Tried searching, got no where. All I want to know is, can these tunes be trusted simply to change the VQ map and K value and nothing else? I want to tune with my emanage but would like to have a more accurate timing situation than I might have otherwise. Can these fly by night guys be trusted for that?
Edub, KATwo40, Devious, I am talking to you guys...
If anyone else has input, please let me know.
eBay Tunes
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scarboroughdub
Re: eBay Tunes (Chezedik)
with experience we know that buying turbo's and manifolds or any quality parts is a no no if its coming from ebay.
what makes you think a tune would be any different, there is alot more scammers than there is legit people out there.
so if you wouldnt trust a turbo or manifold from ebay i would assume that a tune which is much more important than those other items would be something not to buy from ebay.
what makes you think a tune would be any different, there is alot more scammers than there is legit people out there.
so if you wouldnt trust a turbo or manifold from ebay i would assume that a tune which is much more important than those other items would be something not to buy from ebay.
It's my understanding that it is a fairly easy process to change only those two variables, although I am not currently capable.
Also, if it is ready to install then it is cheaper than me buying a chip burner and daughterboard.
But your point is duely noted. And you are very right. If I didn't have that doubt in mind, then I would not have even asked the Q.
Thank you.
Also, if it is ready to install then it is cheaper than me buying a chip burner and daughterboard.
But your point is duely noted. And you are very right. If I didn't have that doubt in mind, then I would not have even asked the Q.
Thank you.
Chez, the issues with this type of deal are many fold.
The first thing that comes to mind is that the tune itself might be encrypted, so it's possible that once you realize you need something changed, you're screwed. This is what JWT and Enthalpy do to keep people from reading their tunes.
Another problem is not so much just the K value and VQ scaling. You'll need to data log to be certain that the cells of operation are tuned appropriately for your particular setup. Adjusting K value won't fix poor cell tuning.
I say get yourself a board from PLMS (or maybe someone on ECCS if you can ever get anyone to respond) and tune it yourself.
The burner I have will accomodate just about any automotive EPROM chip out there and costs about $40 on Ebay (Willem Enhanced burner). I'd recommend Nissan Datascan as well ('bout $100).
Get those items and you'll be golden.
The first thing that comes to mind is that the tune itself might be encrypted, so it's possible that once you realize you need something changed, you're screwed. This is what JWT and Enthalpy do to keep people from reading their tunes.
Another problem is not so much just the K value and VQ scaling. You'll need to data log to be certain that the cells of operation are tuned appropriately for your particular setup. Adjusting K value won't fix poor cell tuning.
I say get yourself a board from PLMS (or maybe someone on ECCS if you can ever get anyone to respond) and tune it yourself.
The burner I have will accomodate just about any automotive EPROM chip out there and costs about $40 on Ebay (Willem Enhanced burner). I'd recommend Nissan Datascan as well ('bout $100).
Get those items and you'll be golden.
Re: (Chezedik)
First off, the Ebay tune. Hell f***ing no! Are you joking?
You have a DE right? You have been monkeying with this stuff long enough to know what you are doing. Why not just get a daughter board and tune your car. There really isn't that much to it.
I personally can't see how a good timing map can be had with out reading MAP. The fact is, boost simply is not fixed to any given map location. Boost will come at different times in different gears. How this can be pinpointed to any given cell for a mirad of boost conditions is beyond me. The only way I can think of to cover all the bases is to pull max timing from everywhere on the map that boost might occur. I think this is how JWT does it. I think Enthalpy takes a graduated approach, guessing where a given level of boost will likely occur.
I know my BTM does nothing untill 5lbs and pulls what I want according to boost. The beauty is this. Say in 3rd gear WOT I hit 15lbs at 3000RPMs but in first I don't hit 15lbs untill 4500RPMs. Here you have a descrapancy in what amount of timing you should have and where. My BTM will overcome this by leaving the timing advanced in 1st untill the 4000 or so RPM at which boost passes 5lbs. But, in 3rd it will pull 10* at 3000RPMs because it works via pressure. With the fixed timing map you would have to go with the lowest number and pull 10* at 3000.
I'm sure fixed map timing can be done. I just don't see much point to it.
