Who here is using PE on E38 PCM to disable closed loop idle with large Cams?

[Allen Vos]

You can use the fuel trims to make fueling adjustments for low to mid load areas, so you don't have to wait on your wideband. A wideband is needed for WOT tuning though. I honestly feel that you need to give it what the trims say it needs. Worst case scenario, you can change it back to the way you have it now. If you have an idle log, post it up so you can get more help.

Oh, does the throttle seem to hang if you blip it?

I think I am going to Focus more on getting the EOIT and some more parameter's figured out so that I know I am not chasing my tail so to speak. Like I said earlier, I haven't even touched the MAF curve or VVE table for the idle tune. Im stuck in Canadian winter here so it will be about 3-4 months before I can even drive the car. Its the perfect opportunity to learn the HP Tuners software so when spring comes I can be ready to tune this thing.

Correct me if im wrong here but from what I read a cam with overlap needs less fuel to idle? I get the stinky idle could be lean or rich, but one thing I will say is in the short time I have been running it with the new camshaft it has guzzled a lot more fuel than it would have normally with the stock cam. I just attributed this to the False lean due to the cam overlap and the computer dumping fuel in to try and match the fuel trims. I never seen any black smoke either but from my experience in tuning black smoke never showed up until excessive rich conditions south of 10:1 AF ratio. I should mention The o2's are switching quickly and range from 70mv all the way to 700-800mv. I do remember when it had the stock LS3 camshaft the O2's would hit 900mv easily. I'm assuming this is because of added cam overlap.

As far as remapping the Drive by wire throttle maps, the correspondence between the right foot and the actual throttle opening felt really soggy or delayed so to speak. I was not having any drivability issues whatsoever but just wanted to make the throttle opening a bit more aggressive than stock so the car felt snappier. It was tricky tuning this as trying to get the throttle to open any quicker than what I have it currently set at would just induce REP and throw the car in limp mode.

[Allen Vos]

Open loop idle tuning was something we did way back in the day primarily in C5s with very specific return to idle issues. It's never been a thing in the E38s.

EOIT will help the smell some, but it's always going to stink. Especially if you're catless.

I'm glad to know that CL tuning with a big cam is still possible with the E38. I definitly expected it to stink a bit, just not water my eyes right out of garage lol. Im sure once I get the tune nailed down it will be fine.

Is there any tuning videos that specifically focus on how to adjust the idle fueling on an E38 ecm for Camshafts with the larger overlap?

[Allen Vos]

If fuel trims are adding fuel to the point where the engine starts to misfire, then that may be an indication of your primary o2 sensors not reading correctly, or not reading at all. Verify your primary o2s are operating correctly.

Hint: Typically, an o2 value of 400-450mv at idle means there is no voltage going to the o2 sensor.

O2's are switching quite nicely from 70mv to almost 800mv. I feel the PCM is just picking up the false lean due to cam overlap and driving it rich. I think I just need to learn a bit more here lol

[Allen Vos]

First, you need to dial in your EOIT.
https://youtu.be/Td6oC9CIUas

Then, you will need to dial in your O2 settings, specifically for the O2 voltage switch points ([ECM] 12530 and [ECM] 12531) for your idle mode profile. Hint you will want to lower the voltage.
https://youtu.be/5hjzI8wSItk

These will help fight the cam overlap false lean situation.

Thank you so much for the link to those videos. They are very nicely done and well thought out with great detail. I started watching some other videos from the same author and must say much care was put into the video to help people understand things.

I wanted to ask. Are these your videos? Your user name here shows up in all the math parameters I was able to download on the google drive, so I kind of put 2 and 2 together lol

I was able to get all the valve events for my cam at .006" so I am going to sit down this morning and figure this out. I found the EOIT assistant as well so I'm going to give that a whirl, so I will prolly have some more questions lol.

[Cringer]

Thank you so much for the link to those videos. They are very nicely done and well thought out with great detail. I started watching some other videos from the same author and must say much care was put into the video to help people understand things.

I wanted to ask. Are these your videos? Your user name here shows up in all the math parameters I was able to download on the google drive, so I kind of put 2 and 2 together lol

I was able to get all the valve events for my cam at .006" so I am going to sit down this morning and figure this out. I found the EOIT assistant as well so I'm going to give that a whirl, so I will prolly have some more questions lol.

