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GMPP tune and tunes in general

7K views 32 replies 9 participants last post by  JohnWR 
#1 ·
Good morning,

As newbie to tuning I would kindly ask the following:

1- Are tunes in general CAR SPECIFIC or Engine SPECIFC or everyone gets the same tune -- say one opts for the GMPP tune, has access to 'the gms1 data file' and has a HP-tunner HPVI2 scanner, is the data the same from car to car? or if one went to a dealer ( as we all know Pontiac is long gone I assume this could be done at a proper Chevy dealership but I digress) would the dealer just load the tune data? or they specifically PER CAR change the tune to suit your specific car, obviously in my case this is a Solstice GXP 2008 in my case.
2- I happen to own a HPVI1 scanner tool, along with obtaining 3-bar sensors, I have found on the net not expensive, could this easily be done by a newbie? or we are looking at something massively complex and one should not tread where only the brave walk ??
3- I wish to learn, since I work on my car myself. I bought my roadster used and as far as I can tell -- so far it is bone stock. The boost comes up 15.22xx PSI -- which as I understand it is the bone non-tuned expected value. it does not have the 3-bar sensors but the original 2-bolt factory ones.
4- I am reading all I can, and also joined the HP_Tunners forum, but after spending hours reading, I have even more questions and confusion. the big issue is simply a lot of contradicting information. what I should 'change re: hardware on the car, like charge pipes, HFC High-flow cat, CAI etc.. and many others saying change nothing -- all show no go -- perhaps not for the HFC. but in regard to the 3-bar sensors many point out not required for some tunes (others , RPM, Trifecta etc) and mandatory for GMPP tune. I even read a very lengthy posting in HP-tuners that the 3bar sensor should always be used since mathematically the 2.5 (or 2.75 bar sensor that is my 2008 Solstice, which according to some exists for my model year) is required because the lower sensors cannot properly handle 21+ PSI mathematically -- and should be used always.

thank you for your time.

regards
Charles2010
 
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#2 · (Edited)
It all depends on what your end goals are for the car... 'canned' tunes (GMPP, Trifecta) work well on non-modded or lightly modded cars. If you are thinking about a turbo swap or running E85 gas, then a custom tune (HP) would allow you to dial in specific parameters for your mods. I went down the middle route using Trifecta's switchable tune, their base tune (similar to GMPP) is running all the time (Trifecta can calibrate it for the 3 bar MAP sensors). When I double tap the traction control button (into competitive mode) a custom tune is activated. This custom tune takes into account all of the mods on my car - CAI, charge pipes, big IC, HFC and race exhaust. If you go with a custom tune, I would partner with a shop that has experience with these cars (engines)... there is a lot that can go wrong.
 
#3 ·
Canned tunes are fine until you do major upgrades like a turbo or IC and HFC. Even with the HFC and IC, a canned tune will still run well.

Just so you know, e85 was mentioned, you CAN NOT run a full e85 tune without a fifth injector. You can run an e47 (1/2 e85, half 91) but they're a pain in the arse to measure and get right with the fuel.

Can you install a tune? Maybe. It depends on your computer literacy.

Can you build a tune? I wouldn't recommend doing your first tune or your first 10 tunes by yourself without anyone that knows the LNF. Too much stuff can be changed and while these motors are bullet proof if tuned correctly, they're really like a delicate rose if tuned improperly. For instance, LNFs do not like knock. They also don't really like anything other then 14.7 AFR at idle.

If you want a good start, do a high flow cat (HFC) an IC (Intercooler), the 3 BAR sensors, and charge pipes. DO NOT put a CAI as it does nothing until after you add a bigger turbo and a lot can be hard to tune with on the vehicle. They look cool and sound cool because you get the ppssshhhhh from the wastegate and internal BOV, but they do nothing other then cause headaches when tuning your car. Then add the GMPP or like tune. You should easily see 330-350 at the crank. Mine is dyno'd and if I had a HFC and IC, the tuner said mine would have been north of 350hp at the crank. Instead I got 283 at the wheels (so 283 x 1.17(loss of hp through the drivetrain) = ~330hp

Be sure to ask any questions, but like belly buttons, Camaros and Mustangs, almost everyone here will have an opinion at one point or another!! :)
 
#4 ·
good evening, thank you both for the excellent replies. I am reading all I can, and a lot of searches. Unfortunately I am rather late to the game, so to speak. I recently purchased my 2008 GXP here in Ontario Canada, and I truly love the car, amazing fun to drive. Just today installed a lighted / etched Windristricter and now want to consider a tune. I reached out to RPM in Arizona, well really he reached out to me initially on a facebook member page I do for Ontario Solstice and Sky owners. I thought it would be interesting to purchase a HP Tuner HPMVi2 tool/scanner suite, since I am a software developer by profession for embedded computers so the ECM programming is very similar in style to what I do with several microcontrollers.