Anyway, If you get things set up I'm sure we can get you a good tune going.
You have a DE right? You have been monkeying with this stuff long enough to know what you are doing. Why not just get a daughter board and tune your car. There really isn't that much to it.
I personally can't see how a good timing map can be had with out reading MAP. The fact is, boost simply is not fixed to any given map location. Boost will come at different times in different gears. How this can be pinpointed to any given cell for a mirad of boost conditions is beyond me. The only way I can think of to cover all the bases is to pull max timing from everywhere on the map that boost might occur. I think this is how JWT does it. I think Enthalpy takes a graduated approach, guessing where a given level of boost will likely occur.
I know my BTM does nothing untill 5lbs and pulls what I want according to boost. The beauty is this. Say in 3rd gear WOT I hit 15lbs at 3000RPMs but in first I don't hit 15lbs untill 4500RPMs. Here you have a descrapancy in what amount of timing you should have and where. My BTM will overcome this by leaving the timing advanced in 1st untill the 4000 or so RPM at which boost passes 5lbs. But, in 3rd it will pull 10* at 3000RPMs because it works via pressure. With the fixed timing map you would have to go with the lowest number and pull 10* at 3000.
I'm sure fixed map timing can be done. I just don't see much point to it.
Anyway, If you get things set up I'm sure we can get you a good tune going.
It's not always an issue of boost, but rather engine load.
If it were such a bad thing, you wouldn't have OEM's using MAF systems. Cars like the EVO, WRX, MR2 turbo, Supra, Mirage, Eclipse, Talon and whatever other factory turbo car you can think of, wouldn't be on the market with MAF systems if speed density was the best.
If it were such a bad thing, you wouldn't have OEM's using MAF systems. Cars like the EVO, WRX, MR2 turbo, Supra, Mirage, Eclipse, Talon and whatever other factory turbo car you can think of, wouldn't be on the market with MAF systems if speed density was the best.
Indeed, and knowing the characteristics of the turbo, you can know where your boost is via MAFSv. The beauty of a system with a MAFS is that it is much more forgiving of modifications or increases in boost levels (either mod for airflow will increase MAFSv).
So you don't have to pull timing anywhere that you think you may have boost, necessarily, you will have to pull timing anywhere you know where there is boost. This is no different than your BTM, since you don't pull timing until 5psi, whereever that may occur. Through logging we can find out at what RPM and MAFSv we have 5psi, given that we can start pulling timing at that point.
Don't get me wrong, the BTM is a good setup, and has done many people a lot of good. I went a different route. I will have a MAP via emanage which I will use as my 'emulator'. By that I mean that I will be able to do some light tuning on the road in various degrees, and log it with emanage with AF and MAPp on the same log as MAFSv and timing (adjustment), and compare it then to the log of Consult via CalumSult or DataScan and find where I was at what point, and how it reacted. I can then make adjustments to the tune I made on emanage and apply them to the ROM, then do it all over again.
When I am happy, I will either sell emanage, or use it to pull timing further for when I need to pull timing for a long trip, for which I want to run 87, and low boost.
What do you guys think about that plan?
So you don't have to pull timing anywhere that you think you may have boost, necessarily, you will have to pull timing anywhere you know where there is boost. This is no different than your BTM, since you don't pull timing until 5psi, whereever that may occur. Through logging we can find out at what RPM and MAFSv we have 5psi, given that we can start pulling timing at that point.
Don't get me wrong, the BTM is a good setup, and has done many people a lot of good. I went a different route. I will have a MAP via emanage which I will use as my 'emulator'. By that I mean that I will be able to do some light tuning on the road in various degrees, and log it with emanage with AF and MAPp on the same log as MAFSv and timing (adjustment), and compare it then to the log of Consult via CalumSult or DataScan and find where I was at what point, and how it reacted. I can then make adjustments to the tune I made on emanage and apply them to the ROM, then do it all over again.
When I am happy, I will either sell emanage, or use it to pull timing further for when I need to pull timing for a long trip, for which I want to run 87, and low boost.
What do you guys think about that plan?
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DRFT(kinda)
- Posts: 546
- Joined: Thu Mar 16, 2006 6:59 am
- Car: 2005 Nissan Titan.
