PE AFR tuneing???

[LSXGOAT]

ok so im looking at my custom tune and i notice that the upper MAF tables are basicaly stock. Then i look at my PE and it's all up and down like thats what was being scaled.....

Im suspecting this is that "cheater" way of tuneing that some people talk about but would like to hear some feedback on it. Is there any advantage of tuneing it like that?

also if i were to start scaleing the MAF like how its shown in the "how to's" would it be ok to keep the spark table that was tuned for me (looks spot on with very minimal KR)? Thanks

[LazMan]

I always zero that out. Then copy the High Octane spark table to the Low Octane. Turn off DoD/AFM, set COT to 1.0, and disable DFCO.

Then multiply the Spark Retard -> Knock Decay Rate table by 4 and the Base Retard 2 buttons under it by 0.5.

Lastly, disable Burst (Predictive) Knock Retard.

Now you are set up to tune spark using the scanner. Then again, this all assumes your fueling is at least close to on.

[BBA]

The PE being all over the place is the factory way of tuning for feel and emmissions. It really makes you think the motor is strong when you get to a good PE spot and it starts pulling, although you will go faster with a flat PE that maintains the perfect WOT AFR. You may not feel it in SOTP, but SOTP is misleading, smooth power is the way to go.

[LSXGOAT]

ok i think everyone is miss understanding me.

First off ive been doing my own tune from the get go, the way ive tuned was where I dial in the MAF for correct AFR then i put the PE at 1.XX for whatever AFR i want when WOT.

The MAF table was re-scaled all the way to it's highest Hz based on what the AFR error was from the WB02. The PE was either the same all the way across or had a couple steps to richen it up some higher up.


Ok, so the tune i have now (which is a custom dyno tune) has the MAF scaled about half way through the high Hz chart but then goes back to stock up top. (i dont get how that could be right because when i was tuneing it there were alot of changes up there)

The PE fluctuates up and down all the way through the chart, at some points it's at ~1.27 up to ~1.33. It looks as if the PE table was changed to get the right AFR instead of changing the MAF table.

As soon as i get my laptop back ill post up some screen shots of what im talking about.


(FYI the VE table was only modified slightly)

[5_Liter_Eater]

It is normal for a stock tune to have a mountainous looking PE. Why they do this I don't know. As you know, tuning AFR on the dyno by playing with the PE further in order to achieve a particular AFR throughout the RPM range is an old school, dare I say hack, way of tuning AFR.

You're doing it right by flatlining the AFR and calibrating the MAF table(s) until the desired AFR is reached throughout the range. After that the only step you could take would be to slap it on the dyno, make a pull with the PE at, say, 13:1 and another at, say, 12.5:1. Match up the dynos and see where you gained and lost power. At the RPM points where you gained power, keep the 12.5 AFR, where you lost or stayed the same go to 13.5:1 and make another pull. Where you lost power (in relation to 13.1) go back to 13:1, where you gained, leave it at 13.5:1. Now your Pe is mountainous again but the numbers are accurate. You know you're getting the AFR you're commanding and that the AFR's you're commanding at each RPM make the most power.

Disclaimer: These AFR's are just examples for NA gas vehicles.

[Gh0st]

It is normal for a stock tune to have a mountainous looking PE. Why they do this I don't know. As you know, tuning AFR on the dyno by playing with the PE further in order to achieve a particular AFR throughout the RPM range is an old school, dare I say hack, way of tuning AFR.

You're doing it right by flatlining the AFR and calibrating the MAF table(s) until the desired AFR is reached throughout the range. After that the only step you could take would be to slap it on the dyno, make a pull with the PE at, say, 13:1 and another at, say, 12.5:1. Match up the dynos and see where you gained and lost power. At the RPM points where you gained power, keep the 12.5 AFR, where you lost or stayed the same go to 13.5:1 and make another pull. Where you lost power (in relation to 13.1) go back to 13:1, where you gained, leave it at 13.5:1. Now your Pe is mountainous again but the numbers are accurate. You know you're getting the AFR you're commanding and that the AFR's you're commanding at each RPM make the most power.

Disclaimer: These AFR's are just examples for NA gas vehicles.

I dont understand how you're supposed to tune for WOT on a dyno without the "hack" way of tuning the AFR via PE when the car doesn't have a wideband to use for MAF tuning.

[5_Liter_Eater]

I dont understand how you're supposed to tune for WOT on a dyno without the "hack" way of tuning the AFR via PE when the car doesn't have a wideband to use for MAF tuning.

You're right, without your own on board WB it is much easier to tune with PE using the shop's WB. it does pose a problem but it is possible. IE: You see that you are off from your commanded AFR at 3000 RPM by +5%. Just go back through your log and see what MAF Hz you were at when you passed through 3000 and alter that frequency by +5% rather than the PE. Do this for all your RPM/frequency points, smooth out the curve and do another pull.

