Twin Turbo '20 GT Dying

[JamesTheriot]

fmem unknown.hpl

JAMES GEN3 038. 85% blend.hpt

Here is the scary looking log from this morning. 70% DI. It leans out bad and I didnt have a passenger to watch it and yell at me but I have no timing in the engine so it doesnt worry me too bad for short pulls.

Few things, why does it take so long to get to WOT lambda sometimes and sometimes it goes right away?

When it is not in WOT lambda the fuel source says OL FMEM.

In the tune Engine>Torque Model>Monitoring>IPC FMEM Cfg 0 and IPC FMEM Cfg 1 Does anyone know what those 31 tables correspond to? Can I turn off certain limiters there?

Why doesnt my alternator voltage increase as much as I ask it to?

[veeefour]

your maf transfer is like 30% to low on upper band, you need to completely rescale the curve

[veeefour]

Attachment 110546

[JamesTheriot]

JAMES GEN3 039. MAF curve update.hpt

Here is how I changed the maf curve. Thanks for letting me know, This is my first time really tuning a high power MAF system. Since the fuel trims were zero I thought I was missing something else.

[JamesTheriot]

Latest issue. The better I get the car running the more I think I al experiencing boost creep.

Heres my latest log which maxes out the MAF again because the car hits 15PSI. Not sure what I will do to combat this issue.

Could I use my cam phasers at high rpm to bleed boost some way? I have a full exhaust system on the car with pypes straight through mufflers. I was reading that I may need to add a restiction to the exhaust or buy bigger wastegates.

26%maf.hpl

[JamesTheriot]

Upon looking more closely I dont believe its boost creep. Air Load is still at 1.84. I must have messed up some setting that caused the Inferred MAP to be incorrect thus the boost pressure reads too high.

[veeefour]

why do you test is on 15 psi lol?

At 15 psi your load should be way over 2...

[murfie]

Aircharge multiplier and maximum load tables in SD need to be populated to allow the demanded torque to go up with load. This should help the engine torque limit.
You will also want to populate the MAP delta table, just leave the lower RPMs, 3000 and under, at 0. This allows the TB model to not freak out about the airflow going through it, because it allows it to not be at barometric pressure.
Load goes up .8, and you only see a 100lbft increase in torque, thats a limit. The increase should be three times that.

Demand and torque limit.PNG

At 15 PSI of boost, 2 bar, you shouldn't be over 2.0 load. Unless you have something lacking in the fuel system. 1 load is standard atmosphere conditions in the combustion chamber, so 2 is double that. You have to account for volumetric efficiency and the fact that your air charge temperature is a bit higher than STD parameters. so 1.8-1.9 load for 15 psi is great.

You are also reaching 13,000hz MAF frequency. There is no limit to a digital MAF in theory, and you could just keep going up, but you are asking a lot of the controller and sensor at this high frequency. Most OEMs shoot for 10k, and don't even populate above 12.5K. This can be fixed with the size of the pipe it lives in.

[JamesTheriot]

Aircharge multiplier and maximum load tables in SD need to be populated to allow the demanded torque to go up with load. This should help the engine torque limit.
You will also want to populate the MAP delta table, just leave the lower RPMs, 3000 and under, at 0. This allows the TB model to not freak out about the airflow going through it, because it allows it to not be at barometric pressure.
Load goes up .8, and you only see a 100lbft increase in torque, thats a limit. The increase should be three times that.

Demand and torque limit.PNG

At 15 PSI of boost, 2 bar, you shouldn't be over 2.0 load. Unless you have something lacking in the fuel system. 1 load is standard atmosphere conditions in the combustion chamber, so 2 is double that. You have to account for volumetric efficiency and the fact that your air charge temperature is a bit higher than STD parameters. so 1.8-1.9 load for 15 psi is great.

You are also reaching 13,000hz MAF frequency. There is no limit to a digital MAF in theory, and you could just keep going up, but you are asking a lot of the controller and sensor at this high frequency. Most OEMs shoot for 10k, and don't even populate above 12.5K. This can be fixed with the size of the pipe it lives in.

My problem with the 15 psi is that I am still on straight wastegates with no boost controller. Boost should be around 10psi. Is there a parameter I could have inputted incorrectly that is making the boost read wrong?

[murfie]

The manifold air pressure is calculated from what the MAF sensor is saying the air mass is getting into the combustion chamber.

When you increase the MAF values of the transfer are you seeing the fuel trims respond appropriately? You could just be increasing the numbers, but not actually getting the fuel that should be there.

You need to look at both port injector pulse width and direct injector pulse to make sure you are not asking too much of one or the other.

here's a math that you need DI start of injection angle(intake), DI injector effective pulse width int., and RPM PIDs. With it you can see if you are out of time on the DI and need to blend more toward the PI. The number will get closer to the spark advance value with longer effective pulse width.

If you add injector pulse width, you should be able to use the predefined duty cycle PID.

EOI -.MathParameter.xml

tools> maths> choose a blank one> open math parameter by clicking on folder icon. select this XML from where you downloaded it.

[JamesTheriot]

The manifold air pressure is calculated from what the MAF sensor is saying the air mass is getting into the combustion chamber.

When you increase the MAF values of the transfer are you seeing the fuel trims respond appropriately? You could just be increasing the numbers, but not actually getting the fuel that should be there.

