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Discussion Starter · #21 ·
I'm in the same boat. Need to tweak min air. It did wind up being the min air tables set too high that cause my car to idle down in the -2 - 0 deg timing advance.....which caused surging, even when fully warmed up. I've since got it to idle smoothly, but the throttle is very touchy....too sensitive IMO.

I definitely have timing to smooth out in those air mass ranges. I'll have to go through and make sure I don't have conflicting data in various tables all competing for the commanded idle and coast down timing.

What did you wind up setting your solid state maff at? I know a lot of variables come into play between our setups, just curious.
This probably gets you close



Lower your min air tables another 5-10% and see if you can run more timing. Makes the transition to high octane ranges easier

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Discussion Starter · #24 ·
#driveslikestock.

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Very cool wrap - looks just like snow!
 

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Discussion Starter · #26 ·
I'm in the same boat. Need to tweak min air. It did wind up being the min air tables set too high that cause my car to idle down in the -2 - 0 deg timing advance.....which caused surging, even when fully warmed up. I've since got it to idle smoothly, but the throttle is very touchy....too sensitive IMO.

I definitely have timing to smooth out in those air mass ranges. I'll have to go through and make sure I don't have conflicting data in various tables all competing for the commanded idle and coast down timing.

What did you wind up setting your solid state maff at? I know a lot of variables come into play between our setups, just curious.

One more thing, in addition to the airflow and timing changes, it's worth taking a look at your open loop Commanded EQ ranges - odds are your filthy rich on cold start if it's anything close to stock (for catalytic light-up), and reducing that will help the excessively rich bogging that typically occurs before the O2 sensors light up and closed loop kicks in.
 

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One more thing, in addition to the airflow and timing changes, it's worth taking a look at your open loop Commanded EQ ranges - odds are your filthy rich on cold start if it's anything close to stock (for catalytic light-up), and reducing that will help the excessively rich bogging that typically occurs before the O2 sensors light up and closed loop kicks in.
Oh no, my open loop cold start fueling tables have been halved damn near.

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Discussion Starter · #28 · (Edited)
- I edited this post to correct some errors -

So fun fact: the high octane tables serve as the upper timing limit in idle ranges.

Idle Timing: target / base timing for idle

High octane timing: max timing advance allowed for idle stability. So leaving this a few degrees higher than your target should help timing to keep idle stable and minimize lope. I had this matching my desired idle timing (prev posts) and you could see the actual timing advance plateau while the idle adv. continued to control idle speed.

The airflow changes are slower to react than idle timing advance changes, but still pretty quick. IMHO the most "happy" idle is where you get a few degrees of timing swing back and forth, and a smaller idle adapt adjustment.

Proportional RPM error: it takes the difference in desired RPM versus actual, and literally adds/subtracts airflow based on your Increment / Decrement Coeff. tables. A good rule of thumb is to reduce the values near "zero" in the Coefficient tables by small steps (for larger cams) so its not trying to chase perfection, and thus reduce the tendency for hunting. Change too much and it will probably go nuts - so I'd suggest small changes in the 3-5% range each time.

Integral airflow is "slower" than proportional - from what I understand takes an average of RPM error over time and multiplies this to effect idle - ideally improving idle stability over time (regardless of min airflow settings). I'd probably leave the Integral RPM error range alone here (but adjusting the integral airflow table is an option).

Think of it like short-term fuel trims vs long-term fuel trims, but for idle air control: Proportional is the STFT equivalent (working in conjunction with timing advance) - but for larger cams we want to reduce the sensitivity by "widening" the correction amounts near zero (as I show below in the attachments). Integral is like the LTFT and will adapt over time to adjust total airflow, my reading suggests this will happen in spite of your "min airflow" tables... much like fueling and fuel trims.

In summary, I'd suggest for larger cams lowering the Proportional Increment/Decrement Coeff tables near zero (so there is less airflow adjustment for small RPM errors), to make it more forgiving - and potentially increase the RPM error by 5-10 RPM at most. I think the keys is to mute how much is adjusted, rather than widening the allowable error, but every car may be different. I would leave the Integral RPM error amount alone, save for lowering the corrections at and near Zero to make it more forgiving.


 

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@random84 Thank you for posting this. For the longest time, I've been wanting to clean up my tune (part throttle) but never knew where to start. After reading your notes and watching the videos, I took the plunge and dove in feet first... and so glad I did. My V hasn't run this good... EVER! I still need some tweaking but it's already a lot better.
 

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So, switching gears to tuning SD. First, I'm no expert. Just a long time amateur tuner. If any of you are/were following my build thread, you'll know I was having some rich decel/rich light throttle issues. Turns out, it's mass airflow sensor related. Now, while I wait for a new mass airflow tube and sensor to come in that moves the sensor away from the 90deg bend that goes into the intake manifold, I thought I would get smart on SD tuning.

A lot of people are moving to high boost with TT or larger blowers and I can see a lot more folks moving to a SD tune.

I thought I'd share what I know and post a couple questions here for discussion.

Fist thing. I just learned that the VVE table goes way beyond 105KPA.....you just have to right click on the column and add the numbers. It's important these numbers match the tables in the scan tool for MAP VS EQ ERR. That way when you copy and paste % to update your VVE, the columns and rows match. Also, you can extend the RPM out if you twist that shit to 7K like I do.

Once you get idle and cruise all adjusted you can get into boost. Here's how you want to set up your tune to fail the mass airflow sensor and how you setup the scanner to log MAP VS EQ ERR.


