Narrow Band Then Wide Band Tuning -Dynojet Power Vision

[hrdtail78]

Those would probably be real widebands.

Does the PV save the information and allow you to recalibrate based on combining the data with the calibration like the Vtune software? or do you have to review data and make manual changes?

http://www.fuelmotousa.com/PVlogtuner.htm gives an overview of the process.  It's somewhat similar to the way vtune operates but a bit less automatic.  It's a bit more automatic than with the TwinscanII+.  They all address VE only.  I'd bet the TTS system typically produces the best, most comprehensive results.

[edit: I just reviewed that page.  I sounds like they're suggesting the PV auto-tune software might pull timing where it was pulled by the Delphi during the log(s) recorded for the "tune".]

That is my understanding with timing as well from my conversations with Jamie.  MyTune also has a feature like that.  I believe you have to accept it, so it gives you a choice not to let it pull timing.

[Sporty 48]

Measurable difference? Yes, that is what we are looking for.
However, the "smoothing" done by fine tuning the VE's is something that might not show up on a dyno trace. The difference in the way the bike feels is very real.
And i know we got a big dip (called pipe inversion) out from the original dyno tune around 2500 rpm by increasing VE's there.

Yes the slower wide bands confuse me a bit. Changing them out is a pain, for just how much gain?

that's the point I was trying to make.  Not that I don't like the wide bands, but the fact that making the switch from the narrow bands in your case is not likely going to give you much of a measurable difference....but the mind can easily play tricks on a fellow so seat of pants might try to tell otherwise.

[mayor]

Measurable difference? Yes, that is what we are looking for.
However, the "smoothing" done by fine tuning the VE's is something that might not show up on a dyno trace. The difference in the way the bike feels is very real.
And i know we got a big dip (called pipe inversion) out from the original dyno tune around 2500 rpm by increasing VE's there.

ok, let's get back into the algebra/calculus talk then.  here's some very specific questions I would like you to answer:

1. what is it that you think the ve's represent? and how are they derived?

2. how many ve's to an afr?  meaning, how much off of your fixed ve do you have to move to represent .5:1 afr change?

3. do you think that more fuel means more power? if so, is that an indefinite gain or does it reach a point of diminished gains? if you do believe there is a point of diminished gains, at what point does that happen?

4. what afr do you think produces maximum power?

5. what afr do you consider to be ideal lighter throttle/cruising afr?

6. do you think that by introducing more fuel, that more air naturally will follow?

7. at what point off of variance off of a desired afr does the operator notice that they are no longer at the desired afr?

8. how transferable to the overall engine performance does the dyno trace represent? meaning, the dip you see on the chart- does it transfer to every throttle position through out the affected Rom's?

9. what columns of ve's do you think correspond with the trace seen on a dyno sheet?

10. what is pipe inversion? (I believe you actually mean reversion).

11. what is it that you think that you are accomplishing by increasing the VE's were there was a dip in the dyno trace?



also: can you post the open loop cal that Bean did for you, your dyno sheet, and your current cal?  is your current cal based on Bean's cal? or did you develop one from vtuning?

[whittlebeast]

Those would be fun to answer....

Who wants to go first?

Beast

[mayor]

I figured Sporty can go first, besides I have a feeling you already know most of the answers....or at least pretty good arguments favoring your opinion (since some questions might not have best fit answers that are agreeable to all). I'm pretty sure my opinion on a few of them would raise some eyebrows.   

[Blackcherry Low]

I figured Sporty can go first, besides I have a feeling you already know most of the answers....or at least pretty good arguments favoring your opinion (since some questions might not have best fit answers that are agreeable to all). I'm pretty sure my opinion on a few of them would raise some eyebrows.   

Alright!!  Now we're getting to the meat and potatos.  I wanna hear the answers to these questions myself. 

I guess my understanding was to get a good cal on the VEs so that we know exactly how much air is really flowing through this engine. 

Changing the VEs to compensate for something else down the road after being tuned seems counter productive to me.

[glens]

Although I understand that in this case the tune originally obtained wasn't done the "standard" way of correctly dialling in the VE tables alone.  Instead, it was done all open-loop and both VEs and AFR tables were juggled to get the results desired by the tuner.  It isn't something that can be just thrown back into closed-loop and work properly.

