Not sure if this will work but I removed the confusing stuff where I use fuel trims and VE and just created a simple speed density from airmass spreadsheet you can try.
Ford Speed Density Simple From Airmass.xlsx
Not sure if this will work but I removed the confusing stuff where I use fuel trims and VE and just created a simple speed density from airmass spreadsheet you can try.
Ford Speed Density Simple From Airmass.xlsx
This is linear. Make sure you zero out the quadratic if you do it this way.Originally Posted by ridenrunwv
For quadratic you need to calculate the sum of squares. sumsq is in excel as a function. It gives a better fitting line to the data.
Last edited by murfie; 07-23-2017 at 02:36 PM.
I added on to your simplified spreadsheet following the steps on the website. https://www.easycalculation.com/stat...regression.php
The Airmass values are very low and not very diverse for the manifold pressure values so its coming up with strange values, but playing with airmass and inHg you can see where the linear and where the Quadratic work out better and why Ford went to the Quadratic speed density.
Ford Speed Density QUAD added From Airmass.xlsx
Cool. I'll look later. I honestly haven't messed with it much.
Oops I made a mistake and was using the PSI reference not the inHg. I updated it and tested with my made up values and now im getting just what the website gets.
Ford Speed Density QUAD added From Airmass.xlsx
Updated back to all 20 columns of the table.
Ford Speed Density QUAD added From Airmass.xlsx
Last edited by murfie; 07-24-2017 at 05:26 AM.
Hi murfie
Thanks for your work...our shop is still on vacation. in the next two-tree weeks, I need to tune a KenneBell boostet coyote and will test, how the SD calculation tab works. Hopefully I can add some HP.
Thanks Henry
The inferred MAP is derived from the SD calculation, if you change the SD values only from stock to the Rouche ones you will see the inferred MAP changes 50 kpa at 150 kpa, with a 7psi boost I saw the MAP calculation log change from 150 kpa to 200 kpa, an external MAP source would be required, I gather the whole point of the SD tables is to calculate the MAP.
Really good info and I hope will help with a last remaining niggling issue I have with my tunes.
Has anyone considered using an analogue input configured to make a measured vs calculated MAP table rather than logging from a dyno sensor?
my dyno has a independent MAP sensor. I plan to collect the MAP values with this sensor.
Yes mine does too, and I can collect data in .xls form but I figured it be easier if the data could be dropped straight into a spreadsheet already averaged to the correct cells by HP.
@murphie. Thanks for the information. Its challenging. I had a play today with the spreadsheet and I jumped into the MAP sensor off the dyno into the Hp Interface so I could check actual vs calculated pressure. The only issue is I can't seem to configure the HP to give me in-Hg, I'm sure there is a formula but i have to convert my (input/0.0077353519507784)-66 which is for kpa to inHg.
Is there any reason you don't use the Hp reconfigured maths for cylinderairmass 8 cyl?
Am I right the theory is to use the correct actual measured MAP values (MAP ref) as the axis and plug in the mass cyl air calculated from the MAF into the respective actual measured MAP locations and the formula solves for the offset slope an quadratic using the actual measured MAP, rpm and Mass Cyl Air.
This process is repeated with all used MP until the full picture is achieved.
I had a look at your layout and rotated the axis so it copy paste into the spreadsheet but I need to make the X axis the actual measured MAP inHg I gather and I used the Hp Math formula for Cylinderairmass 8 cyl.
Thanks
I don't use it because it gives you grams not pounds. LB/min and revolutions per minute are easy units to work with to get lbs like the units in SD tab shows.
Your parameter to fill the table should be the airmass in LBs. If grams are use you will not get the correct values to put in as HP doesnt allow you to change from inHg and LBs.
Your Columns should be your MAP sensor. If you need to put your external sensor through a math to get this in inHg thats fine.
Your rows should be the RPMs of the rows in your MPs.
You have the theory right and need to make the changes to the layout. The table needs to be filled for all 20 columns. That's not going to be easy even after disabling all other MPs. You can also just fill in the gaps with interpolation or just close guesses.
pasting the values from the scanner to the sheet will populate new values for all all RPMs.
MAF Cyl airmass Pound.png
Maybe its part of the updates, I just switched units to pounds.
Values seem correct
If I use your calcualtion with the Cyl airmass math parameter so I get exact 50% values from murphie's custom math parameter??? strange!
SD.jpg
The rpms need to be divided by 2 because four stroke. This would mean multiplying them by two when they are under maf or use parenthesis.
I'm still a litle cunfused!
I need to ask again for x value. do we need the Airmass per one cyl in one workturn, or do we need the Airmass per all cylinders in one workturn?
I have been playing with the spreadsheet, I extended it into boost and individually populated Maps 0-4 and have found the calculated MAP to be much closer to actual. Actual MAP to calculated MAP would be 20-30 kpa error previously and now I am down to about 0-5 kpa error. Excuse the metric but I had to add an axis in kpa to suit my dyno. I am finding populating the table below 1600 rpm to be more difficult, the MAF seems less stable. It is easy enough to check the error between calculated and actual and refine the numbers. There is quite a bit of extrapolation but it all seems to work.
A quick test of the Rouche numbers on my vehicle was showing a 50kpa(200kpa) error at 150 kpa actual.
Many thanks.
I think, the PCM calculate the speed density in depended on the calculated MAP value not the actual MAP. Why should we use for the calulation the actual MAP values? I think it put an aditional error to the calculation.
@4wheelinls1 can you post your extended spreadsheet?
~$Ford Speed Density QUAD added From Airmass rpm map 4.xlsx
Excuse the mess of the spreadsheet as I have been messing around quite a lot on the other sheets.
I have also found that when previously running on single maps the car would behave badly with wild throttle corrections, now as the actual MAP and the Calculated MAP are much closer the car is much more stable in each Map, I am now just looking at the error and multiplying the values in the spreadsheet in the areas that are unstable to log. Ironicallt the closer the calculation becomes the more stable the car becomes and the easier it is to log.
You did not truly extend it. step 1 - N= is the number of columns. Then you would need to modify step 2 and 3 to include the new columns that calculate the Quad and Slope. The offset is then calculated using steps 1,2,3, the quad, and slope values. The more columns you can make the better the values will represent a range of air mass and pressure. I just did 20 as that's what was in the sheet ridenrunwv posted which probably came outta a cobb sheet.
The PCM gets calculated MAP from the speed density values. You want to use the actual MAP values in the sheet to correct the SD values as we have no way of knowing how inaccurate calculated is other than to compare what the ECU calculates to the actual MAP.
The MAF signal at low RPMs and low MAP pressure is the most difficult to tune especially in the very large housings. So you may want to try more low MAP resolution to help with the low RPMs
Last edited by murfie; 08-17-2017 at 07:41 PM.
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