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Thread: VVE Tuning

  1. #21
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    Are you filtering fuel trim cell in the histogram to get rid of deceleration, etc? Paying attention to or filtering on injector tip temp will help as well, to ensure consistent conditions.

  2. #22
    Advanced Tuner HawkZ28's Avatar
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    Not using either as a filter. I'll add them to my channel list and see what comes up during dec. As far as offset vs injector tip temp, I have 0's all through 158*. Do I need to tweak that, or is it more of an IAT table as temperatures currently are fluctuating about 30*+ from a.m. to p.m.
    Hawk

  3. #23
    injector temp issues where on zl1 cars after reflash setting offset to 0 was fix after flash. youll never hit those 180 tip temps unless your frying your motor. how ever after 20 minutes it goes to a normal reading
    Last edited by jpierro79; 10-25-2018 at 12:57 AM.

  4. #24
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    Quote Originally Posted by jpierro79 View Post
    Here's the reason i tune maf second.Its that there is chart that is called intake valve temperature multiplier and it has to to due with the intake valve temps at x rpm and you can have 2 different rpm values and two different intake valve airflow multipliers so if you tune maf first its not correct only making your vve harder to tune.
    Example say at 3200 your intake valve temp read 285 degrees with a multiplier of 1.1 and you have 1/8 throttle but at 2200 rpm 1/4 throttle your intake valve temps are 245 with a multiplier of 1.2 you can have the same exact airflow with about 10 percent difference in required fuel. its just a persay example but airflow DOES NOT DICTATE CORRECT AFR you have to take into account heat and other factors. WOT yes TUNE away with maf but part throttle try to touch it as least as possible and I assure you it takes longer is more complicated but with factory like results. Also heres other thing that stinks is any time you change injectors your intake air temp multiplier is changed and so many shops tunes during summer can run lean or rich during winter. There is no simple way to tune but if you just car about max power ignore me if you want a factory drivable car please listen
    Makes sense to me. So I followed your advice going back to stock and starting with VVE only. I used throttle position greater than 5 percent to eliminate the decel data and had fantastic results! Took about four drive cycles, two with a mix of stop/go, and two long highway drives. To 2600 RPM I'm within -1.0 to -0.7! After, I tuned my MAF and holy smokes it drives freaking smooth! It is like factory. One thing I had to do first was adjust my injector boundry. I used a Excel sheet from another user and it looked like my injectors were firing in the exhaust stroke:-(... Opps!

    I did as an experiment go back to stock with my injectors correct and try MAF first. I got it close doing MAF to VVE but couldn't get it as tight as following your method. Do I see anything wrong going MAF first and/or only, not really but it's enough for me to notice a difference in driveability. To be fair I'm sure the weather has a lot a factor into this. Right now mornings are cold and humid and afternoons are warmer. Makes me wonder if you lived in a area with consistent tempatures would make as much as a difference vs the Midwest.

    Anyways, do have a few more questions if you guys don't mind.

    1 - truck drives good and AFR error is spot on but my VVE table isn't smooth. I have low and high areas between RPMs yet it drives good and if I smooth it throws it off. Is this normal?

    2 - any tips on WOT tuning?

    3 - my most annoying problem... When i drive around a parking lot every once in a while I get surging. This only happens at low speed and I feel like it's only in first gear.

    I know, I'm needy as can be and again I appreciate all of the feedback.

    Thanks

  5. #25
    Advanced Tuner HawkZ28's Avatar
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    Quote Originally Posted by momotunes View Post

    Anyways, do have a few more questions if you guys don't mind.

    1 - truck drives good and AFR error is spot on but my VVE table isn't smooth. I have low and high areas between RPMs yet it drives good and if I smooth it throws it off. Is this normal?

    2 - any tips on WOT tuning?

    3 - my most annoying problem... When i drive around a parking lot every once in a while I get surging. This only happens at low speed and I feel like it's only in first gear.

    I know, I'm needy as can be and again I appreciate all of the feedback.

    Thanks
    1- Mine always seems to end up that way, too. If you look at the 'zone' map of the VVE, you see where it looks as if it's multiple VE tables stitched together to form 1. The problem is that we're creating a visual representation of equations to mimic what we have always known as a VE table.

    2- I've found that doing it on a steep hill helps hit VVE cells that otherwise I can't on a flat area. I have a 7 mile stretch of 2 lane blacktop I like to WOT on. Good combo of flats and hills. Be careful exceeding the 100mph mark on the stock driveshaft.

    3- may need idle tuned or timing adjusted?

    We're all "needy". But we're all here to help eachother out, too.
    Hawk

  6. #26
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    Quote Originally Posted by HawkZ28 View Post
    1- Mine always seems to end up that way, too. If you look at the 'zone' map of the VVE, you see where it looks as if it's multiple VE tables stitched together to form 1. The problem is that we're creating a visual representation of equations to mimic what we have always known as a VE table.

    2- I've found that doing it on a steep hill helps hit VVE cells that otherwise I can't on a flat area. I have a 7 mile stretch of 2 lane blacktop I like to WOT on. Good combo of flats and hills. Be careful exceeding the 100mph mark on the stock driveshaft.

