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#1 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
So now the MAF has failed, but the PCM won't start solely using the VE Table until a failure code is written to the log. So in order to do that we need to go to Engine Diag \ DTCs tab and change the Error Mode on P0103 Mass or Volume Air Flow A Circuit High to MIL on First Error. This way as soon as the PCM sees the MAF has exceed 100 Hz it will write a P0103 code to the log and acknowledge the MAF has failed and only use the VE Table for airmass calculations. If we were to leave the Error Mode on MIL on Second Error, we would need to start the truck run it, then turn it off, and start it a second time and hope the code was thrown on the second start. Now as far as the SES Service Engine Soon light, you can leave that on or you can leave that off it does not effect functionality, it just lights up the check engine light. I prefer not to turn it on because I expect this error, but I may want to see others so I don't want it coming on and me thinking it's just this MAF failure and ignore it. also very important, in Speed Density mode your PCM only relies on the Low Octane table so you must copy the values from the High Octane table to the Low Octane table while calibrating the VE Table GM considers 93 Octane high octane (if all you can find is 91 Octane in your neck of the woods, then be sure to run that) hey if you are taking the time to tune your engine, then I assume you are feeding it the good stuff the High and Low Octane tables can be found under the Engine \ Spark \ Advance section during the calibration process both tables need to match, afterwards you can change the Low Octane table back to Low Octane values or leave it set same as the High Octane if you promise to always fill your tank with High Octane fuel (once we get to tuning Timing Advance we will check for knock and may reduce the Low Octane table manually by 2 or 4 degrees) Last edited by Gregski; 02-19-2020 at 10:25 PM. |
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#2 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
and that's all there's to it to disable the MAF and run in what the cool kids call Speed Density mode (pronounced: only using the VE Table) at this point just save your file (you don't have to do Save As) since we want these changes in our 01 - VE Calibration - Setup file then write / Flash these changes to the PCM and just as with the MAF we don't want to stay in this tune for days, weeks, months, this is just for like a 20 or 30 minute drive with controlled throttle changes and staying out of WOT |
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#3 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
Now we turn our attention to the VCM Scanner where we have to setup some channels to capture the data and create a histogram aka a fancy graph to mimic the VE Table in order to plot the percent errors. Just as with the MAF you can calibrate the VE Table in two ways, using either the stock narrow band oxygen sensors or using an aftermarket wideband oxygen sensor ie AFR gauge. Option 1. Factory Narrowband Oxygen Sensor Method To make things even more complicated, in this method you have three further choices:Option 2. Aftermarket Wideband Oxygen Sensor Method PROS you can tune the entire operational spectrum with this method, Idle, Cruise, and Wide Open Throttle (WOT) so both the Closed and Open Loop.Because this is a basic tutorial intended to wet your appetite for tuning we will be using the factory narrow band Option 1 above relying on both the LTFT+STFT special math function for the win! Nothing stops you from going at it a second time once you have a Wideband and confirming this tune and building upon it by also tuning WOT. Last edited by Gregski; 02-18-2020 at 07:13 PM. |
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#4 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
We only need three sets of Channels to calibrate the VE Table. Engine RPMHow do you know what Channels you need? Well you look at the table you are going to tune and make sure you can build a Histogram (graph) to match. For example, we look at our VE Table and see that the X axis is made up of Engine Speed (rpm) so we know we have to add the Engine RPM (SAE) channel, the names don't match exactly but that's just how HP Tuners does it, you get the idea though, it's basically RPM. Same goes for the Y axis, the VE Table in the VCM Editor has Manifold Absolute Pressure (kPa) as the Y axis, so we add the Intake Manifold Absolute Pressure (SAE) channel in the VCM Scanner. And the values in the table come from the Short Term Fuel Trims and the Long Term Fuel Trims because we are using them to calibrate in Closed Loop as opposed to using a Wideband, that's a decision we made ahead of time. The SAE is the default flavor of the channels that's all, some folks grab them first some grab the ones without the SAE suffix. Once you added your channels I suggest you save them for future use. Last edited by Gregski; 02-18-2020 at 10:03 AM. |
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#5 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
next we will add a Histograph aka Graph to our Channels, remember you can only build the graph out of the Channels you have previously added, if it aint in the list of channels you can't add that parameter to the graph. The graph is in the right pane in the screen shot below, and looks exactly like the VE Table except right now it is blank. Last edited by Gregski; 02-20-2020 at 11:18 AM. |
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#6 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
If we unpin the Channels on the left by clicking on that little thumb tack in the Channels upper right corner, that entire Channels pane will shift out of the way and to the left, so that we can appreciate the Graph in all it's glory. I wanted to just show you how the columns match the RPM break points in the VE Table column for column all the way from 400 to 8000 that's very important, as is matching the Y axis from 15 to 105 kPa or what ever values your VE Table has. Last edited by Gregski; 02-20-2020 at 11:19 AM. |