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drEameRvaJ
- Posts: 473
- Joined: Sun Jan 23, 2005 10:50 am
- Car: 1997 Nissan 240SX SE
Re: (KATwo40)
Is this bikirom he's talking about?KATwo40 wrote:Chez, the issues with this type of deal are many fold.
The first thing that comes to mind is that the tune itself might be encrypted, so it's possible that once you realize you need something changed, you're screwed. This is what JWT and Enthalpy do to keep people from reading their tunes.
Another problem is not so much just the K value and VQ scaling. You'll need to data log to be certain that the cells of operation are tuned appropriately for your particular setup. Adjusting K value won't fix poor cell tuning.
I say get yourself a board from PLMS (or maybe someone on ECCS if you can ever get anyone to respond) and tune it yourself.
The burner I have will accomodate just about any automotive EPROM chip out there and costs about $40 on Ebay (Willem Enhanced burner). I'd recommend Nissan Datascan as well ('bout $100).
Get those items and you'll be golden.
Re: (Chezedik)
Just because a system is MAF based doesn't mean that manifold pressure isn't also used. Even if it isn't, stock low boost setups are much more forgiving.
The problem is that boost is dynamic and will occur at different times based not only on load and RPM but on the gear you are in. A fixed timing map can be made to cover all the basis but you will have to assume full boost at every possible location or risk having too much timing. You can't time by consult because as soon as you tweek it for 1 gear the next will be different. Really, it's quite pointless when a more acurate system can be had for $200, but whatever, it's your car.
The problem is that boost is dynamic and will occur at different times based not only on load and RPM but on the gear you are in. A fixed timing map can be made to cover all the basis but you will have to assume full boost at every possible location or risk having too much timing. You can't time by consult because as soon as you tweek it for 1 gear the next will be different. Really, it's quite pointless when a more acurate system can be had for $200, but whatever, it's your car.
Right, and we are not speaking contradictory points. If you have the ability to run a MAFS and MAP, you are the in the best boat. But even then, I would want the MAFS in the lead seat.
Boost is dynamic, in terms of when it hits, in what gear in what environmental conditions. But we can do enough logging to come up with the information necessary to make very educated guesses as to when we will begin to have boost, and adjust timing accordingly in those cells.
What is the more accurate system you speak of, and when did you get off of the ROM tune horse?
Boost is dynamic, in terms of when it hits, in what gear in what environmental conditions. But we can do enough logging to come up with the information necessary to make very educated guesses as to when we will begin to have boost, and adjust timing accordingly in those cells.
What is the more accurate system you speak of, and when did you get off of the ROM tune horse?
Re: (Chezedik)
That's just my point. There is no one point at which boost will begin. In 3rd gear boost will come on at lower RPM than in 1st or 2nd and you only have 1 timing map.Chezedik wrote:Right, and we are not speaking contradictory points. If you have the ability to run a MAFS and MAP, you are the in the best boat. But even then, I would want the MAFS in the lead seat.
Boost is dynamic, in terms of when it hits, in what gear in what environmental conditions. But we can do enough logging to come up with the information necessary to make very educated guesses as to when we will begin to have boost, and adjust timing accordingly in those cells.
What is the more accurate system you speak of, and when did you get off of the ROM tune horse?
Say you will reach 20lbs by 3000 RPMs in 3rd. You will need at least 10-12* of timing pulled at that point in the map. Yet in 1st and 2nd, 20lbs isn't reached untill 4500. So in 1st & 2nd you have a bunch of timing pulled out that isn't necessary because you need that much pulled for the higher gears. See what I'm saying? You would almost need seperate timing maps for the different gears.
I do have my ECU tuned but only for fuel. I let the BTM handle timing. That way timing is always pulled on a per lb basis rather than on an inconsistant combination or RPM Vs load. Plus the new models start pulling at a set point - mine is at 5lbs with -1* per lb after that and it pulls that amount regardless of where we are on the map.
Plus, if I want to run racing fuel I can just turn my knob and advance timing. And, it only cost $200 which I would have spent on dyno time anyway.
I'm not saying a good blanket timing map can't be made. I'm just saying that given the advantages of the BTM I don't see why one would choose otherwise.
