Tutorial-MAF Scaling for High Horsepower Setups
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From: So.Cal.
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On The Tree
Joined: Mar 2010
Posts: 124
Likes: 8
From: Navarre, FL
Am I correct in my thinking that B4107 CL Mode should be shifted like the spark tables instead of scaled like majority of the tables?
Like Joe said, it's one of the tables where the axis is derived/calculated/using mass air flow? (vs the values in the table themselves)
I worked thru a quick idle example assuming 8 g/s flow at idle and with the scaled tune, at idle you would be sitting at a different "CL mode", which then would propagate into the various STFT base correction or delay tables. It was maybe a tenth of second or so off, but that's also like 50% error or something. Notice both the CL mode and STFT base delay tables are very 'steep' in the lower region.
If/when I get around to going back to a blended VE/MAF tune I'll give it a go and report back.
Like Joe said, it's one of the tables where the axis is derived/calculated/using mass air flow? (vs the values in the table themselves)
I worked thru a quick idle example assuming 8 g/s flow at idle and with the scaled tune, at idle you would be sitting at a different "CL mode", which then would propagate into the various STFT base correction or delay tables. It was maybe a tenth of second or so off, but that's also like 50% error or something. Notice both the CL mode and STFT base delay tables are very 'steep' in the lower region.
If/when I get around to going back to a blended VE/MAF tune I'll give it a go and report back.
I believe it should be shifted, but here is what I ran into....The problem I saw when I did it was with a 50% scaled tune the values shifted it so far up that most of the rows ended up at the max value that it almost made it a pointless table. I have left it stock and turned my fuel trims back on and was correcting to stoich. Personally i would not leave LTFT's on for a high HP, big overlap, etc. setup anyways. Just kept on STFT's and it has been working ok. YMMV.
On The Tree
Joined: Mar 2010
Posts: 124
Likes: 8
From: Navarre, FL
I believe it should be shifted, but here is what I ran into....The problem I saw when I did it was with a 50% scaled tune the values shifted it so far up that most of the rows ended up at the max value that it almost made it a pointless table. I have left it stock and turned my fuel trims back on and was correcting to stoich. Personally i would not leave LTFT's on for a high HP, big overlap, etc. setup anyways. Just kept on STFT's and it has been working ok. YMMV.
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Hi all,
Reviving an old thread vs starting a new one. I am new to tuning and have been researching my mind numb for the past while on everything. With that said, I have decided that I want to go down the path of a scaled maf tune once I hit my 512g/s limit. Currently, I have a card style maf in a 4" pipe, so I should have room to grow on the hz side of things. What I am currently trying to grasp is the "What now?" after the initial scaling as described in the first few posts. While tuning, will I have to be scaling anything on the fly? Or is it all percentage based so the basic tuning should remain the same? AKA scale once and don't worry about it? Still figuring that part out.
Thanks in advance!
Reviving an old thread vs starting a new one. I am new to tuning and have been researching my mind numb for the past while on everything. With that said, I have decided that I want to go down the path of a scaled maf tune once I hit my 512g/s limit. Currently, I have a card style maf in a 4" pipe, so I should have room to grow on the hz side of things. What I am currently trying to grasp is the "What now?" after the initial scaling as described in the first few posts. While tuning, will I have to be scaling anything on the fly? Or is it all percentage based so the basic tuning should remain the same? AKA scale once and don't worry about it? Still figuring that part out.
Thanks in advance!
Hi all,
Reviving an old thread vs starting a new one. I am new to tuning and have been researching my mind numb for the past while on everything. With that said, I have decided that I want to go down the path of a scaled maf tune once I hit my 512g/s limit. Currently, I have a card style maf in a 4" pipe, so I should have room to grow on the hz side of things. What I am currently trying to grasp is the "What now?" after the initial scaling as described in the first few posts. While tuning, will I have to be scaling anything on the fly? Or is it all percentage based so the basic tuning should remain the same? AKA scale once and don't worry about it? Still figuring that part out.
Thanks in advance!
Reviving an old thread vs starting a new one. I am new to tuning and have been researching my mind numb for the past while on everything. With that said, I have decided that I want to go down the path of a scaled maf tune once I hit my 512g/s limit. Currently, I have a card style maf in a 4" pipe, so I should have room to grow on the hz side of things. What I am currently trying to grasp is the "What now?" after the initial scaling as described in the first few posts. While tuning, will I have to be scaling anything on the fly? Or is it all percentage based so the basic tuning should remain the same? AKA scale once and don't worry about it? Still figuring that part out.
Thanks in advance!
Thanks for the response. It is h/c/i now and will soon have a mild Vortech Si setup. Initially on lower boost, but we know how that goes. I'd say a first it'll be 550-600, so it'll be close. That being said, once turned up, it will likely break he 512 barrier.
Ah, ok so you will want to scale. Once you scale the tune, by say 50% then you would follow the normal tuning process by dialing in AFR error to build either the MAF transfer function or the VE tables. Once the AFR is right, then you can tackle things like spark and idle etc. You shouldn't need to rescale unless you reach another limit because you didn't scale enough the first time.
Thanks! That is great to hear. Would be a big pain to have to scale every tune, would not be worth it. Sounds like it's just initial inputs are scaled, then all else is normal.
Thanks again!
