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Old 02-01-2008, 12:17 AM   #51
R4ND0M_AX3
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Originally Posted by williaty View Post
This should make it clearer.


OK, that's a graph of 3 different general shapes for fueling error graphs. Unfortunately, in the real world, you'll usually be seeing 2 or more of them going on at the same time

Error Type 1 is a vertical offset or zero error. The graph has a general trend all in one direction and basically all the same amount. This can be caused by things like incorrect injector scaling, placing the MAF in a different-than-stock sized housing or a new bend before the MAF. This can be fixed with either MAF scaling or Injector scaling. You should alter whichever scaling you've physically changed. This means that if you've just changed injectors, change the injector scaling. Likewise, if you've just altered the intake somehow, change the MAF scaling.

Error Type 2 is a slope error. The graph may or may not all be above or below zero, and it won't all the the same amount. What it will be is a straight line with a constant slope. This is likely caused by injector latency, but with how ornery MAFs are, I bet you could cause this to happen by changing the intake too. This can be corrected with either Injector latency or MAF scaling. Again, fix the scaling for whatever hardware you just changed.

Error Type 3 is a random error. The graph isn't a straight line, has peaks and valleys, and is in general just a mess. 9 times out of 10, this is the MAF being pissy about resonance and turbulence in its new home. This can only be fixed by MAF scaling. Adjust MAF scaling until the error is a straight line, then evaluate it for Type 1 or 2 error lurking within the MAF scaling corrections you just made. Again, if everything was alright before, and you just changed the intake, and then you got a bunch of fueling error, MAF scaling is what you want to change, not anything else.

So as you can see, you can fix any error with MAF scaling. It might not be the right way to do it though.
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Old 02-01-2008, 06:21 PM   #52
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Yes, agreed.
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Old 02-07-2008, 11:25 AM   #53
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i'm glad you know what you're talking about, will... it saves me a lot of time typing in corrections and caveats!

-ken
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Old 02-07-2008, 01:41 PM   #54
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i'm glad you know what you're talking about, will... it saves me a lot of time typing in corrections and caveats!

-ken
I'll take that as a hell of a compliment since in December you were yelling at me for being a n00b
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Old 02-07-2008, 07:27 PM   #55
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You'll need to look at the graph and try to come up with a level where you're keeping as much data as possible, but you're throwing out all the random data points that are too high. For this graph, I would choose 0.3V/s because most of the data is below this level, but most of the spikes are above it.
Anyone know if there is a mathmatical way to select the meaningful data? I'm trying to automate as much of this as possible in Excel.
I've never taken a statistics class so I suck at teh numberz.
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Old 02-07-2008, 07:33 PM   #56
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Anyone know if there is a mathmatical way to select the meaningful data? I'm trying to automate as much of this as possible in Excel.
I've never taken a statistics class so I suck at teh numberz.
I bet you could tell it to look at the entire data set, then select only the portion that was within one standard deviation of the minimum value (since in both IAT and dMAFv/dt we're selecting for low values).
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Old 02-07-2008, 07:37 PM   #57
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Originally Posted by williaty View Post
I bet you could tell it to look at the entire data set, then select only the portion that was within one standard deviation of the minimum value (since in both IAT and dMAFv/dt we're selecting for low values).
apply the 80-20 rule??? take 80% of the data that is closest to 0 is a start.
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Old 02-07-2008, 08:11 PM   #58
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I'd go the other way around, only keep the 20% closest to minimum. Maybe 40%. Definitely less than half.
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Old 02-07-2008, 11:17 PM   #59
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I bet you could tell it to look at the entire data set, then select only the portion that was within one standard deviation of the minimum value (since in both IAT and dMAFv/dt we're selecting for low values).
I don't need it to weed out the data yet. just decide what the dmaf/dt cutoff should be.

Something related to standard deviation sounds like the right route. The 80/20 stuff might be a simpler version. Gonna go look into both methods. I'll take a peak into the ratio of used to discarded data from the manual mehod I did last time.
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Old 02-08-2008, 12:26 AM   #60
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will,
i just sat here, from 9pm-1215am, walking through this 'excel nightmare' LOL

my mean & modes are both positives, and close to each other. so i think ive got something wrong. also, every cell in the two columns, with formulas, has an error stating something about grouped cells having data in adjacent cells..??

Oh, I'm so confused LOL

screenshot:

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Old 02-08-2008, 12:50 AM   #61
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will,
i just sat here, from 9pm-1215am, walking through this 'excel nightmare' LOL

my mean & modes are both positives, and close to each other. so i think ive got something wrong. also, every cell in the two columns, with formulas, has an error stating something about grouped cells having data in adjacent cells..??

Oh, I'm so confused LOL

screenshot:

First of all, I wouldn't worry too much about those numbers, they look ok to me. The mean and mods being close just means that the error is evenly distributed to both sides of the mode, which is probably a good thing. Run with it.

Also, I googled your error and it sounds like it's just excel bitching about the fact that you didn't select all your data. Ignore it.
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Old 02-08-2008, 09:59 AM   #62
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The excel error is just letting you know that the formula is different in one cell than it's neighboring cells. Each of your formulas is looking at a different size data set. It's just trying to help you in case you intend them to all have the same formula. Placing $ in front of the cell column and row pointes should fix it.

ex... change
=MODE(E104:E251)

to
=MODE($E$104:$E$251)



OK, I looked at one set of data that I did manually and I ended up using 73% of the data. I'll try to play with STDEV and the other excel functions tonight.
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Old 02-08-2008, 12:15 PM   #63
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thanks. As long as it isn't an issue, I'm not too worried, then.

