Extremely Weird Airmass Dip Under Cruising Steady State

[cmitchell17]

I ordered some fittings and a flex fuel sensor but it looks like it will be a while before I get it. So I completely ran my tank out and filled up completely with 93. I watched the ethanol content PID but it never moved from 18.4% after driving a good almost 30 min. So I got my tech2 and reset the fuel composition, but for whatever reason it reset itself to 3% but the learn status stayed at inactive the whole time even right after you hit the reset for the fuel composition, so it doesn't look like there is a way to force the tech2 to put it in learn mode.

I also tried to siphon some fuel from the tank to put it in a cheap ethanol content tester, which looks like it just measures the specific gravity of it or something like that, but I couldn't get anywhere with that. If I remember correctly from observing the ethanol content PID back before I put the turbo on, I think the 93 octane from the place I usually get my gas at was 0%, which I thought was kind of weird since I thought by law they had to have some content under 10%, but maybe that doesn't apply for 93 octane. I also think I remember it being 0% for 93 as well on my Camaro, which I added a physical flex fuel sensor to.

So its reading about 20-30% lean. I can't think of anything else that would be effecting the fueling or airmass. I still do have the MAF plugged in and the PIDs are reporting the frequency output and airflow output, but its also always in "MAF Failed" state and calc mode is "Normal" so it should be using speed density only. The only thing I could maybe think could be wrong is I don't have the correct IAT sensor calibration. I got one online from someone who said it was correct for that specific IAT sensor, but the output I see on the scanner seems reasonable and is about 10 or so degrees above ambient so it seems right, either way I don't think a temperature error would account for a 30% error from wideband feedback.

I mean I don't think you would expect the volumetric efficiency to change 20-30% just because a turbo is on there now right? and if the turbo would technically decrease VE, then it should read richer and not leaner.

Only other thing I could think of is maybe the barometric pressure is off? It reads 15.1 psi which is obviously not possible anywhere on earth I don't think, but I can't figure out if these trucks had seperate baro sensors? or if maybe it references the brake booster sensor, or maybe it only infers baro pressure at engine off or something? I currently have the baro sensor linear and slope settings from a LS9 since I am using a LS9 MAP sensor. But I changed it back to stock and its still running lean.

[kingtal0n]

As a non-tuning related question, in everyone's putting forced induction on non forced induction engines experience, how much of a boost leak does it take to start to mess things up? I would guess I could determine a leak rate from the compressor map, but then determining the flow rate of a leak (that you can barely find in the first place) is rather difficult.

Boost leaks will rise EGT and IAT, they are death for cast pistons especially. You MUST pressure test the entire plumbing from compressor cover through engine.
I absolutely require a boost pressure test before tuning any engine. I made a video so people can understand how to properly do this critical test.
https://www.youtube.com/watch?v=w1sb5Y1J068

Next, you absolutely need PCV fully intact to control oil quality and enable high mileage / reliability. Without a full PCV system the engine will begin to smoke and leak gradually over time, it will fill the engine baffles full of oil. The mass fraction of aerated oil trying to return to the oil pan at any instant is related to crankcase pressure, thus controlling crankcase pressure & monitoring crankcase pressure, is the key to oil control for the engine crankcase.

We use short as possible lines from crankcase to intake tube, post air filter, like this
All factory turbo cars use this design for PCV action. This is not something I made up; I merely am showing a completely factory system design.
IMG_8276.jpg
reallife.jpg

You can measure crankcase pressure from around the crankcase orifices. This is a oil cap example you can remove when finished measuring/adjusting crankcase pressure.
oil-measure.png

This is showing how the air filter pressure drop is necessary to drive WOT Pcv action. Without an air filter pressure drop there is no WOT pcv action, oil will push out of the engine.
forced induction apps hold the PCV valve closed during boost. So oil will only flow out towards the breathers which is after the baffles.
PCV-oil-blowing-out.png

Pressure lost as a function of friction due to length of tubes, this why we don't use catch cans or long/large PCV lines
pressure_loss_in_opipe.png

The force of crankcase pressure applies to the bottom of pistons, causing ring flutter and oil to bypass rings and work its way into the ring grooves and combustion chamber over time.
dangerous-gasses-showing-piston-ring-gas.png

The factory PCV valve for chevrolet will leak under boost. I recommend using Toyota Supra 1996-1998 Twin Turbo PCV valve inline with Chevrolet pcv valve as I have shown in the video.

[cmitchell17]

Boost leaks will rise EGT and IAT, they are death for cast pistons especially. You MUST pressure test the entire plumbing from compressor cover through engine.
I absolutely require a boost pressure test before tuning any engine. I made a video so people can understand how to properly do this critical test.
https://www.youtube.com/watch?v=w1sb5Y1J068

Next, you absolutely need PCV fully intact to control oil quality and enable high mileage / reliability. Without a full PCV system the engine will begin to smoke and leak gradually over time, it will fill the engine baffles full of oil. The mass fraction of aerated oil trying to return to the oil pan at any instant is related to crankcase pressure, thus controlling crankcase pressure & monitoring crankcase pressure, is the key to oil control for the engine crankcase.

We use short as possible lines from crankcase to intake tube, post air filter, like this
All factory turbo cars use this design for PCV action. This is not something I made up; I merely am showing a completely factory system design.
IMG_8276.jpg
reallife.jpg

You can measure crankcase pressure from around the crankcase orifices. This is a oil cap example you can remove when finished measuring/adjusting crankcase pressure.
oil-measure.png

This is showing how the air filter pressure drop is necessary to drive WOT Pcv action. Without an air filter pressure drop there is no WOT pcv action, oil will push out of the engine.
forced induction apps hold the PCV valve closed during boost. So oil will only flow out towards the breathers which is after the baffles.
PCV-oil-blowing-out.png

Pressure lost as a function of friction due to length of tubes, this why we don't use catch cans or long/large PCV lines
pressure_loss_in_opipe.png

The force of crankcase pressure applies to the bottom of pistons, causing ring flutter and oil to bypass rings and work its way into the ring grooves and combustion chamber over time.
dangerous-gasses-showing-piston-ring-gas.png

The factory PCV valve for chevrolet will leak under boost. I recommend using Toyota Supra 1996-1998 Twin Turbo PCV valve inline with Chevrolet pcv valve as I have shown in the video.

Thanks for the info. I agree with you, I want my PCV system to function as close to stock like as I can get it. I just don't know how OEM's do PCV with forced induction.

So I have pressure tested the system (as well as smoke tested) and I have sealed all leaks.