You're all wrong here Edub. The load system (MAF tuning) can be calibrated to handle different boost in different gears.
Yes, boost is dynamic, but load is load. 10psi in 1st gear is NOT as much load as 10psi in 4th. Therefore, you don't need as much timing pulled in those low load areas as you do in the high load areas. It doesn't matter if you're hitting those load areas at 3000rpm or 4500rpm.
You talk about OEM MAF systems on turbo cars as they are low boost. However, do you know that the EVO comes from the factory boosting 19psi? It uses MAF tuning and has no problems.
Additionally, the Ford GT40 project car made 1000whp on twin turbos. They kept the stock MAF system and reflashed the ECU to accomodate the added load.
Yes, boost is dynamic, but load is load. 10psi in 1st gear is NOT as much load as 10psi in 4th. Therefore, you don't need as much timing pulled in those low load areas as you do in the high load areas. It doesn't matter if you're hitting those load areas at 3000rpm or 4500rpm.
You talk about OEM MAF systems on turbo cars as they are low boost. However, do you know that the EVO comes from the factory boosting 19psi? It uses MAF tuning and has no problems.
Additionally, the Ford GT40 project car made 1000whp on twin turbos. They kept the stock MAF system and reflashed the ECU to accomodate the added load.
Which is what I was getting at. When the ECU sees increased airflow (load), it will then find it's position on the map by cross-referencing Mass Air Flow Sensor Voltage against RPM. So, at any given RPM you can find yourself at a different MAFv. This is how you will find your load. If you create an island of retarded timing, it can hit your areas of positive manifold pressure in a number of ways.
The higher the MAFSv, the more air passing over the hot wire. Since air becomes boosted after being pressurized by the turbo, we can use the air entering the turbo as a measurement of the amount entering the turbo. When we compare this to actual pressure a map can be made.
While your maps can be more dynamic when you can use MAFSv to measure load, and compare it to Manifold Pressure, it can just the amount of air coming in and the pressure at which it is at. Many manufacturers, including Nissan, have used this system. It is, however, far from necessary to create good levels of power, safely.
The reason NOT to use BTM is that it is a patch, just as SAFC is for fuel. Some people would like reduce the number of parts. I am no better, since I will be using emanage also, but I can tell you my reasoning.
There are many examples of good ways to create fuel+timing using the ECU w/o MAP and I think that Jon has shown that through numberous examples. It may just take a more in depth understanding of EFI and Motronic systems. May I suggest:
How to Understand, Service, and Modify Bosch Fuel Injection and Engine Management by Charles Probst (ISBN 0-8376-0300-5)
This may help you understand how this can be done easily and effectively.
The higher the MAFSv, the more air passing over the hot wire. Since air becomes boosted after being pressurized by the turbo, we can use the air entering the turbo as a measurement of the amount entering the turbo. When we compare this to actual pressure a map can be made.
While your maps can be more dynamic when you can use MAFSv to measure load, and compare it to Manifold Pressure, it can just the amount of air coming in and the pressure at which it is at. Many manufacturers, including Nissan, have used this system. It is, however, far from necessary to create good levels of power, safely.
The reason NOT to use BTM is that it is a patch, just as SAFC is for fuel. Some people would like reduce the number of parts. I am no better, since I will be using emanage also, but I can tell you my reasoning.
There are many examples of good ways to create fuel+timing using the ECU w/o MAP and I think that Jon has shown that through numberous examples. It may just take a more in depth understanding of EFI and Motronic systems. May I suggest:
How to Understand, Service, and Modify Bosch Fuel Injection and Engine Management by Charles Probst (ISBN 0-8376-0300-5)
This may help you understand how this can be done easily and effectively.
Re: (Chezedik)
Well, if someone can show me proof that all these cars are tuned that way than I'll toss my BTM and do the same.
The problem is that the X or "load" axis of our map is not determined by MAF output. I know that's the common beliefe but it's wrong.
Just like it is commonly believed that the TP scale is accessed according to MAF output and must be scaled and that A/F ratio changes with air flow or boost. Again, this is all wrong and I have the tune to prove it.
