How accurate is the AFR line in MpTuner?

[Force Fed Mopar]

Assuming injector size and such is inputted correctly.

[turbovanman²]

Its a starting point, it was pretty close on my last builds but with my new head and header, its way out this time.

[roachjuice]

lol mine is at 11.0 and my afr this morning was 10.x so thats close :eyebrows: honestly ill let you know this afternoon when i get off work how off it is.

[bakes]

Its a starting point, it was pretty close on my last builds but with my new head and header, its way out this time.
that is because your PUMP Efficacy has increased and you havent move the table yet to match the new flow rates

[turbovanman²]

that is because your PUMP Efficacy has increased and you havent move the table yet to match the new flow rates

I know that, :p

[roachjuice]

10:9afr @3500 rpm richened up through out the rpm to 10:1 @5000+ thats as rich as i saw it. if you ask me thats pretty close.

[shackwrrr]

Its accurate if you use the PE table to tune out of boost before tuning the fuel tables. If you throw on a ported head ect. and then just crank the fuel tables it wont be close.

[Aries_Turbo]

it should be dead on for a given displacement thats completely filled with air (no head/manifold restrictions, ie, 100% pumping efficiency) at a given pressure with a known injector size and a known fuel pressure and a correctly working fuel pressure regulator.

the pumping efficiency table is used to iron out the differences that RPM brings as the engine is more or less efficient at certain RPMS due to how everything reacts with the headflow, cams, manifolds, exhaust side of the turbo etc.

Brian

[Force Fed Mopar]

So if the pump efficiency is spot on, you should be able to match the fuel tables to the afr line?

[shackwrrr]

So if the pump efficiency is spot on, you should be able to match the fuel tables to the afr line?

By the way I understand it, yes.

[cordes]

So if the pump efficiency is spot on, you should be able to match the fuel tables to the afr line?

With Chem2 I found it to be so good that I used the line to help me tune the pumping table. Best driving cal I had done to date.

[shackwrrr]

With Chem2 I found it to be so good that I used the line to help me tune the pumping table. Best driving cal I had done to date.

I was just thinking of that, If you aren't right on the line it means you need to adjust the PE table (assuming the AFR table/ engine info is correct)

Now we need some software written to take a wideband and datalog input and enable PE learn functions. I am building a MPFI setup right now for a 600CI BBC, the owner wanted to keep all stock functions like A/C and cruise so I opted for a modified stock computer. It has a board that replaces the calpak and memcal, the board has an extra A2D converter that accepts a wideband and other 0-5v sensors. This doesnt connect with anything on the ECM it's just on board to use the same 232 chip for serial interface. With the computer I got software that has VE learn functions which uses a combo of inputs and is all software based. It make adjustments to the VE table while you drive and then gives you a modified table to burn.

I think this could easily be done on our systems with the SCI/serial interface and a wideband input. Build software that looks at both inputs and makes changes to the table, stop, burn the chip and take another cruise.

[Force Fed Mopar]

So basically the AFR line is a calculation of pulsewidth needed for the set AFR value, and is calculated from the PumpEff table, MAP reading and injector size. Correct?

[turbovanman²]

So basically the AFR line is a calculation of pulsewidth needed for the set AFR value, and is calculated from the PumpEff table, MAP reading and injector size. Correct?

Sure, lol.

BTW, made a new cal for my new injectors, used the MP tuner AFR line, BANG on, scarily bang on. I messed with the WOT tables alot as I prefer over rich first but if I'd only tweaked them a bit, it would have been very close.

[roachjuice]

Sure, lol.

BTW, made a new cal for my new injectors, used the MP tuner AFR line, BANG on, scarily bang on. I messed with the WOT tables alot as I prefer over rich first but if I'd only tweaked them a bit, it would have been very close.

My exact experience too. I didn't believe it first. But it worked.

[Aries_Turbo]

So basically the AFR line is a calculation of pulsewidth needed for the set AFR value, and is calculated from the PumpEff table, MAP reading and injector size. Correct?

not quite. the afr line takes into account the map reading, the injector size and assumes 100% PumpingEfficiency and the engine displacement.

since the engine breathes differently at different RPM's, the pumping efficiency trims the fuel back as not 100% of the air is getting into the cyls at all RPM's.

so if you setup the cal based on the AFR line and the AFR isnt what you have programmed for that boost/vac level, then you need to adjust the pumping efficiency table.

Brian

[Force Fed Mopar]

Okay makes sense now.

[Force Fed Mopar]

Well...