The driver's side PCV system is 100% stock minus the check valve I added to not let flow from the manifold to the crankcase. The GEN IV engines (as far as I know) do not have traditional PCV valves at all, I didn't even think the GEN III ones had them, I thought only the GEN I's had them? So since I don't have one stock, I added one between the manifold and crankcase on the driver's side so I wouldn't pressurize the crankcase under boost. In factory OEM turbo applications I am not sure what they do since obviously you can't make pressure flow from low to high when the manifold is under boost. On a NA engine I would think there would be enough crankcase pressure to drive flow into the manifold but defiantly not for a boosted engine.

For the "clean" side I just have mine open to atmosphere with a small filter. I would assume though it really needs to be connected before the turbo though? I just can't figure out a way I can do that, maybe besides drilling a hole in my filter on my turbo inlet. Eventually I want to figure out how to feed the turbo from the stock airbox to help cut down on noise and try to incorporate the factory filter and PCV as well.

There is an enormous amount of uninformed information out there about PCV, especially when boost is involved. I guess its may or may not be misinformation, but rather just this is what I did and I have no problems kind of thing.

I am paranoid about my cheap check valve failing and pressurizing the crankcase with boost and messing up seals and gaskets, so I will look into a supra PCV valve.

[kingtal0n]

Thanks for the info. I agree with you, I want my PCV system to function as close to stock like as I can get it. I just don't know how OEM's do PCV with forced induction.

So I have pressure tested the system (as well as smoke tested) and I have sealed all leaks.

The driver's side PCV system is 100% stock minus the check valve I added to not let flow from the manifold to the crankcase. The GEN IV engines (as far as I know) do not have traditional PCV valves at all, I didn't even think the GEN III ones had them, I thought only the GEN I's had them? So since I don't have one stock, I added one between the manifold and crankcase on the driver's side so I wouldn't pressurize the crankcase under boost. In factory OEM turbo applications I am not sure what they do since obviously you can't make pressure flow from low to high when the manifold is under boost. On a NA engine I would think there would be enough crankcase pressure to drive flow into the manifold but defiantly not for a boosted engine.

All engines have PCV valves afaik. You can see the OEM Gen3/4 PCV valve in my video raised out of my valve cover during pressure testing.
Smoke test is not sufficient. You must pressurize beyond boost pressure. Make sure you did this... It is not clear whether or not you have. Some leaks will not show until 5+ Psi of pressure.


The PCV valve prevent boost from entering intake manifold. The PCV has a nozzle inside which regulates flow into manifold during vacuum. PCV valves ARE checkvalves but checkvalves are NOT PCV valves. You cannot interchange a check with a PCV valve. There must be a suitable nozzle inside the pcv valve.

dangerous-gasses-pcv-valve-discussi.png

For the "clean" side I just have mine open to atmosphere with a small filter.

This is what 99% of people will do, and without realizing it this will sabotage your engine in many ways. It is dangerous to leave it like this. There is a pretty heavy list of symptoms this will cause, from oil leaks to engine wear. But lets just focus on the correct way instead.

I would assume though it really needs to be connected before the turbo though? I just can't figure out a way I can do that, maybe besides drilling a hole in my filter on my turbo inlet.

Like the pictures show, between filter and compressor cover. This is how all turbo engines are from the factory. Figure it out, do it right, do it like OEM does. Or suffer consequences. I don't get any money or anything if you do or don't; I'm just here to show you the right way. I won't tune a turbo car unless this is setup properly. I know its super annoying but it must be done. You should also measure the crankcase pressure to be sure there is enough pressure drop, otherwise it won't help no matter how you vent or evacuate the crankcase.

There is an enormous amount of uninformed information out there about PCV, especially when boost is involved. I guess its may or may not be misinformation, but rather just this is what I did and I have no problems kind of thing.

I am paranoid about my cheap check valve failing and pressurizing the crankcase with boost and messing up seals and gaskets, so I will look into a supra PCV valve.

The 'problems' that result from incorrect PCV take time to develop. Its like start smoking. Smoke for a week... nothing happens. Smoke for a few years then see, maybe you get lucky or not. PCV Protects oil... protects the engine internals from debris, carbon conglomerates, byproducts of combustion. Protects oil from dilution. Long-term protection comes from air filter and PCV action.

[kingtal0n]

The way I learned about turbos and tuning turbo engines was by examining the JDM variants,

Heres an sr20det for example, 2002 version
Attachment 118481

Here it is out of the car, an old version 1992 showing OEM PCV equipment on the side exposed so we can inspect it.
Attachment 118482

There is alot we can learn from these engines. The 98-02 model 2.0L engine from the factory will 300rwhp using OEM injectors/turbo.
The Silvia weighs 2800lbs so its basically a 12 second car from the factory that will survive for 250,000 miles or more (it will need an oil pump somewhere between 220k to 280k, or else) but I Digress, the point is examine the PCV system on them. Notice the valve cover AND oil pan are connected together to ensure their pressure signals always match and will not clog. The later model uses a hose at the rear to achieve this but the earlier models tie them together in a more obvious way near the center. The front hose of the valve cover... follow it down and see that it attached to the air filter tract, between filter and compressor cover. This ensures during WOT The crankcase (valve cover + oil pan) will be pulled down to the pressure of the intake tract, which is 0.5" Hg to 1.5"Hg for stock setups usually, using OEM air filters with up to 30,000 miles on the filter. This in turn will drive crankcase pressure down near or below atmospheric pressure, which is the ultimate GOAL of the pcv system for all operating conditions of the engine.
Crankcase pressure must never rise much above atmospheric pressure. Ideally it will be in the range of 0.5"Hg to 1.5"Hg. However I like to see 2.5"Hg to 3"Hg for additional cleaning and oil leak prevention. In other words, for stock setups 1.5"Hg is fine but if you are a performance setup you will drive more boost/power and make more blow-by therefore additional cleaning is warranted so just like anything else in performance world , improve it(You raised the boost, you raised fuel flow, you raised injector size, etc... we must also raise crankcase vacuum. It is just like any other setting you adjust).

