how to command richer part throttle AFR

[chizzle1]

What other than Engine>Fuel>General> FA Stoich determines the part throttle AFR?
I am running 11:1 comp on a 6.1 based 426 and I need to have the part throttle AFR at ~14.4 to prevent knock during light acceleration.
I have pulled a lot of PT timing and still having this issue due to the STFT pulling fuel and keeping the AFR at 14.9-15.1 while cruising.
On WOT pulls I have the AFR set to 12.5-12.7 and there is no knock.
I have the stoich set to .0690, which should be 14.5:1
I have tried NN on and VE, same results.

Any help would be appreciated.

[06300CSRT8]

Bring in your WOT pedal threshold much lower, something like 1.5 to 2.0 volts.

Once you cross that line you are going into Open loop, and can command a richer AFR via the Fuel>Power Enrich>vs Aircharge vs Rpm and vs PRatio vs RPM.

Takes a good amount of tuning (its like tuning speed density) but once your VE is dialed in shouldn't be too bad.

[Jay@HAP]

Did you zero out your throttle rate spark table?

[chizzle1]

Bring in your WOT pedal threshold much lower, something like 1.5 to 2.0 volts.

Once you cross that line you are going into Open loop, and can command a richer AFR via the Fuel>Power Enrich>vs Aircharge vs Rpm and vs PRatio vs RPM.

Takes a good amount of tuning (its like tuning speed density) but once your VE is dialed in shouldn't be too bad.

Thanks, I'll try that. I thought if I lowered the pedal wide open throttle setting it would actually have the throttle body open sooner not just go into open loop.

Did you zero out your throttle rate spark table?

Yes, all zeros.

I would like to get it tuned with NN enabled as the transient / part throttle driving is much smoother than with ve.

Thanks for the advice.

Edit: I thought it was either ve or pe (aircharge vs etc... ) does the air charge table play a factor when nn is disabled?
I know the ve tables are not used, or so I have read, when n n is enabled.

[JoshCP527]

they have two wot settings one is for the etc and one is for fueling. Change the fueling one. I have not done any stroker motors but it seems when you go outside of general boundaries of ANN ve seems to be the only way to fix. Stoich doesn't care what you set that to its more for fuel mass calculations and then it trims to the o2 switch point. I don't know if you have a target offset but that would make it idle and well close loop richer. Did you change engine size for the calculations and intake size for the transient fueling otherwise ve it with ANN off?

[lafrad]

How much timing is it pulling?
Is the engine fully up to temp when you see the KR?

if you are talking about 3 degrees or less, just pull the timing. If the KR goes away, you are out of what the car can do and nothing will change that.

2010's are narrowband sensors, you will *never* get it to deviate from Stoich operation in closed loop. It just has no way to properly fuel the car with just a narrowband signal. Changing the "AFR" only changes the computer calculations, and will work against you in your tune. (commanding at richer target for closed loop will actually lean out the base calculations after the VE table adaptives get done with it...)

[lafrad]

Surge without the Neural Network suggests the VE tables or Injector tables need some work. the NN will do a pretty good job at masking any injector problems, but it will not fix the VE table.

the surge could *also* mean the throttle flow tables aren't correct for the TB installed. a good/spot on injector scale will prevent that, but that is difficult to achieve outside of an engine dyno-cell

[chizzle1]

they have two wot settings one is for the etc and one is for fueling. Change the fueling one. I have not done any stroker motors but it seems when you go outside of general boundaries of ANN ve seems to be the only way to fix. Stoich doesn't care what you set that to its more for fuel mass calculations and then it trims to the o2 switch point. I don't know if you have a target offset but that would make it idle and well close loop richer. Did you change engine size for the calculations and intake size for the transient fueling otherwise ve it with ANN off?

I see the fueling WOT setting you are referring to under Engine > Fuel > General > WOT Thresholds
I'm not sure I understand the "target offset" and "well close loop richer" statement, I used the offset tables from the injector data sheet.
For the intake size I used the 6.1 value of 12.57L under Engine > Fuel > Transient since I'm using a 6.1 ported manifold.
I tuned ANN off yesterday and was able to get it running after adding about 45% to the stock VE tables.
I didn't change the value for size or displacement under Engine > General to retain my ESP / traction control.

