Ok so I changed my flow vs kpa table also pulled timong to a limit of 12 deg for now but how do I calibrate MAF and MAP?
Ok so I changed my flow vs kpa table also pulled timong to a limit of 12 deg for now but how do I calibrate MAF and MAP?
53 Mercury pickup triton3v V10 supercharged 150 nos 535rwhp
71 Roadrunner gen 4 viper
53 Chevy pickup 4x4 5.3L twin turbo
You calibrate them separately, but you'll find that MAF is much more important than MAP for now, so focus your attention there. GM uses a blended model, where basically for transient conditions it uses MAP, and for lower rpm stuff it uses a blend of MAF and MAP. Mostly MAF.
To calibrate it, you have to find out where you are vs where you are supposed to be. The PCM has a lot of variances in exactly what type of air/fuel ratio it will command at any moment, especially in open loop. (In closed loop, the O2 sensors are used, and the computer always commands stoich ... which is 14.7:1 in traditional gasoline). We must calibrate in open loop, and we must turn off any fuel adders/modifiers. To trick the computer into temporarily remaining in open loop, you set the closed loop enable temperature thresholds really high, like 500 degrees, across the board. That way the PCM will never try to go closed loop.
Next, you turn off the fuel adders/modifiers. Things like IVT Gain, AIR Gain, and all those tables around that area that are possibly commanding anything other than lambda 1.00, they all need to be turned to lambda 1. We usually leave the modifiers alone at cold temps, so the car will warm up ok while tuning. We're only going to be tuning on a fully warmed up motor anyway. Once all those adder tables are set to 1.0 above say 80 degrees fahrenheit (WATCH your software for Metric vs Imperial here), then we go into the open loop commanded air/fuel ratio table and flat line that to 1.0.
Now that pretty much everything is commanding lambda 1 when warmed up, we know that if we are getting anything other than lambda 1, that's an error. So we measure that error and determine a correction factor by dividing actual lambda by commanded lambda. The result is your correction factor in the cell you're tuning for. You tune each cell (MAF hz point in your MAF table) by multiplying the current cell by the correction factor. Greg's DVD will help you get your head around this tremendously.
But the long and short of it is that we zero the fuel trims (in the scanner), turn off closed loop, shut off the adders/modifiers at warmed up temps, command lambda 1, and measure anything outside lambda 1 to be our error. Then we multiply the cell in the MAF curve we are working on by that correction factor, reflash, and measure again. Also, it's more than just cell by cell modification. We're looking for a general trend as well. So if we test 8 cells and find that they're off by 5, 6, 6, 5, 6, 7, 4, 4, and 5, we can see that a good first correction for that whole area of the MAF curve is 5 across the board. Make that change, then go back and start individual cell tuning.
Once you changed your flow rate table, the car should probably start and run halfway decent. Did it?
Do not forget pure MAF mode, for tuning your MAF sensor. Dynamic High Rpm Enable=2 rpm, Disable=1 RPM. Very importante here.
"pontisteve" is kicking ass right now
Gray Ghost- The abomination. 2007 Chevrolet Silverado CCSB. 98mm turbo, nitrous, 428LSX, Rossler 80E with a brake. Finally finished. 23 psi, no numbers, Slow as hell.
PBM G8- Aluminum 364, twin Precision 67/66 turbos, 6L90 trans swap, CTS-V/Vaporworx fuel system, slowly making progress.
Dads 2011 CTS-V- Stock bottom end, stock heads, LS9 cam, pullies, ported blower, ported TB, D3 goodies, and lots of nitrous.
618/618 motor
906/862 spray
Caterpillar 50 Forklift- Duramax swap
Ok I'll do that as well. I'm not at my vehicle right now (at work) and I cheak in on my breaks! I been inputing this into my file on hp tuners in the evenings and totally pumped to try this on Wednesday when I,m off so I really hope you two-(IDRIVEAG8GT and pontisteve) stay in touch on here this is very valuable info as well as very informative. Now every time that I open hptuners I understand it a little more from the help of you guys! Hats off to you both ...and I will report back on Wednesday with the trial results ..... I really hope you guys are here then! Cheers
53 Mercury pickup triton3v V10 supercharged 150 nos 535rwhp
71 Roadrunner gen 4 viper
53 Chevy pickup 4x4 5.3L twin turbo
Hey man, we're happy to help. I want pictures and sound clips and all the goodies when it's done though!!!!!!!!!Originally Posted by 53mercury
Ok I'll do that as well. I'm not at my vehicle right now (at work) and I cheak in on my breaks! I been inputing this into my file on hp tuners in the evenings and totally pumped to try this on Wednesday when I,m off so I really hope you two-(IDRIVEAG8GT and pontisteve) stay in touch on here this is very valuable info as well as very informative. Now every time that I open hptuners I understand it a little more from the help of you guys! Hats off to you both ...and I will report back on Wednesday with the trial results ..... I really hope you guys are here then! Cheers
Gray Ghost- The abomination. 2007 Chevrolet Silverado CCSB. 98mm turbo, nitrous, 428LSX, Rossler 80E with a brake. Finally finished. 23 psi, no numbers, Slow as hell.