Crankcase pressure diagnostics is not well known on forums for some reason, but the good mechanics always have a keen sense for it, I think.
here is an example from someone online, I forgot where but its a good extra reference point of view from somebody else kinda talking about the same issue from a different perspective.
crankcase-Pressure-testing.png

If you are new or feel unsure about how to measure or understand the crankcase pressure signal, Here is a easy way to introduce it,

The pressure measured inside the intake manifold is measured the same exact way we measure crankcase pressure.
That is, you may use a 2-bar map sensor to measure intake pressure/vacuum. And we may use a 2-bar map sensor to measure crankcase pressure.

here is an example of my setup to measure crankcase pressure using $12 Arduino microcontroller and a cheapy ebay $12 2-bar map sensor

P1330906.jpg

Again just think of it as another intake manifold pressure signal. You measure it... then adjust it using orfices/venturi effects/air filter pressure drop/volume adjustments/baffle designs/aftermarket solutions (vacuum pump, electric or mechanical. Or exhaust driven)

In a way its the simplest of things. PCV is supposed to be simple and easy. But I think its so simple people dismiss it quickly without realizing how important it is. If something is so simple it can't be that important, right? And yet... PCV is probably the most important thing on an engine of all. It interfaces with and is the major component of control with respect to oil leaks, oil quality, piston ring function & sealing. Basically the long term health of an engine and it's ability to hold oil inside. I wouldn't waste my time doing all of this if I wasn't absolutely sure you need it.

[cmitchell17]

The way I learned about turbos and tuning turbo engines was by examining the JDM variants,

Heres an sr20det for example, 2002 version
Attachment 118481

Here it is out of the car, an old version 1992 showing OEM PCV equipment on the side exposed so we can inspect it.
Attachment 118482

There is alot we can learn from these engines. The 98-02 model 2.0L engine from the factory will 300rwhp using OEM injectors/turbo.
The Silvia weighs 2800lbs so its basically a 12 second car from the factory that will survive for 250,000 miles or more (it will need an oil pump somewhere between 220k to 280k, or else) but I Digress, the point is examine the PCV system on them. Notice the valve cover AND oil pan are connected together to ensure their pressure signals always match and will not clog. The later model uses a hose at the rear to achieve this but the earlier models tie them together in a more obvious way near the center. The front hose of the valve cover... follow it down and see that it attached to the air filter tract, between filter and compressor cover. This ensures during WOT The crankcase (valve cover + oil pan) will be pulled down to the pressure of the intake tract, which is 0.5" Hg to 1.5"Hg for stock setups usually, using OEM air filters with up to 30,000 miles on the filter. This in turn will drive crankcase pressure down near or below atmospheric pressure, which is the ultimate GOAL of the pcv system for all operating conditions of the engine.
Crankcase pressure must never rise much above atmospheric pressure. Ideally it will be in the range of 0.5"Hg to 1.5"Hg. However I like to see 2.5"Hg to 3"Hg for additional cleaning and oil leak prevention. In other words, for stock setups 1.5"Hg is fine but if you are a performance setup you will drive more boost/power and make more blow-by therefore additional cleaning is warranted so just like anything else in performance world , improve it(You raised the boost, you raised fuel flow, you raised injector size, etc... we must also raise crankcase vacuum. It is just like any other setting you adjust).

Crankcase pressure diagnostics is not well known on forums for some reason, but the good mechanics always have a keen sense for it, I think.
here is an example from someone online, I forgot where but its a good extra reference point of view from somebody else kinda talking about the same issue from a different perspective.
crankcase-Pressure-testing.png

If you are new or feel unsure about how to measure or understand the crankcase pressure signal, Here is a easy way to introduce it,

The pressure measured inside the intake manifold is measured the same exact way we measure crankcase pressure.
That is, you may use a 2-bar map sensor to measure intake pressure/vacuum. And we may use a 2-bar map sensor to measure crankcase pressure.

here is an example of my setup to measure crankcase pressure using $12 Arduino microcontroller and a cheapy ebay $12 2-bar map sensor

P1330906.jpg

Again just think of it as another intake manifold pressure signal. You measure it... then adjust it using orfices/venturi effects/air filter pressure drop/volume adjustments/baffle designs/aftermarket solutions (vacuum pump, electric or mechanical. Or exhaust driven)

In a way its the simplest of things. PCV is supposed to be simple and easy. But I think its so simple people dismiss it quickly without realizing how important it is. If something is so simple it can't be that important, right? And yet... PCV is probably the most important thing on an engine of all. It interfaces with and is the major component of control with respect to oil leaks, oil quality, piston ring function & sealing. Basically the long term health of an engine and it's ability to hold oil inside. I wouldn't waste my time doing all of this if I wasn't absolutely sure you need it.

So I would image that the PCV orifice system I think is built into the valve covers on the GEN IVs, which probably makes sense since they were trying to make emissions components last 100k + miles. So with that said, do you think we need to remove the internal PCV (not even sure if this is possible or not) from the valve cover? since if I add a Supra PCV in the line between the driver's side valve cover and the top of the manifold, it would effectively be like 2 PCV orifices in series?

[kingtal0n]

So I would image that the PCV orifice system I think is built into the valve covers on the GEN IVs, which probably makes sense since they were trying to make emissions components last 100k + miles. So with that said, do you think we need to remove the internal PCV (not even sure if this is possible or not) from the valve cover? since if I add a Supra PCV in the line between the driver's side valve cover and the top of the manifold, it would effectively be like 2 PCV orifices in series?

Thanks for asking. I will always help if you need clarification or specific direction.

The OEM pcv valve in your valve cover likely pulls out without much effort. I would be surprised to find any other way. Most engines use easy to remove pcv valves since they get coked with carbon buildup over time and are very cheap to replace.
You should replace it, but leave one OEM pcv valve installed for simplicity. The supra pcv valve will not fit the OEM valve cover hole. This is why I suggest using it in-line like mine is.
Did you see mine in the video?

The most important thing is getting the pcv valve installed properly, getting everything pressure tested, and getting a proper vent on the intake tube that allows filtered air to enter the crankcase or pull from the crankcase depending on wot or cruise condition.

From there, its up to you how deep you want to go. Do you feel like measuring and adjusting the PCV system pressure and orifices to suit the engine purpose?
If so, you will need to log a 2-bar map sensor on the crankcase as I have shown above, and then drive the vehicle around collecting crankcase data just like wideband data (0-5v analog data logged). Then, once you see the result, go back and adjust the pcv system as needed to improve PCV pressure signal to your desire.


For example, performance engine, measured crankcase pressure with OEM pcv system:
cruise 50mph crankcase pressure is 0.11" Hg
cruise 75mph crankcase pressure 0.05" Hg
Idle crankcase pressure 0.18" Hg
WOT 4500RPM Crankcase pressure 0.02PSI
WOT 60000RPM Crankcase pressure 0.12PSI

Now lets disconnect the PCV system so the engine crankcase is vented to atmosphere:
cruise 50mph crankcase pressure is 0.18PSI
cruise 75mph crankcase pressure 0.25PSI
Idle crankcase pressure 0.10PSI
WOT 4500RPM Crankcase pressure 1.24PSI (500rwhp)
WOT 60000RPM Crankcase pressure 3.42PSI (800rwhp)
This 'vented' setting will cause oil contamination, endangers the engine oil system, and forces oil out of engine seals creating oil leaks over time.
Higher pressure makes it harder for oil to return to crankcase, turbos will smoke like oil is burning, pcv baffles fill with liquid oil. Piston ring function & sealing declines. Piston ring seal is the most essential seal of all, it should be perfect. We should use a vacuum pump to ensure sealing if possible. But vacuum pump is expensive and going overboard for mild wet sump applications like daily driver turbo 800rwhp or 1000rwhp you don't need a vacuum pump with stock wet sump engine.