[Sporty 48]

Oh, Goody!
Mayor,
Did not look this up, maybe I should have....
1. Volumetric Efficiency, a calibrating factor to adjust fuel levels to meet set Air Fuel Ratio as detected by O2 sensor.
2. No idea of ratio, move VE's up and down 3% at a time, listen to the motor.
3. More fuel, more power? Depends upon where we started. Do an O2 data run, view with MLV HD, chase out the lean spots (motor Killing lean spots) by adding fuel.
4. Do not know, on those posted dyno charts I see 12.8, 13.5, guess it depends upon motor and fuel type.
5. ideal cruise afr 14.3 or 14.2
6. Stoich is 14.7, ideal combustion, everything else is a compromise of sorts I guess, get revving too fast, produce too much heat, add fuel to quench, best to err on rich side of blowing motor.
7. How many AFR's until I feel it? Probably hear it out of my D&D Bobcats first, don't know.
8. Dyno tune was a great start, worlds of improvement over stock tune, fiddling with the tune result is sex on a secluded beach satisfying.
9. On VE chart from top left to bottom right in a downward diagonal curve
10. The exhaust pulses bouncing back at some rpm inhibit exhaust flow as opposed to intake cross talk drawing fuel or air from front or rear cylinder
11. Adding fuel to the fire by increasing VE's at the dip.
Comments?
Mayor, please post your answers so i get the testers feedback.

[Sporty 48]

Interesting, what makes you think an all closed loop performance tune can work properly? I have not seen that evidence yet.
I have only adjusted VE tables. The AFR tables were set by dyno tuner.
Standard way? In my mind what has been done on my bike is very logical and progressing.

Although I understand that in this case the tune originally obtained wasn't done the "standard" way of correctly dialling in the VE tables alone.  Instead, it was done all open-loop and both VEs and AFR tables were juggled to get the results desired by the tuner.  It isn't something that can be just thrown back into closed-loop and work properly.

[glens]

Please quote the things you want to address, and quote them either above your answer or amid your answer.  Replying to something and then quoting it below the reply is counter-intuitive and very time-consuming and tedious to (try to) follow.

Here's your reply formatted for ease of use by others:

Oh, Goody!
Mayor,
Did not look this up, maybe I should have....

1. what is it that you think the ve's represent? and how are they derived?

1. Volumetric Efficiency, a calibrating factor to adjust fuel levels to meet set Air Fuel Ratio as detected by O2 sensor.

2. how many ve's to an afr?  meaning, how much off of your fixed ve do you have to move to represent .5:1 afr change?

2. No idea of ratio, move VE's up and down 3% at a time, listen to the motor.

3. do you think that more fuel means more power? if so, is that an indefinite gain or does it reach a point of diminished gains? if you do believe there is a point of diminished gains, at what point does that happen?

3. More fuel, more power? Depends upon where we started. Do an O2 data run, view with MLV HD, chase out the lean spots (motor Killing lean spots) by adding fuel.

4. what afr do you think produces maximum power?

4. Do not know, on those posted dyno charts I see 12.8, 13.5, guess it depends upon motor and fuel type.

5. what afr do you consider to be ideal lighter throttle/cruising afr?

5. ideal cruise afr 14.3 or 14.2

6. do you think that by introducing more fuel, that more air naturally will follow?

6. Stoich is 14.7, ideal combustion, everything else is a compromise of sorts I guess, get revving too fast, produce too much heat, add fuel to quench, best to err on rich side of blowing motor.

7. at what point off of variance off of a desired afr does the operator notice that they are no longer at the desired afr?

7. How many AFR's until I feel it? Probably hear it out of my D&D Bobcats first, don't know.

8. how transferable to the overall engine performance does the dyno trace represent? meaning, the dip you see on the chart- does it transfer to every throttle position through out the affected Rom's?

8. Dyno tune was a great start, worlds of improvement over stock tune, fiddling with the tune result is sex on a secluded beach satisfying.

9. what columns of ve's do you think correspond with the trace seen on a dyno sheet?

9. On VE chart from top left to bottom right in a downward diagonal curve

10. what is pipe inversion? (I believe you actually mean reversion).

