poormxdad's consolidated tuning shenanigans thread
 

Gentlemen,

I honestly believe Nigel's new injectors have fixed the intermittent issue from the previous thread. I thought I'd start a new thread so there's not a lot of jumping around.

Here's my latest tune and a short log from driving around town. I had to zip the log to upload it. The only difference between this tune and the last is I turned on Baro Correction, set the Default to 100, and left it on.
She seemed just a bit richer, but it could just have been the placebo effect. She ran around town fine. I was expecting to not even get out of the driveway. Does the log reveal anything about baro correction?

I still have a problem with a stumble. This time, I did not go to WOT, I just accelerated gently and when she passed through about 5700, she stumbled. I lifted off the gas and she was fine. Didn't even get the check engine light.

I'm indebted to youse guys for all your help. My plan is to start making the other suggested adjustments, Any advice would be greatly appreciated.

Thanks much,

Okay, I'm even more confused now. I turned on Baro Correction and really didn't notice anything. Is that because the Barometric Correction Table is blank--all zeroes?

Also, it appears that 100% correction on that table is no correction. Is that correct? Jeez.

Thanks,

My advance curve goes up to 7000 rpm. What happens above 7000?

Have you done a lot of auto tuning? Looks like a lot of it is just poor afrs. Also, when you hit 5700, you were only at 40% throttle, is the TPS calibrated? Trying to tune your partial throttle map before full throttle seems a little backwards to me.

Are you supercharged right now? That's stupid of me, yes, you hit 128kpa.

I might take the belt off if I were you and tune that naturally aspirated cells first. You're requesting similar fuel at full throttle and 5000rpms and at idle, but you are asking for boosted afrs. 100kpa row should be more like 12.5-13, not 11.3. You also have EGO correction turned on, leave it off for tuning. Your dead time is also very wrong. There's a few issues to say the least.

I'm learning there are a few things wrong. However, before having the intermittent running like crap issue, I had taken that tune to the track for two seasons with the supercharger and she was a beast. Two earlier seasons had the MegaSquirt, normally aspirated with the squaretop and MSM intake cam. All those values, like baro correction, have probably been in there from the first tune. My lack of knowledge is at fault here. Also, I don't know if any of these issues were caused when I updated the firmware a week or so ago. I had been running 1.2.0.

I've traded several emails with Nigel from Flow Force. He says these are the same injectors as when I bought them before, but he's using a new testing process, and new correction factors. 0.630 was the dead time recommended two years ago, and 621 was where my set flowed. Dead time now looks to be twice that, and my new ones flow at 667. I created a new graph using the chart on the Flow Force website. I have no explanation why my Curve 1 doesn't cross 100% at 13.2 volts. If I were to double the dead time, she would be rich as all hell. Correct? Is that why my VE table numbers are so high? Updating the injector size to 667 should take some of that out. Correct? Is there a general correction for the entire VE table that would get me in the ballpark? It seems like those are the first things I need to fix.

I used to autotune all the time before I got the Rotrex, especially if I knew the weather during the trip to the track would be the same as track day. Now that just scares me. I have not autotuned this tune at all in two years.

I've fixed the MAT Correction Table but there are so many things I just don't understand. Comparing my tune to DNM's also scares me.

Thanks much,

I think, personally, start from a clean map.
That injector deadtime should just be set to whatever Nigel said. Don't touch the graph.
Tune idle. Manually.
(Disable EGO correction, 100% out MAT correction)
Tune WOT. Auto
Tune cruising. Auto
(Enable EGO, change MAT if you want, I don't works a lot better for me.)

Use safe timing numbers until you get to a local tuner who knows his shit and pay him good money to do it right.

That all sounds reasonable.

Seems like the first thing I need to do is figure out why I get the stumble. It was not there before updating to 1.4.1 firmware. It could be a coincidence, but I'm not a big fan of coincidences.

From Nigel's webpage Injector Data ? Flow Force Injectors I get a deadtime of 1.263ms @ 13.2 volts using the 4Bar curve. Does that look right?

It sounds like I should be using an AFR table that isn't so rich. I'm running about 7 pounds of boost max right now. Is there a known good table that someone could share?

I directed that my advance table be conservative. I wasn't looking for every last bit of power. Does it look good enough to keep? It's been used for two seasons of forced induction track time.

Gents, please keep your explanations in noob terminology. I read and write for a living. But sometimes, when I'm told something like the winkiedoodle in my tune is curved too much, I don't necessarily know how to fix that.

