Tune or no tune?
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Tune or no tune?
I added an AFE CAI to my 15 Z51 M7. I have read a few things about possibly being too lean?? Should I get a tune or leave it? I am in CA so also not sure if it will pass smog with a tune when I put the stock air box back in. All other engine is stock. Thoughts? Thanks
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From: cookeville tennessee
ttt
No tune on this one item at all this c7 runs a little rich not lean. I check my plugs before I did a cold air intake with LT headers with x pipe & aftermarket mufflers. Took the car out after that ran it some what hard came back & check them before my plugs was to rich after adding all of those parts plugs was a tan color. Car seem it maybe ran better but also that may just been in my head also.
But I will say this before the plugs was running to rich they where black & then a dry tan color.. Way more on the lean side but also may been the sound 7 what ever but did seem to be a little stronger without a tune 7 ran great... After I got a tune for sure ran much better. But with what it will cost you to get a tune if you are not going to inside the motor do all of your add on's then call it a day & get a good tuner.. Robert
But I will say this before the plugs was running to rich they where black & then a dry tan color.. Way more on the lean side but also may been the sound 7 what ever but did seem to be a little stronger without a tune 7 ran great... After I got a tune for sure ran much better. But with what it will cost you to get a tune if you are not going to inside the motor do all of your add on's then call it a day & get a good tuner.. Robert
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From: DFW TX
More air and not adding fuel is a lean condition, not rich. Adding headers / exhaust and letting the car breath out more without taking fuel out is a rich condition.
To the OP you don't need a tune with a intake just make sure you get everything installed and tightened down good and the MAF back in
To the OP you don't need a tune with a intake just make sure you get everything installed and tightened down good and the MAF back in
Last edited by C7&7; Feb 23, 2021 at 09:53 AM.
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From: Norman OK
More air and not adding fuel is a lean condition, not rich. Adding headers / exhaust and letting the car breath out more without taking fuel out is a rich condition.
To the OP you don't need a tune with a intake just make sure you get everything installed and tightened down good and the MAF back in
To the OP you don't need a tune with a intake just make sure you get everything installed and tightened down good and the MAF back in
Wrong....
That is not how the OEM tune or any tune works on modern GM vehicles, the changes the OP is asking about will make the car run rich. The fueling is determined by what the programmed EQ Ratio is in the tune, that EQ Ratio determines what the commanded A/F ratio is for the car. The ECM then relies on the airflow data from the Mass Airflow sensor to determine for how much airflow it is seeing what fueling the vehicle needs. As long as the vehicle is in Closed Loop mode the ECM uses the Narrow band front O2 sensors to correct Stoich A/F based on the MAF data and information from the VE tables. Once you go WOT and PE mode is enabled the vehicles goes into Open Loop mode and then uses the airflow data from the MAF to determine where the fueling needs to be at and ignores the narrowband O2 sensors.
The MAF scale is programmed all the way to the end of its scale from the factory and it is on the rich side of things for safety. The MAF is scaled in Hertz (Hz).So when the OP adds the CAI and/or frees up the exhaust it will make the airflow more efficient. This will then shift the original airflow point to the right in the scale, thus due to the increased airflow it will make the car run richer as well.
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Joined: Mar 2010
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From: DFW TX
Wrong....
That is not how the OEM tune or any tune works on modern GM vehicles, the changes the OP is asking about will make the car run rich. The fueling is determined by what the programmed EQ Ratio is in the tune, that EQ Ratio determines what the commanded A/F ratio is for the car. The ECM then relies on the airflow data from the Mass Airflow sensor to determine for how much airflow it is seeing what fueling the vehicle needs. As long as the vehicle is in Closed Loop mode the ECM uses the Narrow band front O2 sensors to correct Stoich A/F based on the MAF data and information from the VE tables. Once you go WOT and PE mode is enabled the vehicles goes into Open Loop mode and then uses the airflow data from the MAF to determine where the fueling needs to be at and ignores the narrowband O2 sensors.