10. The exhaust pulses bouncing back at some rpm inhibit exhaust flow as opposed to intake cross talk drawing fuel or air from front or rear cylinder

11. what is it that you think that you are accomplishing by increasing the VE's were there was a dip in the dyno trace?

11. Adding fuel to the fire by increasing VE's at the dip.

Comments?
Mayor, please post your answers so i get the testers feedback.

In respect to a couple of your answers:

1. what is it that you think the ve's represent? and how are they derived?

1. Volumetric Efficiency, a calibrating factor to adjust fuel levels to meet set Air Fuel Ratio as detected by O2 sensor.

Wow!  Volumetric Efficiency tables have been in use since before O2 sensor closed-loop feedback was put into service.  They don't directly serve to "set Air Fuel Ratio".  The are only a component in the calculation of what it takes.  If we had a sensor to directly measure the air flow into the motor we'd only need them as fall-back for if that sensor failed in service.  Even then, they should be populated to correctly portray the airflow through the motor, not as just some means of developing some arbitrary "AFR" out the pipe when/if a more suitable table were available for that.

2. how many ve's to an afr?  meaning, how much off of your fixed ve do you have to move to represent .5:1 afr change?

2. No idea of ratio, move VE's up and down 3% at a time, listen to the motor.

It's not a set number, it's proportional.  If you need 2% change in AFR to match what's being tried-for in the programming, then it will be a 2% change in VE in the same direction as needed to change the resultant AFR.  This is simple.  A target AFR is specified and the pertinent VE table values are used in the calculation.  If that AFR is not met, the VE tables (most likely) need adjustment, or in other words, they're wrong there.

3. do you think that more fuel means more power? if so, is that an indefinite gain or does it reach a point of diminished gains? if you do believe there is a point of diminished gains, at what point does that happen?

3. More fuel, more power? Depends upon where we started. Do an O2 data run, view with MLV HD, chase out the lean spots (motor Killing lean spots) by adding fuel.

Not an answer to the question.  Not at all.

I'm going to quit there.  It seems to me, especially with your final request that mayor post his answers so you can get feedback from "the testers", that you've decided to present these questions/answers/comments elsewhere and want to hear what someone else has to say about them.  You could've looked this stuff up yourself, or asked those other folks what they'd say in response to them...

It's okay that you want to discuss it and thereby learn, don't get me wrong, but I get just now the distinct feeling that's not your primary concern.

Interesting, what makes you think an all closed loop performance tune can work properly? I have not seen that evidence yet.
I have only adjusted VE tables. The AFR tables were set by dyno tuner.
Standard way? In my mind what has been done on my bike is very logical and progressing.

I know an all closed-loop (within limits of whatever type of O2 sensor is being used) performance tune (especially one at the level you're using!) can, will, and does work properly.  What makes you think it couldn't, wouldn't, or won't?

The AFR tables were set by the tuner, but not in the conventional manner.   Right?   Yes, there is a conventional manner.  That would be ensuring whatever target AFR values are set in the tables are provided out the pipe by appropriately adjusting the VE tables.

I can't bring myself to comment on the logic of what's going on with the process on your bike.

[Sporty 48]

Glens,

Thank you for setting the answers to the questions, shows just how little I know.
This is the place to learn tuning as far as I am concerned.
I frequent the XL Forum because a Sportster is more than tuning and just about everything including Andy's tuning help is there.
Not planning on publishing this in my memoirs or elsewhere. It would end up as a comic book or are they called graphic novels now.
While it is understandable that you would not answer all the questions, your input is welcome.

[whittlebeast]

I realize the this is not the technically correct definition of VE but it is far easier to get your head around and will help you keep  your hair from turning gray.

Use the definition of VE as..

VE is final fudge factor that allows you to get your final AFR to most consistently hit your target AFRs.

Regarding Acceleration Enrichment and Decel Enleanment...

AE and DE is the correction factor that helps you better hold those target AFRs as the MAP or TPS is in transition.

Closed Loop...

In a narrow band application.  This is a way to have the ECU chase the target AFR by adding and subtracting some percent of fuel for some amount of time in a attempt to better follow the intended target AFR over time.  That target can be adjusted from about 14.8 to about 14.5 depending on the target O2 bias at the time.

Have fun tuning

[whittlebeast]

Regarding questions 3 and 6...

