[Z06] TUNING: Here is a Comprehensive Explanation of what a TUNE does straight from GM
03-29-2008, 01:52 AM
#1
Le Mans Master
Thread Starter
TUNING: Here is a Comprehensive Explanation of what a TUNE does straight from GM
Let's address some essential issues:
1) Understanding Tunes and GM Validation.
Before anyone can understand what the tune does one needs to understand how GM validates a part.
GM tests their product so there is margin for error. For most folks they never get that close to the limit. GM builds their product so if there is a failure it should be discovered during the warranty period and it will be covered if a repair is necessary. A tune, 'safe or whatever else you want to call it' changes all of that, It puts stresses on components that GM does not test for. Some tuners will tell you the their tune is safe and will not cause any harm. This may be true for 95% of their customers, but...the problem occurs when your car that has the tune which is one of the 5% that fall out side the normal limits. The component may operate perfectly for years at normal levels but when additional RPM is added, or a richer mixture is added, or the spark changes, all of that can put pressure on a piston, a rod or a set of bearings that was never intended. When that pressure is exerted, the component may fail immediately or it may develop a slight crack and will continue to grow until it fails perhaps at 30 miles per hour when driving your kids to school.
We have had a few posts claiming just this....I'm not suggesting any of these cases here where due to this, I plain and simply do not know. Just a heads-up of how it could happen at what would seem to be ridiculous conditions.
2) When will a failure occur?
There is no way you can tell if and when a failure will occur. GM builds in a safety margin so that does not normally occur. When a tune is installed that margin is lost and stress starts to build in the component until something breaks. Expand that thought to the rest of the powertrain,
For instance, GM knows that the half shaft will perform fine at 505 horse power, there is a margin of safety build into it. Now, add 20 more HP to the half shafts and the safety margin is gone. Add a set of drag radials that provides much better grip. Now you have more HP and a tire that does not slip when it should. What do you think is going to break? Probably the half shaft. EXCEPT if the half shaft is a stronger product that the average, say it is a really good one.
Now that additional HP and the higher slip resistance from the changed tires and the additional stress is transferred to something else. Add to that a driver that lets the wheels hop until they catch traction and the differential case is now split in half. This shouldn't be a mystery. All the HP and the force has to go somewhere. If the tires can’t spin because of the increased traction the ring gear and pinion gear start to push away from each other, the case that holds them together is only been tested for stock HP and stock tires. The force between the ring and pinions gears can actually break a differential case in half. Same thing with the transmissions.
The input and output shafts are rated for so much HP and so much tire slip. Alter the safety margin and shafts get twisted off. Not because they are defective but because higher stress loads are being applied than the part was designed to take. It is a very balanced package to a specific HP and a specific amount of tire slip. Changing either one beyond the test limits and things start to break.
3) Why not build the car stronger?
Some ask they why doesn’t GM build them to withstand 600 HP to be safe? The answer is you can’t and keep the car affordable. GM can build the components to withstand 650 HP but they would have to charge the same price as a ZR1. It ends up pushing the car out of the price level that most drivers are willing to spend.
4) Why not just swap the ECM/PCM?
Can the ECM/PCM be changed and no one will know? No! Each module has information stored in it. Some is transferred when it is reprogrammed and some starts all over again when a module is changed. Kind of like keeping score. The module knows the miles how long it has traveled since a emission test was completed and many more little bits and bites. When a new module is put in some of the data gets moved and some does not. When a suspected tune is discovered and a technician starts to look for clues, there are more than enough clues which will not be revealed here to confirm that this is not the PCM that has been running in the car.
5) How is the used car market segment to be addressed?
What about used cars? As soon as the bulletin is published it is public information. I will be glad to post the bulletin number and you can ask your dealership for a copy of it. If I was going to purchase a used Corvette or a Diesel Truck I wouldn’t buy it with out checking it for a modified calibration. Using the bulletin will take less than 5 minutes to determine. If it has a non-GM calibration just be aware that it may have already been discovered by GM and there may be a warranty block on it that the owner or used car dealership may not be aware of. It is worth having a Chevrolet dealership take a look at it just to make sure.
