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[whittlebeast]

Treat MAP * RPM / 100 as a MAF function (weight of air per unit time)

Treat RPM * (PulseWidthFront -1) as a Front cylinder fuel flow function  (volume of fuel per unit time)

Treat RPM * (PulseWidthRear -1) as a Rear cylinder fuel flow function  (volume of fuel per unit time)

Start plotting things in MegalogviewerHD and see what you get

the -1 part of the formula is the opening time of the injectors in ms

Have fun tuning

Andy

[Steve Cole]

Let's talk about these one at a time

MAP * RPM /100

Divide by 100 does nothing other than change the scaling, so I think we can skip that part for now, so we are left with

MAP * RPM

Can you please explain how MAP, which is a measure of absolute pressure, times RPM gets you to a weight of air per unit?
Also what "unit" are we talking about here?

Since MAP is going to change based on where you are (altitude) how can you compare it unless it is the exact same place with the exact same engine under test.

[whittlebeast]

Try it in MLVHD   You will have $40 and an afternoon in the project.

[Steve Cole]

What is MLVHD going to do for me if I do not understand what you are trying to do in the first place? I do not need scatter graphs if I do not understand them. So I am just trying to get you to explain what this formula is going to show me and why. You've stated it is a "weight of air per unit". Please explain to me how and what so I may understand it. I thought the questions were simple enough but if you do not understand them tell me and I will try to word it different.

Can you please explain how MAP, which is a measure of absolute pressure, times RPM gets you to a weight of air per unit?
Also what "unit" are we talking about here?

Since MAP is going to change based on where you are (altitude) how can you compare it unless it is the exact same place with the exact same engine under test?

[whittlebeast]

It is almost impossible to help someone that is not even willing to look.

[HOGMIKE]

  :

[Steve Cole]

It is almost impossible to help someone that is not even willing to look.

More than willing to look, but one must first understand what they are looking at. MLVHD will do nothing that I cannot do already in house so with that now out of the way how about you answer the question to help me understand how you get to a "weight of air per unit" from RPM * MAP.

[whittlebeast]

Once you look and get a grip of just how tight the two things interact, it is far easier to get your head around why it works.

The two most driving changing factors that drive molecules of air processed thru a motor is piston displacement per time (RPM) and air density (MAP).  Sure things like air temperature gets involved but in most rides, the are temperature is relatively constant.

Fuel flow is simply Pulse Width - the Injector Opening time times the number of times this happens in time.

The units all get rolled into a single constant when viewed in a scatter plot generating some slope.  I have yet to find a well tuned motor to not fit this model.

I first stumbled into this looking at Harley data.  A hundred or so motors later, I now start here looking for issues.  Lately we have been looking at factory tunes and they all have fit the model.

Andy

[FLTRI]

Andy,
You have provided graphs but have yet to explain how to read them and the adjustments used to improve performance from analyzing the graph so we can see what to look for.
'Splain yerself please,
Maybe if you could put comment on the graphs with arrows to pinpoint the issues and what is the cause and remedy is?
Bob

[joe_lyons50023]

Andy,
You have provided graphs but have yet to explain how to read them and the adjustments used to improve performance from analyzing the graph so we can see what to look for.
'Splain yerself please,
Maybe if you could put comment on the graphs with arrows to pinpoint the issues and what is the cause and remedy is?
Bob

Its frustrating when somebody doesn't just give you the answers but asks you to do test and to figure it out yourself.

[whittlebeast]

Andy,
You have provided graphs but have yet to explain how to read them and the adjustments used to improve performance from analyzing the graph so we can see what to look for.
'Splain yerself please,
Maybe if you could put comment on the graphs with arrows to pinpoint the issues and what is the cause and remedy is?
Bob

Personally, I start by going straight to where the data is not sitting on the line.  You can almost always find what the situation is that is causing it.  In MLV if you hit and piece of data in on plot, the software shows you where in all of the other plots, the data matches.  It's cool.

Andy

[turboprop]

Its frustrating when somebody doesn't just give you the answers but asks you to do test and to figure it out yourself.

The good thing about Andy is aside from being extremely credible, you know he is his own man and nobody is pulling his strings.

[whittlebeast]

See http://en.wikipedia.org/wiki/Ideal_gas_law  This is the vary basis of all EFI tuning.

Andy

[whittlebeast]

To answer the original post, no you can not use the high o2 voltage to tune the WOT portion of the tune but you definitely can use what you learned at low and medium power to better predict what the motor will need for fueling at the top end.  Low voltage at near WOT is almost always a dead giveaway that you are way lean.

As an o2 gets older, this gets even more true.  As a side note, I checked with one of the EFI coders, They use the max voltage ever recorded off the o2 and assume that is the voltage at say 13 AFR.  They then do the same thing with the lowest voltage and set that to say 16.  They know that 14.7 AFR is always very close to 450 mv.  From those three reference points, they can get reasonably close to an AFR curve when in the midrange of the curve.  They simply assume the o2 voltage is unusable anywhere near the min and max voltage observed.

Andy

[FLTRI]

Its frustrating when somebody doesn't just give you the answers but asks you to do test and to figure it out yourself.

Does it remind you of a procedure used with you in your past? I do...

To answer the original post, no you can not use the high o2 voltage to tune the WOT portion of the tune...

The above statement is the exact reason I wanted, no insisted other non-involved members to test the OP's question.
There have been many who make, or made this statement but no one evidently tested to see if it was correct.

Yep, just another 'ole wives tale perpetuated by rumors and forums.

Remember how synthetic oil would cause the rod rollers to skid and flatten?
or...electronic ign black boxes fail so stick with points.
or...closed loop tuning doesn't work must open loop tune all.
or...carbon core spark plug wires won't take the voltage.
or...6th gear pulls on a Dyno will destroy the tire.
or...an overdrive tranny will provide better mileage.
And the list goes on,
Bob