Thanks again!
TECH Fanatic
Joined: Oct 2014
Posts: 1,220
Likes: 179
From: Virginia
Hi all,
Reviving an old thread vs starting a new one. I am new to tuning and have been researching my mind numb for the past while on everything. With that said, I have decided that I want to go down the path of a scaled maf tune once I hit my 512g/s limit. Currently, I have a card style maf in a 4" pipe, so I should have room to grow on the hz side of things. What I am currently trying to grasp is the "What now?" after the initial scaling as described in the first few posts. While tuning, will I have to be scaling anything on the fly? Or is it all percentage based so the basic tuning should remain the same? AKA scale once and don't worry about it? Still figuring that part out.
Thanks in advance!
Reviving an old thread vs starting a new one. I am new to tuning and have been researching my mind numb for the past while on everything. With that said, I have decided that I want to go down the path of a scaled maf tune once I hit my 512g/s limit. Currently, I have a card style maf in a 4" pipe, so I should have room to grow on the hz side of things. What I am currently trying to grasp is the "What now?" after the initial scaling as described in the first few posts. While tuning, will I have to be scaling anything on the fly? Or is it all percentage based so the basic tuning should remain the same? AKA scale once and don't worry about it? Still figuring that part out.
Thanks in advance!
TECH Resident
Joined: Oct 2006
Posts: 993
Likes: 173
From: Euless, TX
Shout out to joecar and Greg Banish for teaching me most of what I know 
WARNING- I take no responsibility for you following this and blowing something up. Use your head, ask questions, and stay conservative and everything should work out.
I've seen a lot of questions over the years and especially lately about HAVING to remove the MAF once you start making a certain amount of hp; either because its a restriction or because it won't/can't read enough airflow. While we can argue whether or not the MAF is a restriction, very few people I see understand how to get around the max limits of the MAF and assume you must remove it. Many people dont realize that they do have options instead of ditching it and going speed density, so this is a tutorial to help others understand the option and what it takes to keep a MAF.
MAF Alternatives
Most are aware of the 85mm truck maf's, but many dont know that there is the option to put an LS7 MAF on their car very easily. The LS7 MAF is a cartridge style and there are a couple companies that make 4 inch tubes that allow the LS7 MAF to bolt on. Also, what I would consider very important is the airflow straightener, aka. the honeycomb. See below photos of the LS7 maf tube and air straightener. With how large the 4" tube is, having a honeycomb to straighten the airflow across the sensor can make a huge improvement in things like idle quality. Several companies also sell an LS7 to LS1 harness adapter so its truely plug and play. One of the photos is courtesy of Carlrx7 from the HP Tuners forum. Saxon makes the honeycombs and Spectre makes the 4" tube among others.
Why do we need to change MAF's???
The factory PCM has 2 hardcoded limits. One is the MAF frequency that is typically something like 12kHz. The other limit is the maximum airflow which is something like 64lb/min of airflow. The following posts will discuss what to actually change in the tune to scale it. As for the MAF frequency, the frequency the MAF sees is based on how much airflow is moving across it. This is because the frequency output is proportional to the amount of cooling that happens as the airflow cools the hot wire inside the MAF. By moving to an LS7 MAF in a larger tube, this allows more airflow per given step in MAF frequency Typically you can get away with the stock MAF with a scaled tune to around 600rwhp. Above that, you may need to move to a larger MAF.
WARNING- I take no responsibility for you following this and blowing something up. Use your head, ask questions, and stay conservative and everything should work out.
I've seen a lot of questions over the years and especially lately about HAVING to remove the MAF once you start making a certain amount of hp; either because its a restriction or because it won't/can't read enough airflow. While we can argue whether or not the MAF is a restriction, very few people I see understand how to get around the max limits of the MAF and assume you must remove it. Many people dont realize that they do have options instead of ditching it and going speed density, so this is a tutorial to help others understand the option and what it takes to keep a MAF.
MAF Alternatives
Most are aware of the 85mm truck maf's, but many dont know that there is the option to put an LS7 MAF on their car very easily. The LS7 MAF is a cartridge style and there are a couple companies that make 4 inch tubes that allow the LS7 MAF to bolt on. Also, what I would consider very important is the airflow straightener, aka. the honeycomb. See below photos of the LS7 maf tube and air straightener. With how large the 4" tube is, having a honeycomb to straighten the airflow across the sensor can make a huge improvement in things like idle quality. Several companies also sell an LS7 to LS1 harness adapter so its truely plug and play. One of the photos is courtesy of Carlrx7 from the HP Tuners forum. Saxon makes the honeycombs and Spectre makes the 4" tube among others.
Why do we need to change MAF's???
The factory PCM has 2 hardcoded limits. One is the MAF frequency that is typically something like 12kHz. The other limit is the maximum airflow which is something like 64lb/min of airflow. The following posts will discuss what to actually change in the tune to scale it. As for the MAF frequency, the frequency the MAF sees is based on how much airflow is moving across it. This is because the frequency output is proportional to the amount of cooling that happens as the airflow cools the hot wire inside the MAF. By moving to an LS7 MAF in a larger tube, this allows more airflow per given step in MAF frequency Typically you can get away with the stock MAF with a scaled tune to around 600rwhp. Above that, you may need to move to a larger MAF.