It takes more fuel (and air) to make more power.  Adding more fuel (without adding more air) will not necessarily increase power.

Beast

[Sporty 48]

Thanks Andy VE's are where I am at, just about all I think about' cause that is where my tune is at, adjusting VE's to get AFR's right.

Glens, "It's okay that you want to discuss it and thereby learn, don't get me wrong, but I get just now the distinct feeling that's not your primary concern."

This very thread was started because I did not understand why something pretty cool, Dynojet Power Vision, and a site supporter, was not getting any discussion.
This thread has carefully devolved into a discussion of how little I know, which I freely admit.
I am primarily here to learn tuning.

[mayor]

Mayor, please post your answers so i get the testers feedback.

I think you will find that many of my opinions on those questions are well documented through out this site.  The tricky part is, you have to read other posts related to tuning...and even other areas not necessarily tuning specific.  The great part about reading other threads, is you get a variety of opinions from a variety of folks which helps build a greater overall understanding. I think you will also find that most of the other fellows that post here are a deal of a sight smarter than me regarding this efi stuff (and I think that would include GlenS). If you really want to learn more, there's a sticky thread in this section that has a wealth of great information from tuning threads from this section.

In respect to a couple of your answers:

1. what is it that you think the ve's represent? and how are they derived?

1. Volumetric Efficiency, a calibrating factor to adjust fuel levels to meet set Air Fuel Ratio as detected by O2 sensor.

Wow!  Volumetric Efficiency tables have been in use since before O2 sensor closed-loop feedback was put into service.  They don't directly serve to "set Air Fuel Ratio".  The are only a component in the calculation of what it takes.  If we had a sensor to directly measure the air flow into the motor we'd only need them as fall-back for if that sensor failed in service.  Even then, they should be populated to correctly portray the airflow through the motor, not as just some means of developing some arbitrary "AFR" out the pipe when/if a more suitable table were available for that.

Well, I agree with both of you.  I think the key thing to remember is- the VE value is not necessarily a real number.  It's a calculated number based on external feedback (like o2 sampling, whether that be vtuning or afr sampling ). Those VE values are not actual volumetric efficiency values, since there are other tables that factor into the equations to determine actual injector pulsewidths in relation to acieving the desired afr (like the EGR tables).  As Glen eludes too, how relative the actual afr in the engine compared to the desired afr tables is very dependant on how well the two were calibrated to each other.  The VE table values contribute to just about everything related to the fuel delivery portion of the Delphi system.  So having accurate information in the VE tables is key.  That is why it is not advisable to adjust the AFR tables to achieve a sampled AFR that is other than the desired AFR value in the AFR chart.     

2. how many ve's to an afr?  meaning, how much off of your fixed ve do you have to move to represent .5:1 afr change?

2. No idea of ratio, move VE's up and down 3% at a time, listen to the motor.

It's not a set number, it's proportional.  If you need 2% change in AFR to match what's being tried-for in the programming, then it will be a 2% change in VE in the same direction as needed to change the resultant AFR.  This is simple.  A target AFR is specified and the pertinent VE table values are used in the calculation.  If that AFR is not met, the VE tables (most likely) need adjustment, or in other words, they're wrong there.

more over on what Glen posted, just arbitrarily adjusting ve tables based on sound is not a good idea.  You really need to understand how everything ties together before adjusting any one area.  Richening up the fuel by increasing the VE's will likely make the engine have a deeper tone even if the control (the ve's before enrichening) was adjusted to achieve a 14.2-14.4 ratio.  That's mainly due to the fact that cruise afr's are not necessarily at an afr value that creates the most power (so richening up from those values will create more power).  The key to cruise afr's is it creates enough power to propel the bike down the road at an efficient enough manner to keep fuel milage in check without creating engine destroying heat.

3. do you think that more fuel means more power? if so, is that an indefinite gain or does it reach a point of diminished gains? if you do believe there is a point of diminished gains, at what point does that happen?

3. More fuel, more power? Depends upon where we started. Do an O2 data run, view with MLV HD, chase out the lean spots (motor Killing lean spots) by adding fuel.

Not an answer to the question.  Not at all.

I agree with Glen, you skirted the question.  I wasn't asking what you thought specifically regarding how you were adjusting your bike, but rather more general.  Before I answer, I would like you to take another try at the question. 