6) Will this be able to be used on C5 cars too?
Yes!
7) Will the Service Manager at my dealership be able to get around this?
It's not so simple. If a major failure has occurred and the dealership is required to attach both print outs of the calibration numbers which include the VIN to the repair order, there may not be much room for the dealership. If they do the repair and they are audited, the dealership will loose the cost of the parts and the labor. It is actually charged back to the dealership. Also remember many of the engines are now being returned for analysis. If during the inspection the engine plant detects evidence of a tune they will call the dealership for the records. If the dealership can not supply it then the warranty claim can be charged back to the dealership.
8) If the calibration is overwritten for example 10 times, will a dealership still be able top tell a calibration has been added?
Yes.
If you think someone will not question 5 of the same calibrations entered of a period then you don’t understand how serious GM is about this.
Why is GM doing this now?
As many have pointed out repeatedly, some of the information has been available for some time. But it has been tied to the calibration part number. The part number is good information but it is not fool proof. The second part of the equations, the hidden files, have just been established and validated 100%. GM wanted to make sure it was valid and the information was dependable before they took it to the dealerships.
9) Legal Issues:
Is this legal?
Can GM block my warranty?
Yes.
It has been run through the legal beagles and it is legal. In the warranty booklet there are 4 separate notations that modifying the vehicle from the original production will void the warranty and repairs will not be covered.
There were some comments on taking this to court.
Who is going to spend the dollars to try a case when the repair is going to be in the $15,000 area. I image GM has enough lawyers sitting around that they can tie this up for some time all the while the car is not running. The bottom line is when a calibration is changed the car is altered and GM has stated it does not warrant repairs once the vehicle has been altered. I'm not sure why this is such a hard concept to grasp.
10)What about Magnuson Moss?
You're kidding right?
11) Where does the information come from?
Many of you know I have attended many of the NCM HPDEs that include many of the GM engineers. I have built an honest relationship with many of them. I was one of the first lucky one's out on the track with my Z06 on a regular basis. I continually provided real customer information to them and they provide honest feedback to me. It’s a relationship built on trust. This information is coming straight from GM. They trust me not to ask questions I realize they can not and will not answer, and they trust me not to provide their names and positions which would result in bombardment of Internet questions. Those of you who have met me have seen this first hand. Please do not get hung up on which individuals and departments it came from. There are enough forum members here who can verify my integrity and my contacts. Let's keep this about our beloved Corvettes!
Mike
1) Understanding Tunes and GM Validation.
Before anyone can understand what the tune does one needs to understand how GM validates a part.
GM tests their product so there is margin for error. For most folks they never get that close to the limit. GM builds their product so if there is a failure it should be discovered during the warranty period and it will be covered if a repair is necessary. A tune, 'safe or whatever else you want to call it' changes all of that, It puts stresses on components that GM does not test for. Some tuners will tell you the their tune is safe and will not cause any harm. This may be true for 95% of their customers, but...the problem occurs when your car that has the tune which is one of the 5% that fall out side the normal limits. The component may operate perfectly for years at normal levels but when additional RPM is added, or a richer mixture is added, or the spark changes, all of that can put pressure on a piston, a rod or a set of bearings that was never intended. When that pressure is exerted, the component may fail immediately or it may develop a slight crack and will continue to grow until it fails perhaps at 30 miles per hour when driving your kids to school.
We have had a few posts claiming just this....I'm not suggesting any of these cases here where due to this, I plain and simply do not know. Just a heads-up of how it could happen at what would seem to be ridiculous conditions.
2) When will a failure occur?