The MAF scale is programmed all the way to the end of its scale from the factory and it is on the rich side of things for safety. The MAF is scaled in Hertz (Hz).So when the OP adds the CAI and/or frees up the exhaust it will make the airflow more efficient. This will then shift the original airflow point to the right in the scale, thus due to the increased airflow it will make the car run richer as well.
That is not how the OEM tune or any tune works on modern GM vehicles, the changes the OP is asking about will make the car run rich. The fueling is determined by what the programmed EQ Ratio is in the tune, that EQ Ratio determines what the commanded A/F ratio is for the car. The ECM then relies on the airflow data from the Mass Airflow sensor to determine for how much airflow it is seeing what fueling the vehicle needs. As long as the vehicle is in Closed Loop mode the ECM uses the Narrow band front O2 sensors to correct Stoich A/F based on the MAF data and information from the VE tables. Once you go WOT and PE mode is enabled the vehicles goes into Open Loop mode and then uses the airflow data from the MAF to determine where the fueling needs to be at and ignores the narrowband O2 sensors.
The MAF scale is programmed all the way to the end of its scale from the factory and it is on the rich side of things for safety. The MAF is scaled in Hertz (Hz).So when the OP adds the CAI and/or frees up the exhaust it will make the airflow more efficient. This will then shift the original airflow point to the right in the scale, thus due to the increased airflow it will make the car run richer as well.
Also you take a LT4 or a LT5 and throw a new intake on it and the car will throw codes because it is running lean.
Last edited by C7&7; Feb 24, 2021 at 02:37 PM.
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From: Norman OK
Sure I suppose if we're talking within the limits of the factory ECU and how it will react to a small difference in incoming air flow. However you don't just add air to a engine and not need to add fuel. You don't bolt a supercharger to a engine and not need to add fuel.
Also you take a LT4 or a LT5 and throw a new intake on it and the car will throw codes because it is running lean.
Also you take a LT4 or a LT5 and throw a new intake on it and the car will throw codes because it is running lean.
How much tuning have you done on GM vehicles, what tuning software are you using to tune vehicles? What you are saying is wrong and is not how things work on modern GM vehicles in regards to GM's tuning, I came from a fully modded 17 Camaro SS 1LE that was putting down 650rwhp to a 19 C7Z that is modded. My 19 C7Z is running on the stock OEM GM programming right now with a Halltech CAI, AWE catless x-pipe and a Mamo Ported TB. Dyno runs are showing the car is running rich, data logs from the car are confirming the same thing as well, exhaust tips are showing the same signs of the car being rich as well as the plugs.
When you allow the intake side to breath easier and open up the exhaust it will make the car run richer. I have been missing around with GM performance vehicles since 1993 starting with a 1989 Pontiac Formula 350, then moved onto a 2001 Pontiac Formula Firebird and all the way up the GM realm of performance vehicles. I have dabbled in tuning my cars using HP Tuners myself since my 2006 Pontiac GTO all the way up to my current 2019 C7Z.
Last edited by TJay74; Feb 25, 2021 at 10:46 AM.
Le Mans Master
Joined: Mar 2010
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From: DFW TX
How much tuning have you done on GM vehicles, what tuning software are you using to tune vehicles? What you are saying is wrong and is not how things work on modern GM vehicles in regards to GM's tuning, I came from a fully modded 17 Camaro SS 1LE that was putting down 650rwhp to a 19 C7Z that is modded. My 19 C7Z is running on the stock OEM GM programming right now with a Halltech CAI, AWE catless x-pipe and a Mamo Ported TB. Dyno runs are showing the car is running rich, data logs from the car are confirming the same thing as well, exhaust tips are showing the same signs of the car being rich as well as the plugs.
When you allow the intake side to breath easier and open up the exhaust it will make the car run richer. I have been missing around with GM performance vehicles since 1993 starting with a 1989 Pontiac Formula 350, then moved onto a 2001 Pontiac Formula Firebird and all the way up the GM realm of performance vehicles. I have dabbled in tuning my cars using HP Tuners myself since my 2006 Pontiac GTO all the way up to my current 2019 C7Z.