Now my questions are tuning the VVE table and running PE. I don't really understand the two together. So, when running SD, do you just pick an RPM and MAP for PE? Is that how you determine you want all the fuel and the VVE table is only for adjust 1.0L fueling? Or do you adjust the VVE table for your desired PE EQ by logging EQ error and adjusting for target fueling in boost, i.e. .78L.

Basically that's what I want to understand. When running SD, is how you control PE with MAP and RPM triggers, i.e. PE MAP = 90KPA and PE RPM = 2,000 (or whenever your setup needs it) and do you hold your VVE table accountable for the commanded EQ error and get the fucker dialed in to desired lambda in boost. I know it sounds like I just said the same thing twice, just trying to be clear.

Happy tuning ya bastards.
 

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My very VERY amateur tuning understanding is that VVE is 1L and you use PE to add fuel on top of that to get your desired .78L. You pick the MAP and RPM based on your particular setup... turbos most likely later in the RPM band when boost comes in as opposed to an LSA blower where you want it sooner.
 

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My very VERY amateur tuning understanding is that VVE is 1L and you use PE to add fuel on top of that to get your desired .78L. You pick the MAP and RPM based on your particular setup... turbos most likely later in the RPM band when boost comes in as opposed to an LSA blower where you want it sooner.
So it seems the VVE table above where you set your PE to enable via map signal, is where you adjust for fueling to match your commanded EQ ratio. I just did some SD tuning with my mass airflow sensor completely failed and it's working great so far. As soon as I cross 90KPA, my commanded EQ goes to .78L and because I set my scanner to data log EQ error across MAP and RPM, I'm now controlling fueling via the VVE table. It's pretty cool and not hard to do....would be easier on a dyno, but what are ya going to do. God bless the interpolate button.....and the smoothing button, lol.

The car is silly though. I've got a lot of timing pulled out of it while I tune and it ripped the tires loose at 50% throttle once the boost came on (8psi). Man I need some drag radials....come on summer, lets get some heat on the roads.

Here's my VVE table after a couple of flashes. The higher KAP (160 and up and most of the RPM ranges) is still untouched and set to being very rich until I hit those cells and am able to see what lambda those values generate. So far, when I got over 130KPA, lambda was .66 which I obviously leaned out.

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just joined the site and do alot of my own tuning also helping a US guy tune his CTSV street drags car gen4 with big single turbo 25+ lb boost running 100% VVE on manifold referenced fuel reg, i always recommend to zero out the maf values when tuning SD (just leave say 12g/s in the zero cell) and also zero all the predictive coefficients so nothing extra plays any part in it, when finished the the VVE table in 3D should be nice and smooth, also found the 3bar MAP sensor can be scaled to suit the 255kpa limit so u can adjust fuel above 22psi when going full SD, even tho i dont have a V i hope to help where i can and also gain knowledge also as learning with tuning never stops
 

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Id like to see the same car, on the same day at the track making 1 pass using a properly dialed in MAF tune and then 1 pass using a properly dialed in SD tune. Or the same could be said for a pull on the dyno, fuel consumption, or anything measurable. In a couple of months, I might actually put mine on the line to see the results.

Does the SD tune have any affect on the trans torque tables? That's where I have the least amount of knowledge when tuning a V...the transmission.
 

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dynamic airflow is used so either maf or SD will have the same results for the torque figure so the trans wont be affected, if both are tuned right then u shouldnt really notice a difference between maf or SD, only thing is SD may be a barely measurable more responsive if anything (also why its used), no such thing as MAF only the VE/VVE is always used/looked up as a check
 

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Discussion Starter · #36 ·
So I finally tweaked my throttle area. The car was super snappy and jerky at low speed, like in rush hour under 10mph.

I reduced the opening rate in low gears and also reduced throttle area by ~10% in the part-throttle areas I was seeing, generally in the 10-30% throttle range.

Believe it or not, it was a YUGE difference. Probably due to my high compression and output; muting the throttle tamed down the manners in low speed. No codes so far, but all reports say don't get crazy with the throttle area maps or you'll throw a REP.


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Discussion Starter · #37 ·
@JAustin

Check out the throttle position tweaks I posted above for your low load drivability, it's really working awesome for me.

I was just re-reading this thread for your FPCM tweaks and wanted to mention it.
 

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great thread random84. It may be worth clarifying EQ error in post 1 for the new guys or moderately interested potential tuners that you are plotting the percentage of error between your wideband input in lambda and your requested EQ ratio.
 
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Sheesh. Reading a lot of these posts is luke reading Rubber Duck's posts. I need to go watch the Goat Rope HPTuner YouTube playlist I found.
 

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Discussion Starter · #40 ·
So I was able to flash my FPCM without paying extra - I guess HP Tuners took pity on me, or I managed to make enough revisions to my tune over the years that I unlocked a bonus level!

Anyway, I finally got rid of my CEL from the Dsteck Aux pump. @adam112 ran a dedicated relay when he helped me install his amazing fuel hat, and I got the CEL every time I hit boost for a Fuel pump secondary circuit low voltage due to the relay (P0231). Although I disabled the code and even FPCM reporting altogether in the ECM, the code would persist - the FPCM has many of these codes duplicated onboard, and only when I disabled the FPCM DTC reporting did the CEL finally disappear!

It also looks like JAustin's fuel pressure tweaks bought me a little extra headroom on the supply side - so far it looks like the rail pressure dip that's commonly reported has been minimized. The dip is still there, just not nearly as severe. I suspect there is more to here as my FP starts to ramp back up at higher RPM but I'm not quite sure what to change. It probably has something to do with one of the fuel flow rate vs voltage tables (or similar).

Fun fact: with the 9.55 / 3.0 pulley ratio, I'm hitting almost 19psi in 65*F ambient. yay!
 
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