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Discussion Starter · #1 ·

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my tune seems to have the "learn down" feature still on.
That feature is a myth, your ecm is tuned for a certain hp rating and it'll stick to it no matter what, every tune is like that.
One thing i noticed is that the only people that talk about this learn down thing are people who don't have hptuners or do any of their own tuning, and that's a fact. Do your own tuning and you'll forget about any learn down bs.
 

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I have the budget tune and it came with a red cable... the one thing I love about the tune is i only use it when I need it (mine I put in competition mode), works out great since most of my commute is sitting in traffic on the Sothen state on LI, but when i wanna have fun, just push a button and bam no longer stock and fun as hell....
 

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Just did a budget tune last week.Best $200 I have spent in a long time. Car was pretty quick b-4,but now it flies. Boost goes to 25# now. Doesn't cost anything to use their cable, just a refundable $200 deposit.
 

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That feature is a myth, your ecm is tuned for a certain hp rating and it'll stick to it no matter what, every tune is like that.
One thing i noticed is that the only people that talk about this learn down thing are people who don't have hptuners or do any of their own tuning, and that's a fact. Do your own tuning and you'll forget about any learn down bs.
Actually the factory tune for the 2.0 car is torque managed.

While its true that every car has a "tune" not every tune is torque managed and will "learn down" to meet its torque target.

My 1968 GTO was tuned but it was tuned by the fixed cam shape, duration, and timing, and the fixed mechanical advance and vacuum advance on the distributor managed the spark timing and duration. The jets in the carburator working in conjunction with the opening of the butterfly valves managed the air / fuel ratios.

Early single board computer engine management systems took the basics of the mechanical systems and moved them to a combination of mechanical and software driven. But in the main, they worked to maintain the proper air/fuel mixture and if you added "hop up" parts, the new parts would actually provide you an improvement in performance much of the time because the "tune" wether mechanical or electro/mechanical was designed to provide the proper air/fuel mixture and the relative imprecision of the mechanical systems resulted in them not being able to "learn down" to some fixed set of tune objectives.

The ECM and tunes that came from the factory on our cars are very different from all the early mechanical and electro mechanical tunes and even from other peer tunes in other cars.

From an old post
There is a very lengthy post on this subject. Westers did a write up on the GMPP tune and what it does and does not do to the car.
The way the code is written in the ECM, the 2.0 is torque managed. The factory tune manages the engine parameters to produce 260 ft pounds of torque. The horse power is a result of achieving that torque value.
If you add hardware that is capable of producing torque values (and resultant HP) above the 260 ft pounds target, the ECM will "learn down" to achieve 260 ft pounds.
Basically, there are a set of data tables that are fixed. And there is memory that is controlled by the ECM. The fixed parameters cover all the possible variables, timing, fuel, air, boost, cam timing etc. It’s more complicated than that but conceptually you get the idea.
The ECM is constantly looking at all the sensors it has available. It is constantly "learning up and learning down" the various parameters it can control to maintain what it believes to be the settings that produce 260 ft pounds of torque.
It’s not strictly learning down because the ECM is constantly varying in real time the engine parameters it controls. What is really happening is the ECM is choosing specific settings from the pre-programmed tables for timing, fuel, air, boost, cam timing etc. based on near real time calculations. The calculations include throttle pedal setting, ambient temperature, air flow rates, O2 sensor readings etc.
The ECM "remembers" where it is at in each of the data tables. It "learns" where it is in each of the tables as it changes its mind on where to pull the settings from the tables based on current sensor readings. It does not create data per se, it uses the data it has in the tables but changes where it pulls the data in the tables based on a set of rules programmed into the ECM operating system.
Since the ECM can react faster than the mechanical systems it is managing, there is a built in time constraint on how much it can change its entry points into each of the data tables. The time constraint is a real time - mille seconds for some setting changes and key cycles for others.
Typically when you are running an unmodified car, when you start the car it "remembers" where it was when it was shut down and begins with that location as the current setting. It looks at the MAF to update air density and watches the O2 sensors to make sure it’s managing the settings. But it does not make any big changes when you start the car. It is making small "make play" environmental changes to optimize the startup and initial running experience. It may make small changes during that run cycle but is constrained to making small changes per run cycle.
If you bolt on a piece of hardware that can produce 10+ hp, the ECM makes small adjustments per its constraints, but it will experience an increase in torque measured because of the hardware update. It will adjust the engine parameters to avoid damage - that is crank up the fuel to avoid lean runs and vary the timing to avoid knock. So you may see the 10 hp increase for that cycle.

When you shut the car off and restart it - executing one key cycle - the ECM will recognize that it is producing MORE than the target of 260 ft. pounds and will crank down the parameters it controls as much as it can in that key cycle. Over the course of 5-6 key cycles, the ECM will be incrementally adjusting the engine parameters to get back to the ideal 260 ft pounds. After 5-6 key cycles, with each cycle resulting in the maximum "learn down" allowed, the car will be producing 260 ft pounds of torque. Again the HP is a product of producing the value that results from the ECM setting parameters.