There is no way you can tell if and when a failure will occur. GM builds in a safety margin so that does not normally occur. When a tune is installed that margin is lost and stress starts to build in the component until something breaks. Expand that thought to the rest of the powertrain,
For instance, GM knows that the half shaft will perform fine at 505 horse power, there is a margin of safety build into it. Now, add 20 more HP to the half shafts and the safety margin is gone. Add a set of drag radials that provides much better grip. Now you have more HP and a tire that does not slip when it should. What do you think is going to break? Probably the half shaft. EXCEPT if the half shaft is a stronger product that the average, say it is a really good one.
Now that additional HP and the higher slip resistance from the changed tires and the additional stress is transferred to something else. Add to that a driver that lets the wheels hop until they catch traction and the differential case is now split in half. This shouldn't be a mystery. All the HP and the force has to go somewhere. If the tires can’t spin because of the increased traction the ring gear and pinion gear start to push away from each other, the case that holds them together is only been tested for stock HP and stock tires. The force between the ring and pinions gears can actually break a differential case in half. Same thing with the transmissions.
The input and output shafts are rated for so much HP and so much tire slip. Alter the safety margin and shafts get twisted off. Not because they are defective but because higher stress loads are being applied than the part was designed to take. It is a very balanced package to a specific HP and a specific amount of tire slip. Changing either one beyond the test limits and things start to break.
3) Why not build the car stronger?
Some ask they why doesn’t GM build them to withstand 600 HP to be safe? The answer is you can’t and keep the car affordable. GM can build the components to withstand 650 HP but they would have to charge the same price as a ZR1. It ends up pushing the car out of the price level that most drivers are willing to spend.
4) Why not just swap the ECM/PCM?
Can the ECM/PCM be changed and no one will know? No! Each module has information stored in it. Some is transferred when it is reprogrammed and some starts all over again when a module is changed. Kind of like keeping score. The module knows the miles how long it has traveled since a emission test was completed and many more little bits and bites. When a new module is put in some of the data gets moved and some does not. When a suspected tune is discovered and a technician starts to look for clues, there are more than enough clues which will not be revealed here to confirm that this is not the PCM that has been running in the car.
5) How is the used car market segment to be addressed?
What about used cars? As soon as the bulletin is published it is public information. I will be glad to post the bulletin number and you can ask your dealership for a copy of it. If I was going to purchase a used Corvette or a Diesel Truck I wouldn’t buy it with out checking it for a modified calibration. Using the bulletin will take less than 5 minutes to determine. If it has a non-GM calibration just be aware that it may have already been discovered by GM and there may be a warranty block on it that the owner or used car dealership may not be aware of. It is worth having a Chevrolet dealership take a look at it just to make sure.
6) Will this be able to be used on C5 cars too?
Yes!
7) Will the Service Manager at my dealership be able to get around this?
It's not so simple. If a major failure has occurred and the dealership is required to attach both print outs of the calibration numbers which include the VIN to the repair order, there may not be much room for the dealership. If they do the repair and they are audited, the dealership will loose the cost of the parts and the labor. It is actually charged back to the dealership. Also remember many of the engines are now being returned for analysis. If during the inspection the engine plant detects evidence of a tune they will call the dealership for the records. If the dealership can not supply it then the warranty claim can be charged back to the dealership.
8) If the calibration is overwritten for example 10 times, will a dealership still be able top tell a calibration has been added?
Yes.
If you think someone will not question 5 of the same calibrations entered of a period then you don’t understand how serious GM is about this.
Why is GM doing this now?
As many have pointed out repeatedly, some of the information has been available for some time. But it has been tied to the calibration part number. The part number is good information but it is not fool proof. The second part of the equations, the hidden files, have just been established and validated 100%. GM wanted to make sure it was valid and the information was dependable before they took it to the dealerships.
9) Legal Issues:
Is this legal?
Can GM block my warranty?
Yes.
It has been run through the legal beagles and it is legal. In the warranty booklet there are 4 separate notations that modifying the vehicle from the original production will void the warranty and repairs will not be covered.
There were some comments on taking this to court.