I don't know for sure how the ECU follows the X axis but it is at least somewhat independant of MAF reading. That theory doesn't even make sense when you consider that the flow through the MAF is more physically linked to RPM than to cylinder filling which is a minimul change by comparisson. Plus if load was determined by MAF reading SAFCs wouldn't work because they would fall in the wrong load range and fail. It makes perfect sense.
The fact is, the ECU will follow the X axis by exactely the same amount regardless of airflow (at least for fuel). You can run it NA or run 20LBS and you can see this is true by observing your wideband. It will follow your A/F map the same regardless of boost or no boost at all.
If you can disable your WG so it stays open, put the hammer down and watch your wideband, it will enter your rich area just the same as if your turbo was boosting. Try it and see.
Also, if I am wrong then correcting fuel or timing for that matter needs only be done in the final column since the ECU would look all the way to the right as soon as boost begins. This isn't the case and it isn't the case that changing TP values will cause the ECU to follow the X axis any differently. I tried it and my wideband followed the same fueling pattern no matter what I did to the TP scale.
In the end, I wound up adjusting K and making pretty much a steep runup to a flat mesa in the upper RPM, high load range which I can watch on my wideband like a depth finder on a boat. My TP values are all stock, my car ildles and drives like stock in closed loop with the narrow band installed and I've run from 5 to 17lbs with no change in A/F ratios or in the fueling pattern. My car is freak all fast and I have 0 drivability issues.
I don't pretend to know everything about our ECU, but I know what I observe.
The problem is that the X or "load" axis of our map is not determined by MAF output. I know that's the common beliefe but it's wrong.
Just like it is commonly believed that the TP scale is accessed according to MAF output and must be scaled and that A/F ratio changes with air flow or boost. Again, this is all wrong and I have the tune to prove it.
I don't know for sure how the ECU follows the X axis but it is at least somewhat independant of MAF reading. That theory doesn't even make sense when you consider that the flow through the MAF is more physically linked to RPM than to cylinder filling which is a minimul change by comparisson. Plus if load was determined by MAF reading SAFCs wouldn't work because they would fall in the wrong load range and fail. It makes perfect sense.
The fact is, the ECU will follow the X axis by exactely the same amount regardless of airflow (at least for fuel). You can run it NA or run 20LBS and you can see this is true by observing your wideband. It will follow your A/F map the same regardless of boost or no boost at all.
If you can disable your WG so it stays open, put the hammer down and watch your wideband, it will enter your rich area just the same as if your turbo was boosting. Try it and see.
Also, if I am wrong then correcting fuel or timing for that matter needs only be done in the final column since the ECU would look all the way to the right as soon as boost begins. This isn't the case and it isn't the case that changing TP values will cause the ECU to follow the X axis any differently. I tried it and my wideband followed the same fueling pattern no matter what I did to the TP scale.
In the end, I wound up adjusting K and making pretty much a steep runup to a flat mesa in the upper RPM, high load range which I can watch on my wideband like a depth finder on a boat. My TP values are all stock, my car ildles and drives like stock in closed loop with the narrow band installed and I've run from 5 to 17lbs with no change in A/F ratios or in the fueling pattern. My car is freak all fast and I have 0 drivability issues.
I don't pretend to know everything about our ECU, but I know what I observe.
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nissanfanatic
- Posts: 1314
- Joined: Mon Nov 01, 2004 8:41 pm
- Car: 1992 Nissan 240sx SE
- Contact:
Edub, you can't just say, "Well, my wideband shows the same AFR regardless of boost, so the ECU must use the same cells for atmospheric as it does for 20psi boost."
You have to actually MAP TRACE THE DATA and watch the cells being accessed in real time.
To say that MAF voltage means nothing in the entire equation is just silly. Why would the damn sensor even be there if it wasn't used in the calculation?
Go to ECCS and download the publicly released file of the Nissan hand written flow chart depicting the ECCS design. It clearly states that the MAF voltage determines TP.
Sure, you adjusted the K value and the car runs great. So what? Maybe you're not running toward the end of the map yet? Maybe the stock TP scale has enough buffer (overhead, expansion area, etc.) to accomodate your boost level. Until you actually map trace it, you'll never know for sure.
You have to actually MAP TRACE THE DATA and watch the cells being accessed in real time.