Next, lets reinstate the OEM Pcv system but we will replace the high flow air filter with a high quality paper air filter:
cruise 50mph crankcase pressure is 0.11" Hg
cruise 75mph crankcase pressure 0.05" Hg
Idle crankcase pressure 0.18" Hg
WOT 4500RPM Crankcase pressure 0.01PSI
WOT 60000RPM Crankcase pressure 0.45" Hg
Note the high quality filter didn't change idle and cruise pcv suction but it did help with WOT suction. Now the engine won't blow oil, leak oil, and it will maintain it's oil quality over high mileage because combustion products are being whipped out of the crankcase as fast as they are forming instead of building up and exposing to the engine oil repeatedly.


Lets bring those idle and cruise values up by installing a second pcv valve in parallel with the first which will double PCV flow rate during idle and cruise. So now we have 2 Supra PCV valves next to each other.
cruise 50mph crankcase pressure is 0.21" Hg
cruise 75mph crankcase pressure 0.15" Hg
Idle crankcase pressure 0.35" Hg
WOT 4500RPM Crankcase pressure 0.01PSI
WOT 60000RPM Crankcase pressure 0.45" Hg

That would be some very clean oil. Still, one last thing to do. Lets put a small restrictor orifice on the crankcase vent tube (the tube between crankcase and turbo intake). This will create a slight depression for idle and cruise without having to increase pcv flow rate any further.
cruise 50mph crankcase pressure is 1.15" Hg
cruise 75mph crankcase pressure 1.75" Hg
Idle crankcase pressure 2.05" Hg
WOT 4500RPM Crankcase pressure 0.01PSI
WOT 60000RPM Crankcase pressure 0.45" Hg
Notice the restrictor didn't affect WOT crankcase pressure. It only ensures the crankcase has a powerful vacuum during idle and cruise. Most factory Turbo engines from Toyota and Nissan feature some kind of restrictor like the one I Just "added" to this engine example. That is where the idea came from, not something I invented. I take no credit for any of this, it is merely an extrapolation of OEM quality PCV apparatus.

[cmitchell17]

Thanks for asking. I will always help if you need clarification or specific direction.

The OEM pcv valve in your valve cover likely pulls out without much effort. I would be surprised to find any other way. Most engines use easy to remove pcv valves since they get coked with carbon buildup over time and are very cheap to replace.
You should replace it, but leave one OEM pcv valve installed for simplicity. The supra pcv valve will not fit the OEM valve cover hole. This is why I suggest using it in-line like mine is.
Did you see mine in the video?

The most important thing is getting the pcv valve installed properly, getting everything pressure tested, and getting a proper vent on the intake tube that allows filtered air to enter the crankcase or pull from the crankcase depending on wot or cruise condition.

From there, its up to you how deep you want to go. Do you feel like measuring and adjusting the PCV system pressure and orifices to suit the engine purpose?
If so, you will need to log a 2-bar map sensor on the crankcase as I have shown above, and then drive the vehicle around collecting crankcase data just like wideband data (0-5v analog data logged). Then, once you see the result, go back and adjust the pcv system as needed to improve PCV pressure signal to your desire.


For example, performance engine, measured crankcase pressure with OEM pcv system:
cruise 50mph crankcase pressure is 0.11" Hg
cruise 75mph crankcase pressure 0.05" Hg
Idle crankcase pressure 0.18" Hg
WOT 4500RPM Crankcase pressure 0.02PSI
WOT 60000RPM Crankcase pressure 0.12PSI

Now lets disconnect the PCV system so the engine crankcase is vented to atmosphere:
cruise 50mph crankcase pressure is 0.18PSI
cruise 75mph crankcase pressure 0.25PSI
Idle crankcase pressure 0.10PSI
WOT 4500RPM Crankcase pressure 1.24PSI
WOT 60000RPM Crankcase pressure 3.42PSI
This 'vented' setting will cause oil contamination, endangers the engine oil system, and forces oil out of engine seals creating oil leaks over time.


Next, lets reinstate the OEM Pcv system but we will replace the high flow air filter with a high quality paper air filter:
cruise 50mph crankcase pressure is 0.11" Hg
cruise 75mph crankcase pressure 0.05" Hg
Idle crankcase pressure 0.18" Hg
WOT 4500RPM Crankcase pressure 0.01PSI
WOT 60000RPM Crankcase pressure 0.45" Hg
Note the high quality filter didn't change idle and cruise pcv suction but it did help with WOT suction. Now the engine won't blow oil, leak oil, and it will maintain it's oil quality over high mileage because combustion products are being whipped out of the crankcase as fast as they are forming instead of building up and exposing to the engine oil repeatedly.


Lets bring those idle and cruise values up by installing a second pcv valve in parallel with the first which will double PCV flow rate during idle and cruise. So now we have 2 Supra PCV valves next to each other.
cruise 50mph crankcase pressure is 0.21" Hg
cruise 75mph crankcase pressure 0.15" Hg
Idle crankcase pressure 0.35" Hg
WOT 4500RPM Crankcase pressure 0.01PSI
WOT 60000RPM Crankcase pressure 0.45" Hg

That would be some very clean oil. Still, one last thing to do. Lets put a small restrictor orifice on the crankcase vent tube (the tube between crankcase and turbo intake). This will create a slight depression for idle and cruise without having to increase pcv flow rate any further.
cruise 50mph crankcase pressure is 1.15" Hg
cruise 75mph crankcase pressure 1.75" Hg
Idle crankcase pressure 2.05" Hg
WOT 4500RPM Crankcase pressure 0.01PSI
WOT 60000RPM Crankcase pressure 0.45" Hg
Notice the restrictor didn't affect WOT crankcase pressure. It only ensures the crankcase has a powerful vacuum during idle and cruise. Most factory Turbo engines from Toyota and Nissan feature some kind of restrictor like the one I Just "added" to this engine example. That is where the idea came from, not something I invented. I take no credit for any of this, it is merely an extrapolation of OEM quality PCV apparatus.

So to answer your question before, I have checked for leaks using smoke test and with a leak down tester regulator and I couldn't detect any leaks and I went to 20 psi. I also did watch your youtube video and see where you have your PCV inlet hose.

