Different A/F and numbers from Different Dynos

[swampking]

Had a map built by a local tunner that has been doing them for years on a DJ 150 then and got 103 HP and 111 Torque He does not use a tunning link. Then last night I had it but on a DJ 250 and just a base line run done and it showed 84 HP and 101 torque. But the part that really puzzles me is that the A/F ratio on the 250 showed way rich at 100% as rich as 11 near the top. I know the 150 operator used std and the 250 used sae so there should be around 3% difference but it's the A/F that bothers me. according to the print out I got on the 150 the A/F looked fine.any ideas?

[Herko]

Yes, there can be variances from dyno to dyno with AFR readings. It's not so much as a 150 vs a 250 thing in AFR like it can be with power readings between the two.

AFR differences can vary with:
-The condition and health of the sensor(s) being used.
-The software/hardware/connections being used to recv a signal from a sensor to in turn show AFR.
-The method and cleanliness used to take the AFR sample.
-Any combination of the above.

The question becomes..."Would the real AFR please stand up?"
There's ways to determine this.
But, the dyno operators would need to invest a little time and money as well as take a competent position when executing the verification process.

[Doc 1]

Yes, there can be variances from dyno to dyno with AFR readings. It's not so much as a 150 vs a 250 thing in AFR like it can be with power readings between the two.

AFR differences can vary with:
-The condition and health of the sensor(s) being used.
-The software/hardware/connections being used to recv a signal from a sensor to in turn show AFR.
-The method and cleanliness used to take the AFR sample.
-Any combination of the above.

The question becomes..."Would the real AFR please stand up?"
There's ways to determine this.
But, the dyno operators would need to invest a little time and money as well as take a competent position when executing the verification process.

Herko is correct and I will add that the 150 dyno came with an poor excuse for a pump to get the sample to the 02 sensor it was like an over sized fish tank pump....the updated version was a double pumper that came out about 7 years ago and now they have eliminated the pump all together and use air pressure to create a vacume to draw the sample to the 02 sensor.
Ask each of the dyno owners when is the last time he changed the 02 sensor....this will give you a good idea of the shape of the equipment used.
One more thing to consider is the PE table in the ECM adding more fuel in the 100% throttle position as the bike spooled up on the 250....if it showed less power it took more time to get to red line which allows the PE table to add fuel.
What is your mileage....that should tell you if it is overly rich or lean also.
Doc

[whittlebeast]

Remember that the stock 02s are dead on accurate when the bike is warmed up and passing through 14.7 AFR.  Learn to do data logging and get a good data log viewer and you will start to see the limits of the stack ECU.  You will need to do about 15 logs of about 45 min each before you will start picking up on the patterns.  You will be convinced there is some serious fuzzy logic going on under the covers.

AW

[Herko]

"...the stock 02s are dead on accurate when the bike is warmed up and passing through 14.7 AFR."
Then:
"...and you will start to see the limits of the stack ECU."
Which witch is which here?

You saying the Delphi (OE Harley) ECU has flaws to the point of not properly utilizing the benefit of the "accurate" OE sensors?
If so, what would be a good solution?

[FLTRI]

Remember that the stock 02s are dead on accurate when the bike is warmed up and passing through 14.7 AFR.  Learn to do data logging and get a good data log viewer and you will start to see the limits of the stack ECU.  You will need to do about 15 logs of about 45 min each before you will start picking up on the patterns.  You will be convinced there is some serious fuzzy logic going on under the covers.

AW

Please explain what you've discovered as related to your comment fuzzy logic. Since I do not normally do 10+ hrs of data logging I have not noticed what you refer to.
Always eager to learn,
Bob

[whittlebeast]

The ability of the o2 to detect 14.7 and the ECU's ability to take effective advantage of the ability are two very different things.

A little basic EFI math...

If the commanded pulse width from the ECU is 4.75 ms and the injector opening time is .75 ms then the effective injector spray time is 4 ms

If the commanded pulse width from the ECU is 4.30 ms, then the effective injector spray time is 3.55 ms

4ms / 3.55ms = 12% change delivered fuel.   If the starting AFR was 14.7 and the commanded pulse width is changing 12% the resulting AFR is 14.7 * (4 / 3.55) = 16.56

16.56 - 14.7 = a swing of 1.8 AFR points.