My questions revolve around the TUNES themselves -- for example:

- you can purchase online a 'kit' from a famous web-site somethin-engines for 700+ u.s. dollars -- it includes the 3-bar sensors and the adapter cables so you do not have to solder, I assume this also includes the ACTUAL TUNE but you have to go to a dealer to get it -- I would imagine? or are you paying 700 dollars for roughly 100 dollars in parts, the 3bar sensors are easily obtained -- 29.00 dollars each and the adapter cables same. -- strange this costs so much I assume this is for the 'tune data itself' -- the actual loading is more even on top of that.

- my question is, if someone had the tune already, and had it READ OUT and written to a file, is this DATA from the tune on another identical car the same one would be written to 'another car' provided one had 2-credit and a HP Tuner MPVI2 tool ? is the tune itself CAR Specific? or it is just settings -- applies one to all ??

- is the tune itself a copyrighted thing? is there a repository of tunes on the internet? HP TUNERS -- has a repository and they have the GMPP tune there -- but I am told it is a 'sample ' one -- is this correct?

- I want to learn what this all means - -with respect to the values you enter -- for the various tables/PIDS ?? for example a given stock car can be logged -- data recorded -- by driving the car, the question is:

- ok we have data for the tune -- the parameters of the tune itself. however one drives the car to get it 'data logged' -- is this data how the car REACTS to the tune settings? or this is the actual tune? this is not clear to me. if the data-logger / data -recorder of a given car STOCK or NOT is the result of driving it, how does GM sell the 'tune' i.e. the GMPP tune as a canned file? or specific to your CAR -- i.e. they go out record the data and special create a file specific to your car -- load the data which makes up the tune, and then re-drives the car again and re-records the data -- make sense?

- this contradicts Trifecta, since they lock the tune, and it is essentially plug-and-play you PAY them money, they provide a cable and the tune file (I assume) and you upload it to your car -- this is not data logging, this is not custom to specific car but a general thing -- is this correct? I have not purchased or know anyone whom is using the Trifecta method/tune only what I can see on their web site.

From what I can see tuning is 'the art of changing the various values of the given tables visible to the HP-TUNER PC application for example. The GMPP (done by GM dealer if you can find a qualified one) or the Trifecta which essentially says -- plug this in and pow done.

I want to learn at a much deeper level, to truly understand the tuning -- I am reading the tune bible on HP-TUNER forums and reading all I can here. It is sad I have not found too many other Solstice owners here in Ontario, that have the knowledge about tuning and working on the car directly, I am certainly there are VERY qualified people here in Ontario or people like yourself; thank you for your kind assistance; so that I may learn about my car and enjoy it all the more.

I purchase the car as a father/son project -- more quality time with my son -- maintaining the car, when I purchased the Solstice I did not even know there was such thing as a tune or the ability to do so. I wanted to teach my son basic maintenance -- oil change, brakes, etc.. the tuning became interesting because I do something very similar for a living. -- but where to start?

there is a lot of contradictory information on the forums, and I guess the only way to learn is real world experience -- but at the same time I certainly do not want to brick my ECM !!

Any information about tunes and how they related to 'specific car or general ' would be nice to learn, and I am speaking right now of a stock not altered Solstice -- and applying the tune to this.

is the 3-bar sensor really needed-- many say no, but then say 24 PSI boost and the math says that stock sensors would be inadequate to handle them and you are out-of-control -- or is this truly not the case?

things like this. step-by-step procedures and advice from one whom has done this already -- would be nice to hear.

later on, I may consider adding / changing hardware -- i.e. HFC. IC, charge-pipes -- but first let's learn what I have in front of me.

thank you --regards
Charles2010
 
#5 ·
Greatgab made a comment about knowing what your goals are, so I will ask: What are your goals?
>Do you want more power?
>Do you want a project that you can fiddle with?

