Determining an intake restriction on a boosted setup from logs
10-08-2019, 09:32 AM
#21
TECH Fanatic
only way i could figure they would know without more sensors or seeing it in person would be if they are VERY familiar with the platform and know that a specific combo 'should' perform a certain way. Theres a few guys in the evo world i bet could identify something similar to what you are describing.
I cannot say with confidence anything bad about the guys you are referring to here, since I understand Evo's about as well as I understand women, which is in the zero to absolute zero range on the kelvin scale.
However, I can say my knowledge on GM is pretty solid. As far as what you see in the scanner for airmass, this number essentially comes from ONE place; the injectors. Regardless of which airmass model you use to predict airmass, MAF or VE, the injector values decide what those numbers will be. Let's say you have a VE of 50 on a cell, with 40# injectors, and perfect AFR. That SAME cell would end up being closer to 100 if you plugged in data for 80# injectors and made no other changes. Doesn't always directly translate to this due to other calculations, but the injector values are directly linked to their calculations. You are basically telling the PCM to dump twice the fuel in the same amount of airmass, and naturally it will raise all of the numbers on your VE and MAF tables when tuned.
So, now, regardless of engine setup, VE is going to differ engine to engine, and actual values from injectors will too. With all real world factors added in, there's no freaking way you can just look at a log, review a tune, and determine with any real certainty that there is an airflow restriction somewhere in the intake. Because again, the values are coming from injectors, and the settings vary engine to engine. When we scale a tune, we start with the injector data, and go from there reducing all other air tables by that percent.
I don't think they can do it. I don't think it's possible without looking at other factors with other sensors not normally present on a stock sensor array, unless it's saying like 5 g/s at idle with 80# data in there. Then yeah, MAYBE. Cause normally it's going to be like 15 g/s. But again, this number is decided by the VE and MAF (if used) calcs, and the injector data. Could also just be a small cam too, or low compression ratio, or both. See? Too much other stuff to accurately determine if your dynamic airflow value is wrong, or not, since this number, like all of the airflow numbers, is completely adjustable.
10-08-2019, 02:22 PM
#22
I cannot say with confidence anything bad about the guys you are referring to here, since I understand Evo's about as well as I understand women, which is in the zero to absolute zero range on the kelvin scale.
However, I can say my knowledge on GM is pretty solid. As far as what you see in the scanner for airmass, this number essentially comes from ONE place; the injectors. Regardless of which airmass model you use to predict airmass, MAF or VE, the injector values decide what those numbers will be. Let's say you have a VE of 50 on a cell, with 40# injectors, and perfect AFR. That SAME cell would end up being closer to 100 if you plugged in data for 80# injectors and made no other changes. Doesn't always directly translate to this due to other calculations, but the injector values are directly linked to their calculations. You are basically telling the PCM to dump twice the fuel in the same amount of airmass, and naturally it will raise all of the numbers on your VE and MAF tables when tuned.
So, now, regardless of engine setup, VE is going to differ engine to engine, and actual values from injectors will too. With all real world factors added in, there's no freaking way you can just look at a log, review a tune, and determine with any real certainty that there is an airflow restriction somewhere in the intake. Because again, the values are coming from injectors, and the settings vary engine to engine. When we scale a tune, we start with the injector data, and go from there reducing all other air tables by that percent.
I don't think they can do it. I don't think it's possible without looking at other factors with other sensors not normally present on a stock sensor array, unless it's saying like 5 g/s at idle with 80# data in there. Then yeah, MAYBE. Cause normally it's going to be like 15 g/s. But again, this number is decided by the VE and MAF (if used) calcs, and the injector data. Could also just be a small cam too, or low compression ratio, or both. See? Too much other stuff to accurately determine if your dynamic airflow value is wrong, or not, since this number, like all of the airflow numbers, is completely adjustable.
However, I can say my knowledge on GM is pretty solid. As far as what you see in the scanner for airmass, this number essentially comes from ONE place; the injectors. Regardless of which airmass model you use to predict airmass, MAF or VE, the injector values decide what those numbers will be. Let's say you have a VE of 50 on a cell, with 40# injectors, and perfect AFR. That SAME cell would end up being closer to 100 if you plugged in data for 80# injectors and made no other changes. Doesn't always directly translate to this due to other calculations, but the injector values are directly linked to their calculations. You are basically telling the PCM to dump twice the fuel in the same amount of airmass, and naturally it will raise all of the numbers on your VE and MAF tables when tuned.
So, now, regardless of engine setup, VE is going to differ engine to engine, and actual values from injectors will too. With all real world factors added in, there's no freaking way you can just look at a log, review a tune, and determine with any real certainty that there is an airflow restriction somewhere in the intake. Because again, the values are coming from injectors, and the settings vary engine to engine. When we scale a tune, we start with the injector data, and go from there reducing all other air tables by that percent.
I don't think they can do it. I don't think it's possible without looking at other factors with other sensors not normally present on a stock sensor array, unless it's saying like 5 g/s at idle with 80# data in there. Then yeah, MAYBE. Cause normally it's going to be like 15 g/s. But again, this number is decided by the VE and MAF (if used) calcs, and the injector data. Could also just be a small cam too, or low compression ratio, or both. See? Too much other stuff to accurately determine if your dynamic airflow value is wrong, or not, since this number, like all of the airflow numbers, is completely adjustable.
Does anyone watch the walking dead? I read this in my head in Eugene's voice. lol
Anyways, This thread got me thinking about upping the size on my air filter tube and air filter......
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ChopperDoc (10-08-2019)
10-08-2019, 02:44 PM
#23
TECH Fanatic
Spent most of my time flying around, occasionally getting shot at on the more memorable missions. Good times. My voice is definitely boring compared to that guy though.
Oh, and the more air the better. Air is power, so... There's that.
10-08-2019, 02:56 PM
#24
Lol. I had to look that up... I kind of wish I talked like him, to some degree, other than the coward stuff. Can't say that about myself lol. Too many combat tours to the point I don't even care or bother to get up unless the mortars literally start landing next to me. Which has happened. In the place I am now they just send a text when rockets are inbound. No *****. If it's my time it's my time.
Spent most of my time flying around, occasionally getting shot at on the more memorable missions. Good times. My voice is definitely boring compared to that guy though.
Oh, and the more air the better. Air is power, so... There's that.
Spent most of my time flying around, occasionally getting shot at on the more memorable missions. Good times. My voice is definitely boring compared to that guy though.
Oh, and the more air the better. Air is power, so... There's that.
I have a 4" silicon 90 off the turbo.....then about a 10" long 4" aluminum tube with a small crook in it then a long filter at the end. I was thinking 4.5" or 5" tube, filter and machine a transition ring on the turbo flange for the silicon elbow to mount to.
04-15-2020, 05:05 PM
#25
Teching In
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LSA Swap- Boost Signal How was the boost signal communicated in the original CTSV, vacuum or CAN serial messaging?
Which harness port connection provides the boost signal on a 2009 LSA?
Can the same boost connection point be captured with an aftermarket, OBD II digital gauge if we are using the OEM ECM on this LSA swap?
Assumptions:
2009 CTSV LSA/6L90
OEM ECM
PSI engine harness
Dakota Digital OBDII digital boost gauge