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#7 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
and here are the detailed properties of that graph Label: call it what ever you want "VE Tune" or "LTFTSTFT VE" what ever fits in that little box Parameter: LTFT + STFT [Math] this is a special computation provided to us by HP Tuners Cell Hits Required: the more the better I think I usually set this to 20 High Value: 20 make it show lean in Red Low Value: -20 make it show rich condition in Green Column Axis Parameter: and here's our X axis aka Engine Speed [Sensor] aka RPM Note: to make RPMs look like RPMs set the Header Cell Factor to 1 otherwise they will look like decimals such as 1.2 or 1.6 instead of 1200 and 1600 Values: cut and paste these from the VE table in the VCM Editor by right clicking anywhere in that table and choosing Column Axis / Copy Labels Row Axis Parameter: and this is our Y axis aka Manifold Absolute Pressure [Sensor] so kPa Values: cut and paste these from the VE table in the VCM Editor by right clicking anywhere in that table and choosing Row Axis / Copy Labels Last edited by Gregski; 02-20-2020 at 11:20 AM. |
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#8 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
Once you created your graph I suggest you save it for future use. |
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#9 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
alright with the changes in the VCM Editor written to the PCM, and our Channels and a Graph setup in VCM Scanner we are ready to do some driving around and logging, but first make sure you warm up your truck How do we ensure our rigs are properly warmed up? Take it for a spin around the block, it's honestly the best way to bring it up to operating temp - think 194* F. Now all you are going to do is log the data as you drive around. No one says you have to use this information to do anything, you can just look at it. I say this to relax you, so that if you forgot to do something - missed a step, if your laptop dies half way through the drive, so what, no big deal, no problem, no worries. Gentlemen, and ladies, we are learning here, so please give yourself the permission to fail, it's ok, that's how we learn. Last edited by Gregski; 02-18-2020 at 11:32 AM. |
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#10 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
after your first test drive is over save the log file with a name that means something to you, 01 Test Drive Around the block.hpl I like to make my first test drive nice and short just around the block to catch any huge anomalies such as you running way too lean, or the engine running way too hot, or crazy knock etc I also create a folder under my VE Calibration called Logs and under that create sub folders called First Attempt and Second Attempt and save all my logs there like so again this isn't so much for now ie today, it is for looking back at it six months from now... think long term historical data Last edited by Gregski; 02-18-2020 at 01:56 PM. |
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#11 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
So now that we've recorded our short (5 mins) test drive around the block lets take a peek at the results, so open the log file in VCM Scanner. It may look something like this, pink! |
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#12 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
Let's just zoom in on that graph aka the right side of the previous screen shot. This is pretty typical of what you may see, when doing this for the first time on your stock(ish) engine. The factory likes to run these engines hot and lean do to fuel economy and emissions constraints. We will take some liberties with these settings and tune for Power and Performance. As with the MAF based on this data we could just go into the VCM Editor and bump the entire VE Table by 10% so multiply it by 1.10 again going from lean (pink) to rich (green) in such a big jump fashion is acceptable as you are not going to hurt anything by going fat and happy |
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#13 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
As with the MAF, before we go making any changes to the VE Table don't forget to take a look at the graph. We do so by clicking the Horizontal Split icon on the top menu bar (red arrow) or which ever split you prefer. Unlike the two dimensional MAF graph the VE graph is three dimensional, and you can rotate it aka spin it around to see it from all the different angles, simply right click it with your mouse and have at it. |
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#14 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
So this is a close up of the stock factory VE Table graph, notice how it's pretty good but still has some sharp peaks and valleys, that's ok, when you create your own don't get too carried away with smoothing it out, you don't want crazy random spikes in it, but also you don't want to smooth it out so much that you smooth out majority of your changes. |
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#15 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
Alright so based on your first test drive you may determine that you are 5% lean or 10% lean or 15% lean, etc. At this point you can increase your VE Table 10% for example and lift the entire graph up to get yourself out of the Danger Zone. There are some tuners who will bump the VE Table up 15% before even going for the first test drive if they are tuning an engine with a bigger cam for example. PROS of bumping the entire graph by a fixed amount include:However keep in mind, this is just the first step, the first attempt, nothing saying you can't go for a second drive, then adjust the graph some more, then go for a third drive and adjust it even further. |