When I load up a stock cal, the fuel tables are nowhere near the AFR line, not in boost anyway. Are the stockers really that rich, or are we missing something? I mean, I just loaded the B151 template and it's showing the fuel to be like 10.8:1 at 11 psi part throttle?! WOT fuel is like in the 9's?! I know the stock cals are rich, but I didn't think they were that far off.

[shackwrrr]

Well...

When I load up a stock cal, the fuel tables are nowhere near the AFR line, not in boost anyway. Are the stockers really that rich, or are we missing something? I mean, I just loaded the B151 template and it's showing the fuel to be like 10.8:1 at 11 psi part throttle?! WOT fuel is like in the 9's?! I know the stock cals are rich, but I didn't think they were that far off.

Did you adjust the afr tables

[Force Fed Mopar]

Adjust them as in...?

[turbovanman²]

Adjust them as in...?

LOL, you have to put in your values, go to misc, fueling setup then set the AF ratio you want, engine size and fuel your using. I put the IAT at 80 deg's. Remember to click AFR in the lower right corner after your done.

[Force Fed Mopar]

No I just loaded a stock cal, clicked the Show AFR button. So you have to set the AFR settings for every cal?

[turbovanman²]

No I just loaded a stock cal, clicked the Show AFR button. So you have to set the AFR settings for every cal?

AFAIK, yes.

[ShelGame]

No I just loaded a stock cal, clicked the Show AFR button. So you have to set the AFR settings for every cal?

Yes, after you set it up, it's stored in the template itself. So, you would have to do it for every cal. But, if you're handy with a text editor, you could copy over the same A/F setup to multiple cals.

Maybe we should ask Morris for an A/F data export/import...

[turbovanman²]

Yes, after you set it up, it's stored in the template itself. So, you would have to do it for every cal. But, if you're handy with a text editor, you could copy over the same A/F setup to multiple cals.

Maybe we should ask Morris for an A/F data export/import...

Damn, that would be cool, :nod:

[Force Fed Mopar]

So what would you input for a stock cal?

[wowzer]

Yes, after you set it up, it's stored in the template itself. So, you would have to do it for every cal. But, if you're handy with a text editor, you could copy over the same A/F setup to multiple cals.

Maybe we should ask Morris for an A/F data export/import...

rob just sent me the link to this. sorry i missed it.

in mpt2, once you set up the afr settings and save them and then save the cal, the settings are stored in the cal so the next time you open it the afr stuff is setup. the afr settings screen/grid allows you to not only "interpolate" between two cells but also allows you to highlight a range of cells and copy them. when you copy the cells, mpt2 is actually copying them to the regular windows clipboard. this means that you can then paste that data into another program like excel, notepad, etc. OR BACK INTO ANOTHER OPEN CAL IN MPT2. this feature has been there for awhile. can't remember who requested it.

bottom line, select the afr cells you want to copy from a cal already setup, press copy, switch to the "new" cal, press paste, and then the magic happens!

(btw, there is a tiny, weeny, little bug in the pasting, i.e. it doesn't turn on the save button. just edit a cell after the paste and it should work).

[ShelGame]

rob just sent me the link to this. sorry i missed it.

in mpt2, once you set up the afr settings and save them and then save the cal, the settings are stored in the cal so the next time you open it the afr stuff is setup. the afr settings screen/grid allows you to not only "interpolate" between two cells but also allows you to highlight a range of cells and copy them. when you copy the cells, mpt2 is actually copying them to the regular windows clipboard. this means that you can then paste that data into another program like excel, notepad, etc. OR BACK INTO ANOTHER OPEN CAL IN MPT2. this feature has been there for awhile. can't remember who requested it.

bottom line, select the afr cells you want to copy from a cal already setup, press copy, switch to the "new" cal, press paste, and then the magic happens!

(btw, there is a tiny, weeny, little bug in the pasting, i.e. it doesn't turn on the save button. just edit a cell after the paste and it should work).

Cool, I didn't realize it already did that...

[wowzer]

its a secret feature

[turbovanman²]

So what would you input for a stock cal?

I use these for my cals, 14.7 or leaner for idle, 13.5 for part throttle and 11.5 for WOT, so use that or something close or leaner or richer, ;)

[Force Fed Mopar]

I use these for my cals, 14.7 or leaner for idle, 13.5 for part throttle and 11.5 for WOT, so use that or something close or leaner or richer, ;)

I already have that set, I was talking about the other settings ;) Like the temp. Why is it in Celsius anyway, for starters? Everyone knows Celsius is ghey... lol j/k. But what temp should you put in? An average of what temps you will see, or the hottest temp it will see? Or the coldest? Plus higher boost levels are going to see more heat.