I am currently trying to figure out how I can tap into my air filter turbo inlet intake. I have been trying to figure out how I could hook up the stock resonator and stock airbox (because I weirdly like stock stuff, but mainly to try to suppress as much noise as possible). My problem is I can't find any intake tubing to mate up with my compressor inlet and airbox. At least until I can get all that stuff I think I can tap a barb fitting onto the air filter I have (which I doubt really filters any air at all haha).

One thing though, is with a turbo you have to drain your oil return on the turbo to the crankcase, so I wonder how that effects everything? Seems like it would create a vacuum leak pretty bad since its a pretty big hose and I have mine drilled straight into the top of the oil pan? Is there anything we can do about this?

I still think I have airmass scaling/offset/vacuum leak issues, even though I have SD mode working without any errors, I still feel like I am not converging trying to tune the VVE table. It's like I will do a iteration with 20% error, then do another iteration and its still around 20% of error, then I will do that a few more times, then all of the sudden its now -20%.

Even though I have the dynamic airflow enable maxxed out at 8192 rpms, the air calc mode switches from "normal" to "unknown" at around 4000 or so rpms (which is where the stock setting enables).

Even if you moved the MAF pre turbo compressor, so you could meter the air being drawn into the crankcase from the PCV "clean" side, you would then have to figure out how to compensate for the air vented from the BOV, or I guess either recirculate it or maybe just not run a BOV.

Also, about your testing where a stock style air filter (one that actually filters air unlike a "performance" aftermarket one) showing vacuum generated in the crankcase at WOT, I wonder if the OEMs have to deliberately make a airbox/air filter that flows less than it could so they can create a restriction to therefore create the necessary vacuum to provide to the crankcase at WOT?

[Matt_lq4]

It's crazy to read about this happening. I went through this a few years ago and many top names tried to assist but nobody knew truly why the airmass would drop to zero. This is when I was VVE-only tuning a 2009 e38 ecu'd 6.0 with a turbo setup. OS ID 12630501.
This NEVER happened to me on any naturally aspirated e38 setup, only with boost.

I don't recall all the details but I scanned every parameter and observed them during these odd airmass drops.
I forget if it was NicD but I was told to put all the VE coefficients back to stock despite tuning material I read over the years telling me to zero out certain tables that relate to that.

Some said they dealt with similar issues and it was ground related. My customer with this e38 turbo setup said he forgot to tighten/add certain grounds as this was a swapped vehicle with a re-worked harness.

Long story short, he fixed his grounds related to the coils/injector area while I put all VE/VVE related coefficients back to stock, except for the usual coefficients that change when you select "calculate coefficients" when changing VVE table values.
Hard to say which step truly helped but he didn't have the airmass drop anymore for the rest of the summer.

[Matt_lq4]

While you troubleshoot, to avoid getting a surprising 40 degrees of timing at full boost, here's a small trick.
From 3500 rpm to redline, change your ignition timing values at very low airmasses, to something low like 13 degrees of timing. So if you do visit this ridiculous scenario of airmass drop while in boost, you will see 13 degrees of timing rather than 40.

Btw I had 'Speed Density Air Mode' applied from the operating system options, but 'Manifold Vacuum Boost' patch wasn't enabled/applied nor was the TCS patch.
In the Dynamic airflow section, 'High RPM Disable' was set to 8192 rpm, 'High Rpm Re-enable' set to 8191, setup was utilizing a Maf but simply for the iat readings.

Maf table values were left populated the entire time and not zero'd out, so that aspect can be ruled out as I saw 0 airmass at times when the issue was present despite a normal maf table.

[Matt_lq4]

To add a little more, the injector pulse width when this would occur, also dropped to 0.x ms despite being at full throttle the entire time, delivered engine torque went to a negative number during this event also.

I'm looking at the log file now, I'll post a pic below of the various parameters during this event.

Although the air-calc mode says "Hi Speed" during this event, it bounces around between Normal, Hi Speed, and Hi Speed Exit during issue-free steady full throttle boost pulls anyways. So don't get too hung up on the air calc mode.

[kingtal0n]

So to answer your question before, I have checked for leaks using smoke test and with a leak down tester regulator and I couldn't detect any leaks and I went to 20 psi. I also did watch your youtube video and see where you have your PCV inlet hose.

I am currently trying to figure out how I can tap into my air filter turbo inlet intake. I have been trying to figure out how I could hook up the stock resonator and stock airbox (because I weirdly like stock stuff, but mainly to try to suppress as much noise as possible). My problem is I can't find any intake tubing to mate up with my compressor inlet and airbox. At least until I can get all that stuff I think I can tap a barb fitting onto the air filter I have (which I doubt really filters any air at all haha).

For now you can vent the crankcase while you sort the details of tuning. It won't kill the engine to leave it vented for a short time. The main thing is learn, be aware of PCV system performance and the necessity of it for long term. If you start boosting the engine every day without the pcv hooked up properly it will develop issues. So tackle it, but at your own pace. You can kind of leave it for last if you want, finish tuning first and worry about pcv once the vehicle starts to see mileage and boost all the time.

One thing though, is with a turbo you have to drain your oil return on the turbo to the crankcase, so I wonder how that effects everything? Seems like it would create a vacuum leak pretty bad since its a pretty big hose and I have mine drilled straight into the top of the oil pan? Is there anything we can do about this?

I'm not sure what you mean. The more crankcase pressure in psi, the harder it is for turbo to drain oil, the more oil will backup in the lines. Having a low crankcase pressure, a vacuum in the crankcase, will help drain the turbo and prevent oil leaks and turbo smoking. This is one of the key points to knowledge of PCV systems- see how it positively impacts every device related to oil and the very oil quality? Super important to understand pcv or things like turbos start to smoke and have difficulty draining, they can also push oil into the turbine causing exhaust to smoke like oil. Control crankcase pressure = control oil leaking and oil blowing out behaviors.

I still think I have airmass scaling/offset/vacuum leak issues, even though I have SD mode working without any errors, I still feel like I am not converging trying to tune the VVE table. It's like I will do a iteration with 20% error, then do another iteration and its still around 20% of error, then I will do that a few more times, then all of the sudden its now -20%.

Even though I have the dynamic airflow enable maxxed out at 8192 rpms, the air calc mode switches from "normal" to "unknown" at around 4000 or so rpms (which is where the stock setting enables).

Even if you moved the MAF pre turbo compressor, so you could meter the air being drawn into the crankcase from the PCV "clean" side, you would then have to figure out how to compensate for the air vented from the BOV, or I guess either recirculate it or maybe just not run a BOV.