PBM G8- Aluminum 364, twin Precision 67/66 turbos, 6L90 trans swap, CTS-V/Vaporworx fuel system, slowly making progress.
Dads 2011 CTS-V- Stock bottom end, stock heads, LS9 cam, pullies, ported blower, ported TB, D3 goodies, and lots of nitrous.
618/618 motor
906/862 spray
Caterpillar 50 Forklift- Duramax swap
Well I'm a day late.....OT can't pass it up! but gonna try this in the next hr hope you guys chime in.
53 Mercury pickup triton3v V10 supercharged 150 nos 535rwhp
71 Roadrunner gen 4 viper
53 Chevy pickup 4x4 5.3L twin turbo
Taking baby steps I changed the flow rate and backed out a bunch of timing and it actually runs ok (not flooding like before) so now I'm gonna try commanding lambda..... see what happens.
53 Mercury pickup triton3v V10 supercharged 150 nos 535rwhp
71 Roadrunner gen 4 viper
53 Chevy pickup 4x4 5.3L twin turbo
FYI, if you have a large cam with plenty of overlap (choppy idle), that will fool the wideband at and just above idle. If this is the case, concentrate on 1500 rpm and up for now.
Turn off all the adders, force open loop, and command lambda 1. Measure with your wideband and see where you're at. Don't get too caught up on individual cells or percentages. At first, just look for trends across a wider range of cells. If several cells follow the same overall trend, hit that whole area in the table with the same correction. This will get you in the zip code much faster.
By the way, remember that turbos and blowers generally have bypass valves that, under lighter loads including idle, bypass any boost back into the inlet side of the blower. This means that while the blower is bypassing, you can expect the timing maps to have similar needs to a naturally aspirated motor. It's when you start building boost that the timing values start going down proportionally to load going up.
Centrifugal blowers build boost linearly with RPM, so you really don't have full boost until high rpm. If you picture your boost curve plotted on a piece of paper (a line traveling upward with RPM), the inverse of that will be what your timing retard vs stock timing should be. This is a graphical representation, not a numeric one. But it does work out often that roughly 1 degree for each lb of boost is a good place to start with your timing retards.
Baby steps... for now, forget timing and full throttle ANYTHING. Learn to tune first, and a good place to do that is in the idle to 3000 rpm, part throttle range.
Ok this is what I've accomplished so far- changed flow rate, backed timing out tried truck {idling} runs pretty good and keeps stoich in closed loop! Now I removed all fuel modifiers that I can see (set them to 1.0)' changed rpm enable to =2 disable to=1, changed open loop vs ect to 308 (thats as high as it will go) but I don't follow what you mean when you said go into the open loop commanded air/fuel ratio table and flat line that to 1.0???? I can't see that anywhere? So I stopped there for now till I hear further from you! I know I'm leaning on you ALOT but can't find help anywhere! After today I have a couple of questions- first- I record whats going on in vcm scanner now up to say 3000rpm. -second- when I run it with everthing in lambda and open loop I record again and then compare the differences and MULTIPLY OR DIVIDE the difference? And the pid I'm watching is airflow vs frequency right? I do this under light load driving or can I do it in park in the driveway? may be stupid questions but I'm unsure! I have a centrifugal blower on a BONE STOCK engine no cam, head,intake work nothing. If I hear back from you I will proceed...........thanks a million. My AFR gauge is in one pipe (l/h) that should'nt matter though but I wonder how it changes from 14.7 under vac to 11.5 under boost? A question for later.... I'm definitely in to the baby step thing.
53 Mercury pickup triton3v V10 supercharged 150 nos 535rwhp
71 Roadrunner gen 4 viper
53 Chevy pickup 4x4 5.3L twin turbo
Engine>Fuel>Open & Closed Loop> Under the Open Loop section in the left hand side, you'll see all the tables the PCM uses when the car is in open loop.