[ShelGame]

I already have that set, I was talking about the other settings ;) Like the temp. Why is it in Celsius anyway, for starters? Everyone knows Celsius is ghey... lol j/k. But what temp should you put in? An average of what temps you will see, or the hottest temp it will see? Or the coldest? Plus higher boost levels are going to see more heat.

Use the hottest temp you think it will be. The charge temp sensor adds fuel when it's colder. The stock cals have this set to ~70C.

[cordes]

I already have that set, I was talking about the other settings ;) Like the temp. Why is it in Celsius anyway, for starters? Everyone knows Celsius is ghey... lol j/k. But what temp should you put in? An average of what temps you will see, or the hottest temp it will see? Or the coldest? Plus higher boost levels are going to see more heat.

I agree that it would be nice to change the units. I don't like the injectors being measured in BAR either.

---------- Post added at 10:14 PM ---------- Previous post was at 10:13 PM ----------


I agree that it would be nice to change the units. I don't like the injectors being measured in BAR either.

ETA: We may as well be using stones per square furlong.

[88C/S]

This has been very informative. Was wondering why the wideband I just installed was showing a higher AFR than what I had set for part and full throttle. Made the adjustment as mentioned and now see the change in the fuel tables. In regards to the PE table, how would you know what to change when you are using a ported head, cast TU header w/ 3 inch exhaust and a T3/T4 turbo.

Thanks for any input.

[cordes]

This has been very informative. Was wondering why the wideband I just installed was showing a higher AFR than what I had set for part and full throttle. Made the adjustment as mentioned and now see the change in the fuel tables. In regards to the PE table, how would you know what to change when you are using a ported head, cast TU header w/ 3 inch exhaust and a T3/T4 turbo.

Thanks for any input.

The easiest way to tune the PE table is to drag the brakes to hold the RPM at a set point. Ride it for at least 10 seconds like that and then record your readings. If the AFR is higher numerically than what it should be according to the AFR line in MPT2, then up the PE table in that RPM spot. If it's lower numerically, then lower the PE table.

If you use that process in 500RPM increments you should have the PE table dialed in perfectly in no time at all.

[Force Fed Mopar]

Where it says injector rating (bar), is that supposed to be the pressure that the injectors are rated at? I guess the 3.7xx it is defaulted at is 55 psi?

[cordes]

Where it says injector rating (bar), is that supposed to be the pressure that the injectors are rated at? I guess the 3.7xx it is defaulted at is 55 psi?

You're correct on both accounts. I think it's probably more accurate to say that it's the static pressure you're running though.

[csxtra]

The easiest way to tune the PE table is to drag the brakes to hold the RPM at a set point. Ride it for at least 10 seconds like that and then record your readings. If the AFR is higher numerically than what it should be according to the AFR line in MPT2, then up the PE table in that RPM spot. If it's lower numerically, then lower the PE table.

If you use that process in 500RPM increments you should have the PE table dialed in perfectly in no time at all.

So Brian...I'm assuming you want to do this at 0 lbs of boost and WOT to eliminate the turbo from the equation as much as possible?

If so, what is the best way of keeping boost out? I need to fine tune my pumping efficiency table and I was going to disconnect my intercooler piping from the throttle body, hook an air tank through a regulator to the wastegate can, putting about 30PSI against the can to keep the wastegate open (to reduce backpressure from the turbine wheel and keep the turbo wheel speed down). Then do some WOT runs dragging the brakes to log the AFRs at each 500 RPM point, and adjust the Pumping Efficiency table accordingly. Does this sound like a valid method, or am I off base somewhere?

[Aries_Turbo]

yeah thats a decent way to do it but you may have to do a little tweaking once all the piping is hooked up cause it changes flow some.

after doing the no boost baseline, do as low as possible boost and do some tweaks.

Brian

[cordes]

I've honestly done it at about 6PSI and it's worked great throughout the range. Of course I didn't really get any boost until much higher RPM anyway so that did eliminate the turbo up to at least 2.5K. I did have to adjust the part throttle fuel table up a little in vac though other wise I would have needed the PE table ridiculously high from 1K-2.5K RPM. I also found that Frank's Turbo Calculator PE numbers were a great place to start. They would be especially good for you since you'll actually know so much of the information for real rather than just guessing based off of other people's stuff. Since you're just fine tuning, that may be irrelevant though.

[csxtra]

Thanks Brians! I knew you two would have the real scoop!