When you allow the intake side to breath easier and open up the exhaust it will make the car run richer. I have been missing around with GM performance vehicles since 1993 starting with a 1989 Pontiac Formula 350, then moved onto a 2001 Pontiac Formula Firebird and all the way up the GM realm of performance vehicles. I have dabbled in tuning my cars using HP Tuners myself since my 2006 Pontiac GTO all the way up to my current 2019 C7Z.
And if we need to compare resumes yes I have been modifying and working on my cars since the late 90s.
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From: Norman OK
Dude... I think we're saying the same thing here. Within the limits of the stock ECU it will try to compensate for certain changes in incoming air or outgoing exhaust. I get that... what I am saying is you don't just throw a super charger on a LT1 or a bigger intake on a LT4 or LT5 and expect the car to be RICH... That is just not the case...
And if we need to compare resumes yes I have been modifying and working on my cars since the late 90s.
And if we need to compare resumes yes I have been modifying and working on my cars since the late 90s.
Which tuning software have you been using, just wondering?
The OP posted in the C7Z forum about adding a CAI to his Z06, which is already supercharged from the factory. So my response still stands as a Z06 owner who did the very exact mode the OP asked about, putting a CAI on the car can make it run rich, not lean. If a person gets lean codes from a CAI install they either have a unmetered air leak or have damaged the MAF sensor.
My logs from my bone stock runs show exactly where the car is at on the stock programming on the MAF scale and the modified runs show where the car is at now on the MAF scale. As I mentioned, the new point is shifted to the right in the scale which makes the car more rich. The car will stay that was until the MAF scale is cleaned up and the EQ Ratio tables are adjusted.
Le Mans Master
Joined: Mar 2010
Posts: 7,052
Likes: 945
From: DFW TX
Which tuning software have you been using, just wondering?
The OP posted in the C7Z forum about adding a CAI to his Z06, which is already supercharged from the factory. So my response still stands as a Z06 owner who did the very exact mode the OP asked about, putting a CAI on the car can make it run rich, not lean. If a person gets lean codes from a CAI install they either have a unmetered air leak or have damaged the MAF sensor.
My logs from my bone stock runs show exactly where the car is at on the stock programming on the MAF scale and the modified runs show where the car is at now on the MAF scale. As I mentioned, the new point is shifted to the right in the scale which makes the car more rich. The car will stay that was until the MAF scale is cleaned up and the EQ Ratio tables are adjusted.
The OP posted in the C7Z forum about adding a CAI to his Z06, which is already supercharged from the factory. So my response still stands as a Z06 owner who did the very exact mode the OP asked about, putting a CAI on the car can make it run rich, not lean. If a person gets lean codes from a CAI install they either have a unmetered air leak or have damaged the MAF sensor.
My logs from my bone stock runs show exactly where the car is at on the stock programming on the MAF scale and the modified runs show where the car is at now on the MAF scale. As I mentioned, the new point is shifted to the right in the scale which makes the car more rich. The car will stay that was until the MAF scale is cleaned up and the EQ Ratio tables are adjusted.
We're talking about logging a car and allowing the FACTORY ecu to adjust within the MAF limits to adjust for fuel on it's own not tuning it for anything remember? I think we're established that the factory ECU has limits and it can adjust for certain changes in incoming or outgoing air. I am not arguing with you there and that's fundamental fuel control logic since we went to MAF. The point I am trying to make and you know it's true is there are limits to how much air you can add before you're out of bounds with what the MAF can read and it will just freak out and dump fuel. That fuel dump MAY OR MAY NOT be enough.... Hence the reason you don't slap a 5 inch intake on a LT4 or a LT5 and everything is perfect. Or you don't pulley a LT4 or LT5 and magically it's just gonna have enough fuel. Or you don't throw a blower on the LT1 and say "ah it'll be fine the ECU will figure it out"
We can argue tomato or tomato about this all day. At the end of it all, you know, if you're adding air to an engine you have your limits before it needs more fuel. Period.
Last edited by C7&7; Feb 25, 2021 at 06:20 PM.