Hey guys... working with TunerCat and the $3A here...

Anywho, I need to lean out WOT a tad. I'm blowing black smoke when I floor it, so I figure I need to change the '%change AFR @ WOT' table.

Now, from what I read in the $32b tuning article, this table doesn't actually change the A/F ratio, as instead it will change the pulsewidth, by whatever percentage @ a given RPM (when in WOT)

Is this correct? So that if I had a 2.7 @ 2000 rpm, it would increase my fuel pulsewidth by 2.7%, if I'm at WOT when at 2000 rpm?

Just want to make sure I'm understanding correctly.

 

Raising the pulsewidth (relative to load and RPM) IS richening the Air Fuel ratio. Percent fuel increase is also fairly close to directly changing air fuel ratio - i.e. 14.7/12.5*100=117.6%, so adding 17-18% will take a 14.7:1 AF straight to 12.5:1. The stock calibration is set extremely rich like 11:1. All it takes for the black smoke to show up is to be about another10-15% rich in the VE table.

One thing to be careful of is that if Acceleration Enrichment is too rich, it can easily shoot out a big puff of black smoke initially, while at the same time the PE and VE can be acceptable - but it's not likely.

For safety sake, I'd recommend setting PE to 20% across the board (stock can be 30%+), then start with getting the VE dialed in using the block learn values ~ every 1% of VE change was like 2 points of BLF this weekend on a 7747 - so if BLFs are 118, take 5% out of that region. You can calibrate the WOT VE by doing the 90 kPa (4.0 Volts of MAP) while in closed loop and block learn, and using the same number at 100 with maybe a 2 or 3 percent VE increase. Try to get all BLFs to 128 everywhere, then just leave PE flat across the board until you can get on a dyno and experiment with where it likes richer and leaner than 12-12.5:1.

Then do spark.

 

Tune VE? I've got no VE tables. Just a 'PW vs LV8' table, and it's not even RPM based (I emailed TunerCat about that)

This is a MAF based system, so what have I got in place of VE tables? I'm under the impression that if I've got a stock MAF, unmodified, no need to be messing with the MAF tables...

 

Sorry, didn't even look at your setup, and was just spitting out tuning strategies in general.

What is your setup? Turbo? What injectors? Standard pressure regulator?

On MAF if you change injectors or fuel pressure, you have to let the ECU know - it calculates PW based on what it thinks it knows as air flowrate and fuel flowrate - and it assumes the static injector flow rate is not changing due to fuel pressure. Also, with a turbo, you may be flowing more than the ECU is told is the maximum at each RPM, and could be hitting some limp default mode, but I don't have any experience with the V6 MAF code.

If you are running an FMU, dial it back a little if it's adjustable.

Are your block learns during normal driving close to right? This will tell you how well the MAF table and injector flow rate are jiving (engineer speak, j/k, but I am an engineer, an EFI engineer actually).

Are you sure you want to keep tuning without a wideband? I wouldn't even consider doing it without it on a turbo engine - one wrong guess, and blamo.

On a turbo engine with naturally aspirated compression ratios, I would have to recommend you start the WOT tune at 11:1, run less than .030" plug gap, and pull some timing out (20-24° at WOT total). The percent change for going from 14.7 to 11:1 is about 30 to 35% IF your MAF PW table is correct.

 

Well, as far as the fuel goes -

I pulled 70% of the BPW out of the Injector Pulse Width vs LV8 table... I did that, because I went from 13pph injectors, to 22.

I think there's a PW for LV8 vs RPM table buried in this $3A, and emailed TunerCat about it... we'll see. I really hope there is some sort of RPM based fuel table in there!

Timing? Currently @ 21 total. Will stay there until I'm sure I can go with more.

No FMU, just all in the code right now. I'm pig rich, so I don't have to worry about leaning out!

Yes, it's a 16G turbo (550 cfm) on a 3.1L motor with '88 MAF '302 ECU, 5 speed, with 22pph injectors.

More datalogging to come tonight... I'm working on the Throttle Follower right now, to get my idle nicer (when I hit the clutch, and let off the gas, the idle soars to 2500rpm, and takes its sweet time coming back down to 1000)

 

In theory, you don't really need a LV8 vs RPM table for Fuel with MAF, since mass air flow is mass air flow, for the most part (ideal world etc - look at $6E - no RPM variable - look at 32B stock tables - same cal at each RPM). With MAP systems - you most definitely need it because manifold pressure is not mass airflow. I'm a little surprised that taking 70% out left you still rich. If I were to do the math, I'd be multiplying the table by .6, which is subtracting 40% when going from 13 to 22s (think 13/22). Maybe my math is wrong, who knows? I think the way you thought of it was that you're adding 70% more injector, so take 70% out. What if you were adding 100% more injector by going to 26pph inj? You wouldn't take 100% out would you?

What would help calibrating with different injectors is a linearization function that tells the flowrate at each PW especially when the PWs are small (sub 2.5 ms). But that's more from an engineering standpoint, and won't effect your WOT fueling.

My calculations also say that 6 22's won't get you very far HP wise.

 

It may not get me very far... I'm just looking for 240rwhp. That's enough for 13s in a 2950lbs car