I say "Hack" but PE tuning is commonplace for people doing their own tuning without their own WB. I can see doing it in that case. What I don't get is why big name tuners would do this. They should be tuning by calibrating the MAF (or VE table).

[Gh0st]

You're right, without your own on board WB it is much easier to tune with PE using the shop's WB. it does pose a problem but it is possible. IE: You see that you are off from your commanded AFR at 3000 RPM by +5%. Just go back through your log and see what MAF Hz you were at when you passed through 3000 and alter that frequency by +5% rather than the PE. Do this for all your RPM/frequency points, smooth out the curve and do another pull.

I say "Hack" but PE tuning is commonplace for people doing their own tuning without their own WB. I can see doing it in that case. What I don't get is why big name tuners would do this. They should be tuning by calibrating the MAF (or VE table).

I completely agree especially considering the high cost that "Pro" tuners are charging nowadays to just modify your PE and be done with it.

Do you know if its possible to take a dynojet wideband and plug it in to the HPTuners box?

[DSteck]

Here's a quick little trick to help WOT tuning without the Pro version. This is what I used, and it has worked pretty well for me.

Set up a histogram using MAF Air Flow (Hz) HI as the X-axis. Then, log engine RPM and filter for throttle position values over 90% (so that it's not counting engine RPM when you're in decel or something). Look at the average values logged, and it will give you a good idea of which MAF frequency corresponds to an RPM point in the AFR log of the dyno.

Once I finally got my head out of my ass and set this up, I was able to quickly make my changes between pulls. You may find that from one frequency to another, you'll only change 200rpm... but from another frequency to another, you may jump 600rpm... This is fine, because the MAF isn't a direct relation to the engine speed. Your engine has different efficiencies at different RPMs, so sometimes it may pull very similar airflow within an RPM spread.

[5_Liter_Eater]

That's a beauty idea but how about flipping it? Since the PE table is what you will be ultimately editing, use the PE table for the X axis and plot the average frequency against it (plot filtering for WOT).

So you can look at the dyno plot and mouse over each RPM point to see the Afr error, gp tp your histo and see what frequency that exact RPM correlated to and edit the MAF table.

[DSteck]

The way I intend to use it is to set PE equal to the same number across the entire RPM band and calibrate the MAF, then go back and change the PE table to my desired numbers.

In my case, calibrating the MAF was the ultimate thing I'm editing, which is why I chose to set it up the way I described. I originally tried to correlate MAF frequencies to exact RPM values, but you end up with a MAF frequency that might be halfway between two cells at 6000rpm, so it makes it really hard to determine how to modify the MAF table properly.

It definitely works both ways though, it just depends on what table you're making your changes to.

[BBA]

They way I look at it is calibrating the MAF with no PE and no DFCO in closed loop forced on using narrowband will set non PE to the stoich. Once closed loop non PE is near perfect, simply set the PE to a constant for what ever AFR you want, you will end up with a smooth power band and no peaks/dips in the power curve, except the LS2 does like to run a little fat in low RPM's to make the most off the line torque so the PE down low is adjusted accordingly.

Except for using the dyno wideband, thats how superchips tuned it. I watched their dyno pulls and adjustments on the TBSS. It worked great. They really did not have to change MAF much at all with the stock engine, and flattening the PE curve really brought the AFR flat steady at all higher rpm's. They ended up at around 12.8:1 and gained near 30 HP all the way up the RPM band and got rid of the dip and peak in power the stock PE curve had. I did more experimenting and it seems to clock the best 0-60 with PE curve at 1.24 off idle and tapering to 1.94 at 3000 RPM then staying that the rest of the way up.

Since I had the luxury of having Superchips test on mine and give me a free tuner, I gained a lot of practical experience and have since learned a lot of how to make the LS2 run doing it somewhat their way but using HP Tuners to fix everything else. (Superchips trans tuning flat out sucks though, I had to really play with that part to get it to feel right everywhere).

[5_Liter_Eater]

The way I intend to use it is to set PE equal to the same number across the entire RPM band and calibrate the MAF, then go back and change the PE table to my desired numbers.

In my case, calibrating the MAF was the ultimate thing I'm editing, which is why I chose to set it up the way I described. I originally tried to correlate MAF frequencies to exact RPM values, but you end up with a MAF frequency that might be halfway between two cells at 6000rpm, so it makes it really hard to determine how to modify the MAF table properly.

It definitely works both ways though, it just depends on what table you're making your changes to.

Gotchya, if you're using it to change the MAF then the way you have it is ideal.