Factory turbo cars use a pre-compressor maf sensor. This is the most reliable way of using a maf sensor on a turbo vehicle. The PCV flow of the entire crankcase system is negligible to the maf so it does not need to be accounted for. The same way brake booster supplies un-metered air when you stab the brake pedal- it is insignificant to the overall airflow rate and doesn't need to be measured by the maf, as you tune the engine the airflow difference is integrated with the tune.

We like to eliminate the maf whenever possible, when using a turbo. The maf sensor is very sensitive and must be installed perfectly or it will read 'noise' data noisy from the turbos whipping-actions, vorticity, turbulence, and compressor surge, will impact maf sensor readings. The only way to use a maf successfully on a turbo setup that I have found is to copy the OEM layout:
1. As much straight pipe on both sides of the maf, with the same diameter tube as the maf, to prevent turbulence and perturbations
2. Far enough from the compressor to avoid disturbances caused by the wheel behaviors
3. You must control compressor surge and simultaneously provide a pathway for recirculated airflow , away from the maf

Here is a recirc I setup recently
20210622_184445.jpg

-> See the bypass valve feed the air filter intake tract. The bypass shall hang open at idle. This is how stock Turbo engines are setup for max response.
By leaving the bypass open at idle the compressor wheel can speed up dramatically in a positive feedback loop where kinetic energy is being conserved.
Anytime you release air from the bypass into the atmosphere you are losing / trashing all of the kinetic energy provided by the turbo.
Turbos do not create pressure, they invest kinetic energy to air molecules, that kinetic energy is converted to pressure when the air molecules encounter the restriction of the engine's flow rate.
Thus, conserving kinetic energy is at the top of your "things to do" list when it comes to turbocharging for a superior response from the turbo.
We do this many ways, here are some random I think up atm
A. Use the right size intercooler. Intercoolers add friction which reduces kinetic energy of the flow, so using 'too large' an intercooler is throwing away energy
B. Use smooth curves, no tight 90's bends, and don't change the size of the plumbing suddenly
C. Pressure test ensures no air molecules leak out with their kinetic energy
D. Recirculate the bypass to the intake tract so the kinetic energy can be conserved somewhat
E. Insulate the exhaust heavily, blankets, foils, wraps, coatings, everything you can stand to trap the energy inside

It isn't necessary to recirculate the bypass, however you may find it difficult or impossible to use a maf sensor without re-circulation. And also you will never find optimal response from a turbo without a recirculated bypass. Smaller turbos tend to move higher wheel speeds near idle so it has a greater influence on small turbos than large units.

Also, about your testing where a stock style air filter (one that actually filters air unlike a "performance" aftermarket one) showing vacuum generated in the crankcase at WOT, I wonder if the OEMs have to deliberately make a airbox/air filter that flows less than it could so they can create a restriction to therefore create the necessary vacuum to provide to the crankcase at WOT?

Yes of course this is exactly how OEM designs the filter and intake system.
Almost all OEM vehicles can gain 5% HP or whatever when you install a high performance air filter by removing that small pressure drop provided by original filter.
Whether Corolla or Corvette; there is a measured, anticipated pressure drop based on vehicle application (corvette filters tend to flow a bit more as they age I would imagine). The OEM must ensure that the WOT pcv pressure drop will provide oil cleaning benefits due to air filter pressure drop as the filter ages, especially without being changed. The air filter pressure drop INCREASES with mileage, as the filter gets more filthy. These parameters are specified by the OEM, like this
pressure-drop-curve.png

If somebody buys the car, then fails to change the air filter, what did the engineer plan for that situation? If the air filter isn't being changed, there is a good chance the oil isn't being maintained either. So the engine is in dire need of extra cleaning and extra oil maintenance. Thus, the pressure drop of the filter increasing over time = more oil quality maintenance, the engine is trying to clean itself more and more as the filter becomes more and more filthy, trying to preserve whatever quality is left of the oil. Thus, more mal-maintenance = stronger self cleaning for the OEM air intake tract.

[kingtal0n]

Also, about your testing where a stock style air filter (one that actually filters air unlike a "performance" aftermarket one) showing vacuum generated in the crankcase at WOT, I wonder if the OEMs have to deliberately make a airbox/air filter that flows less than it could so they can create a restriction to therefore create the necessary vacuum to provide to the crankcase at WOT?

Its a secret to everybody

1. Buy a 'new vehicle' and install an aftermarket high flow air filter or remove air filter
2. Drive for 10k to 50k miles (depends on many factors)
3. Find oil all up inside the intake manifold and complain about the 'poor quality' OEM pcv system and baffle design


et al;
The original filter setup pulls the crankcase pressure down at WOT which keeps baffles clear from oil and keeps the PCV valve from flowing heavily into the intake manifold.
Remember that PCV valves are not just check valves, they have a nozzle inside which can "open" to allow blow-by into the intake manifold when crankcase pressure is high (On Natural aspirated setups this is the primary concern for oil flow to intake manifold).


Picture of restrictor:
In post #67 I mentioned a restrictor that the OEM often uses on turbo engines to improve PCV pressure signal at idle and cruise, here is a picture of that restrictor often as found in 2.0L/2.5L/2.6L turbo engines,
this is the OEM restrictor pictured
rb25airinlet-704292f6.jpg

[cmitchell17]

While you troubleshoot, to avoid getting a surprising 40 degrees of timing at full boost, here's a small trick.
From 3500 rpm to redline, change your ignition timing values at very low airmasses, to something low like 13 degrees of timing. So if you do visit this ridiculous scenario of airmass drop while in boost, you will see 13 degrees of timing rather than 40.

Btw I had 'Speed Density Air Mode' applied from the operating system options, but 'Manifold Vacuum Boost' patch wasn't enabled/applied nor was the TCS patch.
In the Dynamic airflow section, 'High RPM Disable' was set to 8192 rpm, 'High Rpm Re-enable' set to 8191, setup was utilizing a Maf but simply for the iat readings.

Maf table values were left populated the entire time and not zero'd out, so that aspect can be ruled out as I saw 0 airmass at times when the issue was present despite a normal maf table.

So I have yet to have any issues at all and its been 2 or 3 weeks after I fully calibrated my MAF (and tuned it after accounting for the PCV "leak"), full flashed once after applying all 3 SD patches available on my OS, and leaving the MAF plugged in and functionally reporting its Hz value back to the ECM (minus the IAT sensor wires which I still have broken out of the MAF and ran into a separate IAT sensor).

I guess as long as the ECM sees a valid and plausible MAF signal, you can have the dynamic airflow disabled with the MAF DTCs set to fail instantly and it stays happy.

Now what I don't know is if maybe the MAF could be secretly providing airmass calculation input, which would of course throw me off trying to dial in VVE since my PCV flow goes around the MAF.