Data log any Sporty at 3000 RPM on the highway and report back what you see.  This is just on example of the sort of thing you are up against.

AW

[whittlebeast]

Next experiment..

Fully tune any Harley o2 bike with the bias set to 720 or so throughout and set the AFR in the entire range from 20 kpa to 80 kpa to 14.6.  Do 4 or 5 V Tunes per the instructions.  The o2 should be running real close to about 700 average but swinging down thru 500 mv lots.  This is just as designed.  Now that you the entire VE table set to perfection, (at least where the V Tune got to) set all of the cells that were set to 14.6 for the V Tune session to 14.5

In theory the bike should still average real close to 14.1 on the wide bands.  Now turn on the data loggers set to generic 02 and report back what you see from the o2s.  Remember that anywhere the o2s are reporting 200 ms or so for any long period of time the motor is running leaner than 14.7 and more like 15.4 or even leaner.

Run the bike on the loggers for an hour of so and report back what you see from the o2s.

Remember that a good narrow band has far faster response time and is extremely accurate as you pass thru 14.7 compared to almost all of the wide bands that you will ever find in a shop.

AW

[whittlebeast]

Experiment three...

Find the richer of the two VE tables and copy that table to the leaner VE table.  Now set all of the AFR targets to 14.0 so that the o2 integrators don't get involved.  You should get the same pulse width front and rear, correct?  See what you get on the data logs.  I wonder if the MAP that the front cylinder is using is different than the MAP the rear cylinder is using???  Now do a V Tune log and check out the MAP voltage plot???  What's up with that?

AW

[whittlebeast]

Example of things that come up...

Look at this trace.  The bike is idling in closed loop with an o2 bias of 720.  All looks textbook.

http://www.ncs-stl.com/SertTune/IdleTextbook.jpg

but a few minutes later the same bike on the same ride does this and adds 5% more fuel to one of the cylinders.

http://www.ncs-stl.com/SertTune/IdleUnstable.jpg 

If you don't do data logging you will never catch this sort of thing.  I also see this happening when I ride the same loop say three times in a row on the same ride and the ECU will take one of the cylinders dead lean on just one of the passes.  Also you will never see this sort of thing on one pass on a dyno.

When the bike is running open loop, you will see this effect run that cylinder supper lean all of a sudden.

Remember that you will never duplicate on road air flow and the resulting changes to intake air temp and engine cooling on a dyno.

Have fun tuning

AW

[FLTRI]

AW,
Thanks for sharing with us your findings based on some very tedious testing.
What bike(s) was this testing done on?

I'd like to get a bit more familiar with the test subjects you have found to run dead lean @ different times. Fortunately I have not had complaints from customers who say their bike seems to run 1 way for a while then change and miss (dead lean) then not, etc.

Sure hope your test subjects are the exceptions rather than the rule 'cause if your findings represent the norm, there are thousands of bikes that, while they may be tuned precisely on a dyno, run like crap intermittently on the street.
If so, I guess I've been lucky my customers haven't noticed a dead cylinder while riding.
Thanks again for sharing,
Bob

[FLTRI]

Example of things that come up...
...The bike is idling in closed loop with an o2 bias of 720.

The above statement indicates you have compared idling EFI behavior, which can be influenced by exhaust reversion cooling the sensor and producing reactions not programmed or expected.

When the bike is running open loop, you will see this effect run that cylinder supper lean all of a sudden.

So you are saying the AFR changes all by itself @ idle even in open loop (no AFR changes from O2 sensors)? This would seem to indicate the warm-up enrichment, which is based on engine temp, is affecting the idle AFR as programmed.

Remember that you will never duplicate on road air flow and the resulting changes to intake air temp and engine cooling on a dyno.

Not necessarily true. As a matter of fact I see complete running temperature swings typically during tuning sessions, then go back to verify AFR by letting the engine cool and watch the AFRs as temperatures go through accepted operating ranges. I also vary intake temp by allowing the engine to ingest ambient (room) air, climate controlled (cooled) air, with and without forced (approx 50mph) air to make sure the temperature and wind speed changes have little or no affect on running AFR readings.

