tuning wot with out wideband

[BBA]

Yes you can. Filter for a commanded AFR that is above your commanded AFR during PE. I use it all the time. You can do it in terms of EQ ratio as well if you want to stick to lambda. I typically run 0.85 lambda during WOT, so set up a filter that only includes trims when commanded EQ ratio is greater than 0.9 or something.

I understand what you are saying, but I can not get trims when PE is active. As soon as I leave closed loop, Trims all go to zero. Do you know a way around this?

[DSteck]

Why would you want trims during PE? They will just lock at whatever the trim was the instant before entering PE.

[5_Liter_Eater]

He wants to do fuel trim tuning at WOT...

[BBA]

He wants to do fuel trim tuning at WOT...

Actually, I wanted to illustrate how PE tuning will NOT work with narrowband by using trims.

Dsteck was confusing the question: His previous reply implied that using PE correction could be done for WOT tuning, but the point he missed was the part about WITHOUT a wideband O2 sensor. Of course, the only way to do that tuning at WOT with STFT on narrowbands is WITHOUT enabling PE and forcing closed loop on. This works well and allows you to know exactly what stoich is so you can reliably set open loop lambda simply with setting PE multiplier.

[BBA]

Why would you want trims during PE? They will just lock at whatever the trim was the instant before entering PE.

Not sure about them locking at any value, they always go to zero. At least that's been my experience, your experience may be different (maybe PCM differences between years/models?).

[DSteck]

Not sure about them locking at any value, they always go to zero. At least that's been my experience, your experience may be different (maybe PCM differences between years/models?).

Any time I have a positive trim, it shows up during WOT. Negatives don't. Either way, you can filter out trims from your collective data by filtering according to commanded EQ ratio/commanded AFR.

[BBA]

Any time I have a positive trim, it shows up during WOT.

But...have you specifically looked for those trims while actually in open loop? There will be points in WOT where you are still closed loop, depending on PE enable/delay settings (and probably a slew of other settings as well).

[Deeker1]

I am very green on tuning and have been reading non-stop before using my HP Tuners on my '09 G-8 6.0. It seems that a mv signal would be more accurate or does the signal bounce around too much? What makes the O2 sensor different that is used with a AFR guage as to the stock O2 sensor? I am trying to figure out what the difference is on the O2 sensors then if I do decide a different one is n where exactly to put it in my exhaust of my G8? Thanks for answering.

[murphinator]

I am very green on tuning and have been reading non-stop before using my HP Tuners on my '09 G-8 6.0. It seems that a mv signal would be more accurate or does the signal bounce around too much? What makes the O2 sensor different that is used with a AFR guage as to the stock O2 sensor? I am trying to figure out what the difference is on the O2 sensors then if I do decide a different one is n where exactly to put it in my exhaust of my G8? Thanks for answering.

stock 02 sensors on most cars ( there are a few exceptions) are "narrowband" oxygen sensors, they are used to keep your car running around stoich which for gasoline is around 14.6/14.7 to 1. narrowband sensors only read accurately in a narrow afr window from stoich and 14 to 1 is about as rich as they can read accurately away from stoich.

normally aspirated cars at WOT are typically tuned to run approx 13 to 1 on a gasoline scale while it is not uncommon for forced induction cars to be tuned for 11.0-11.5 to 1 again on a gasoline scale. a wideband sensor has no issues reporting accurate air fuel ratios in this wide range as well as richer if need be hence the name wideband

so in a nutshell if you want any amount of accuracy with your air fuel ratios at WOT you will need a wideband to verify this in a straight forward simple manner

[Roger Ramjet]

Here is a typical narrow band O2 sensor output. Note the problem area in red.

[IndyPete]

Silly thought... Any I'm new to this.

If you know exactly how much air is coming in to the motor. You know the displacement. You know the temperature of the incoming air before it gets mixed with fuel. You know how much fuel is needed for stoich.

Wouldn't it be theoretically possible to calculate your AFR if you knew how much extra fuel you added at a specific RPM? I'm thinking that you should be able to get that pretty darn close to what you want. I'm not making the argument that actually measuring it is a bad thing.

To me BBA's point makes perfect sense, No need to hunt for a magic AFR #, just tune it until it gives best power. Then record the value for shits and giggles

Maybe I'm way off on this. It's just something I woke up with this morning. Any thoughts?