I am also running a LS7 style MAF, not the stock L92/L9H truck style GEN IV MAF.

[cmitchell17]

Its a secret to everybody

1. Buy a 'new vehicle' and install an aftermarket high flow air filter or remove air filter
2. Drive for 10k to 50k miles (depends on many factors)
3. Find oil all up inside the intake manifold and complain about the 'poor quality' OEM pcv system and baffle design


et al;
The original filter setup pulls the crankcase pressure down at WOT which keeps baffles clear from oil and keeps the PCV valve from flowing heavily into the intake manifold.
Remember that PCV valves are not just check valves, they have a nozzle inside which can "open" to allow blow-by into the intake manifold when crankcase pressure is high (On Natural aspirated setups this is the primary concern for oil flow to intake manifold).


Picture of restrictor:
In post #67 I mentioned a restrictor that the OEM often uses on turbo engines to improve PCV pressure signal at idle and cruise, here is a picture of that restrictor often as found in 2.0L/2.5L/2.6L turbo engines,
this is the OEM restrictor pictured
rb25airinlet-704292f6.jpg

Thanks for the info Kingtalon.

Also what I mean by the turbo oil drain thing was that it would seem that maybe atmospheric air could get into the crankcase from the oil drain hole or line or somewhere in the turbo. In theory though I guess the oil should be sealed, or maybe even under slight pressure from the oil pressure feed from the engine.

I do intend to fix my PCV (I just got my Supra PCV valve in today) and also try to integrate my stock airbox back in. I just can't get anywhere looking for the tubing and couplers I need. I just can't figure out a way to connect anything with the odd sizes of my turbo inlet.

[kingtal0n]

Thanks for the info Kingtalon.

Also what I mean by the turbo oil drain thing was that it would seem that maybe atmospheric air could get into the crankcase from the oil drain hole or line or somewhere in the turbo. In theory though I guess the oil should be sealed, or maybe even under slight pressure from the oil pressure feed from the engine.

I do intend to fix my PCV (I just got my Supra PCV valve in today) and also try to integrate my stock airbox back in. I just can't get anywhere looking for the tubing and couplers I need. I just can't figure out a way to connect anything with the odd sizes of my turbo inlet.

Air from the compressor side is always mixing into the engine crankcase through the oil seal of turbo. I'm surprised you thought of that... it is very true according to Borg Warner engineers who I have had such discussions with.

Same with exhaust I would imagine. Those turbo shaft seals are not perfect and this is why engineers from Borg Warner warned not to spray water into the turbo. And also why you need very clean oil and very clean air circulating around... a little mixing is fine when its all pure and able to achieve a gas state. Gaseous water does not worry me so much when its pure and able to reach high temperature to maintain a gas state (210*F~ of engine oil is sufficient)
An issue occurs when say water or carbon fragments interact with stationary conglomerates, deposits if you will, which are able to collect more and more as time goes on, and sometimes a piece breaks off, a massive chunk (it might be invisible to the eye at 50uM but its 'huge' to an oil system) and floats on down the 'river' (of oil) causing downstream atherosclerosis (a blockage in the oil system). These type of deposits occur because of poor filtration and/or poor PCV system performance, and sometimes due to poor oil 'washing' (there are some places inside an engine where oil tends to collect or is difficult to reach over long periods which facilitates deposit forming or stagnation). Oil becomes chewed up over time which literally means the fragments of carbon may become kinked, bent, damaged, unrecognizable, and that can also lead to hydrocarbon deposit formation and oil flow blockages.

Water is one of the primary components of combustion, entering the crankcase because fire creates water and CO2 when it is burnt in perfection ratios (Which never happens, the ratio can't be 'perfect').
CO2 although inert undergoes its own slew of potential side participation in the presence of water such as helping to form carbonic acid which may attack engine materials.
Modern oil is designed to 'carry and contain' all sorts of potentially dangerous materials, ranging from water to pollen to metal I'm sure... however it should be considered a 'final barrier' and not the primary means of protection. Alot of people think they can just 'change the oil back to clean' but in reality a small fraction of oil contents can never be removed and is pumped all over the engine and deposited often permanently, where more collects over time. One PCV objective is to remove potential oil contaminants before they can interact with engine oil, which improves oil life and reduces the engine deposits and engine wear associated with filthy oil. If you are familiar with reverse osmosis systems, PCV is acting like a pre-filter system for the reverse osmosis filter in an RO water system... the RO filter is an incredible filter but it can't handle the bulk of materials found in regular water. You have to pre-filter out the majority of garbage and feed the RO filter a mostly clean water input. Likewise engine oil should be fed a mostly clean combination of blow-by gas which contains mostly hot water, CO2, and a minimal mass of partially combusted hydrocarbon fragments. This is how you get 200k 300k 400k etc... high mileage

[cmitchell17]

Air from the compressor side is always mixing into the engine crankcase through the oil seal of turbo. I'm surprised you thought of that... it is very true according to Borg Warner engineers who I have had such discussions with.

Same with exhaust I would imagine. Those turbo shaft seals are not perfect and this is why engineers from Borg Warner warned not to spray water into the turbo. And also why you need very clean oil and very clean air circulating around... a little mixing is fine when its all pure and able to achieve a gas state. Gaseous water does not worry me so much when its pure and able to reach high temperature to maintain a gas state (210*F~ of engine oil is sufficient)
An issue occurs when say water or carbon fragments interact with stationary conglomerates, deposits if you will, which are able to collect more and more as time goes on, and sometimes a piece breaks off, a massive chunk (it might be invisible to the eye at 50uM but its 'huge' to an oil system) and floats on down the 'river' (of oil) causing downstream atherosclerosis (a blockage in the oil system). These type of deposits occur because of poor filtration and/or poor PCV system performance, and sometimes due to poor oil 'washing' (there are some places inside an engine where oil tends to collect or is difficult to reach over long periods which facilitates deposit forming or stagnation). Oil becomes chewed up over time which literally means the fragments of carbon may become kinked, bent, damaged, unrecognizable, and that can also lead to hydrocarbon deposit formation and oil flow blockages.