One last point:
Using the AFR table to adjust expected tailpipe AFRs is a calculated result rather than a manually tuned results. For this reason I do not use the AFR table to alter expected tailpipe AFR. I use VE tables to adjust to the resultant tailpipe AFR. This way I know what comes out the tailpipe rather than assume the calculations from the software are always exact. I believe there are variables in the math that can and do deliver a bit different AFR result than planned.
Plus there are a lot of variables designed into he calibrations, some we have access to, and others we do not, that can and do have an effect over the VE/AFR tables.

Have fun tuning

That I will. As I said, I'm sure glad the engine idle findings you have presented are such that my customers either don't experience it or simply don't notice it.
As always, JMHO, Bob
PS - "Remember that a good narrow band has far faster response time and is extremely accurate as you pass thru 14.7 compared to almost all of the wide bands that you will ever find in a shop."
I do not feel the respose time differential between the narrow band and wide band is important considering the slow acceleration time and small operating rpm range these engines run at.
And finally, the fact the narrow band sensor is more accurate than an inexpensive wide band sensor @ 14.7, is moot to me as I do not tune to 14.7. As a matter of fact, I tune AFRs from 13.2-14.2, so narrow band sensors are virtually useless for my tuning applications. I do realize using V-tune to adjust AFRs uses the OEM narrow band sensors and the only way this procedure works is to tune to 14.6-7 for every RPM/TP, then change the AFR table to hopefully get to the exact tailpipe AFR desired. This procedure assumes the VE tables are precisely adjusted (tuned) which maybe not be a correct assumption for all applications, especially depending on exhaust system and its reversionary characteristics that affect O2 readings.

[Steve Cole]

The ability of the o2 to detect 14.7 and the ECU's ability to take effective advantage of the ability are two very different things.

A little basic EFI math...

If the commanded pulse width from the ECU is 4.75 ms and the injector opening time is .75 ms then the effective injector spray time is 4 ms

If the commanded pulse width from the ECU is 4.30 ms, then the effective injector spray time is 3.55 ms

4ms / 3.55ms = 12% change delivered fuel.   If the starting AFR was 14.7 and the commanded pulse width is changing 12% the resulting AFR is 14.7 * (4 / 3.55) = 16.56

16.56 - 14.7 = a swing of 1.8 AFR points.

Data log any Sporty at 3000 RPM on the highway and report back what you see.  This is just on example of the sort of thing you are up against.

AW

While you want to present cases that are in your head and on the paper your looking at you cannot use basic math when you leave out as many parts of the math as you do, maybe it's time to come play in the real world

#1 you have left out the fact that the ECM knows the opening time and adjust for it
#2 you have left out the injector closeing time as well
#3 Since the stock ECM knows about these things your arguments are invalid

Did you forget about the test that was preformed by rider57 where he checked his bike in a EPA lab and found on the lab equipment that Vtune hit the numbers as tested and that your method that you tuned missed the mark and caused the bike to have a bad vibration! You must spend your days and nights dreaming things up that never come into play, most people just want a good running bike that they can go enjoy and that's just what they get by Vtuning it.

[whittlebeast]

FLTRI

I have seen those sort of dropouts in all sorts of conditions, both closed loop and open loop.  The screen shots that I gave were during idle as it happened to be a controlled example.  In the first example the IAT was at 133 degrees and the engine temp was at 329.  In the second example the IAT was 95 and the EGT was 343 degrees.

The motor was about 12 min into the ride on a hot start so the motor was well out of cold start mode.  The desired idle had settled down to 1000 RPM at 135 sec or about 10 min before.

Most of these dropouts are not severe enough to be extremely noticeably from the seat.  When this is all tuned out though the bike takes on an entirely new personality.

I have seen most of this on several big twins.  The 3000 RPM o2 induced throbbing that is so noticeable on the Sportys is not nearly as bad on the big twin codes.

As a side note, I have seen IATs on the baggers in the 135 and greater range on cold days when running the typical Harley style ACs and people wonder why they are getting detonation in the summer.