Let me pause here and define closed loop for you. In closed loop, the PCM starts out with your tune, but then it allows the O2 sensors to work, and it "perfects" your tune towards stoich (14.7:1). To some degree, your tune is just a starting point here. The O2s trim the tune to whatever creates that perfect switching point in the sensor. When the PCM is not in closed loop (normally that would be when it's warming up, or when you go WOT), it is in open loop. And in open loop, it looks at all those tables under the open loop heading in the page I referenced above.
So it starts by looking in Gas (Gear) or Gas (Park/Neutral), whichever you are shifted into. It looks up the commanded air/fuel ratio here, and then it modifies this ratio with the modifier tables below the gas (gear) table on that screen. You can ignore the alcohol tables if you don't have a flex fuel vehicle, but the ones under that, like Airflow Gain or AIR Airflow Gain, are modifier tables. In other words, they take the commanded a/f ratio from the gas (gear) table, and multiply that number by what's in the modifier table.
By zeroing out all of the modifier tables, we can fully control the open loop air/fuel ratio by modifying it in the gas (gear) or gas (p/n) table. At this point, we command a 1.00 in the gas gear table, and we should be getting a 1.00 at the wideband. If we're not, our tune is off by the amount that the wideband is reading differently from 1.00.
All EFIs work basically the same in one regard. They ultimately have a commanded air/fuel ratio table, and an airflow table. We command the air/fuel ratio we want for temporary tuning, like 12.5:1 for a NA motor, and then we modify the airflow table (MAF or VE table) until the car produces the 12.5:1 that we are commanding. Once that's done, then we can go back and command whatever we want, and know that the PCM is going to deliver that. So maybe we want 13:1 at low rpms, and slowly taper down to 12:1 at high rpms. All we would have to do is enter that in the commanded air/fuel ratio table (Gas/Gear), and we would get it, because the tuning work has already been done. See?
The only odd thing I've told you here is that we are only modifying the gas gear table from a certain temperature and up. The reason for that is that when motors are cold, they need more fuel. Like a choke on a carb. So I leave that in there, so the motor can warm up correctly. Once fully warmed, we've jumped well over that area of the table anyway, and the PCM will not be looking at those numbers any more. So we command everything that's warmed up to be 1.00.
Ok, so let me give you an example to follow. Go to the gas (gear) table, and look at the left side of that table. That's intake valve temperatures. While maybe a little hotter, these temps will probably overall be somewhat similar to coolant temperatures, since coolant transfers heat away from the valves via coolant passages that run around the valve guides. See the top line? When the IVT is -40 degrees F (I'm working in Imperial terms here, not metric), the PCM looks at that top line and sees a number of 3.27, right?
That's the enrichment ratio, or Phi, or EQ ratio, or equivelance ratio. All the same terms for a percentage of fuel above stoich, an enrichment amount. Stoich is programmable in a table elsewhere in the tune for different fuel alcohol contents, but for now lets just keep stoich as 14.7:1 air/fuel ratio. To get your commanded air/fuel ratio, you would divide 14.7 by 3.27 to get 4.4954:1. Yes, you read that right. When your motor is at -40 degrees, the air fuel ratio is 4.5:1! That's about 3.27 x the normal amount of fuel it will burn when warmed up, which would be 1.00 EQ, or 1.00 x 14.7 = 14.7:1.
Normally, we won't be working with enrichment ratios anywhere near that. We'll generally be working between 1.00 and 1.25 somewhere. For a centrifugally supercharged motor at WOT and medium to high RPMs, you'll probably want to run about a lambda .80. Lambda is the norm for wideband readings, and is basically the inverse of EQ. So to convert from lambda to EQ, we divide 1 by lambda (and vise versa as well). So 1 / .8 = 1.25. So you'll want your Procharged motor to end up at about a 1.25 EQ ratio under full throttle.
Now this Gas (gear) table isn't really a full throttle table. That table is called EQ Ratio vs RPM, and is under the Fuel>Power Enrichment tab.
You can basically tune two ways. Wideband or stock narrowband O2s. Wideband is the only way to go really, but for part throttle stuff you can get by with narrowband sensors, and some would even argue there's some reasons to. With a wideband, we'll be turning every modifier off, commanding a specific EQ ratio like 1.00, and comparing the wideband reading with the EQ ratio reading. With lambda 1.00, it's very easy as the math is much simpler when one of the equations is just a 1. So if you command 1.00 and you get 1.06 lambda, you're 6% too lean. So you mutiply the cell you are tuning by 1.06, which is raising the fuel up 6%.