Who is going to spend the dollars to try a case when the repair is going to be in the $15,000 area. I image GM has enough lawyers sitting around that they can tie this up for some time all the while the car is not running. The bottom line is when a calibration is changed the car is altered and GM has stated it does not warrant repairs once the vehicle has been altered. I'm not sure why this is such a hard concept to grasp.
10)What about Magnuson Moss?
You're kidding right?
11) Where does the information come from?
Many of you know I have attended many of the NCM HPDEs that include many of the GM engineers. I have built an honest relationship with many of them. I was one of the first lucky one's out on the track with my Z06 on a regular basis. I continually provided real customer information to them and they provide honest feedback to me. It’s a relationship built on trust. This information is coming straight from GM. They trust me not to ask questions I realize they can not and will not answer, and they trust me not to provide their names and positions which would result in bombardment of Internet questions. Those of you who have met me have seen this first hand. Please do not get hung up on which individuals and departments it came from. There are enough forum members here who can verify my integrity and my contacts. Let's keep this about our beloved Corvettes!
Mike
03-29-2008, 02:22 AM
#2
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Question Mike;
Is there a possible grace period for those that have a tune and CAI that wish to return to stock? If so, can a dealer then re-flash the ECM to stock and verify that no components were damaged because of the tune or is everyone who has a tune just poop out of luck?
Is there a possible grace period for those that have a tune and CAI that wish to return to stock? If so, can a dealer then re-flash the ECM to stock and verify that no components were damaged because of the tune or is everyone who has a tune just poop out of luck?
03-29-2008, 04:41 AM
#3
Team Owner
so to simplify what you said to four wirds "it's your dime now" 
When the pieces or _hit hit's the fan see how the service writer / dealer stands behind you. Will they risk fraud with GM? I am sure GM has eaten eonough 4th to 2nd shifts just to be nice over the years.
When the pieces or _hit hit's the fan see how the service writer / dealer stands behind you. Will they risk fraud with GM? I am sure GM has eaten eonough 4th to 2nd shifts just to be nice over the years.
Last edited by John Shiels; 03-29-2008 at 04:46 AM.
03-29-2008, 04:52 AM
#4
Team Owner
Question Mike;
Is there a possible grace period for those that have a tune and CAI that wish to return to stock? If so, can a dealer then re-flash the ECM to stock and verify that no components were damaged because of the tune or is everyone who has a tune just poop out of luck?
Is there a possible grace period for those that have a tune and CAI that wish to return to stock? If so, can a dealer then re-flash the ECM to stock and verify that no components were damaged because of the tune or is everyone who has a tune just poop out of luck?
03-29-2008, 07:52 AM
#7
Melting Slicks
Mike,
Just a quick question. Is your yellow Z06 stock or does it have a tune and after market parts? If so, are you going to leave it as is, or get it back to stock? You news comes at a very bad time, I just bought a new Z and planned to do a few minor mods.....now, I must re-think my intentions.
Just a quick question. Is your yellow Z06 stock or does it have a tune and after market parts? If so, are you going to leave it as is, or get it back to stock? You news comes at a very bad time, I just bought a new Z and planned to do a few minor mods.....now, I must re-think my intentions.
03-29-2008, 08:28 AM
#8
Racer
Mike,
Just a quick question. Is your yellow Z06 stock or does it have a tune and after market parts? If so, are you going to leave it as is, or get it back to stock? You news comes at a very bad time, I just bought a new Z and planned to do a few minor mods.....now, I must re-think my intentions.
Just a quick question. Is your yellow Z06 stock or does it have a tune and after market parts? If so, are you going to leave it as is, or get it back to stock? You news comes at a very bad time, I just bought a new Z and planned to do a few minor mods.....now, I must re-think my intentions.
However, there are a whole host of other components besides powertrain that could fail and, frankly, are more likely to fail then some in the driveline. Things like power windows, fobs, roofs, speakers, hvac, airbag modules are still covered even if you have a thumping cam and headers. Diagnosing electric gremlins is still a timely and costly issue and will still be covered.