Yes Cringer = SilverSurfer77
I am happy you are finding the videos helpful. I have spent a lot of time learning and digesting, and then trying to figure out how best to communicate that, record videos, re-record, edit, etc...and making software to help...takes a TON of time!

You are correct in that you need to sort out the EOIT first, this is architectural stuff that is the underpinning of your fuel trims...so don't waste time on airflow modeling first.

Correct me if im wrong here but from what I read a cam with overlap needs less fuel to idle?

A large aftermarket cam needs more AIR to idle correctly...more air = more fuel. It is just that the O2 sensors are getting tricked by the overlap to artificially add more fuel (making the mixture richer). So yes you need less fuel to lean it out to get it back to stoich...but I don't consider this the same thing as you said, "needs less fuel to idle".

EDIT: I do cover this in the EOIT theory video here: https://youtu.be/Td6oC9CIUas
A lot of talk about EOIT is about the fuel short circuiting during overlap. But no one really talks about the air short circuiting.

[GHuggins]

Yes Cringer = SilverSurfer77
I am happy you are finding the videos helpful. I have spent a lot of time learning and digesting, and then trying to figure out how best to communicate that, record videos, re-record, edit, etc...and making software to help...takes a TON of time!

You are correct in that you need to sort out the EOIT first, this is architectural stuff that is the underpinning of your fuel trims...so don't waste time on airflow modeling first.



A large aftermarket cam needs more AIR to idle correctly...more air = more fuel. It is just that the O2 sensors are getting tricked by the overlap to artificially add more fuel (making the mixture richer). So yes you need less fuel to lean it out to get it back to stoich...but I don't consider this the same thing as you said, "needs less fuel to idle".

EDIT: I do cover this in the EOIT theory video here: https://youtu.be/Td6oC9CIUas
A lot of talk about EOIT is about the fuel short circuiting during overlap. But no one really talks about the air short circuiting.

The "air reversion" is part of the reason I do injection timing the way I do. Air short circuiting as I believe you're calling it is where raw unburnt oxygen goes into the exhaust stream and can cause skewing although I haven't watched your vid about it yet. Idle rpm and inj timing can aid in working around this either way. 800 should be high enough on idle to keep scavenging down while smoothing out reversion. Then work injection.

[Cringer]

The "air reversion" is part of the reason I do injection timing the way I do. Air short circuiting as I believe you're calling it is where raw unburnt oxygen goes into the exhaust stream and can cause skewing although I haven't watched your vid about it yet. Idle rpm and inj timing can aid in working around this either way. 800 should be high enough on idle to keep scavenging down while smoothing out reversion. Then work injection.

When I think of reversion, I think of two things:

1) caused by a late IVC angle that allows the piston to push air out of cylinder backwards through the intake valve during the beginning of the compression stroke at low/mid RPMs. Nothing can be done about this.

2) occurs during valve overlap where exhaust manifold pressure > intake manifold pressure allowing gasses to move backwards through the intake valve. The solution here is to use proper long tube headers.

However, "air short circuiting" (as I refer to it as I am not sure if there is as correct name for this) is different that these reversion scenarios. It occurs when you have sufficient RPM/long tube headers which create enough of a vacuum signal that fresh air enters the cylinder and then immediately exits via the exhaust valve during overlap and keeps going down the exhaust system...that fresh air then causes the O2 sensors to read lean, falsely. So even if you have a spot on perfectly stoich air:fuel in the cylinder, it will be diluted with that fresh air. The ECM then responds by adding more fuel. Nothing can be done about this other than setting your O2 switching voltages lower to compensate. Even then, it is a shot in the dark about exactly when the fresh air is getting short circuited.

Greg I know you have a complicated and specific set of instructions for dialing in EOIT. Are you able to publicly share that and explain it?

[GHuggins]

I have several times There's even a link in this thread where I describe the method.

You are also correct on the aboves Also why I will use the wideband to set the O2's. If it's a huge cam with a lot of exhaust duration then all you can do is the best you can. Exhaust back pressure and a proper crankcase vent system will help a lot. Just get them close and go by sound and feel more than anything. I rely on a lot of feedback from customers for this reason.

[Allen Vos]

Yes Cringer = SilverSurfer77
I am happy you are finding the videos helpful. I have spent a lot of time learning and digesting, and then trying to figure out how best to communicate that, record videos, re-record, edit, etc...and making software to help...takes a TON of time!