I am going to assume that the $700 tune is from crateenginedepot, and is the GMPP tune. This is the one that was released by GM through its dealers and came with a factory warranty. That price includes the hardware, the software, and the installation.

The Trifecta (and others') "canned tune" works the same way that the GMPP tune works, except for providing more power at lower cost and not requiring the 3-bar sensors.

Neither of these require data logging or adjustment unless you have a car that is abnormal either through modification or some fault. Both are install-and-forget because the engines are consistent enough, and adaptable enough, that no after-install adjustments are necessary.

Beyond that are custom tunes that will cost more, take longer, and are more likely to cause problems, but are needed if you are heavily modified and desired if you want the ultimate in performance and are willing to deal with the potential problems.

Beyond bricking your ECM you should worry about destroying your engine. The LNF is not tolerant of some operating conditions and you can do serious damage if you don't know what you are doing and/or aren't paying attention.
 
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#6 ·
Good day, thank you very much one and all for the excellent feedback and very good advice. Perhaps I was not clear, I will be using a professional tuner to assist in the tune of my car, my goal; which really is not to have the ultimate HP gains or performance, it is learning. While I certainly do not want to brick my ECM or heaven forbid destroy my engine; which the more I read about tuning; the more I lean how easy it would be to do so; my intention is simply to understand what is being done and what the various changes mean -- what does x-do or y-do or why is this changed etc. I purchased my car as a learning experience and once again to spend quality time with my son.

While yes, I can certainly go and purchase a CANNED tune -- GMPP ( I did not mention createnegines because I did not know the rules of the forum with respect to noting other vendors) and/or Trifecta. I contacted Martin Scott at RPM whom has been VERY informative and VERY NICE to work with -- high compliments to him here; I purchased from him the HP _TUNER HPMVI2 scanner and suit, not just to TUNE my car but to examine my car and learn what the tables and contents mean. As I noted earlier I am a software developer and work regularly with embedded controllers, much like the ECM our cars.

I am looking to:

- apply a tune -- with of course the FULL GUIDENCE and CONTROL Of a proper professional tuner. I thought the trifecta is very nice and many a member says go and do this, it does not teach me anything , I cannot see what is done -- this is not my goal.

- change the charge pipes -- why ? because I simply like working on my car and I can show and have my son actually wrench the car. I know, I have read countless posts that say they will not really increase anything, fine I think they look nice.

- change the HFC - this as I read does add to performance but once again this is another thing to change the work involved.

- CAI -- cold air intake -- looks nice. do I want to do this, not sure right now, on the fence here, I can put in a K&N filter replacement for my stock one in the black box and leave as is, but again the CAI looks nice -- is it a good idea -- not sure more reading required.

my car is long long long out of warranty, and I purchased it as a project, to actually work on it -- not just drive it, actually I have to admit I am very surprised at how well this car drives, I wanted a smaller roadster, thought hmm -- should I buy a miata -- no not as aggressive looking, so I thought buy the orphan -- the Solstice - found a excellent condition 2008 with rather low KM's up here in Canada and thought this would be a nice place to start.

I plan ultimately some day to build a Cobra, so I thought this would be 'a great place to start with a baby-Cobra' dare I say....

learning is my goal here really. Not outfitting the car with the greatest HP or torque, I do not plan on changing the IC or the turbo, really I just wanted to understand the GMPP upgrade really this is what got me started with looking into TUNES -- after I had purchased my GXP I read the article --totally by chance that these cars could get a factory TUNE -- but I wanted to understand what really does this mean -- does this add to my life? does this make ownership of the car better? does this make the driving of the car better -- no not really; none at all most likely, but I am the type of person whom likes to understand the toys I am playin with.

Once again thank you everyone with the great advice. I will be working with a trained and 'safe' expert (I assume based on all I read) tuner -- to modestly tune my car and at the same time permit me to 'RE_EXAMINE IT over time' not to change it mind you, just examine / log the car-- what is doing what, what means what etc...

