Originally Posted by
jfunkey
Even more the fact that peole know so little just shows here. You dont need a custom tune for eaxh mod...rockets lack of experience shows right here...this isnt a gm or a ford or a evo...this system adapts learn what your talking about before you tell people how smart you are..
To start, I never stated things as simply as "you need a full custom retune for any mods you do". However, if you do something like a CAI, for instance, and that CAI replaces the sample tube that the MAFS electronics are in then yes the airflow calculations will be extremely off, which also mean load will be off, WOT fueling will be off, and also spark timing advance too. That was what I was talking about. Even in vehicles such as the B6 S4 where the MAFS electronics are in their own housing a CAI install can sometimes change the airflow enough to require a retune. That depends on the car itself, the CAI, etc. In theory since the MAFS itself was not modified a change should not have to be made since as airflow speed increases through that same size of tube the MAFS is in the corresponding calculated air volume will change proportionally. However, that doesn't always happen in the real world. At the very least it never hurts to datalog the vehicle to ensure that WOT AFR's haven't changed and ensure the ECU isn't pulling any knock retard for any reason. Sometimes that will warrant retweaking the ECU tune and sometimes not. I hope I clarified that enough. Feel free to dispute this with me on a technical basis if you prefer to. All I ask is that you cite specific examples and not just mere conjecture such as, "it just don't work". Please tell me more about how the system "automatically adapts" when it comes to airflow mods. Are you referring to the metering range still left in the MAF transfer function to allow the reading of additional airflow or something else? I really hope you aren't referring to the adaptive learning algorithms because that doesn't control WOT fueling. That is why it is called "open loop". Adaptive learning will affect long term fuel trimming while at idle and cruise though during closed loop mode. But even that can only go so far before most vehicle's narrowband O2's freak out and cannot take an accurate enough reading to allow the ECU to trim the fuel out to stoich. This is why I temporarily turn adaptive off while tuning so it is not fighting me, dial the short term fuel trims to at least +/- 2% of stoich, then turn adaptive back on and let it trim them towards stoich even further. Being that general OEM spec is usually within +/- 3% I figure 2% isn't bad at all.
Originally Posted by
jfunkey
Nobody is saying you can do whatever you wsnt...juzt know the facts before you do...these cars dont need custom tuning they just need someone that knows how to do it...these cars dont have a tuning system for them like honda gm evo or Ford hecsuse tjis type of ecu is that much different. ..if all ot took was tuning a few domestic cars to know it all amd to have it all foggured out....we would be installing tunes from SCT or Diablo or the other dominant domestic tuners...experience isnt in how to add timing or fuel. Experience is measured in experience with each motor and what it likes..
I don't believe that anyone has claimed that the ECU's are the same between Hondas, Ford, GM, Evo, Audi, etc. However, if you really have been tuning for as long as you say you have, then you will also know that the logic used is all extremely similar (aka part throttle fueling, WOT fueling using MAFS data to calculate mass of aircharge to then figure for resulting fuel to add, load vs RPM based spark timing advance tables, etc) Though the ECU's are very different, and their tuning can appear to be very different when initially looking at the tunefiles in a tuning program, you still cannot change the fact that they are all controlling an internal combustion engine which all operate in the same basic fashion. So, while initial tune comparisons may appear to be apples to potatos, when you look a little more you will start seeing the vast amount of similarities. Peek in a Ford tune with SCT and oh wait I want to set what base fueling the ECU will try to command, go to the Base Fuel Table.....wait a minute, now I am tuning a GM....lets go ahead and look at the Power Enrichment Table. Again, if you have the tuning experience recalibrating a wide variety of vehicles like you claim to have done, then you will know exactly what I am talking about here when it comes to doing a comparative analysis from previous experience tuning a car with a platform like SCT and then moving into tuning a GM car with EFILive or HPT. While there will obviously be differences to sort through, the logic is still the same. GM MAF Hz, Ford MAF Ad Counts, GM g/cyl for cyl airmass calc, Ford in % Load, and on and on. The ECU still uses either a MAFS or MAP sensor to take a signal reading in Hz, Volts, Ad Count, etc that will then cross reference that voltage with an airmass in the transfer function, then do its backwards calculation to determine how much fuel it needs to inject to achieve the predesignated WOT AFR. If logged WOT AFR is off from desired, then change that corresponding cell(s) in the MAF transfer function by the % fueling was off by to dial the airmass calculations in; which will in turn dial the fueling into spec. That same logic, or extremely similar, is used across the board with most any modern EFI vehicle.
Also, no one ever claimed to "know it all" as you have sarcastically stated. By the way, SCT and Diablo do not "make the tunes" themselves. However, they are the ones that supply their dealers with the tuning software/hardware to recalibrate their customers ECU's. So it is not like Jerry Wroblewski was sitting at SCT (when he still worked there) writing every SCT customer's tune; though I know he has the experience to be able to do so. The dealers/speedshops do that. I want to clarify that because even though others may not think that is a big thing, you and I do. That is, if you have as much experience as you claim to have.
Experience with one vehicle, while not exactly directly applicable in the to another specific model, still does cross over from vehicle to vehicle generically speaking. What I mean by this is, of course if you are tuning a C6 Corvette with the LS3 in it and through logging you find that the engine likes 26* total timing at peak you will not just assume that all other engines in the world will operate at peak power efficiency with 26* timing up top. However, the process of logging and recalibration that you would go through to determine how much spark timing needs to be retarded or advanced in that C6 vette would be the same as when tuning an Audi, Ford, Honda, or whatever have ya. Datalog to check if the knock sensors are picking up any knock and at what RPMs and loads is that happening. Listen to the engine for pinging during the WOT pulls. Check the spark plugs directly after a run to see if any detonation has occured, etc. That process would be the same whether tuning a GM or an Audi. Are you picking up what I am putting down so far? Does direct repeated experience count between a person who has only tuned a few of a model of car versus one that has tuned 500? Hell yes it does, and I haven't been debating that. While both may know how to tune, the person who has more direct tuning experience with that specific model of vehicle will already know what it likes and doesn't like. This point harkens back to my point in my previous post when I mentioned JHM developing their canned tune for the B6 S4 when I mentioned that after a while of tuning the B6 S4's they would get to know what it likes and does not like when balancing power, driveability, and safety. I never claimed that I can tune a B6 S4 as well as JHM can, but considering the mods I plan to install on my car, I know that JHM's canned tune will not work as well as I would like for the car; which is why I plan to retune it myself.
I have never claimed that I am beyond questioning. But if you do so, then I suggest that you bring your A game when it comes to a technical discussion regarding modern EFI custom tuning because I am not new to this stuff at all. I always like a good discussion on EFI tuning; and I am sure that other members here who are interested in this stuff may even learn a thing or two from the resulting discussion between us. So, have at it.
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