You are correct in that you need to sort out the EOIT first, this is architectural stuff that is the underpinning of your fuel trims...so don't waste time on airflow modeling first.



A large aftermarket cam needs more AIR to idle correctly...more air = more fuel. It is just that the O2 sensors are getting tricked by the overlap to artificially add more fuel (making the mixture richer). So yes you need less fuel to lean it out to get it back to stoich...but I don't consider this the same thing as you said, "needs less fuel to idle".

EDIT: I do cover this in the EOIT theory video here: https://youtu.be/Td6oC9CIUas
A lot of talk about EOIT is about the fuel short circuiting during overlap. But no one really talks about the air short circuiting.

Dude, you should be proud of what you have done. I have watched goat rope garage and HP Tuner academy and a few others and you by far get into things with much greater detail.
I have gotten valuable info from those other guys but you take the time to explain things and that's huge. I am a licensed technician here in Ontario and I'm quite familiar with the terminology but a guy like yourself just makes the software so much easier to understand things and how different strategies are accomplished.

So I watched your EOIT video and have a few questions.

My stock camshaft is an LS3 cam with the following specs.
267/275 advertised duration(.006")
IVO - 7 degrees BTDC
IVC - 80 degrees ABDC
EVO - 66 degrees BBDC
EVC - 29 degrees ATDC
Overlap is 36 degrees

My new/current cam is a TSP Stage 2 LS3 NA Cam
282/297 advertised duration (.006")
IVO - 32 degrees BTDC
IVC - 70 degrees ABDC
EVO - 83.5 degrees BBDC
EVC - 33.5 degrees ATDC
Overlap is 65.5 degrees

So with some quick calculations my old cam had an EVC of 29 degrees and the new camshaft has a EVC of 33.5 degrees.

So that's a difference of 4.5 degrees to subtract from the values of the ECM 13337 - Normal ECT chart , and 4.5 degrees to add back into the ECM 13338 normal RPM chart.

Yes I know to only go from 154 degrees F and up.

So with my overlap, IVO - 32 BTDC and EVC - 33.5 ATDC I now have an overlap of 65.5 degrees as opposed to my original LS3 cam of 36 degrees.

So my start of injection should be roughly 25.5 degrees ATDC if you include the 9 degrees it sprays with the EV still open?

Here is my ECM1336 Injection boundary chart. I want to show you here as its not a flat chart like yours and wondering If i should change it to be flat?

Attachment 141532

I also have makeup mode turned on and set up at multiple from the factory and my makeup ect chart is set at 30 flat all the way across and the makeup rpm is all at zero so I need to incorporate the 30 into the SOIT formula

So for right now I am trying to get this thing to idle nicer to clean get the EOIT correct and my formula is this

SOIT = 507(boundary angle) - 105.5( corrected normal ECT) -30 (makeup RPM) which = 367 degrees?

if you take the 9 degrees off that GM has spraying prior to EVC than SOIT=358?

I am a bit confused here because SOIT at 358 degrees is pretty much one revolution and it starts spraying at TDC in the middle of the overlap yet the EVC at 33.5 degrees and its spraying like 35 degrees before the EV closes.

What am I missing here?

Does the injection boundary angle need to be changed in the ECM 13337 Chart?

[Allen Vos]

Yes Cringer = SilverSurfer77
I am happy you are finding the videos helpful. I have spent a lot of time learning and digesting, and then trying to figure out how best to communicate that, record videos, re-record, edit, etc...and making software to help...takes a TON of time!

You are correct in that you need to sort out the EOIT first, this is architectural stuff that is the underpinning of your fuel trims...so don't waste time on airflow modeling first.



A large aftermarket cam needs more AIR to idle correctly...more air = more fuel. It is just that the O2 sensors are getting tricked by the overlap to artificially add more fuel (making the mixture richer). So yes you need less fuel to lean it out to get it back to stoich...but I don't consider this the same thing as you said, "needs less fuel to idle".

EDIT: I do cover this in the EOIT theory video here: https://youtu.be/Td6oC9CIUas
A lot of talk about EOIT is about the fuel short circuiting during overlap. But no one really talks about the air short circuiting.

Attachment 141538

Attachment 141539

I have attached my Tune and a cold startup letting it warm up to operating temp.

I haven't done any logging yet so this is all new to me. I hope this shows everything it needs to

I tried to include the Narrow band O2 sensors and the ST and LT fuel trims.

