes from both the new open-loop region VE values and any Spk adv changes from this new MPG map to your fully open loop map.

Save this completely open loop map as a "hot weather" map or even a "stuck in traffic" map that runs richer and therefore cooler than your closed loop "economy" map. You probably see that under the same conditions your CL-Eco map will run 15-20+ degrees hotter than the fully OL map

Hopefully that makes sense. So far this approach has worked well for me to improve fuel economy and really strengthen my "performance" map by eliminating most knock events of significance. Good luck.

 

OK, got it. Will likely do this weekend and report back. I feel I am very close. Thx again.

TedMan