With full throttle tuning, it can be slightly more complicated. If you command a lambda .80 (1.25 eq ratio), and your wideband reads .89, you divide actual a/f by commanded a/f to get your correction factor. In this case .89 / .80 = 1.1125. So you would be 11% too lean, and mulitiplying your cell or cells by 1.1125 would fix that.
If you're working on your MAF table (which you are), you'll be logging the MAF Hertz PID. The table you'll be modifying is the Airflow vs Frequency table, found in the Engine>General tab under MAF calibration heading.
Think about what you're doing here. It's real simple. The MAF is at say 3000 Hz at idle. In your MAF table, that shows .960 lbs/min. (Again, Imperial terms). The MAF truly IS putting out whatever Hz at idle your scanner shows, but how much airflow does that Hz represent is not a fixed variable. It's a calibratable variable. The PCM calculates fuel shot based on air mass. So if the computer thinks you're at .960 lbs of air per minute, and your air/fuel ratio is 14.7:1, then it will deliver 1/14.7th of that airmass in fuel mass thru the injectors, or .0653 lbs of fuel. Obviously if we want more fuel because we're lean, we just raise the air mass in that cell up, and the PCM will do the math. If we told the computer we had 10% more airflow at that 3000 hz cell, it would calculate 10% more fuel mass at that cell. So the PID you want to watch is MAF Frequency (in Hertz). That tells you where you are, as in what cell the PCM is looking at, at any given moment.
To get from 14.7 to 11.5, the PCM will detect your intentions by reading the TPS sensor and seeing that you have your foot on the floor. Then, it will read the MAP sensor and see that the engine has lost all vacuum (inherent to WOT conditions). After satisfying all conditions for going open loop/WOT, the PCM will then quit looking at the gas (gear) table, and start looking at the Power Enrichment table, which has much richer numbers in it. If your airflow modeling is correct, it will inject the right amount of fuel to get the a/f ratio to your commanded ratio.
Ultimately, to get your airmass tables (MAF and VE) right, you need a load bearing dyno. But you can get them close by just driving the car with a real steady consistent right foot. In your driveway under no load will work too, but you'll be off more because of the lack of load. But that's ok. For now, that's all I want you to do. Practice with idle to 3000 rpm free revs in park. Just be careful not to overheat the motor.
Understood.... you are incredibly knowledgeable. I will try that today and report back ......makes more sense now. THANK YOU.!
53 Mercury pickup triton3v V10 supercharged 150 nos 535rwhp
71 Roadrunner gen 4 viper
53 Chevy pickup 4x4 5.3L twin turbo
Did you end up getting the DVD from Summit? A lot of the things you're asking about here are shown very clearly in the video examples.
See Greg, I'm always propping you up. You're gonna owe me one... :-)
Hey guys, well I used up a whole (computer) battery life and about 1/4 tank of fuel but I got to say I think I'm gonna wait for the CD to arrive! It seems I need another set of eyes just to follow whats all goin on and as you know when you new at it I kinda get lost! I'm the type of person that needs to screw it up or look at it ten times to get it! Lol. But the good news is the truck still runs!!! Ordered your CD Greg from summit but in Canada it takes some time to get here. I would LOVE nothing more than attend one of these classes and maybe cheak out Florida but time and money won't allow it this year!!! I will try this again when the CD shows up but for now I'm gonna keep reading on here to soak up as much as I can! I do have one more question I also own a 06 ford v10 ( disguised as a 1953 ford) and would like to maybe make some changes on this as well can I use the same interface and just purchase ford credits or is there a different interface with a different driver? I guess I could just go on HPTuner website and find out! Thank you guys sooooooo much (pontisteve especially) I will still cheak back here and will still keep you guys up to date on progress. I will post some picks soon. Thanks again.
53 Mercury pickup triton3v V10 supercharged 150 nos 535rwhp
71 Roadrunner gen 4 viper
53 Chevy pickup 4x4 5.3L twin turbo
Greg's DVD will help a lot, but let me make a suggestion that will help you. Everything in tuning revolves around datalogging, and then interpreting the data. The more familiar you are with the sensors and what they do, and with looking at datalogs, the better. You should especially focus on MAP, MAF, IAT, CTS, and TPS sensors. Datalogging these on a stock vehicle in good running order might help you to see what to expect. And read the help files in the software.