Water is one of the primary components of combustion, entering the crankcase because fire creates water and CO2 when it is burnt in perfection ratios (Which never happens, the ratio can't be 'perfect').
CO2 although inert undergoes its own slew of potential side participation in the presence of water such as helping to form carbonic acid which may attack engine materials.
Modern oil is designed to 'carry and contain' all sorts of potentially dangerous materials, ranging from water to pollen to metal I'm sure... however it should be considered a 'final barrier' and not the primary means of protection. Alot of people think they can just 'change the oil back to clean' but in reality a small fraction of oil contents can never be removed and is pumped all over the engine and deposited often permanently, where more collects over time. One PCV objective is to remove potential oil contaminants before they can interact with engine oil, which improves oil life and reduces the engine deposits and engine wear associated with filthy oil. If you are familiar with reverse osmosis systems, PCV is acting like a pre-filter system for the reverse osmosis filter in an RO water system... the RO filter is an incredible filter but it can't handle the bulk of materials found in regular water. You have to pre-filter out the majority of garbage and feed the RO filter a mostly clean water input. Likewise engine oil should be fed a mostly clean combination of blow-by gas which contains mostly hot water, CO2, and a minimal mass of partially combusted hydrocarbon fragments. This is how you get 200k 300k 400k etc... high mileage

Thanks... very interesting info.

One last thing, I know you said the PCV flow was pretty small compared to the overall MAF error. I know you said the MAF should prefereably be in the stock like location pre compressor, but is the PCV flow small enough to not worry about achieving airmass accuracy, especially at WOT (ensuring consistent and accurate AFR for cooling and power) if the MAF is just before the throttle body?

[kingtal0n]

Thanks... very interesting info.

One last thing, I know you said the PCV flow was pretty small compared to the overall MAF error. I know you said the MAF should prefereably be in the stock like location pre compressor, but is the PCV flow small enough to not worry about achieving airmass accuracy, especially at WOT (ensuring consistent and accurate AFR for cooling and power) if the MAF is just before the throttle body?

PCV flow depends on engine build. Loose rings, big piston wall clearance, needs a larger PCV flow.
Additionally, targeting more vacuum inside crankcase = additional PCV flow needed.

So lets call the total mass of air from PCV flow as the variable X.
Stock engine has X = 1
Loose engine has X = 1.5 to 2.5
Stock engine with PCV flow increase could be 1.5X I suppose, targeting deeper vacuum

In any case, PCV flow is negligible because

1. When you tune the engine, X is integrated with the tune. X will never change. Its tuned around just like PCV flow is in a carburetor idle adjustment.
2. Overall PCV flow mass rate is insignificant compared to total engine flow rate at WOT


The only time PCV flow can significantly offset the tune's a/f ratio is if you suddenly change the PCV setup while using a MAF, it doesn't matter where the maf is though.
For example if you tuned a carb engine then decide to hook up the pcv flow, now suddenly the idle is too high and lean because of all the extra air. The same thing happens to EFI, air will increase but that raise the idle causing IACV to close and map should wind up in the same place as it was previously- correcting the idle and all is well except now the IACV is open too far because it looks at PCV Like a vacuum leak. With a maf however the air is bypassing the maf as it enters the intake manifold causing a lack of compensating fuel. Vacuum leaks are treated just like PCV from maf perspective. A vacuum leak which is consistent is tuned around but one that suddenly appears is going to swing A/F ratio just like when you pump the brakes at a stop light, it will go lean because brakes pump unmetered air into the engine unexpectedly. Notice its not a problem or issue to have this air swing the a/f ratio at idle - for any engine, they all have brakes they all go lean momentarily. Its not a concern.

[cmitchell17]

PCV flow depends on engine build. Loose rings, big piston wall clearance, needs a larger PCV flow.
Additionally, targeting more vacuum inside crankcase = additional PCV flow needed.

So lets call the total mass of air from PCV flow as the variable X.
Stock engine has X = 1
Loose engine has X = 1.5 to 2.5
Stock engine with PCV flow increase could be 1.5X I suppose, targeting deeper vacuum

In any case, PCV flow is negligible because

1. When you tune the engine, X is integrated with the tune. X will never change. Its tuned around just like PCV flow is in a carburetor idle adjustment.
2. Overall PCV flow mass rate is insignificant compared to total engine flow rate at WOT


The only time PCV flow can significantly offset the tune's a/f ratio is if you suddenly change the PCV setup while using a MAF, it doesn't matter where the maf is though.
For example if you tuned a carb engine then decide to hook up the pcv flow, now suddenly the idle is too high and lean because of all the extra air. The same thing happens to EFI, air will increase but that raise the idle causing IACV to close and map should wind up in the same place as it was previously- correcting the idle and all is well except now the IACV is open too far because it looks at PCV Like a vacuum leak. With a maf however the air is bypassing the maf as it enters the intake manifold causing a lack of compensating fuel. Vacuum leaks are treated just like PCV from maf perspective. A vacuum leak which is consistent is tuned around but one that suddenly appears is going to swing A/F ratio just like when you pump the brakes at a stop light, it will go lean because brakes pump unmetered air into the engine unexpectedly. Notice its not a problem or issue to have this air swing the a/f ratio at idle - for any engine, they all have brakes they all go lean momentarily. Its not a concern.

Yeah I think I may just need to start accepting my error.

I just tried pasting the stock VVE table back in (still running SD) (under 100 kPa), and tried it and it immediately went way lean by almost 40-50% and the histogram was showing 15-30% lean. It makes no sense because if anything you would think for a completely stock engine with just a turbo, intercooler, and piping added, it, if anything, would be rich with the stock VVE table because of the extra restriction of the turbo compressor and intercooler and piping causing less actual VE.

My understanding is that you need to be within about +/10% and I guess maybe +/-5% would be "good" and "tuned".

The problem is when I tuned my MAF, I unhooked my PCV hose from the manifold and plugged the hole in the manifold, so that would mean the PCV vacuum leak is no longer built in an accounted for in the MAF calibration.

I guess at this point I might just go back to running MAF if the PCV flow won't be significant enough. I guess I will still have to account for the BOV air getting dumped and creating a rich condition.

[cmitchell17]

So I figured VVE is as good as I am willing to get it, tuning it from both the wideband and narrowbands. Looks like I may just need to live with the errors and weirdness. Although I really worry for the clutches in my transmission haha. It seems like the airmass will be artificially high and ill get too hard of shifts (better than too soft), but then now I am randomly getting too soft (not meeting shift times/too slow) shifts. Hopefully I haven't damaged my clutches as I think they are pretty sensitive and it only takes a few times of slipping them a little bit and they start to fail.

I am still getting what appears to be way to high of airmass right before boost, which is way higher airmass when at was stock NA at the same load I would get around .65, now its almost .9:
Capture.JPG

Also you would think boost and airmass would be at least somewhat proportional to each other, but somewhere past this point where the marker is at on the tune file, there is an inflection point it hits and airmass starts to climb way higher than it seems it should:
Capture2.JPG

White Truck Turbo ECM TCM FICM.hpt

White Truck Turbo Log 10 Tuned VVE Again then Turned MAF Back On.hpl