To say that MAF voltage means nothing in the entire equation is just silly. Why would the damn sensor even be there if it wasn't used in the calculation?
Go to ECCS and download the publicly released file of the Nissan hand written flow chart depicting the ECCS design. It clearly states that the MAF voltage determines TP.
Sure, you adjusted the K value and the car runs great. So what? Maybe you're not running toward the end of the map yet? Maybe the stock TP scale has enough buffer (overhead, expansion area, etc.) to accomodate your boost level. Until you actually map trace it, you'll never know for sure.
Re: (KATwo40)
Honestly, I don't care to convince anybody. If you guys want to believe it works that way it's fine by me.
The thing is, we have to be real carefull not to confuse corelation with cause. Just because the ECU climbs the TP scale at the same time as the MAF volatage increases doesn't mean one is causing the other, just that you have observed them happening together. Don't forget, your ECU will also climb the TP scale at the same time you increase throttle. And you can watch that with map trace too.
I'm also not saying that MAF voltage has nothing to do with it, just that map location is not determined 100% by MAF voltage.
Consider these facts:
A) As RPMs increase, flow, hence MAF voltage will increase - does this cause a change in TP or does it climb the Y axis? If MAF voltage determines TP then the ECU must move to the right as RPMs increase. If MAF voltage is the key, how can the ECU differentiate flow from climbing RPMs from flow from greater VE? Especially since RPM will increase flow more dramatically than VE ever could. The affect of this would be that load would be more RPM dependant than anything else. This is an obvious falsehood.
B) I can and have observed with my wideband how my ECU follows my fuel map. Think about how this works. Durring boost, MAF voltage will shoot up and should cause the ECU to shoot to the right. But this doesn't happen. I have observed that my ECU was passing a certain lean spot just right of the half way point of the map weather boosting or not. If MAF voltage was the sole determinate, this would not be the case.
Now it is possible that the ECU uses MAF voltage as part of the equation. And it defenitly uses it to determine fuel but what I've observed is that the ECU scales TP more according to throttle position. Once the ECU finds the appropriate column, it reads the cell value and uses this to determine what A/F ratio is desired. Once it does this, it takes the MAF value and calculates the fuel needed to maintain that ratio.
You see, the cell value is an instruction to tell the ECU to maintain this value for all MAF readings as long as the ECU is in that cell or that column. So, the idea in the end is that somehow the ECU determines what column to be in and what the RPMs are and then it looks at MAF voltage after the fact in order to maintain correct fueling.
It is also possible that the ECU first checks RPMs and is allowed only to proceed when MAf voltage surpasses what low load high RPMs would produce.
Bottom line, it was believed that TP was directly related to MAF voltage and scaling needed to be done. This is clearly wrong and it is safe to say that there is reasonable doubt as to how the ECU scales TP but I do know that it will scale it more or less the same way with a turbo that is does without. And that this does not follow the current understanding. If you guys want to try to tune your timing based on this, have fun.
One more thing - how do you guys figure that an SAFCII works?
If TP is determined by MAF, the following would happen - think about it.
A guy uses injector 2X as big, so the safc cuts the MAF signal in half. This would make the ECU only use half of the fuel map which is nearly all closed loop. Therefore, the fuel would way, way out of wack.
This isn't the case. It isn't the case because even with the MAF cut in half the ECU still follows the x axis of the map as it normally would. What it does, is cuts the MAF signal which is a direct variable used to determine fuel. The safc works because a direct fueling variable is halfed and the injectors are 2x. The fuel map is not linear and therefore a re-position on the table would not produce the desired affect. If you think about this for a while it becomes absolutely clear that map position is unchanged when MAf signal is halfed because re-positioning on a non-liner map simply would not work.
The method works because the ECU always follows the map the same way. It finds the appropriate cell value for load & rpm and THEN it reads the maf signal for that fixed spot and adds the necessary fuel. This is the only way an safc would work.
If I'm wrong, explain how an safc works when it would create a condition that only uses the first half of the map.