Once you have a pretty good idea of what you're looking at, try modifying small things and watch the results. When you're changing the MAF or VE tables, think of every change in terms of percentages, not solid numbers. Greg's book Advanced Tuning is a great intro to it all, and defines pretty well what every sensor does, and how the EFI uses those sensors. Research and understand what AFR, Lambda, and Equivalance ratio mean. Without understanding lambda very well, the rest will be harder to grasp.
Well I like to think I got a pretty good understanding of EFI I am auto certified as well as heavy equiptment tech certified. I think the biggest thing is understanding the software (program) that HP is using! I have scanners of my own that show lines of data that I diagnose with but everthing is within stock parmeters of that certain vehicle what HP tuners does is a little different than that and I completely agree that I would like to know what each section of hp does and what I'm affecting. I've always repaired but never modified I guess is what I'm tryin to say! I am however very determined to figure this out and love the help I'm get on here. Thanks.
53 Mercury pickup triton3v V10 supercharged 150 nos 535rwhp
71 Roadrunner gen 4 viper
53 Chevy pickup 4x4 5.3L twin turbo
That's right, I forgot you were a mechanic. That's good, that will give you a much easier time of learning this. In that case, think along these lines.... you're used to seeing data in the scan tool, like grams per second or lbs per hour. But you're used to assuming that data is correct.
When you change the airflow into the motor for reasons below, you can change that to an incorrect number. Once tuned properly, that number will be correct again.
Things that change these ever-so-important airflow numbers are as follows; for MAF, it's either a change of the MAF itself, or for a slot-style newer MAF, a change in the size of the tubing the MAF goes into. Or, a change in how the air flows thru the MAF. Air is meant to flow linearly, as in straight thru. For example, if you put a 90 degree bend right in front of the MAF (some sort of cold air kit), that air is now turning on it's way to the MAF, and will favor the long side of the turn. Depending on where the sensor wire is in the MAF, you might get more or less air crossing the actual sensor wire, making the airflow numbers go higher or lower than reality. That's why a nice straight pipe in front of the MAF is desirable. But either way, you can tune for it by remapping the MAF table.
GM's VE table is slightly different. VE is Volumetric Efficiency, or the percentage of airflow relative to the cubic inches of the motor. So if your engine is 350" and your VE is 85%, then your actual cubic inches the motor is ingesting in air is 297.5, see? VE changes at every load and RPM point, so we use a 3D table that describes this change, and the computer interpolates between points in the table.
Unlike air going thru the meter, VE changes with engine mods. Exhaust system, cam, headers, intake, port work, heads, etc all change the VE of the motor. Like with a cam for example, with a larger cam we are generally trading low rpm VE for high RPM VE.
GM uses a blend of VE and MAF to decide actual airflow at the lower rpms. And GM uses VE to estimate upcoming airflow when you are in a transient state (when you're accelerating or decelerating via the pedal). This transient state doesn't last long. Think of it as an accelerator pump shot. Since GM favors the MAF reading more than it does the VE reading, fixing the MAF table is of the most importance. But since the accelerator pump shot is based on VE, getting proper "accelerator pump shot" depends on having the VE Table right.
FYI, you don't always get answers on here. I'm being generous, because I know what its like to be new and not get any help with such an overwhelming new technology.
I have to give a big thanks (pontisteve) for all the time you gave me and the knowledge that came with it! I still open the program while I'm waiting for the cd to arrive and read over the info that you have given me on this forum I will report back next days I have off (shift worker) hopefully the cd will be here and I will try again. Again a big thanks.
53 Mercury pickup triton3v V10 supercharged 150 nos 535rwhp
71 Roadrunner gen 4 viper
53 Chevy pickup 4x4 5.3L twin turbo
No problem. Perhaps after you watch the DVD, you might get more out of the info I've given here. A lot of it is more eloquently stated on the DVD, and pictures help tremendously. But sometimes hearing the same thing 2 different ways is helpful too.
Got the cd and I have to say I've made some headway I think I'm even pretty close! Got a Dyno appointment for next week so I'll post some #s! Thanks a billion guys. I will stay posted.
53 Mercury pickup triton3v V10 supercharged 150 nos 535rwhp
71 Roadrunner gen 4 viper
53 Chevy pickup 4x4 5.3L twin turbo
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