The GMPP tune provides a new set of data tables and a new entry point in those tables. The new tables allow more growth in torque (much higher limit for "learn down") and they change the baseline starting point in the tables to the settings that are predicted to produce 340 ft pounds of torque. At that baseline torque, the resultant HP is about 290. There is some variability in HP measured for different cars because there are detail differences in the hardware across the sample set.

All tunes do basically the same thing. They change some of the values in the existing data tables. No tune will support unlimited HP growth because the physical size of the data tables is limited. All have an "edge" somewhere that forms the practical limit for power growth. The GMPP tune and the Westers tune all change the key parameter values in the tables to produce the desired result.
 

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I personally, while totally comfortable tuning a mechanical or electro mechanical tune would be very hesitant to start playing around with the ECM tune on our cars. The very flexibility that gives the potential to make a lot more power also provides the ability to damage the engine easily if you are not fully familiar with what the impact of a change might be. I leave that to the experts and just enjoy the end results. :thumbs:
 

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I personally, while totally comfortable tuning a mechanical or electro mechanical tune would be very hesitant to start playing around with the ECM tune on our cars. The very flexibility that gives the potential to make a lot more power also provides the ability to damage the engine easily if you are not fully familiar with what the impact of a change might be. I leave that to the experts and just enjoy the end results. :thumbs:
I agree. I don't buy books about how to perform surgery on yourself either! Some things are better left to those with the expertise, especially if you don't have the spare time to gain the expertise (referring to the programming, noty the self-surgery....)

Thanks for posting that complete response.
 

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Just my two cents, if you're getting anything other than a one size fits all budget tune from Trifecta, I would steer clear of them. There have been tons of complaints on cobaltss.net about long wait times for Vince to make adjustments to their tunes to dial it in. He has sort of moved on from the platform, and I can't blame him. There are bigger fish for him to fry than making tuning adjustments for cars no longer in production :lol:.

Personally if I were going the one size fits all tune route, I would just find someone with HP tuners, and pay them the $100 to unlock my car, to flash on the GMPP tune file after I spent the $100 to buy the 3 bar map sensors.

Here's something to think about too. If you are running a tune above 22 psi on the stock map sensors (the stock ones are only good for 2.5 bar, or 22 psi), the computer is just sort of predicting what the boost is actually at.
 

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I run the budget tune on my GXP, best bang for your buck, cheaper then a intake, and nets you the most power gain of any mod in its price range. Best $200 ever spent...I peak 23psi, hold 19-20psi to redline.
 

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Actually the factory tune for the 2.0 car is torque managed.

While its true that every car has a "tune" not every tune is torque managed and will "learn down" to meet its torque target.
You're right, its a torque rating and not hp since that's just a formula.
I've played with the stock and gmpp tunes and noticed zero difference when all the tables were set the same, the first few pulls have the highest numbers and then they settle down, the numbers were basically identical in the stock and gmpp tunes, if the gmpp tune has more leeway than its not noticeable.
But you did prove my second point.
 

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Here's something to think about too. If you are running a tune above 22 psi on the stock map sensors (the stock ones are only good for 2.5 bar, or 22 psi), the computer is just sort of predicting what the boost is actually at.
To my knowledge the OEM bar sensors are 2.7 bar. and not 2.5 bar.
 

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You're right, its a torque rating and not hp since that's just a formula.
I've played with the stock and gmpp tunes and noticed zero difference when all the tables were set the same,
Shabby, These number you’re talking about, was the stock numbers brought up to the GMPP tune table numbers or the GMPP tune brought down to the stock numbers?
 

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To my knowledge the OEM bar sensors are 2.7 bar. and not 2.5 bar.
Negatory sir, they are 2.5 bar. I was trying to find the stock map sensor part number to link the specs here, but couldn't find it. Both ZZP and Perf Autowerks reference the stock map sensors as 2.5 bar on their websites though.
 

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Shabby, These number you’re talking about, was the stock numbers brought up to the GMPP tune table numbers or the GMPP tune brought down to the stock numbers?
I didn't compare the tunes at stock numbers, i just copied my already modified stock tune onto a gmpp tune and compared them, only thing i gained was the ability to read more boost and no lift to shift.
Perhaps i should of tried what you mentioned but it never occurred to me.
 

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Discussion Starter · #15 ·
Hey thanks guys. I will be getting the Trifecta tune soon....and report back. I want to keep my current (if I can) and get the Trifecta one....
 

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Discussion Starter · #16 ·
So looking at the Trifecta tune I wouldn't mind getting the GMPP MAP sensor.... My only issue with this would be that I can't go back to my current tune if I don't like the Trifecta. What are the part numbers for it and where can I get them?
 

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So looking at the Trifecta tune I wouldn't mind getting the GMPP MAP sensor....
According to Vince you don't need them. If you do get them, consider buying from Crate Engines as they have a harness with plugs that makes reversing it much easier.
 

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Trifecta budget tune is great bang-for-the-buck. I was able to buy a used cable (cost of which was split with a buddy who has a Sky RL) and the flash process was pretty painless, though they did need to make an update to get my car to take the tune (my buddy's Sky worked first time).

You can clearly see the difference in the below dyno chart - first pull was with the tune off, second two pulls had the tune on. My car has a stock drivetrain, intake, and exhaust with the exception of a Werks intercooler.


 
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