[chizzle1]

How much timing is it pulling?
Is the engine fully up to temp when you see the KR?
if you are talking about 3 degrees or less, just pull the timing. If the KR goes away, you are out of what the car can do and nothing will change that.
2010's are narrowband sensors, you will *never* get it to deviate from Stoich operation in closed loop. It just has no way to properly fuel the car with just a narrowband signal. Changing the "AFR" only changes the computer calculations, and will work against you in your tune. (commanding at richer target for closed loop will actually lean out the base calculations after the VE table adaptives get done with it...)

it was initially pulling between 7-10* but the AFR was very lean (15+) due to bad injector pw tables, after the AFR was back to ~14.7 it dropped to 1-3, but I have pulled atleast 10 off the PT and WOT tables and it still shows 1-2* during part throttle acceleration.
When I richen it up by removing 10% from inj pw fuel mass I get no knock but I get the bank 1 & 2 too rich CEL.
Yes, the ECT is 185-195 when the KR occurs.
I thought the Stoich value was used in conjunction with the PE tables to determine the AFR during WOT?

[chizzle1]

Surge without the Neural Network suggests the VE tables or Injector tables need some work. the NN will do a pretty good job at masking any injector problems, but it will not fix the VE table.

the surge could *also* mean the throttle flow tables aren't correct for the TB installed. a good/spot on injector scale will prevent that, but that is difficult to achieve outside of an engine dyno-cell

the throttlebody is slightly larger than stock so I added the percentage difference to the Throttle Body Airflow table under Engine > Airflow > General.
The only surge I am getting is a slight amount under decel when approaching 1500-1200 rpms, once I clutch in it goes to idle and stabilizes at 850.

When ANN is disabled do the PE tables under Engine > Fuel > General have any effect or is it only the VE tables?
I thought (I am probably wrong) that when ANN is enabled the PE tables control AFR under WOT and when ANN is disabled the VE tables control AFR.

[Jay@HAP]

it was initially pulling between 7-10* but the AFR was very lean (15+) due to bad injector pw tables, after the AFR was back to ~14.7 it dropped to 1-3, but I have pulled atleast 10 off the PT and WOT tables and it still shows 1-2* during part throttle acceleration.
When I richen it up by removing 10% from inj pw fuel mass I get no knock but I get the bank 1 & 2 too rich CEL.
Yes, the ECT is 185-195 when the KR occurs.
I thought the Stoich value was used in conjunction with the PE tables to determine the AFR during WOT?

What injectors are you using?

WOT F/A is the Stoich F/A+the air charge/P ratio table. Take that number and divide it into 1.0 and that will tell you the AFR.

The narrow bands are always going to go to switch at Lambda.

What octane of fuel are you using?

post a log and a tune if you can.

[chizzle1]

What injectors are you using?

WOT F/A is the Stoich F/A+the air charge/P ratio table. Take that number and divide it into 1.0 and that will tell you the AFR.

The narrow bands are always going to go to switch at Lambda.

What octane of fuel are you using?

post a log and a tune if you can.

52# Deatschwerks injectors DWK-13U-XX-0042-X rated for 52# at 58 psi

understood, is that table always in effect or only when NN is on?
i have read that the VE table is used exclusively when NN is off.

Lambda is the same as the desired AFR, just measured differently?

93 always, usually chevron or shell.

I will capture a log today at lunch with one of the older tunes that runs it decent.
it's super rich but part throttle is ok.

I appreciate everyone taking the time to assist me. i don't have the coin to have the car professionally tuned at the moment.

[06300CSRT8]

VE is always used NN or not, but with NN on its one very small input to the final equation. NN is very fast to always calculate and end up back at a total calculated engine required airflow and fuel. Even if VE is all wacked out, the NN will apply algos to get back to whatever aircharge your engine displacement should need, that's why you see almost no change with NN on and changing your VE. On the otherhand, the fuel supply is a much simpler calc for the ECU and so that is why changing injector data is a faster and more direct way to change fueling with NN on.

[chizzle1]

VE is always used NN or not, but with NN on its one very small input to the final equation. NN is very fast to always calculate and end up back at a total calculated engine required airflow and fuel. Even if VE is all wacked out, the NN will apply algos to get back to whatever aircharge your engine displacement should need, that's why you see almost no change with NN on and changing your VE. On the otherhand, the fuel supply is a much simpler calc for the ECU and so that is why changing injector data is a faster and more direct way to change fueling with NN on.

thanks, that makes sense. I think I'll switch to NN off and use VE. With NN off I don't need to worry about the Power Enrich tables under engine > fuel > general correct?

