The narrow band O2 sensors work by switching. They are looking for 14.7 as an AFR. If they sense richer then fuel is removed, if they sense leaner, then fuel is added. SmartTuning uses these corrections to determine what the actual VE performance is and suggests new values. The O2 sensors are not trying to sense 12.5 or other values outside their range. This is not how they work.

Smart Tune does not tune the AFRs to a specific value. Rather it is used to correct the VE tables to match the actual VE performance of your engine. If your VEs are accurate then you can go to the AFR table and enter the desired AFR and that is what you should get.

Remember when I said this? When in Smarttune mode a special map is uploaded to the ECM that among other things changes all the AFR cells to 14.7. This allows the narrow band (switching) O2 sensors to collect data across the entire AFR Range. SmartTuning is not trying to tune specific AFR cells to say 13.5. Rather It is correcting my VE so that I can enter 13.5 in a specific cell and the ECM will have an accurate base of information to adjust the pulse width to produce 13.5 where desired.

You may be limited with the power vision, but the SEPST has no such limitation with the Narrow Band O2 sensors because in SmartTune they are working well within their range.

 

Perhaps. I have completed many SmartTune sessions and I run a custom AFR map that is 100% Open Loop. I am satisfied w/my tune, no popping and runs like a scalded ape.

 

We are talking about the same exact thing. We must be just confusing eachother. The Powervison LogTuner tunes the VE's the same exact way the SEPST does. My whole point was that the PowerVision is not limited. It is the stock O2 sensors that are limited. I was just giving an example of WOT tuning. The stock O2 sensors are not going to be reliable at tuning WOT or any other areas of the entire map that it can not sense.

We just set the areas of the AFR map to 14.6 first so the LogTuner knows to collect data for that cell to make corrections to the VE's. We can run full open-loop as well. There is no limitation on the Powervision.

These tuners all do the same thing. We are just confusing eachother.

However, the stock O2 sensor is actual limitation. Just because you can gather data across the entire rpm range does not mean the stock O2 sensor is giving you reliable information on anything too far away from stoich values. That is why they are called "Narrow-band" sensors. To tune the "entire" rpm range the correct way, you need a Wide Band O2 sensor, just like on the dyno. I would love to see a shop that tunes bikes on the dyno with only a stock O2 sensor. HAHA!

 

Nope. You don't get it. When you auto tune with the stock narrowband sensors the entire map is set to stoic so they work across the entire range, their limitation of only being accurate at stoic then doesn't matter as they are doing precisely that.

As for " I would love to see a shop that tunes bikes on the dyno with only a stock O2 sensor. HAHA!" ...they wouldn't use any wideband sensor fitted to a bike either, they would use an up-the-pipe sensors the same they would on any bike, so whether there are narrowband or wideband sensors fitted you would get the same tune.

The only advantage to wideband sensors is that they can keep the tune more accurate in open loop as well as closed loop. Big deal. If you got the bike tuned on a dyno or you had a good canned map plus did a good job of the auto tune to bed it in then its not going anywhere.

 

Sorry bro, but your wrong and I think your the one that doesn't get it. Let's just start with the difference between Narrow-Band and Wide-Band Sensors first.

Instead of me trying to explain it to you, I will enlist the help of this Autometer article. http://www.autometer.com/tech_faq_an...x?sid=1&qid=48

Please call any reputable tuner you like, that tunes cars, trucks, or bikes, and ask them which type of O2 sensor they are using to tune with. I guarantee you they are using a Wideband sensor, whether they shove it up your tailpipe or replace your stock O2s.

Also, you don't know the difference between Open Loop or Closed Loop either. When the car, truck, or bike goes into Open Loop, it is no longer using any O2 sensor input, it is using the A/F table directly. When the bike goes back to Closed Loop, it will then start using the O2 sensor and keep switching/correcting based on the values set in the A/F table.

My whole point for even replying in the first place was because someone tried to say the Powervision was limited in ability, when that just isn't true. It does the same **** as an SEPST, TTS, etc. Please read that article and then reread my earlier posts and you will understand what I was saying.

Also, this stuff is just basic knowledge of tuning too. My 600HP Cobra would not still be living on the same dynotune since 2004 if it were tuned using the stock O2 sensors. It would have blown up long ago!!!

 

I know the difference between wideband and narrowband sensors, thanks. Been tuning for a long time using narrow band and wideband systems (and a long time before that on carb machines). I can also assure I most definitely understand the difference between closed and open loop.

Are you sure that you know the difference between tuning a bike and smart/auto "tuning"?

Yes, you tune with a wideband sensor - obviously. However, once you have done that there is little advantage in having a wideband over a narrowband sensor on the bike to keep things in trim and you can do auto/smart tune with a narrowband sensor setup.

 

Well, it sounds like we were on the same page then. Like I said in a previous post, we are all talking about the same thing and just confusing eachother with what we were trying to say.

You tried getting at me sideways and I was just backing up what I was saying. Not trying to beef with ya!

I just don't want some dude reading this thread, with a freshly built 107 motor, thinking he can just "autotune" his way to a perfectly safe WOT tune using only the stock O2 sensors. It just is not gonna happen.

 

Evidently we are not.

You do appear to be confused about how the narrow band O2 sensors work.

I never said it was limited, but if you cannot tune WOT with it due to the factory narrow band O2 sensors, then I consider this a serious limitation of the PowerVision. Perhaps they should change the name.

Setting a cell to 14.6 14.7 whatever puts that cell into closed loop where the AFR is controlled by the switching of the O2 sensor.

Ok, so you set all the cells to the stoic value and data is collected in those areas that are hit during the run process, including the WOT areas because the O2 sensors are looking at the exhaust flow and switching from too lean add fuel, too rich remove fuel. They have no idea that this is a WOT area, they just know that below a certain voltage is rich, above a certain voltage is lean (actually this is the ECM interpreting the voltage recieved from the O2 sensors).

I never said it was limited.

I am not confused, but I believe your understanding of the tuning process as it applies to SmartTune is flawed. I have no experience with PowerVision but I believe the process using the Narrow band sensors is likely the same.

The limitation here appears to be your understanding of this process. They are called narrow band sensors because they produce a narrow voltage range.
Their function is to sense a specific AFR and return a specific voltage based upon what they sense (there is a small degree of adjustment in the O2 bias table).

Wide band sensors are able to return a wider range of voltages based upon what they sense, so yeah a wide band sensor can return a value that the appropriate ECM could interpret as 12.5 but SmartTune isn't trying to tune to specific AFRs. It is correcting your VE tables so that the open loop values in your AFR table will be accurately reproduced.

Like I said before, SEPST is designed to produce a race quality WOT tune, and can be used very effectively on a Dyno. Once VE tables are calibrated, I could use a wide band exhaust sniffer to verify the AFRs.

 

Damn. We agree - where's the fun in that?

 

Well,it's back to the dealer for a retune.The decell popping is getting worse and the wife says she can smell a bit of gas as I take off.When I first got it tuned I was very pleased with the performance of my bike,she was faster and smoother and a little bit of a rummble and hardly no popping,the bike was smooth at 100mph,now it vibrates like a SOB and I won't take it that speed until it's fixed,it's a scary situation right now,it's either not getting enough fuel or too much,but it will be fixed on Thursday afternoon,I'll keep in posted.

It is shaking a lot more at higher speeds than before,so I'm thinking it needs a bit more fuel.