Virtual VE Tuning questions......

[turboffr]

Getting ready to install a cam in my '08 vette, and would like to be able to tune the Virtual VE tables. Can someone confirm if my basic understanding of the tuning process is correct using Bluecat's VE program?

1.) Copy VE equations from my tune into the software to build a VE table
2.) Force MAF off in the tune
3.) Force open loop
4.) Scan AFR % error (commanded vs. actual -Wideband) in histogram (VeLoAltd table) where MAP is column headers and RPM area row headers.
5.) Adjust virtual VE table in the program by the error % observed in the histogram, save table.
6.) Load VE equations into tune from software

Assuming the steps I have outlined are correct, could I also use fuel trims in closed loop to tune the VE table in step 4?. I have 10% ethanol fuel in my area so when I tune the lower rpm/MAF ranges in open loop the wideband the trims are always correcting. If I changed stoich to 14.2 would open loop with the wideband be the preferred option? I've heard the o2's are pretty accurate in idle and part throttle.

Thanks.

[eficalibrator]

For step #4, I made a YouTube video showing exactly how to set up the scanner with the same breakpoints you'll be using in the BlueCat tool.

Also, working in units of Lambda instead of Air-Fuel Ratio will also make your life much easier when it comes to sorting out correction factors when the wideband, ECU, and fuel have unique stoichiometric points.

[turboffr]

For step #4, I made a YouTube video showing exactly how to set up the scanner with the same breakpoints you'll be using in the BlueCat tool.

Also, working in units of Lambda instead of Air-Fuel Ratio will also make your life much easier when it comes to sorting out correction factors when the wideband, ECU, and fuel have unique stoichiometric points.

Thanks Greg. That's a great overview!! I had already setup a histogram to plot AFR error and it seems to coincide with the bluecat table. I used the VE Reversion Lo Altd table in the histogram and it plotted the same MAP and RPM values as the Bluecat table.

I don't think my wideband can report lamda. It's an NGK AFX. Do you suggest I change stoich for the 10% ethanol fuel and tune the VE tables and MAF in open loop vs. AFR error%

[MikeOD]

Your NGK AFX is reporting 0 to 5 volts...and you can convert that voltage to lambda in VCM Scanner.

[DSteck]

Thanks Greg. That's a great overview!! I had already setup a histogram to plot AFR error and it seems to coincide with the bluecat table. I used the VE Reversion Lo Altd table in the histogram and it plotted the same MAP and RPM values as the Bluecat table.

I don't think my wideband can report lamda. It's an NGK AFX. Do you suggest I change stoich for the 10% ethanol fuel and tune the VE tables and MAF in open loop vs. AFR error%

To make the AFX report lambda, your adder is 0.62 and the divisor is 10.42.

[SargeZ06]

To make the AFX report lambda, your adder is 0.62 and the divisor is 10.42.

Some where I came up with .618 and 10.42 for mine. Is that wrong?

[turboffr]

Okay, I setup a user defined AUX input for the NGK to report Lambda using the settings provided. Then I setup a user defined PID to compare the NGK Labmda to commanded EQ ratio and calc the % error 100*([SENS.120]-[PID.68])/[PID.68]. Do I now need to update stoich in my tune for the 10% methanol fuel to 14.20. I also read that the NGK stoich is 14.57. My tune is currently at 14.67. This is what has me confused. Thanks for yoru help.

[02Ls1]

Not to high jack this thread but is there another way to tune this new pcm's(e38) without using the blucat program?
like just tuning the Maf on a 09 vette with cam, heads and intake?

[DSteck]

You can do cars with just the MAF and ignore SD.

[turboffr]

Do I now need to update stoich in my tune for the 10% methanol fuel to 14.20. I also read that the NGK stoich is 14.57. My tune is currently at 14.67. This is what has me confused. Thanks for your help.

?

[DSteck]

When you use lambda for everything, the stoich crap ceases to matter. The display on the AFR is based on 14.57... you can program the output for whatever stoich point you want. The output just outputs lambda, like any other wideband. All widebands do is convert lambda to AFR.

[Xjas]

As a noob I found it easier to copy the ve table generated by the bluecat tool into an LS2 tune table in HP tuners (any LS2 tune downloaded from the repository will do) and then copy my completed table back to the bluecat tool for conversion to coefficients after I was done adding the AFR error and generally smoothing the table in the LS2 tune.

[DSteck]

As a noob I found it easier to copy the ve table generated by the bluecat tool into an LS2 tune table in HP tuners (any LS2 tune downloaded from the repository will do) and then copy my completed table back to the bluecat tool for conversion to coefficients after I was done adding the AFR error and generally smoothing the table in the LS2 tune.

This is the best way to do it so that you have access to the table smoothing and viewing tools that HPT had available.

Hopefully 2.24 will include virtual VE.

[turboffr]

When you use lambda for everything, the stoich crap ceases to matter. The display on the AFR is based on 14.57... you can program the output for whatever stoich point you want. The output just outputs lambda, like any other wideband. All widebands do is convert lambda to AFR.

Makes sense. Am I correct using "commanded EQ" vs. The wideband to compare lambda error?

[DSteck]

Yes.

[SargeZ06]

Hopefully 2.24 will include virtual VE.

I was told, in a one word response, "NO" by Bill via an email when I asked him this question.

[DSteck]

Pffffft, what does Bill know.

[IDRIVEAG8GT]

Hopefully 2.24 will include virtual VE.

That's a hum-dinger right there!

I'm still patiently waiting on RTT. That would be a badass Christmas present.

[Hemi2slow]

I don't mean to hijack here either, but for VVT, as I understand it the Bluecat program doesn't take the VVT constant tables into account. But can you just adjust your VVT where you want it, and leave the VVT constants tables zeroed out? Then tune the virtual VE as you would if there was no VVT? Those tables are constants, right? And the size of the VE table should not change with whether those constants are zero or have a value, correct?

So if those are merely constants that don't add to the size of the VE table, only to the complexity of the calculation, can't you simply leave them blank and calculate VE using the Bluecat program? Wouldn't that give you the same outcome as having the VVT constants present? Am I thinking too far outside the box on this?

[LSxpwrdZ]

This is the best way to do it so that you have access to the table smoothing and viewing tools that HPT had available.

Hopefully 2.24 will include virtual VE.

That's basically what HPT's "Custom OS" is, all it does is incorporate the tool into the program...