Interesting, what makes you think an all closed loop performance tune can work properly? I have not seen that evidence yet.
I have only adjusted VE tables. The AFR tables were set by dyno tuner.
Standard way? In my mind what has been done on my bike is very logical and progressing.

The AFR tables were set by the tuner, but not in the conventional manner.   Right?   Yes, there is a conventional manner.  That would be ensuring whatever target AFR values are set in the tables are provided out the pipe by appropriately adjusting the VE tables.

to better understand what Glen is referring too, read the answers he and I gave on question 1. 

by you adjusting the VE tables, the afr tables are no longer relative to what your tuner adjusted.....regardless to how the two compared prior to your adjusting.  The ECM uses the VE tables when it calculates what to do to reach the desired AFR in the AFR tables. 



Glen, I think you took Sporty's response incorrectly regarding the tester's opinion.  I think he was referring to me being the tester....as in the person giving him the test.   

[mayor]

3. do you think that more fuel means more power? if so, is that an indefinite gain or does it reach a point of diminished gains? if you do believe there is a point of diminished gains, at what point does that happen?

6. do you think that by introducing more fuel, that more air naturally will follow?

Regarding questions 3 and 6...

It takes more fuel (and air) to make more power.  Adding more fuel (without adding more air) will not necessarily increase power.

so, how much more fuel can you add to the fixed amount of air that you have and still make more power?  is there a point of deminshed returns?

[mayor]

This very thread was started because I did not understand why something pretty cool, Dynojet Power Vision, and a site supporter, was not getting any discussion.

well, that very well could be due to very few people on this site is using it or that the folks that are using it are happy enough not to share their experiences. It looks like a pretty nice system, but it's relatively new and somewhat expensive compared to competitive products.  The fact that it's "pretty cool" might not be relative to fellows who just want to get the two tuning variables of their bike dialed in.   

I also do not believe that DynoJet is a site supporter, one of their dealers is, but unless I'm mistaken DynoJet is not. We run a slightly different kind of forum here than most though, since our forum is advertisement free we have no obligations perceived or otherwise to discuss the virtues of anything we do not personally use.    

[whittlebeast]

so, how much more fuel can you add to the fixed amount of air that you have and still make more power?  is there a point of deminshed returns?

Most riders would be hard pressed to "feel" the difference from 14.0 to about 12.0

On most naturally aspirated applications, I shoot for about 14.2 AFR in low load areas of the map and about 13.2 in the high load and high RPM sections of the map.

Holding within about .5 AFR of these targets almost all of the time is getting fairly close.

Beast

[glens]

8. Dyno tune was a great start, worlds of improvement over stock tune, fiddling with the tune result is sex on a secluded beach satisfying.

That was not an answer to the question, but it's an interesting starting point for another aspect of the entire discussion.  Well, it's not really pertinent to this thread, but let's pursue it nonetheless.

Taken at face value, that you'd started with a stock closed-loop calibration on a stock-configured motorcycle, your statement makes it sound like the bike ran like total crap that way and that a dyno tune (of any kind?) made it run so much better.

Something we (think) know is that you're actively (still?) pursuing an alternative method of altering that tune manually, not using a dyno but instead reading datalogs taken during normal operation and (arbitrarily?) altering facets of the current calibration based upon things you see in those log files.

Let's back way up and cover some elementary ground.

First, it'd be nice to know whether you'd actually thought the bike ran like crap as it came from the factory.  Do you think it did?

It would stand to reason that you'd altered the breathing apparatus at some point.  Did you?  Assuming "yes", why did you do that?  Was to to obtain greater performance, a better sound, or both?

Were you aware at that time that doing so would require changes be made to the EFI calibration to match your hard-parts changes?  (On a side note, were you aware that changes to the calibration, even with all the stock parts still in place, might prove to be beneficial?  After all, the stock "tune" is created to cover the normal window of tolerances in the assembled packages of parts and is often not absolutely "ideal" for many of the bikes rolling out the door.)