Thanks much,

Spark table looks fine. Just take your 105 afr row and set it to more like 12, along with the 95 row that has some 11s. And no matter your boost, I wouldn't run 11.3 anywhere, 11.5 is fine. At 7psi you're probably fine running 11.5-11.7, that's not a lot of boost. And yes, use the 4 bar graph for any NB, 3 bar for any NA. After those changes, you'll probably have to take a lot out of your fuel table.

Remember this handy calculation, if you're running a certain percentage richer than desired, multiply the effected portion of the fuel table by that percentage to gain your desired afr.

For example, if you're idling at 11afr but want 14.7, 11/14.7=.74, multiply your idle cells by .74 to achieve 14.7. Works great for EGO too, if you're averaging 105% in cruise, select your cruise cells and multiply by 1.05, etc etc.

NB FPR is not intake manifold pressure referenced,
so 5bar graph for correct idle would be better

I thought FPR pressure was about 60 psi. I think mine read 61.5 with a cheap HF gauge. That's why I chose 4Bar. I also have the high pressure Walbro 190. The 4Bar graph seemed like the right choice for both idle and boost.

differential pressure across the injector = fuel rail pressure - intake manifold pressure = 61.5 -(-9psi@idle)=70.5psi

Hmm, you read a lot of books, don't you...

From Injector Dynamics Tech Support Ticket # 32051 :

Question: "Please confirm: for non-MAP referenced returnless fuel system with 61psi base pressure I have to choose offset for 70psi(Differential Fuel Pressure during idling is 70psi=61psi fuel rail -(-9)psi manifold vacuum) "

Answer: "Confirmed. And given an offset error is largest when the pulse width is smallest, it will be best to use the offset data at 70psi in your situation, it's the best compromise. Tony Palo, T1 Race Development,Injector Dynamics "

I have not been able to come up with any benefits of using baro in a speed density system.

I would love to be educated here if there are any.

If it was my car, I would turn baro off.

Gents,

I increased the injector dead time to 1.263 while idling in the driveway. AFRs went way rich. Is there a formula I can use to reduce the entire VE table based on increasing the dead time?

Thanks,

you could derive it. Would come down to something like newVE = oldVE + (oldDeadTime - newDeadTime)/(ReqFuel / squirts)



that is just an example, don't use it, derive it for yourself.

edit: there is absolutely an error in that equation! DO NOT USE IT!!!

I interpolated the 5Bar curve and get ~1.46ms dead time @13.2 volts. Is anyone else running something close to that number with the Flow Force injectors?

I understand the simple math relationships above. I was wondering if there were some kind of mathematical correlation between the dead time and the VE Table. For example, if I double the dead time, I need to cut the VE Table in half to get me in the ball park. Or, if I increase the dead time by 0.600ms, I should multiply the VE Table cells by 0.600 times the square root of pi.

Nigel passed me a dead time, a voltage curve and a small pulse width curve, attached.

He also said the injectors are flow tested at 43psi. Mine would flow about 788 corrected for 60 psi. Should I change the injector size to 788, since I'm making all these other changes?

Can anyone tell me why changing one curve in Tuner Studio messes up the remaining curves? It doesn't duplicate the new Curve 1 in the other curves, but rather just changes them, like it's adding the new values into the old curve rather than replacing them.

Thanks,

Yes, you should change your required fuel to include the 788 size.

This should help lean out your fuel table, but I don't think it'll be enough.

Dead time is directly added to your pulsewidth, so after MS calculates your PW off your VE table, warm up enrichments, etc etc, it adds dead time. It's a big chunk. I'd find the PW calculation and solve for X. X being your VE btw. Then you'll have your multiplication factor.

I decided to hang it all out and make a bunch of changes all at once.

I changed the AFR Table after reading through all the AFR table threads here. I changed the Required Fuel and Injector Size, Dead Time, Dead Time Voltage Curve, and Injector Small Pulsewidths Curve based on Nigel's suggestions. Nigel's dead time number comes from the 4Bar graph. I changed the MAT Air Density Table per the suggestions here, and turned off Baro Correction (after resetting the Default to 100 kpa), She started right up but was running really rich. I pulled about 40 units from the Idle VE Table--90s to 50s. Then I messed with the Idle Valve calibration. She idles nice and smooth, but the rest of the VE Table is obviously crap now. I'm sure I missed a few things.

I removed the Rotrex belt. If the weather is decent tomorrow, I'll take her out for some autotuning.

I still have to deal with the stumble.

Thanks for all the inputs so far.