Where did you get the tune?
Seeing a max 16 PSI boost with GMPP tune (HP Tuners)
I recently replaced the MAP sensors and pushed the stock GMPP tune via HP Tuners. I found 2 different versions of the specific calibration for my car and all the parameters matched between them, except the vehicle details in the file, so I'm pretty sure it's the right data. I downloaded my stock calibration, updated it with the differences, and pushed it back. If I download the calibration, it matches what I pushed to it.
The car certainly feels much stronger now - I can barely go WOT in 2nd gear before getting a traction warning and I couldn't hit barely more than 5000 rpm without more than doubling the local speed limit. However, I just logged a run with VCM Scanner and the most I'm seeing is just a hair over 16 PSI boost?? I'm about 800 feet above sea level here so should be seeing much more, I think?
All the VCM Scanner data looks good to me, but I'm a novice here. What sticks out is this (pedal was to the floor):
Accelerator Position D (SAE) - 49.4%
Throttle Position (SAE) - 83.1%
Relative Throttle Position - 68.6%
Commanded Throttle Actuator (SAE) - 99.6%
Throughout my recorded run, 83.1% Throttle Position is the max I see. But I really don't know if that's an issue at all!
Otherwise, thoughts on what to check out? The battery was disconnected for some time so is there some relearning that needs to occur perhaps?
The car certainly feels much stronger now - I can barely go WOT in 2nd gear before getting a traction warning and I couldn't hit barely more than 5000 rpm without more than doubling the local speed limit. However, I just logged a run with VCM Scanner and the most I'm seeing is just a hair over 16 PSI boost?? I'm about 800 feet above sea level here so should be seeing much more, I think?
All the VCM Scanner data looks good to me, but I'm a novice here. What sticks out is this (pedal was to the floor):
Accelerator Position D (SAE) - 49.4%
Throttle Position (SAE) - 83.1%
Relative Throttle Position - 68.6%
Commanded Throttle Actuator (SAE) - 99.6%
Throughout my recorded run, 83.1% Throttle Position is the max I see. But I really don't know if that's an issue at all!
Otherwise, thoughts on what to check out? The battery was disconnected for some time so is there some relearning that needs to occur perhaps?
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Okay, so here is what is going on.I recently replaced the MAP sensors and pushed the stock GMPP tune via HP Tuners.
...the most I'm seeing is just a hair over 16 PSI boost?? I'm about 800 feet above sea level here so should be seeing much more, I think?
All the VCM Scanner data looks good to me, but I'm a novice here. What sticks out is this (pedal was to the floor):
Throttle Position (SAE) - 83.1%
...
Commanded Throttle Actuator (SAE) - 99.6%
Throughout my recorded run, 83.1% Throttle Position is the max I see. But I really don't know if that's an issue at all!
Otherwise, thoughts on what to check out? The battery was disconnected for some time so is there some relearning that needs to occur perhaps?
On throttle position, 83.1% is most likely full throttle. It's weird but it is. My 2.4 is the same way. Each car may be slightly different but I've verified the butterfly is full open at 87.3% Throttle Position on my car.
For boost, our ECM uses torque based power management. It has a target torque number it tries to hit and will adjust things like timing and boost to hit it. This is called the "Learn Down" feature. If it is targeting 260 ft/lbs, add a performance exhaust, and now the ECM sees 270 ft/lbs it will reduce boost until it sees the engine making 260 ft/lbs again.
Every aftermarket tune sets this target torque level to it's maximum value...a value the engine will NEVER obtain. This causes the ECM to increase boost until it hits the target (which it won't) or the maximum allowable boost level in the tune. This is what people describe as a tune "getting ride of the learn down feature". It really doesn't "git rid" of it but effectively uses it to manipulate the ECM to hit a boost level they set.
The GMPP tune you downloaded is different. Since this tune was smog legal in CA and maintained the factory warranty (and came from GM), it doesn't max out the target torque value, it just raises it. So now rather than targeting 260 ft/lbs, it targets 325 ft/lbs (not actual numbers but you get the idea).
Now you are in Canada...and at 800' sea level. Lower air is denser air and colder air is denser air. Denser air makes similar power at lower boost pressures as thinner air does at higher boost pressures. So while a RPM tune may make 23 psi where you live, it may make 360 ft/lbs of torque at your elevation! The GMPP tune won't let that happen so to hit it's target of 325ft/lbs it only needs 16psi. In summer in Denver Colorado (a mile above sea level), your car may need 22 psi of boost to make 325ft/lbs so the GMPP tune will allow it to hit 22psi rather than 16.
For your location, 16 ft/lbs on the GMPP rune would seem right. Did you ever see what the stock tune was making?
Probably the HPTuners repository. I've seen the stock calibration files and the GMPP tune files there. Just ASSuME from what he says in his post. lolWhere did you get the tune?
Both from HP Tuner website - one from the tune library, and one from the forums. The vehicle info is different so pretty sure they came from different cars, but the tune data matches exactly.Where did you get the tune?
I was originally going to go with the same tune, but my understanding is that there are more parameters that GM can access that are not unlocked in HPTuners, so you won't get the whole tune. I'm just repeating what I was told though, but it also makes sense to me. If you already have HPTuners, I would consider the ZZP tune. Matt worked with me over a couple of weeks last year to get it figured out. I think it was $200 for the original tune and around $60 for any updates. The tune on an otherwise stock car really unlocked a lot of power. I paid for the update recently for all my bolt ons and my injectors. Hoping to be able to get the injectors in soon.
It's a shame though, I think it was cobaltoverboost on the HPTuners forums had a step by step video series on how to tune the LNF, but the videos are no longer on YouTube and I can't find any copies of them.