Additionally, people have to stop worrying that adding an air intake and a tune is somehow going to make your car explode, and thus require dealer intervention. It's not. If you're really worried about dropping a valve or breaking a spring, replace the springs first as it's only a few hundred bones. I have almost 6K on my cam, headers, and coilovers and have yet to see a problem other then a damn airbag light (guess who is taking care of that?). These cars are not weak little gentle flowers who will wilt under some mild mods!
Finally, if this is true (I've read Mike's posts over the years and don't doubt he believes what he is writing, but nothing is finalized until it's finalized) there will be a work-around. The tuning world is just too big and there is too much money at stake here for them not to be motivated to find a way to spoof (if they haven't already). I have seen everything from ways to hacking onstar to the ability to roll back odometers to not believe for a second there won't be a solution to this.
So in sum: the sky is not falling, people will still continue to mode their cars and retain a warranty (hey they can't void it if you never bring it in). Furthemore, many of you should really consider what a warranty gets you and how many of you will actually ever use it (I've owned a few Corvettes and have only had them at the dealership for very minor things, and never one powertrain related).
JMHO of course
03-29-2008, 08:35 AM
#9
Pro
Mike,
Thank you ,for this very imformative post..It answers alot of questions,that I have had..
This forum has given me a wealth of information.
Thanks again,
Larry
Thank you ,for this very imformative post..It answers alot of questions,that I have had..
This forum has given me a wealth of information.
Thanks again,
Larry
03-29-2008, 08:43 AM
#10
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Finally, if this is true (I've read Mike's posts over the years and don't doubt he believes what he is writing, but nothing is finalized until it's finalized) there will be a work-around. The tuning world is just too big and there is too much money at stake here for them not to be motivated to find a way to spoof (if they haven't already). I have seen everything from ways to hacking onstar to the ability to roll back odometers to not believe for a second there won't be a solution to this.
JMHO of course
JMHO of course
03-29-2008, 08:43 AM
#11
Racer
What information has this given you? That a bulletin might be posted? Why don't we all wait and read the bulletin once it's posted before we start a round of congrats here. Mike could very well be right, but he could just as easily be wrong. Furthermore, if this does happen, details will emerge on how this is done. There is no substance as to really how this will be done other then some vague indication to "hidden files" -- whatever that means. Furthermore, Mike himself said that this will be used for "major failures" what constitutes a major failure and how many of us Z06'ers are ever going to see such a thing (1 in 40?)?
I appreciate Mike sharing information with us, but I think we should all reserve final judgement till this actually happens and then analyze the campaign (will it require an update, what will be the criteria for checking for a tune, and what methods will be used), before we all start deciding HOW this impacts modding and the car market.
Again, we are all just oppining on this matter so JMHO.
03-29-2008, 08:53 AM
#14
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Great reading. Thanks!
I am about to take delivery of a brand new Z06 that just rolled off the assembly line so this info is especailly interesting to me.
Thanks again.
I am about to take delivery of a brand new Z06 that just rolled off the assembly line so this info is especailly interesting to me.
Thanks again.
03-29-2008, 08:57 AM
#15
Racer
Ok, well if you say so it must be true.
Regardless the point is that there will be a work-around. I have scoured the EFILive boards and there is no indication of this coming, furthremore, isn't it interesting that no tuners have weighed in on this? Do you think that they are going to just close up shop and stop tuning cars? Will tuners not start offering a tune that is "not GM detectable?"
Unfortunately, people will still chose to actively decieve GM after blowing up a motor from a missed 2 to 4 shift, just like they will still bring their cammed cars in. This is a reality, and I am not advocating it. As I said before, I wouldn't bring my car in for anything drivetrain related to a dealer. If for no other reason that the dealerships by me are barely able to handle driving my car onto a lift, let alone working on it. For me I'd rather continue to pay my tuner to work on it for something motor-related.