I guess I am now concerned with the Corr% column, as I don't quite understand what it's doing, or how I am supposed to use it. As you can see, my Mean/Mode values are very close to one another. I suppose it's the lack of complete data I have come up with, that is really throwing me off.??
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Old 02-08-2008, 06:24 PM   #64
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thanks. As long as it isn't an issue, I'm not too worried, then.

I guess I am now concerned with the Corr% column, as I don't quite understand what it's doing, or how I am supposed to use it. As you can see, my Mean/Mode values are very close to one another. I suppose it's the lack of complete data I have come up with, that is really throwing me off.??
OK, your cor% tells you what to do to your MAF g/sec. For instance, at 1.65V, your modal correction is 1.68%. You then go to your MAF scaling table and multiply the value in the 1.65V column by 1.0168. In other words, you add the correction to the g/sec that's already there. Positive corrections make g/sec get bigger, negative corrections make g/sec get smaller.

Don't worry about the mean and mode being similar, that's a good thing.
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Old 02-08-2008, 06:59 PM   #65
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sweet! so I did it right? LOL
I thought I pissed the hours away!

So, I guess, this increase in the MAF table that I need to change would, in essence, "add" fuel, or richen it up, for that given example?


btw, Excel 2007 blows goats. The "dots" are little diamonds. I had to reduce the size to "2" for the dots, just to make the scatter plot less muddy. Still sucked, tho, but workable. I hate Vista more and more each day.
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Old 02-08-2008, 07:06 PM   #66
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sweet! so I did it right? LOL
I thought I pissed the hours away!

So, I guess, this increase in the MAF table that I need to change would, in essence, "add" fuel, or richen it up, for that given example?


btw, Excel 2007 blows goats. The "dots" are little diamonds. I had to reduce the size to "2" for the dots, just to make the scatter plot less muddy. Still sucked, tho, but workable. I hate Vista more and more each day.
Drop the opacity of the diamonds to about 50%

Yup, if the correction is positive, the ECU is adding fuel to hit the target AFR. If you tell the ECU more air is coming in, it'll add more fuel and hit the target to begin with and not have to rely on corrections.

BTW, plot your modal correction values. Then compare them to the 3 types of fueling error I talked about earlier in the thread. I haven't graphed it, but I think you'll see something.
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Old 02-08-2008, 07:55 PM   #67
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btw, Excel 2007 blows goats. The "dots" are little diamonds. I had to reduce the size to "2" for the dots, just to make the scatter plot less muddy. Still sucked, tho, but workable. I hate Vista more and more each day.
Conditional formating in 2007 kicks ass.
BTW you can use whatever image you want in place of the diamonds.
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Old 02-08-2008, 08:35 PM   #68
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Conditional formating in 2007 kicks ass.
BTW you can use whatever image you want in place of the diamonds.
I will say, that some stuff is much easier, like freezing pains, etc. as for changing from dots, my options were diamonds, squares, dashes, and a couple other odd-balls.. why not just a "." LOL
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Old 02-08-2008, 09:06 PM   #69
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Did you plot your modal corrections yet?
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Old 02-08-2008, 09:15 PM   #70
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no, not yet... I am at work, but plan to look into it again, here in an hour or so..
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Old 02-09-2008, 07:25 AM   #71
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so I piddled with it some more, trying to plot the last part... My plot looks like arse, as I can't figure out the graphing functions. Yes, it is true, I'm not well-versed in Excel.. But here's a screenshot of my Mean/Mode columns, after re-reading the directions, and using the Cor% column for my data, rather than the MAFv column....

the LEFT Mead/Mode columns are where I used the incorrect MAFv column for calcs. The RIGHT Mean/Mode is using Cor% column.



The one with #N/A, I've got no idea why. It's =MODE(E5:E6). Cells E5 and E6 are the Cor% column, containing 17.96 & 16.4, respectively. It's a "value not available" error, so I've got no idea..

But as for the scatter plot, using Cor%, Mean, and Mode, I can't get that to work for crap..
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Old 02-09-2008, 07:41 AM   #72
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If you only have 2 values for the 1.74 MAFv cell, you can't have a modal value because neither of the values occur more often than the other

I'm not sure what you're on about by the right/left columns, but in both columns I see a trend you might want to look into. Have you changed injectors by any chance?
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Old 02-10-2008, 11:58 AM   #73
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ok, ignore the above data. i did it wrong..
So Ive been working on it this morning, and I've got the correct data for Mean/Mode/Cor%.. The last scatter plot, though, with the dotted Cor%, and the lined Mean/Mode values, I cannot duplicate. IOW, I cant figure out how to create that type of chart. Again, I am not Excel literate, by any means!
I'm running 3" intake (MAF housing), modded stock injectors..
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Old 02-10-2008, 12:02 PM   #74
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This is my current results:



My Cor% is about 20k lines deep.
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Old 02-10-2008, 12:08 PM   #75
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OK, let me see if I can remember the order of the steps. I'm doing this without Excel in front of me, so I might be missing things...

1) Make sure MAFv is to the left of the Cor%, Mean, and Mode columns
2) Highlight the MAFv, Cor%, Mean, and Mode columns
3) Click the Chart Wizard
4) Select the XY (Scatter) plot and make sure it has selected the one that doesn't link the points together
5) Let it generate the chart
6) Adjust the X and Y scales to make the chart make sense
7) Pull the chart out to fill the screen left to right
8) Rightclick on one of the data points for Cor% and select format Dataseries
9) Set the foreground and background color to black, set the size to the minimum, set the opacity to 50%.
10) Rightclick on one of the data points for Mean and select Format Dataseries
11) Reduce the size of the marker to the minimum and tell it to add a line between points
12) Do the same thing to Mode
13) ?????
14) Profit!
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