[06300CSRT8]

You will always have those power enrich tables controlling your open loop fueling, NN on or not.

Just be aware when you switch to NN disabled, your VE table is going to be VERY far off from what is ultimately needed. Be prepared for some aggressive recalibrating. So far mine was off close to 25% to start.

[chizzle1]

You will always have those power enrich tables controlling your open loop fueling, NN on or not.

Just be aware when you switch to NN disabled, your VE table is going to be VERY far off from what is ultimately needed. Be prepared for some aggressive recalibrating. So far mine was off close to 25% to start.

so VE is transient and PE is WOT? (regarding fueling)

and yes, I had to add a ton to the VE table to get it to start, then more to drive without running in the 16-17 AFR range.

[06300CSRT8]

so VE is transient and PE is WOT? (regarding fueling)

and yes, I had to add a ton to the VE table to get it to start, then more to drive without running in the 16-17 AFR range.

VE is in all conditions, any time, any throttle, WOT or transient or cruising. It is the base model of what % your motor is consuming of the maximum calculated air and fuel it could consume. At anything but full throttle (i.e. open loop) the ECU is use the VE table to determine proper fuel and air, and then uses your throttle body and fuel injector data to deliver that air and fuel, but it then studies the oxygen sensors and adjust fuel accordingly to achieve stoich. At no point during this closed loop operation do you have the ability but to target a single air fuel ratio, it will always chase lambda of 1, or stoich.

Because WOT will produce maximum power at varying air fuel ratios, the ECU lets you command varying air fuel ratios throughout the rpm and pressure ratio bands. This is the Power Enrich table. But the ECU does squat for monitoring, it injects the fuel it calculates and you have to determine if it was right or wrong on your own with a wideband, and tweak your VE table (assuming injector data is accurate) to get the output result AFR to be in line with what you are commanding.

Again, VE table is always in use. Power enrich adds on top of your single stoich value to give you a varying air fuel ratio during open loop conditions.

[chizzle1]

VE is in all conditions, any time, any throttle, WOT or transient or cruising. It is the base model of what % your motor is consuming of the maximum calculated air and fuel it could consume. At anything but full throttle (i.e. open loop) the ECU is use the VE table to determine proper fuel and air, and then uses your throttle body and fuel injector data to deliver that air and fuel, but it then studies the oxygen sensors and adjust fuel accordingly to achieve stoich. At no point during this closed loop operation do you have the ability but to target a single air fuel ratio, it will always chase lambda of 1, or stoich.

Because WOT will produce maximum power at varying air fuel ratios, the ECU lets you command varying air fuel ratios throughout the rpm and pressure ratio bands. This is the Power Enrich table. But the ECU does squat for monitoring, it injects the fuel it calculates and you have to determine if it was right or wrong on your own with a wideband, and tweak your VE table (assuming injector data is accurate) to get the output result AFR to be in line with what you are commanding.

Again, VE table is always in use. Power enrich adds on top of your single stoich value to give you a varying air fuel ratio during open loop conditions.

thanks. so first I need to get the VE dialed in, then I can work on the PE tables...
then I can command it to go into open loop via the WOT Threshold if I need more fuel to prevent knock...

I'll make some changes to the tune, log it during lunch, and post the tune and log file afterwards.

[06300CSRT8]

Yea exactly. The idea is to get the vehicle to produce a stoich fueling with little or no fuel trims doing the work for you. Once that is done you know you have a solid VE table.

Then determine what AFR you want to start working with in part throttle scenarios that you feel you are getting knock from. I have found just a little change goes a long way, i.e. commanding something like 13.8-14.0 is plenty enough. So you do the math to command that air fuel in the PE table in the aircharge or pressure ratio rows you tend to hit in that table under part throttle conditions. You then blend those higher up rows down to the lower rows in the same table that start to cover the areas where you are foot to the floor. Then set your WOT threshold to be where the pedal voltage is around when you see this part throttle knock (can log pedal voltage) and use that as your threshold to entire open loop, WOT fueling.

[chizzle1]

Many thanks, i hope I didn't ask too many stupid questions...this is much more in depth (difficult) than tuning the 5.7 VVT I had before.