-Charles2010
 
#7 ·
Looks like an HP tune is in your future... good luck with your research and enjoy your Father-Son time! :wink:
 
#8 ·
Charge pipes - no more power but look nicer than stock (may add power on seriously modded cars with larger turbos)

CAI - no more power but look nicer than stock and eliminate a weak plastic bit that can break and cause grief

Larger capacity IC - no more power per se, but you keep whatever you have longer before heat soak gets to the engine and saps it.

Tunes - GMPP is a modest tune that many people used while under warranty. No point in going that way today as it costs more for less result and uses sensors that are unneeded by other tunes (although several can accommodate them)

Trifecta - can be a basic canned tune that suits stock or mildly modded cars, or custom with datalogging, the latter being necessary when more fundamental mods are performed (e.g. larger turbos). Their tunes are 'locked' presumably so no one can blame them for blow ups that might result if others could meddle with them.

HP tuners tunes - done by everyone from novices to experts - choose wisely!

PS - I have run stock, GMPP, canned Trifecta and custom Trifecta.
 
#15 ·
Trifecta - ... Their tunes are 'locked' presumably so no one can blame them for blow ups that might result if others could meddle with them.
Their tunes are locked to:

1. Encourage vendor lock-in, which is evil

2. Prevent users and tuners from "stealing" their switchable tune feature.

It doesn't have anything to do with liability.
 
#9 ·
Just curious, assuming someone bought GMPP and put on the 3-bar sensors that are required. What is to stop someone with a HP-TUNER -- readout the data setting and then put the same data onto another car by writing the data out?

this is my question are tunes car specific, I do not see how since Trifecta is loaded without any -pre-scanning- of your car you just buy it and upload it and done. With respect to the GMPP tune, is this not the same, ok you need 3-bar sensors but they cost like 100 dollars for both and the two pig-tail adapters so you do not have to solder. it is the CODE the data part I assume costs all the money?

is this copyrighted? meaning you cannot share this data? It is not truly yet clear to me if a TUNE is car specific or just a file of data that everyone gets and you put it in and done with.

I understand CUSTOM TUNES -above and beyond standard TUNES (meaning not the factory one, the one that gives you more performance like the GMPP for example -- I would call that a standard TUNE on top of the factory tune/settings -- replacing it, or the trifecta doing the same - replacing It. This is not CUSTOM TUNE because -- as I read and understand it - these are all the same - come one come all tunes for Solstice cars.

the Custom tune then goes beyond that, much beyond that and ties into equipment upgraded in the car, way beyond GM parts, like a new turbo or more -- this is not where I am going, I may change a few pieces mostly for cosmetic reasons but I still would like to understand the TUNE and what the parameters mean, which in most cases; I see means little to nothing to others, since they simply want to go fast !! totally reasonable and understandable, I am looking to learn mostly, going fast is really nice, sure but is not my primary goal in my work with the car.

I tell you a funny story, I was going to buy 100 dollar car, but the wife would not let me she knew it would be in pieces most likely for ever in the garage, yes I would be spending a lot of time with my son but we would never get to drive the car, so the Solstice while an orphan at least runs !!


Tuning the car - I am not about to do this myself, I will talk with a pro fist, but I just as I noted above want to learn.

This is why I am asking so much.

When I spoke with RPM -- Martin whom will ultimately do my tune, said I have to log/data record my car, which I will do. then he will TUNE - so to speak either a stage1 or 2 (2 if I purchase the charge pipes and optionally on top of that HFC or CAI too -- but I agree with all the comments here regarding add-ons).

it is the concept and the underlying understanding of what is being done to my car, I am looking to learn. there is a lot of information on the HP-TUNERS forum and I am reading a lot and trying to learn but that is many different types of cars, I thought to ask fellow Solstice / sky owners what they have done in the past.

thank you
Charles2010
 
#12 · (Edited)
Just curious, assuming someone bought GMPP and put on the 3-bar sensors that are required. What is to stop someone with a HP-TUNER -- readout the data setting and then put the same data onto another car by writing the data out?Charles2010
Nothing. With HPTuners, you can copy and paste the tune to as many cars as you want as long as the VIN matches and you buy credits for each VIN.