The "conventional" way of deriving, at least the fueling parts, of a calibration is to set the target "AFR" to a safe fixed value across the board, then adjust the VE tables so that that result is obtained everywhere (as much as possible) out the pipe.  Setting different "AFR" values in different areas and attempting to get the VEs optimized this way is problematic because whenever an operational area is in use that doesn't pertain to exactly the middle of a table cell (and not just the "AFR" table; it's that way in all of them), the actual target is derived in proportion to the values in the adjacent cells in the direction the operational area happens to be from that cell center to those cell centers..  If you need an example of how this works, let me know.  I'll pretty much have to sketch it out and scan the image, but I will if you need it.

Suffice it to say for now that the same "AFR" target throughout the "AFR" table makes getting the VEs correct everywhere a much simpler task.

I understand that the dyno tune you'd gotten was not a "conventional" one in at least a couple of ways.  First is that, even though you've got a closed-loop-capable bike, the tune was done to totally exclude that mode of operation.  Furthermore, it was done not using (just?) an O2 sensor, but rather another device to determine the exhaust gas composition.  Lastly, and perhaps the most unconventionally, both the AFR and VE tables were juggled to achieve the desired exhaust composition such that, at least in some cases, those tables don't really reflect what would normally be expected just by looking at them.  Have I got this part right?  How much have you changed anything besides VE values so far?

[glens]

Andy, in that ricer scenario you'd posted and pulled, how do you know the AFR was actually drifting like that, and if it was, how do you know it's not what the Asian engineers wanted to happen?

I think you can get yourself into trouble if/when you try to do things differently than the ECM programming wants to do, agreed?

[whittlebeast]

Andy, in that ricer scenario you'd posted and pulled, how do you know the AFR was actually drifting like that, and if it was, how do you know it's not what the Asian engineers wanted to happen?

I think you can get yourself into trouble if/when you try to do things differently than the ECM programming wants to do, agreed?

I was just watching the pattern of the wideband trace.  I kept seeing that pattern.  That was just an obvious example.

see http://www.ncs-stl.com/pc5wb/SlidingAFR.jpg

I have no idea why they do that?

Beast

[glens]

What I'm getting at in part is how do you know there isn't some sort of pressure stackup in the exhaust or something causing the broadband sensor to drift while the ECM is smart enough to know this (or not care) and actually keep the AFR constant?  Really, it could be any one or a combination of several things.  By trying to address it with the PC you could well be causing problems when there weren't any to begin with.

[whittlebeast]

One of my euro friends called the problem and I just swapped back to the US revision ECU.  Problem solved.  It has to do with the way the Euro interprets the lack of a o2 signal as opposed to the US code.  Testing and looking at the data is everything in this sport.

Beast

[Steve Cole]

I realize the this is not the technically correct definition of VE but it is far easier to get your head around and will help you keep  your hair from turning gray.

Use the definition of VE as..

VE is final fudge factor that allows you to get your final AFR to most consistently hit your target AFRs.

This is not correct at all. VE is the base that the calculations start from. In a world where testers had the equipment they would be adjusted only based on the amount of AIR entering each cylinder. Since the equipment could not be used by most we developed a method to back into the VE values based on what was there to be used. Do not confuse our method of backing into the numbers for anything other than that. In order for people to learn the system they need to understand what it really is, not what it isn't.

Regarding Acceleration Enrichment and Decel Enleanment...

AE and DE is the correction factor that helps you better hold those target AFRs as the MAP or TPS is in transition.

This is correct for AE but incorrect for DE. DE is used to remove fuel when it is not needed. When in decel fuel does no good so you are just wasting it. By cutting back on fuel at the time the decel starts the fuel consumption and emission are improved as well as carbon build up in the cylinder.

Closed Loop...

In a narrow band application.  This is a way to have the ECU chase the target AFR by adding and subtracting some percent of fuel for some amount of time in a attempt to better follow the intended target AFR over time.  That target can be adjusted from about 14.8 to about 14.5 depending on the target O2 bias at the time.

This is true in ALL closed loop applications the ECM looks at the result from the O2 sensor regardless of type and makes necessary fuel adjustments to get the mixture to the desire ratio set in the code. You will always have wander or switching as the system adjust. A narrow band sensor can and does adjust just fine +/- 0.5 AFR around stoichometeric. For gasoline that would be 14.2 - 15.2.

[whittlebeast]

I stand by my VE definition as a great functional definition.  It is not technically correct, but I really do not care.

Beast