Modified by Edub1 at 11:58 AM 1/18/2007
The thing is, we have to be real carefull not to confuse corelation with cause. Just because the ECU climbs the TP scale at the same time as the MAF volatage increases doesn't mean one is causing the other, just that you have observed them happening together. Don't forget, your ECU will also climb the TP scale at the same time you increase throttle. And you can watch that with map trace too.
I'm also not saying that MAF voltage has nothing to do with it, just that map location is not determined 100% by MAF voltage.
Consider these facts:
A) As RPMs increase, flow, hence MAF voltage will increase - does this cause a change in TP or does it climb the Y axis? If MAF voltage determines TP then the ECU must move to the right as RPMs increase. If MAF voltage is the key, how can the ECU differentiate flow from climbing RPMs from flow from greater VE? Especially since RPM will increase flow more dramatically than VE ever could. The affect of this would be that load would be more RPM dependant than anything else. This is an obvious falsehood.
B) I can and have observed with my wideband how my ECU follows my fuel map. Think about how this works. Durring boost, MAF voltage will shoot up and should cause the ECU to shoot to the right. But this doesn't happen. I have observed that my ECU was passing a certain lean spot just right of the half way point of the map weather boosting or not. If MAF voltage was the sole determinate, this would not be the case.
Now it is possible that the ECU uses MAF voltage as part of the equation. And it defenitly uses it to determine fuel but what I've observed is that the ECU scales TP more according to throttle position. Once the ECU finds the appropriate column, it reads the cell value and uses this to determine what A/F ratio is desired. Once it does this, it takes the MAF value and calculates the fuel needed to maintain that ratio.
You see, the cell value is an instruction to tell the ECU to maintain this value for all MAF readings as long as the ECU is in that cell or that column. So, the idea in the end is that somehow the ECU determines what column to be in and what the RPMs are and then it looks at MAF voltage after the fact in order to maintain correct fueling.
It is also possible that the ECU first checks RPMs and is allowed only to proceed when MAf voltage surpasses what low load high RPMs would produce.
Bottom line, it was believed that TP was directly related to MAF voltage and scaling needed to be done. This is clearly wrong and it is safe to say that there is reasonable doubt as to how the ECU scales TP but I do know that it will scale it more or less the same way with a turbo that is does without. And that this does not follow the current understanding. If you guys want to try to tune your timing based on this, have fun.
One more thing - how do you guys figure that an SAFCII works?
If TP is determined by MAF, the following would happen - think about it.
A guy uses injector 2X as big, so the safc cuts the MAF signal in half. This would make the ECU only use half of the fuel map which is nearly all closed loop. Therefore, the fuel would way, way out of wack.
This isn't the case. It isn't the case because even with the MAF cut in half the ECU still follows the x axis of the map as it normally would. What it does, is cuts the MAF signal which is a direct variable used to determine fuel. The safc works because a direct fueling variable is halfed and the injectors are 2x. The fuel map is not linear and therefore a re-position on the table would not produce the desired affect. If you think about this for a while it becomes absolutely clear that map position is unchanged when MAf signal is halfed because re-positioning on a non-liner map simply would not work.
The method works because the ECU always follows the map the same way. It finds the appropriate cell value for load & rpm and THEN it reads the maf signal for that fixed spot and adds the necessary fuel. This is the only way an safc would work.
If I'm wrong, explain how an safc works when it would create a condition that only uses the first half of the map.
Modified by Edub1 at 11:58 AM 1/18/2007
Datalogging in the rpm climb is your error.
Get on a steady-state dyno, hold the rpm @ 3000 with the dyno, increase and decrease throtle input.
You'll then watch the ECU access different cells for that rpm range. This is because airflow is varied, despite maintaining an rpm constant.
This is why the MAF system can be tuned for different boost in different gears. Once you get on a steady-state dyno and do some actual tuning, you'll get it.
Get on a steady-state dyno, hold the rpm @ 3000 with the dyno, increase and decrease throtle input.
You'll then watch the ECU access different cells for that rpm range. This is because airflow is varied, despite maintaining an rpm constant.
This is why the MAF system can be tuned for different boost in different gears. Once you get on a steady-state dyno and do some actual tuning, you'll get it.
Re: (Edub1)
Watch the timing values with a datalogger. You should see increased timing retard as a result of big fat injectors.Edub1 wrote:One more thing - how do you guys figure that an SAFCII works?