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#16 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
We are going to take the more precise approach for demonstration purposes. In the VCM Scanner select all the data in the Histogram (graph) by clicking in the upper most left hand cell (just like you would in Excel) then right click and click on Copy, we want to copy all the cells, one's with and without values, doing so will ensure that when we go to paste these correction in the VE Table their position will be relative, ie they will only change the exact cells that have these corrections. |
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#17 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
Now you go to the VCM Editor you pull up the VE Table and you select all the cells and right click and do Paste Special \ Multiply by % This is a special feature of HP Tuners that makes our lives easier, no longer do you need to remember if you need to multiply by a number greater than 1 such as 1.10 to richen things up when your graph in VCM Scanner show pink values, or multiply by a number less than 1 such as .90 to lean things out if your scanner shows green values that are too rich. Also on the first calibration attempt it is ok to multiply by percent afterwards on your second and third test drives you can Multiply by % - Half to make more incremental changes, but as always you do you! |
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#18 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
and here's the result of that Paste Special - Multiply by % notice how only the cells with values in our VCM Scanner graph have been altered here and the rest were un affected, that's how that works OK so save this file with a new name, something like 02 - VE Calibration - Multiply By Percent.hpt and write / Flash the changes to the PCM Last edited by Gregski; 02-19-2020 at 10:02 PM. |
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#19 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
OK, now it is time to go for a second drive and test our changes. So just as before go around the block again, replicate the same first drive with no sudden throttle changes and record / log the data. Save your file as something like 02 Secont Test Drive Around the block.hpl |
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#20 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
lets compare the results of our second test drive, looks like the numbers went down, we are less pink, we are moving in the right direction but still no green cells |
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#21 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
alright, time to rinse, lather, and repeat so copy the values from the graph in the VCM Scanner and this time Paste Special \ Multiply By % - Half |
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#22 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
again this should only change the cells that had corrections in them (screen shot below) of course you want to hit as many cells during your test drive as you can, but we just went around the block to see how bad things are, after these test drives you can head out on a 20 - 30 minute ones keep in mind you will never hit all the cells, so don't die trying so as before save this file with a new name, something like 03 - VE Calibration - Multiply By Percent Half.hpt and write / Flash the changes to the PCM Last edited by Gregski; 02-19-2020 at 10:04 PM. |
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#23 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
Volumetric Efficiency VE Table Calibration
and you keep repeating this process until green cells start to show up, and just like with the MAF anything +/- 4% is good, and anything +/- 2% is amazing... single digits are OK. |
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#24 |
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Re: HP Tuners Tutorials - Volumetric Efficiency VE Table Calibration
OK, so lets say you are done calibrating for the day, or you nailed your numbers and you are happy with them, what do you do next?
Well you have to re enable the MAF, put the Codes back to normal, etc. and get out of the VE Calibration setup tune. The easiest way I found to do that is to copy the values of your newly calibrated VE Table over to that very first file we saved called 00 - VE Calibration - Initial.hpt and do a Save As new name and call it something like 04 - VE Calibration - Tuned.hpt or what ever number increment you left off of, if it took you 15 tries to calibrate it then call this one 16 - something something remember that initial file has the correct settings to re enable the MAF put all the codes back to normal and even has the original Low Octane values in that table to keep us safe until we tune Timing and Knock Retard. and finally write / Flash that last file to the PCM and that's that, we have now Calibrated both the MAF and the VE Table essentially taking care of "Fueling" next we'll take a look at Timing Last edited by Gregski; 02-20-2020 at 11:30 AM. |
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#25 |
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Re: HP Tuners Tutorials - Engine Phases
Engine Phases / Tuning Phases
1. Startjust wanted to post this as a sort of Road Map to get us thinking about all the phases the engine goes through from START to WOT when we tune we can use this as a guide for which area we are concentrating on, I hope you find it helpful / meaningful they are sort of to scale in terms of duration, ie Start only takes 1 or 2 seconds, Warm up can take minutes, where as Cuise can take hours, you get the idea (Accelerate & Decelerate are only that wide so the words could fit, ha ha) |
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