As always, Have fun tuning

AW

[FLTRI]

AW,
Sure glad you are unique in your findings. While I have nowhere near the logging hours you have, after some 12 years and 3000+ tunes, the idiosyncrasies you profess to be the norm are undetectable to riders.
I would think excessively lean running as you point out with your test bikes and tunes would be readily identifiable to even the numbest of riders.
I must admit I have far fewer Sportster tunes than Big Twins so if you are referring mainly to a Sportster's running issues you have experience with, I have had no Sportster comebacks for ill-running characteristics.
I guess what you are referring to is simply not felt and observed by those who ride the bikes.
Recalibrating the EFI on a Harley is great fun for me as each one is individual in its needs and requirements making it very challenging and interesting to me as a tuner,
Bob

[whittlebeast]

I don't think that I am anywhere near the only one with these issues.  I am one of the few that is willing to look at the data coming from the bike.

I fixed a link above that apparently nobody had even noticed that both links were the same image. (fixed now)

If the data stream is broke in the code, fix the code.  If the data stream is correct, be willing to look at the data.  I would not trust a company that the motto is "good enough for the customers I have... just don't teach them to look at the data and they will never know the difference"  We did that with the banks (investors, congress...) and look how that worked out.

AW

[nc-renegade]

When the bike is running open loop, you will see this effect run that cylinder supper lean all of a sudden.

Remember that you will never duplicate on road air flow and the resulting changes to intake air temp and engine cooling on a dyno.

Have fun tuning

AW

I would of thought those environmental conditions would be applicable to both cylinders though.....should see it happening on both.

[Steve Cole]

WB is just looking to tell everyone that the code doesn't work, the only issue is he himself does not know how the code works. If he did then just maybe he could figure out what is going on. The truth is that the code works just fine and that his interpretation of the data is flawed since he doesn't understand how it works. It does not do any good to point it out as he just doesn't listen.

[FLTRI]

I would not trust a company that the motto is "good enough for the customers I have... just don't teach them to look at the data and they will never know the difference".

Yet, would you spend your money and trust your dear bike to a company that the motto is: "Tell the customer his bike doesn't have an EFI system that works correctly consequently that's why, after we tune it, it will not run very good."
I'll bet you're glad you don't tune for a living......or do you?

Glad our motto is: "100% customer satisfaction no matter how long or what it takes".

Bob

[whittlebeast]

So did you try the experiments from the posts above?

AW

[FLTRI]

So did you try the experiments from the posts above?

AW

Not sure I need to log hours of data to determine whether the bike runs good or not. Also have years and many miles of smiles from those customers who have done vurtually all the advertising for us as we do not.
I suspect you are barking loud about issues you have identified with bikes you or someone you know has tuned and doesn't run very well. Am I correct?
Bob
PS - The unstable idle graph of O2 integers you offer may simply indicate an exhaust system that allows for reversion to cool the sensors and affective skew the data to the ECM. I see nothin that indicates defective operation. No instant drop-outs or spikes from the integers but gradual change from whatever is in play that affects the result.
Just for imformational value, what is the subject test bike and the exhaust system used in this experiment?
Most riders do not spend a lot of time sitting in one place, but do spend a lot of time riding down the road, which would be some really valuable data if you have some that illustrate your points.

[whittlebeast]

Nope,  They run great now that we have all the dropouts filled in.

AW

[whittlebeast]

That is a totally stock 2007 Sporty with the exception of a Harley Heavy Breather installed to control intake air temp swings caused by stock aero issues that are unbelievable on the Baggers.

AW

[Herko]

"So did you try the experiments from the posts above?"

Golly gee Miss Landers, when are these homework assignments due?

[FLTRI]

Nope,  They run great now that we have all the dropouts filled in.

AW

AW,
So the test bike was a Sporty with stock exhaust and a free breathing A/C, right? You feel the Heavy Breather corrects intake problems you've also identified with the production and/or std SE air cleaner/filter?

What intake air temp swings are unbelievable with baggers? I will see anywhere from 75deg to 130 degs given time and tuning circumstances, but have verified those temps to be accurate by using a infrared temps gun shot into the intake. While i realize that method is not perfect it does show temps very close to ECM reported temps.

Maybe I have been reading your posts incorrectly. Are you saying once you realized/learned how to tune these bikes you have been successful in getting them to run right or are you saying because of your knowledge and expertise you have discovered special tuning techniques to override or get around design and production errors?
Bob