this is my question are tunes car specific, I do not see how since Trifecta is loaded without any -pre-scanning- of your car you just buy it and upload it and done. With respect to the GMPP tune, is this not the same, ok you need 3-bar sensors but they cost like 100 dollars for both and the two pig-tail adapters so you do not have to solder. it is the CODE the data part I assume costs all the money?
Charles2010
As stated above, the GMPP tune was for cars that were still under factory warranty. They also extended the factory warranty as long as the vehicle was still under factory warranty. The code is not vehicle specific...per say. In other words, a Trifecta tune for an LNF motor in a Solstice is "probably" different then a tune in a Cobalt LNF motor. One is transverse mounted, one is front/rear mounted. You can do specific tunes for cars, but it "usually" involves either going through 4 of the 5 gears with a heavy foot, or a dyno to get the most out of your car. Trifecta and GMPP tunes are very similar....in fact I believe that Trifecta used the GMPP as a baseline. My advice to you is to find either a GMPP or Trifecta tune and use it as your baseline tune.

You must also understand that parts wear as do sensors. So your MAF sensor might not register the same as mine, thus causing a different condition in the motor. There is a tolerance built into these sensors and to the canned tunes. With a custom, specific tune, you are taking that tolerance out, as I did with my dyno tune. Which means when parts start to wear, the vehicle will act differently whereas with a canned tune, it won't be very noticable.

Furthermore with tunes, what many people here don't know, is that with every "overlay" of a new tune, the ECM counts. So if you upload a tune 15 times, the ECM will always hold and GM engineering can tell, how many times your car has been tuned. So everytime someone uses the 2 layer Trifecta tune and it write and rewrites internally, the ECM does keep track of that and GM engineering can pull those numbers. Not that it's that big of deal anymore since everyone is out of warranty....

the Custom tune then goes beyond that, much beyond that and ties into equipment upgraded in the car, way beyond GM parts, like a new turbo or more -- this is not where I am going, I may change a few pieces mostly for cosmetic reasons but I still would like to understand the TUNE and what the parameters mean, which in most cases; I see means little to nothing to others, since they simply want to go fast !! totally reasonable and understandable, I am looking to learn mostly, going fast is really nice, sure but is not my primary goal in my work with the car.
Charles2010
Be very careful how you say "Much beyond that"... It does not!! It took 5 dyno pulls for my car starting with the GMPP tune. GMPP tune was tuned to within 90% of what the car was capable of and still be "safe and reliable". Above that threshold, things start to break and become unreliable. GM when they release specs and tunes on vehicles, most are done to within certain percentage (I've heard 75%-85%) of what the powertrain can handle and still be reliable.

One other word of advice, NEVER use an oiled air filter (ie K&N). The oil comes off the filter and messes up your MAF sensor.

With everything said above, a tune will shorten the life of the engine....a custom specific tune will probably shorten it even more....
 
#13 ·
Thank you "The Ghost" that response was extremely informative and very helpful. Would you consider the RPM Tune by Martin a 'custom tune' along the lines you note say over a trifecta tune?

Since the GMPP tune has been 'out' for some time, how hard is it to find a copy for Solstice GXP - it would be interesting to examine one and compare the 'data / number sets' BEFORE flashing it to my car, since I have a reader tool. the issue I have I guess is no others with cars I can read to compare with. is the GMPP tune available by download somewhere, or is this copyrighted material perhaps? I would have imagined over the years the tune data would have been made available or easily obtained since the cars are now all orphans.

Is there proper 'form' to ask for a copy of the GMPP tune? or is this not really done. As a newbie to this world, please excuse my ignorance of the data portion. In my world of programming for micro controllers the code is often public-domain or placed into public domain to help others. Since this does sound like product, perhaps the GMPP is not easily obtainable.

Just as side question an K&N filter --are you referring to the square type that can replace the one currently in the stock engine air filter? I have recently changed mine, to a new one from Purolator and is working fine. I have read the K&N washable filter is a smart purchase? but you state a very interesting point here, NEVER USE an oiled air filter i.e. K&N -- is this the case?

A will point out I certainly do not want to "shorten" the life of my engine (too much....) I want to stay well within the safety levels -- I guess the GMPP is my way -- I will talk to Martin at RPM and compare and learn more. I have to walk before I can run.

thank you everyone for your excellent sage advice.