Keep in mind I have done no MAF or VVE tuning

This is just strictly a get the car up and running so I can move it around

[Cringer]

Attachment 141539

I have attached my Tune and a cold startup letting it warm up to operating temp.

I haven't done any logging yet so this is all new to me. I hope this shows everything it needs to

I tried to include the Narrow band O2 sensors and the ST and LT fuel trims.

Keep in mind I have done no MAF or VVE tuning

This is just strictly a get the car up and running so I can move it around

Here is a good starting point from my experience.

TSP Stage 2 Camshaft - Cringer.hpt

[Allen Vos]

Thank you for modifying that for me.

The math at idle warmed up gives me a SOIT of 385 degrees which is perfect as the EVC event is 393.5 degrees.


I'm going to post the before and after and I am wondering if you would'nt mind explaining to me why you made the changes you did?

Attachment 141544 My Tune

Attachment 141543 Tune with your changes


I noticed on the injection boundary table you more or less reversed the numbers I started out with and increased them a fair bit from 4000 rpm and up.

On the E13337 Normal ECT you decreased the numbers from 110 to 85.

On the E13338 Normal RPM the higher numbers are cut almost in half and the numbers were also raised a bit to reflect the power band of the Cam as compared to stock.

Now lastly Im very curious and noticed that you turned Make Up mode off. It was set to Multiple. Can I ask why you did this?


I am in no way doubting what you changed as I am sure it will work better than what I have and I really really appreciate it, but I'm the kind of person that would like to understand why the things that were changed, were changed.

I will flash the changes to the car tomorrow and report back on how it runs

[LS ROB]

Just going to put out a FYI here. Not even sure if it matters but i find it odd that the MAF table doesn't show any differences when comparing those 2 files, BUT if you actually click on the MAF table and look at the original file then the compare file, THEN hit "show differences," it doesn't show numbers but it does show a change. Maybe the injection timing changes something in the background?


maf .jpg

[Cringer]

Thank you for modifying that for me.

The math at idle warmed up gives me a SOIT of 385 degrees which is perfect as the EVC event is 393.5 degrees.


I'm going to post the before and after and I am wondering if you would'nt mind explaining to me why you made the changes you did?

Attachment 141544 My Tune

Attachment 141543 Tune with your changes


I noticed on the injection boundary table you more or less reversed the numbers I started out with and increased them a fair bit from 4000 rpm and up.

On the E13337 Normal ECT you decreased the numbers from 110 to 85.

On the E13338 Normal RPM the higher numbers are cut almost in half and the numbers were also raised a bit to reflect the power band of the Cam as compared to stock.

Now lastly Im very curious and noticed that you turned Make Up mode off. It was set to Multiple. Can I ask why you did this?


I am in no way doubting what you changed as I am sure it will work better than what I have and I really really appreciate it, but I'm the kind of person that would like to understand why the things that were changed, were changed.

I will flash the changes to the car tomorrow and report back on how it runs

I did the best I could with the log you sent, I whish it had more IPW vs RPM data at hand. The tune I sent is going to be a rough start based only on ideal valve events. Flash it and log it and then the real EOIT tuning begins. I have also attached a pic of the EOIT graphing out the setup I gave you calling the specific areas of interest as detailed in the following text.


We will start at idle.
EVC is 394
SOIT is 385
We are gambling (spraying early) by 9 degrees and hoping no fuel short circuiting occurs.
Try this first and log obviously. Then create two new tunes altering the Normal ECT table by changing the 85 to something of your choosing. Maybe start with 3 degree increments, make a tune with 88 (spraying earlier at 388) and one set to 82 (spraying later at 382).

I also turned off the Make Up Mode because I don't like it. I urge you to experiment on NONE, SINGLE, and MULTIPLE to see what the fuel trims do.
My theory is this...and this is based on the logs I captured...turning this off forces all the fuel to be sprayed in one large shot at the beginning of the induction cycle which has two main benefits.
1) Most importantly it gives the fuel more time in the cylinder to tumble, swirl and mix with the air which translates to less chance of misfire, less chance of detonation, more complete combustion. So it is safer, reduces fuel consumption, and emissions.
2) By spraying early you give the fuel more time to work its magic through latent heat of vaporization. That is, fuel cools things down...which means a denser air charge = more power, and less heat = less chance of detonation.
I do not expect that this effect is huge, however, it is not negligible either and when it comes to pushing equipment to its limits safely, I will take every fractional percent I can get.