[DSteck]

Being able to accurately measure the airflow is the million dollar task at hand. That's why we use O2 sensors to correct the airflow model (assuming we already have correct calibration data for injectors).

Cars all tend to pretty much make the best power around the same operating conditions (plus or minus some tming). If you want to tune for power and you have a load dyno, then sure, go right ahead and do it and tune for power. Chances are, most people don't have easy access to a load based dyno, and are left doing things on the street according to wideband feedback. Using the horsepower/torque calculations from the PCM is not a reliable way to gauge maximum power production.

[8850]

Using the horsepower/torque calculations from the PCM is not a reliable way to gauge maximum power production.

Very true but I have had some success logging mph vs. time.

[BBA]

Using the horsepower/torque calculations from the PCM is not a reliable way to gauge maximum power production.

And you base this on what? The PCM has a built in real load dyno calibrated for the actual vehicle it's built into. What you thought they just added the software for fun? They use that torque value for almost all safety controls (Stabilitrak, TC, ABS, etc...) not to mention trans shift quality and feel, etc...

But by all means, it can be verified by time runs, but you can't zero in each RPMs best PE just by doing time runs, with calculated delivered torque you can.

[8850]

But by all means, it can be verified by time runs, but you can't zero in each RPMs best PE just by doing time runs, with calculated delivered torque you can.

Good point! I actually use both.

[DSteck]

And you base this on what? The PCM has a built in real load dyno calibrated for the actual vehicle it's built into. What you thought they just added the software for fun? They use that torque value for almost all safety controls (Stabilitrak, TC, ABS, etc...) not to mention trans shift quality and feel, etc...

But by all means, it can be verified by time runs, but you can't zero in each RPMs best PE just by doing time runs, with calculated delivered torque you can.

I base it on comparison to real dyno runs. I've yet to see reported horsepower match a dyno run dead nuts. Yes, the value is used for various operating conditions and systems, but that doesn't mean it's exactly accurate. I stopped bothering to even log delivered torque when it didn't match the Dyno Dynamics that I sometimes use.

[69lt1bird]

And you base this on what? The PCM has a built in real load dyno calibrated for the actual vehicle it's built into. What you thought they just added the software for fun? They use that torque value for almost all safety controls (Stabilitrak, TC, ABS, etc...) not to mention trans shift quality and feel, etc...

But by all means, it can be verified by time runs, but you can't zero in each RPMs best PE just by doing time runs, with calculated delivered torque you can.

All of this is fine on a factory stock engine. Change the injectors, heads, stall converter, etc. all of the fine factory parameters that they spent thousands of hours dialing in are now gone. After several runs to see if your readings are consistent you can use the torque values to see if you are perhaps making gains with timing or fueling changes but not for how much torque you are actually making if you are not stock.

[BBA]

All of this is fine on a factory stock engine. Change the injectors, heads, stall converter, etc. all of the fine factory parameters that they spent thousands of hours dialing in are now gone. After several runs to see if your readings are consistent you can use the torque values to see if you are perhaps making gains with timing or fueling changes but not for how much torque you are actually making if you are not stock.

I am not implying that you will get an absolute accurate number per se, but you do get accurate comparisons from one tune parameter change to another by using calculated torque. Thus, tuning for max power is still tuning for the highest number, no matter what the absolute value of the number is.

It's really no differnt than using one dyno shop then the next on the same car, no two chassis dyno's read the same numbers either, it's only a reference value to judge by. That is, unless you just happen to be one of those 'dyno queen' types.

[johnh]

I've found on a stock/nearly stock motor, if your trims and maf are dialed in properly you'll be pretty close to commanded at WOT. Perfect no? but usually close enough. The PCM/ECM does a pretty decent job of giving the right amount of fuel given the correct inputs...

[BBA]

I've found on a stock/nearly stock motor, if your trims and maf are dialed in properly you'll be pretty close to commanded at WOT. Perfect no? but usually close enough. The PCM/ECM does a pretty decent job of giving the right amount of fuel given the correct inputs...

I'll also add that on a stock or nearly stock motor, MAV/VE will be dialed in pretty close from the factory, any change that is needed will be from fuel composition and can be corrected by adjusting the Stoich value to reduce fuel trims.