Regards
Charles2010
 
#14 ·
I am following this thread with great interest because I am on a similar quest. I have two 2.4 NA Solstices, both with DDM superchargers. One is running DDM tune and the other has been custom-tuned by ESTunes. I bought an HP Tuner so I could understand the basics of electronic engine tuning and the difference between stock, performance and custom tunes. What I am finding is that there is an overwhelming number of tuning parameters and that it is a steep learning curve even for an engineer.

One thing that no one has mentioned is that even after a new tune is loaded the ECM will continue to "learn". I understand that short term learning is needed for adapting to a different temperature, altitude, octane, etc. What I have observed is that after about 500 miles my engine suddenly performed better. I have no idea what this long term learning is all about.
 
#16 · (Edited)
I have no idea what this long term learning is all about.
I'm not a tuner, but this is what I've come to understand. Others may jump in with more (or more accurate) information.

The "learning" is all about adjusting fuel trims and ignition timing. The ECM has an initial, generic fuel map indicating what amount of fuel should be injected vs inputs for RPM, oxygen sensors, knock sensors, MAP, MAF and a few other things. Fuel trims are scalars applied to those initial fuel delivery values to adapt to the specific car's quirks and features. :)

The ECM initially makes an educated guess about what amount of fuel to inject based on the sensor inputs. It uses the O2 sensors to determine if the mixture is rich (too much fuel) or lean (not enough fuel). If it's too much, the short-term fuel trim (STFT) is modified to reduce the amount of fuel injected. Long-term fuel trims (LTFT) are also adjusted, but by a smaller amount over a longer period. (Fuel trims are values that correspond to the adjustment in fuel delivery previously mentioned.)

After resetting the fuel trims by flashing the computer or other methods, the STFT will jump around a bit until the ECM finds a value that it's happy with. Those adjustments gradually affect the LTFT. Over time, both LTFT and STFT stabilize, though STFT will always oscillate a bit depending on current driving conditions, altitude, fuel quality, etc.

For timing: if the ECM detects significant knock, it can retard ignition timing to compensate (within reason). If it gets really bad - like, multiple misfires - it'll go into reduced power mode and angrily flash the CEL. I'm not sure how persistent the timing adjustments are. The tunes also set the ignition timing. For instance, when running an E85 tune, you can advance timing quite a bit to get a lot more power.

Every engine is slightly different. This is the software's way of adapting to those differences.
 
#21 ·
The tune is data driven. The ECM uses a set of rules to determine where in the various data tables it pulls its settings then applies them. It doesn't "learn" because it can't chang any of its own software or data. Once the "tune" is installed and the ECM boots up, if it's an initial start it goes to the "baseline " initial point and "looks" at the data coming from the MAF on start up during the calibration part of the start sequence and adjusts the data points accordingly. If it's a restart- which is almost always the case, the EVM uses its last stop point as its start point then adjusts for the MAF input

All engines that are in mobile devices have some kind of systems that allow them to self adjust for changes in air density. They must adapt to altitude changes and temperature variations that can affect the fuel air mixture

The ECM can only adapt to changes in perveived environment. No learning going on

As the temp goes up, it will change fuel timing and quantity to match changes of air density to fuel delivered The ECM does this for all the parameters it can affect. No learning going on

This ability to change its operating parameters is limited by start cycle. There are two opposing needs in balance. It must be able to adjust parameters but if it is seeing faulty data it may adjust too much and cause running issues. So the amount of change is limited by "start cycle". 5 or 6 cycles caused the stock tune to eliminate the gains from adding a high flow cat

What all tunes do is mace changes to the data used by the ECM to manage the engine, for example adding more fuel at some settings or adding more timing. The tune "enhances" performance by modifying data in tables

The people who designed the engine and the tune initially hit a very conservative power target that was adequate and had. Very large safety factor for reliability. When the GMPP tune followed later it changed the data to achieve a significant improvement in power, at a still high acetylene factor though it was reduced. See failing intercoolers and the odd broken block.