Again I am a realist that is all.
Regardless the point is that there will be a work-around. I have scoured the EFILive boards and there is no indication of this coming, furthremore, isn't it interesting that no tuners have weighed in on this? Do you think that they are going to just close up shop and stop tuning cars? Will tuners not start offering a tune that is "not GM detectable?"
Unfortunately, people will still chose to actively decieve GM after blowing up a motor from a missed 2 to 4 shift, just like they will still bring their cammed cars in. This is a reality, and I am not advocating it. As I said before, I wouldn't bring my car in for anything drivetrain related to a dealer. If for no other reason that the dealerships by me are barely able to handle driving my car onto a lift, let alone working on it. For me I'd rather continue to pay my tuner to work on it for something motor-related.
Again I am a realist that is all.
03-29-2008, 09:02 AM
#16
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Actually, on a different thread below a tuner did offer his self-serving views, but this came from the same person who has no idea how the oiling system works. Gives one lots of confidence, eh?
03-29-2008, 09:02 AM
#17
Racer
Oops, I mispoke! Apparently this HAS been floating around the tuner boards for quite some time. Here are some reads on it:
http://forum.efilive.com/showthread.php?t=7460
http://forum.efilive.com/showthread.php?t=7461
So I was wrong in my estimation of whether this would happen or not. Apparently the folks at EFILive and other tuning related sites have noted this to be in the works for quite some time. However, people are optomistic that there will be a work-around.
http://forum.efilive.com/showthread.php?t=7460
http://forum.efilive.com/showthread.php?t=7461
So I was wrong in my estimation of whether this would happen or not. Apparently the folks at EFILive and other tuning related sites have noted this to be in the works for quite some time. However, people are optomistic that there will be a work-around.
03-29-2008, 09:05 AM
#18
Racer
The good news is that it appears GM is not changing the protocol for anything, other then they are just checking to see if modifications has occured. So this means it will be possible to still tune these cars (for Chrysler products it's not so easy!).
Time will tell, but I am confident that where there is a will, there is a way!
03-29-2008, 09:12 AM
#19
The funny thing about this thread is that is making me seriously consider accelerating my trip to Katech for the StreetAttack. I have a few hundred miles with a tune and CAI so it appears that I am now a pariah to GM.
Given that there have been some problem areas for the LS7 I might as well pay the pros to make sure it's put together right and thoroughly void the warranty.
EDIT: Just to clarify I never expected full warranty coverage with a tune but I must admit the spate of failures on '08 Zs recently does have me a bit spooked. I had hoped that GM would work with me if there was a problem that might have been pre-existing and I was honest about the mods but that sure doesn't appear to be the case based on this thread.
Given that there have been some problem areas for the LS7 I might as well pay the pros to make sure it's put together right and thoroughly void the warranty.
EDIT: Just to clarify I never expected full warranty coverage with a tune but I must admit the spate of failures on '08 Zs recently does have me a bit spooked. I had hoped that GM would work with me if there was a problem that might have been pre-existing and I was honest about the mods but that sure doesn't appear to be the case based on this thread.
Last edited by Poor-sha; 03-29-2008 at 09:17 AM.
03-29-2008, 09:25 AM
#20
Excellent post Mike and well worth waiting for. Thanks for the information. 
I'll wait for him to answer, but think I recall reading somewhere that he has two Z06s and one of them is completely stock, the other is the race car.
Mike,
Just a quick question. Is your yellow Z06 stock or does it have a tune and after market parts? If so, are you going to leave it as is, or get it back to stock? You news comes at a very bad time, I just bought a new Z and planned to do a few minor mods.....now, I must re-think my intentions.
Just a quick question. Is your yellow Z06 stock or does it have a tune and after market parts? If so, are you going to leave it as is, or get it back to stock? You news comes at a very bad time, I just bought a new Z and planned to do a few minor mods.....now, I must re-think my intentions.