If TP is determined by MAF, the following would happen - think about it.
A guy uses injector 2X as big, so the safc cuts the MAF signal in half. This would make the ECU only use half of the fuel map which is nearly all closed loop. Therefore, the fuel would way, way out of wack.
This isn't the case. It isn't the case because even with the MAF cut in half the ECU still follows the x axis of the map as it normally would. What it does, is cuts the MAF signal which is a direct variable used to determine fuel. The safc works because a direct fueling variable is halfed and the injectors are 2x. The fuel map is not linear and therefore a re-position on the table would not produce the desired affect. If you think about this for a while it becomes absolutely clear that map position is unchanged when MAf signal is halfed because re-positioning on a non-liner map simply would not work.
The method works because the ECU always follows the map the same way. It finds the appropriate cell value for load & rpm and THEN it reads the maf signal for that fixed spot and adds the necessary fuel. This is the only way an safc would work.
If I'm wrong, explain how an safc works when it would create a condition that only uses the first half of the map.
Modified by Edub1 at 11:58 AM 1/18/2007
Again, this will not happen unless you are using a steady state dyno to create a stable operation environment for testing. Otherwise, the mapping moves too quickly to monitor through the rpm sweep.
Re: (Edub1)
Your misunderstanding is profound. I am done here. Sometimes, it's not always best to assume that you are so smart that no one can teach you anything.
Re: (KATwo40)
Wrong. It is not because the air flow changes. It is because you are increasing throttle. Do the same thing with a restrictor piece in place to limit air flow and you will observe the exact same ECU behavior.KATwo40 wrote:Datalogging in the rpm climb is your error.
Get on a steady-state dyno, hold the rpm @ 3000 with the dyno, increase and decrease throtle input.
You'll then watch the ECU access different cells for that rpm range. This is because airflow is varied, despite maintaining an rpm constant.
This is why the MAF system can be tuned for different boost in different gears. Once you get on a steady-state dyno and do some actual tuning, you'll get it.
You see, you guys have some ad hoc findings locked into your brain and you are not considering other possibilitties. Like the possibility that you are confusing corelation for cause. Which you are - I promise.
The ECU tracks along the X axis regardless of air flow. I have formally tested this 100+ times. Have you ever tried disconnecting your TPS and trying it? How do you explain that my car passes the same map point under boost as it does NA? This is impossible by your logic. How do you explain that an SAFCII even works. By your theory there is no possible way it would work as it would only use half of the maps. How do you explain what makes 0 sense?
Bottom line, read the questions I have pointed out and you will see that there is a reduction to absurdity. Your way the car would not run with the MAF signal cut in half, my way it would run just like it does in reality. How do you explain this?
I'm telling you, looking at map trace means nothing because you are opening the throttle and feeding the ECU with info besides what the MAF is doing.
The ECU goes to where it goes and THEN uses MAF reading as part of a formula to keep things steady.
How do you explain that the ECU can remain in one column as RPMs rise? Wouldn't the increased flow push it to the right?
Really, think about these questions instead of just repeating the old saw, you will see that I am raising issues that conflict directly with the current understanding.
How does an safc find the right spot on the map with maf voltage cut in half? And don't say it doesn't because that is just an old assumption based on the MAF TP theory. In reality, the safc does find the right place on the map regardless of maf output being cut in half. That pretty much closes the case.
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Re: (KATwo40)
sorry to butt in but instead of arguing about this y didn;t u just tell them to unplug there mafs so they would see that it still runs but like s**t then a whole lot of confusion would have been laid aside then they can see that tp and rpm give a baseline for the maf and o2 to dial in on but I could still sit back and watch if you wanna keep goin
But then I may have misinterpreted that as a limp mode function, not really a determinate of correction table function.
One of the reasons we are good at what we do (Edub, WD, Chez, myself and others on this board) is that we don't swallow what just anyone says, but rather we require substantial proof and backing to support the theory.
We're not really much for following blindly.
One of the reasons we are good at what we do (Edub, WD, Chez, myself and others on this board) is that we don't swallow what just anyone says, but rather we require substantial proof and backing to support the theory.
We're not really much for following blindly.