You need to look at both port injector pulse width and direct injector pulse to make sure you are not asking too much of one or the other.

here's a math that you need DI start of injection angle(intake), DI injector effective pulse width int., and RPM PIDs. With it you can see if you are out of time on the DI and need to blend more toward the PI. The number will get closer to the spark advance value with longer effective pulse width.

If you add injector pulse width, you should be able to use the predefined duty cycle PID.

EOI -.MathParameter.xml

tools> maths> choose a blank one> open math parameter by clicking on folder icon. select this XML from where you downloaded it.

I have your math parameter downloaded into my scanner but I cannot add it as a channel to my logger. I cant get any of the maths to add.

[JamesTheriot]

My fuel injectors came in yesterday and my BAP will be here today. I plan to put it all on this evening and hopefully I have a little better luck after.

[veeefour]

At 15 PSI of boost, 2 bar, you shouldn't be over 2.0 load. Unless you have something lacking in the fuel system. 1 load is standard atmosphere conditions in the combustion chamber, so 2 is double that. You have to account for volumetric efficiency and the fact that your air charge temperature is a bit higher than STD parameters. so 1.8-1.9 load for 15 psi is great.

That is not correct, it would be in Dodge for example if you take Cylinder Airmass into equation.

For 15 psi of boost which is over 1 bar Air Load should breach 2 if SD is correct - math is math for model. PCM work on a model not on real conditions.

[murfie]

I have your math parameter downloaded into my scanner but I cannot add it as a channel to my logger. I cant get any of the maths to add.

You don't add math as a channel, you need channels to make the math work. When you have those you can use math's in the charts and graphs.

Mathchannels.PNG

[murfie]

That is not correct, it would be in Dodge for example if you take Cylinder Airmass into equation.

For 15 psi of boost which is over 1 bar Air Load should breach 2 if SD is correct - math is math for model. PCM work on a model not on real conditions.

There's a VE correction table for real conditions. The model you are talking about is a VE model.

14.7+15= 29.7
29.7/14.7= 2.02
that would be 100% VE gets you 2.02 load at most. You are probably not getting 100% VE in real conditions and the model isn't saying that either. So saying you should be way over 2 load is not correct. You might touch 2.0 load as a brief peak, every where else you will be under it, and that really depends on how good of a turbo kit this is.

[veeefour]

There's a VE correction table for real conditions. The model you are talking about is a VE model.

14.7+15= 29.7
29.7/14.7= 2.02
that would be 100% VE gets you 2.02 load at most. You are probably not getting 100% VE in real conditions and the model isn't saying that either. So saying you should be way over 2 load is not correct. You might touch 2.0 load as a brief peak, every where else you will be under it, and that really depends on how good of a turbo kit this is.

Way over 2 statement is correct and comes from experience not from theory - load is calculated from MAF in this case which is far from TB.
What happens between MAP and MAF plus how good SD model really is plus to trust that inferred MAP is... another story.

You equations don't get factors like that into perspective - you are correct from academic perspective professor Murfie but my experience says otherwise.
I'd say his load should be around 2.1-2.2 if he wants it to be running good and safe.

[JamesTheriot]

First I'd like to say I really appreciate all the info you guys throw out. Trying my best to understand it all at once, but this is a huge learning curve over older GM and Megasquirt cars.

I just installed my BAP and fuel injectors.

Will I have to remap my entire MAF curve after I input the injector data?

What tune changes should I make before driving on the BAP?

[JamesTheriot]

And I found out that I need a real boost gauge. If you change Engine>airflow>speed density>Calc MAP Max then whatever number you have inputted there is the number that shows up on the scanner. I had this number set to 65inhg and my scanner read 15-17psi at 1.8 air load. I set the MAP Max to 50.90 and the scanner reads 10-11psi at 1.8 air load. These are supposed to be 8PSI wastegates so I guess I truly do not know how much boost it is making without a Mechanical gauge. Really wish these cars came with an actual MAP sensor.

[JamesTheriot]

Injector data all loaded in and the car idles good with the fuel trims about where they were. Success. Now to really figure out this load and speed density side.

[Plimmer]

Injector data all loaded in and the car idles good with the fuel trims about where they were. Success. Now to really figure out this load and speed density side.

On my 2015 turbo the BAP was only good for 800hp, about 10psi of boost, and even at that point above 6,000 rpm the fuel leaned out. You on e85? If not your end goal should be e85 and a twin pump setup, although the 2020 may have a bigger fuel pump, not sure.

Also now that you have the correct size injectors in and a fuel pump working better, you will need to go back and check your MAF curve. When fuel pressure drops, the fuel trims look like MAF is off, but it could really be the ecu struggling to get more fuel in under a low fuel pressure condition.

The wastegate springs are pretty accurate, so if you put 8psi springs in, then that’s what you have. You should also plan to get a good boost controller with boost by gear and boost by rpm. Don’t get an eBoost2, those controllers belong in a museum. I recommend the cortex ebc.

FYI 15psi is about 900 to 950 whp on these motors, you’ll know when 15psi hits, it’ll feel like someone activated the warp drive lol.

In the speed density section you should consider flattening the air change multiplier as rpm increases. You’ll notice the stock file decreases the air charge multiplier as rpm rises, but in my tune this caused a lean condition that fuel trims could not correct. Once I made the multiplier constant with rising rpm then my fueling was spot on and fuel trims and maf calibration responded as expected. This issue didn’t happen at boost pressures less than 11psi, but once I started to go above 15psi this became an issue. Don’t know why.