Other tunes that go to higher power levels do so by changing the data tables and come with some level of increased risk

In addition to changes to the data tables, some tunes modify the rules built into the code. GMPP added the no lift shift for example. The changes in RPM limit are I believe data driven

Unless you replace the operating system on the car, all tunes use the same code. They make data changes based on the experience and skill of the tuner

All tunes bring added risk to the longevity of the powertrain

The more power, the greater the risk

So, one could make a case that all tunes are identical in a very fundamental way, the differences are does a specific tuner really know the car well enough to improve performance with an acceptable level of risk

And

Can I maintain this tune

I chose the RPM tune first and had a bad experience. This was in 2009

I then went to the GMPP tune because it is still maintained by them and while it makes comparable performance improvements it's the least risk solution

I was willing to pay more up front with the knowledge it would be more likely to avoid breaking something later that cost more
 
#23 ·
...if it's an initial start it goes to the "baseline " initial point and "looks" at the data coming from the MAF on start up during the calibration part of the start sequence and adjusts the data points accordingly. If it's a restart- which is almost always the case, the ECM uses its last stop point as its start point then adjusts for the MAF input.
Call this nit-picking or semantics, but I thought that was the definition of learning.

Anyhow, it does not explain what I think I experienced - a noticeable increase in performance after about 500 miles of driving. My friend said he experienced the same. Or did he just plant that idea in my head and then I imagined it happened?
 
#25 ·
The trims vairy on a “continuous “ basis but are always performing within the constraints of the code. It’s not artificial intelligence which can “learn”. It’s not my definition of learning when it’s tsking a pre selected input value and giving a pre defined output value.

The code is fixed. The values are fixed. The “tune” matches the values of the inputs to the allowable values of the outputs. Nothing happens that is not defined in the code and the data. It’s a basic machine not a learning device in my definition of learning.

If you go back and read the threads about “learn down” the GM engineers did not want to use the term learn but let people use that short hand to make their understanding easier.

NOTHING happens in the code, the data or the algorithms in the code that is not written down and stored. It’s not “making decisions”. Or figuring things out. It’s a Moore machine. If this, then that.

The normal tune. achieves performance gains by changing the data that defines “then that” to achieve gains. An advanced tune may make changes to the actual code, but to do so means you would need the ability to read the compiled code or have access to a version you could operate on to make changes then be able to compile the chanced code and install it.
 
#26 ·
All learning isn't the same, and the definition can change with the application.

The ECM starts out with default values, and uses short-term and long-term trims to adjust its operation to produce the desired result based on measurements that it makes. Those trims are retained for use the next time it runs because it has learned its environment and the ways that its system varies from the assumed nominal system. It has therefore learned.

It is no different than your behavior when you perform a particular task, but aren't happy with the result. You may do exactly the same thing the second time you do it, but vary the force or speed that you do it. Your "program" hasn't changed, but you learned that your initial parameters weren't optimum, so you adjusted them.

The fact that unpowering the ECM for a period of time "resets" it to the defaults demonstrates that it has "learned" something, otherwise it couldn't "forget" anything.
 
#29 ·
I completely agree John!!

Newer vehicles DO learn. My Charger's TCM learns. Otherwise it wouldn't leave itself in 6th gear when I'm trying to get fuel mileage. It has learned my driving habits (yeah...I'm a bit heavy footed in it!). It knows that I like power and will downshift manually if I have to, so now, it seems to keep itself in 6th until I hit 50mph. Then 7th at 50, and 8th at 65+. And that's in economy mode. Switch to performance and it's 1 gear lower and never hits 8th gear. My understanding from the Charger forums is that it "develops" a sort of graph and tries to follow it...much like programming the AFR in our cars.

Also with AEVs coming, AI is being implemented more and more, even though we are still years off from full AI.
 
#28 · (Edited)
Yeah, I’ve read that here and elsewhere.

That’s going to be very difficult to enforce. They could do it during annual safety inspections, I suppose.

I’ll just buy a second ECM.

As if I needed another reason to not let anyone else work on my cars...

At the end of the day, there will always be options. Standalone harness and ECM are easily available and not crazy expensive. A bit much for a $7k car, but for any serious application, a couple of grand isn’t unreasonable.


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#30 ·
As if I needed another reason to not let anyone else work on my cars...

At the end of the day, there will always be options.

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There will not be options if GM and John Deere get their way. Nobody will be able to access any of the data that's stored in your ECM except a dealership. That information will be sent ONLY to them...and nobody else will have the tools to fix your car. If you guys don't want this, I would highly suggest getting involved in the fight!! Follow MEMA news and start watching articles about it.
 
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