It's a shame though, I think it was cobaltoverboost on the HPTuners forums had a step by step video series on how to tune the LNF, but the videos are no longer on YouTube and I can't find any copies of them.
Great info...thx! I suspected this might be the case but knowing the Throttle Position value is not abnormal is good to hear! I do intend to start optimizing the tune some, so we'll see where it goesOkay, so here is what is going on.
On throttle position, 83.1% is most likely full throttle. It's weird but it is. My 2.4 is the same way. Each car may be slightly different but I've verified the butterfly is full open at 87.3% Throttle Position on my car.
For boost, our ECM uses torque based power management. It has a target torque number it tries to hit and will adjust things like timing and boost to hit it. This is called the "Learn Down" feature. If it is targeting 260 ft/lbs, add a performance exhaust, and now the ECM sees 270 ft/lbs it will reduce boost until it sees the engine making 260 ft/lbs again.
Every aftermarket tune sets this target torque level to it's maximum value...a value the engine will NEVER obtain. This causes the ECM to increase boost until it hits the target (which it won't) or the maximum allowable boost level in the tune. This is what people describe as a tune "getting ride of the learn down feature". It really doesn't "git rid" of it but effectively uses it to manipulate the ECM to hit a boost level they set.
The GMPP tune you downloaded is different. Since this tune was smog legal in CA and maintained the factory warranty (and came from GM), it doesn't max out the target torque value, it just raises it. So now rather than targeting 260 ft/lbs, it targets 325 ft/lbs (not actual numbers but you get the idea).
Now you are in Canada...and at 800' sea level. Lower air is denser air and colder air is denser air. Denser air makes similar power at lower boost pressures as thinner air does at higher boost pressures. So while a RPM tune may make 23 psi where you live, it may make 360 ft/lbs of torque at your elevation! The GMPP tune won't let that happen so to hit it's target of 325ft/lbs it only needs 16psi. In summer in Denver Colorado (a mile above sea level), your car may need 22 psi of boost to make 325ft/lbs so the GMPP tune will allow it to hit 22psi rather than 16.
For your location, 16 ft/lbs on the GMPP rune would seem right. Did you ever see what the stock tune was making?
Probably the HPTuners repository. I've seen the stock calibration files and the GMPP tune files there. Just ASSuME from what he says in his post. lol
My thought is that your bootleg tune doesn't have all of the parameters that you need, like maybe the proper calibration curve for the uprated MAP sensors.
In HP Tuners you can perform a compare on two config files and it will list all the differences and allow you to compare values for each change. It would be easy for OP to confirm the two changed MAP values by loading the downloaded tune and comparing it to the stock tune from his car. The proper values for the upgraded GMPP 3 bar MAPs are well documented on the HP Tuners' forums.My thought is that your bootleg tune doesn't have all of the parameters that you need, like maybe the proper calibration curve for the uprated MAP sensors.
Also, if those numbers are off, you'll get a CEL as the MAP will be reporting out of expected range. It took me a couple tries to get the right number for my 3 bar 2.4l MAP sensor as it is different from the ones used in the 2.0 GMPP tune kit.
Yup, noted the values for the 3 bar on ZZPs site some time ago and made sure the tune I used had these values (MAP and Boost sensor linear at 65.89kPa, and offset for each at -6.35kPa).
My understanding is that the only known thing missing is "no lift shift".I was originally going to go with the same tune, but my understanding is that there are more parameters that GM can access that are not unlocked in HPTuners, so you won't get the whole tune.
Yep, the GMPP tune on the repository had the right numbers.Yup, noted the values for the 3 bar on ZZPs site some time ago and made sure the tune I used had these values (MAP and Boost sensor linear at 65.89kPa, and offset for each at -6.35kPa).
So Speaking as a tuner that tunes close to 1000 LNF's per year.. and you say that you "Pushed" the file onto your car... Did HP Tuners make you license both the Tune file you pulled from their repository and the file from your car (4 Credits)?? If this is the case then it means you may have got a hold of a GMPP tune but the background OS that you cant see was probably different. When you open a tune file and go to Calibration Details.. their are both OS ID and the CVN need to match the car the calibration is being flashed to. Now I hope you did a full read on your car and saved that as your backup that you can Write Entire back to the car to save yourself from this debacle.. If not the ECM has to come to someone like me who can pull your exact Calibration off the GM Worldwide Network and restore the ECM.. then from there we can talk about tuning... Hope this helps... Martin RPM-Motorsports (PS if anyone knows how to change my screen name DM me )
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Hey Martin. I'm not even aware that you can "buy" (via credits) tunes from HP Tuners? The Tune Repository is free - you just need an account on their site. Regardless, I didn't download and then flash the tune I downloaded. Rather, I downloaded the stock calibration from my car, modified it so that the parameters matched the downloaded file, and flashed it back.
The way you made it sound was you downloaded a file from the tune repository and did a "Write Entire" onto your car... if you took your stock tune and made changes then did a "Write Calibration" back to the car then that was the "Correct" way to do it. You can reach out to me via [email protected] and I can help you if needed
I didn't even think to ask this as it is so automatic for me to do this when copying a tune. lol
Much appreciated!The way you made it sound was you downloaded a file from the tune repository and did a "Write Entire" onto your car... if you took your stock tune and made changes then did a "Write Calibration" back to the car then that was the "Correct" way to do it. You can reach out to me via [email protected] and I can help you if needed
I used to have 22 psi with trifecta tune and loved it, after a while it went down to 15 psi and felt flat.
Discovered I had the old boost leak at the intercooler. Split seam! had a friend tig it up. back to full boost!
check for boost leaks!
Discovered I had the old boost leak at the intercooler. Split seam! had a friend tig it up. back to full boost!
check for boost leaks!
Good tip! Is there a particular method for shop testing leaks in these cars?
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