Sweating the details of reversion (this is covered at the end of my first EOIT video, not the tool demo/how to video), my pet theory...
I have set the EOIT to 470 so that no matter what, fuel is not sprayed "in the danger zone" of getting reversed. IVC is 610, BDC is 540, 610-540 is 70. So 540-70=470. We don't want any fuel sprayed during the transition of the piston transitioning between intake and compression with the intake valve open. Hard to explain via text, but there is a graphic in the video that should clear this line of thinking up.


Mid RPM's (1,700 - 2,500)
This is where you will most likely need to experiment to see what your setup needs. Right now 2,048+ RPMs is where we see the first sign of changing the SOIT. It is a fine line here. We are still in danger of short circuiting the fuel by spraying too early. You will defiantly need to experiment with the SOIT here (both moving the Boundary Angle and Normal RPM). I like to have all my mid-RPM spraying done right before, or as close to, peak piston velocity as possible to get the fuel in right before the violence can mix everything up just right.


High RPM's
This is where everything changes and I wish I had a dyno to test things. I set my EOIT to occur 30 degrees before the IVC. IVC is 610, so EOIT for you is 580.

Most injectors are going to have such a long pulse width in comparison to the injection window that there is no choice but to spray on the back of the closed intake valve. This is not necessarily bad when you consider the violence that happens here at peak horsepower. Fuel will be sitting in a puddle on the closed valve. The valve starts to open. The piston is still moving up and breaking over TDC...so the intake stroke has not technically begun and once the piston breaks over TDC the vacuum signal it is creating is lack luster as piston velocity is slow and lazy. But what we do have working for us is the overlap in combination with the vacuum from the exhaust, which jolts the induction cycle into life! That puddle of fuel is sucked into the chamber with great force and atomization factor 360 degrees around the valve margin...perfect annular flow. This puddle (most likely) is going to be the majority of your fueling during PE, the remaining bit is topped off at the end. Not a lot of air is moving into the cylinder during the last 30 degrees either...and if normal cam lobes are in play (which they are) we are in sub .050" lift and we are going to be hitting the back of the intake valve as it closes any way.


So in summary...
1) For CL operations, focus on SOIT
2) For PE operations focus on EOIT

EOIT.jpg

[GHuggins]

The 580, 575 realm for boundary is where I normally run any of them max so that's spot on. Dyno testing backed up those settings even on stock cams. You have to watch out on injector sizing though. If too much raw fuel mix vs fuel spent on the hot intake valve vaporizing it better changes things then it needs to be moved. This is where shifting it around after the fact to see if it gets richer any shows it's face. Running timing in the rpm table can affect things too. You're going from somewhat advanced to really retarded timing. Good to 0 out and just use the boundary to simplify things.

[GHuggins]

Just going to put out a FYI here. Not even sure if it matters but i find it odd that the MAF table doesn't show any differences when comparing those 2 files, BUT if you actually click on the MAF table and look at the original file then the compare file, THEN hit "show differences," it doesn't show numbers but it does show a change. Maybe the injection timing changes something in the background?


maf .jpg

There's a big change toward the end there for some reason? Fat fingered possibly?

[Cringer]

There's a big change toward the end there for some reason? Fat fingered possibly?

I am not seeing this...what am I missing?
Compare.jpg

[Cringer]

The 580, 575 realm for boundary is where I normally run any of them max so that's spot on. Dyno testing backed up those settings even on stock cams. You have to watch out on injector sizing though. If too much raw fuel mix vs fuel spent on the hot intake valve vaporizing it better changes things then it needs to be moved. This is where shifting it around after the fact to see if it gets richer any shows it's face. Running timing in the rpm table can affect things too. You're going from somewhat advanced to really retarded timing. Good to 0 out and just use the boundary to simplify things.

Good to know about the magic of 580! Thanks for that nugget!

[GHuggins]

I am not seeing this...what am I missing?
Compare.jpg

I was referring to the above pic Rob posted. I don't show any differences with the MAF when I compare your changes to the original posted file. May even be the editor version?

[07GTS]

if u set the makeup to ''none'' and then zero out the makeup tables do u then have to adjust the degrees that was allocated for the makeup back into the other eoit settings so they stay the same or does it not affect them ?