    3- may need idle tuned or timing adjusted?

    We're all "needy". But we're all here to help eachother out, too.
    That makes sense on the VVE table. I'll leave it as it drives good with good ARF.

    I got a good hill in mind to WOT. Do you adjust VVE for WOT tuning or MAF? I thought VVE disables at WOT? I'm fairly decent with GEN 3 but have been thrown off with GEN 4 lol.

    Last time I attempted WOT I had a lean Spike and my AFR was off 20% for a second. Scared the hell out of me although it did drop to 13.2 after. I'm not sure if fueling didn't catch up when I gunned it or what but enough to make me stop until I seeked clarification.

    I'll work on idle tuning. So many guides out there that are fairly different from each other. Just need to spend more time with it.

    Thanks!

  7. #27
    Advanced Tuner HawkZ28's Avatar
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    How is anybody filtering on fuel trim cells with the E38? I was logging and watching in OLSD, and my FTC go a million miles a second, but to 14 and 15 on decel. Problem is I get 14 at idle, cruise and under throttle. Afraid to filter that out with the 15, but can't effectively filter decel without 14. Any tips? TPS filtering isn't fast enough without eliminating light throttle parts of VVE.

  8. #28
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    Quote Originally Posted by HawkZ28 View Post
    How is anybody filtering on fuel trim cells with the E38? I was logging and watching in OLSD, and my FTC go a million miles a second, but to 14 and 15 on decel. Problem is I get 14 at idle, cruise and under throttle. Afraid to filter that out with the 15, but can't effectively filter decel without 14. Any tips? TPS filtering isn't fast enough without eliminating light throttle parts of VVE.
    I was using my wideband afr math for VVE tuning. I set the plot up for anything greater than 5% throttle position. When id drive I was careful to throttle it when needed and let off the throttle completely when I didn't need to. I tried TPS sensor and it didn't work as you stated. Throttle pedal position is what I used. Right or wrong I don't know but it worked for me. I'm not experienced though so I might be completely wrong :-(

  9. #29
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    Quote Originally Posted by HawkZ28 View Post
    How is anybody filtering on fuel trim cells with the E38? I was logging and watching in OLSD, and my FTC go a million miles a second, but to 14 and 15 on decel. Problem is I get 14 at idle, cruise and under throttle. Afraid to filter that out with the 15, but can't effectively filter decel without 14. Any tips? TPS filtering isn't fast enough without eliminating light throttle parts of VVE.
    Not sure if this was your question, but this is a good video on setting up some filter parameters.

    https://www.youtube.com/watch?v=_3Va9NyuM8U
    07 Silverado 5.3 full exhaust, CAI, BTR Stage 2 turbo cam and springs 226/231 .605"/.598" 113+4

  10. #30
    Advanced Tuner HawkZ28's Avatar
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    That doesn't quite answer it regarding the FTC, but it definitely helped with the steady state and TPS.

    Great find! Thank you!

  11. #31
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    This takes out only deceleration, with either EVAP condition (open or closed):

    [6310]<7 OR ([6310]<15 AND [6310]>7)

    It includes everything else (including idle). If you want to kill idle, too, you can remove cells 6 and 14 with this:

    [6310]<6 OR ([6310]<14 AND [6310]>7)

    Here's the cheat sheet to set it up however you like (I think credit for this goes to Ed Mowton, I believe):
    EVAP Open
    0 - 5 defined by the LTFT Airflow Mode Purge On boundaries
    6 - Idle
    7 - Decel

    EVAP Closed
    8 - 13 defined by the LTFT Airflow Mode Purge Off boundaries
    14 - Idle
    15 - Decel

    I'm not sure about your FTC being all over the place. Mine is consistently a stair step. Example: it hangs out in 0,1 or 8,9 during cruise, moves to 7 or 15 during decel, drops to 6 or 14 at idle. Most of the time, my EVAP is open and my FTC is either 0, 1, 6, or 7 if just cruising around.

    If yours is jumping all over the place, maybe check the airflow mode purge boundaries?
    Last edited by RobZL1; 10-28-2018 at 08:47 PM.

  12. #32
    timing can slightly throw your driveability but please understand as your VVE calculates your spark airlfow. This will always change your timing. Thats why i say VVE first. Do not add timing below 1/2 throttle as its useless unless you have a full build. Now sometimes using eq error will not give you a clean idle because your stock o2 do not function the same. Heres the hardest part clean idle. Unless your running a cam outside factory do NOT MESS WITH IDLE LOW HIGH TIMING. meaning maximum variation based upon rpm differences. What you can do is offset your low o2 mv to higher than 450 in first 3 zones and see how it idles. Again keeping maf above idle. Then and only then take your low rpms idle zone as shown in my picture i will attach and even it out. DO NOT GO CRAZY you have to log the idle spark and see what is directly in the middle of max advance vs lowest during idle and set this low area. AGAIN if your vve and maf blend still cause lean even with o2 adjustment just log idle eq error and use idle increase decrease function 600-1000 and back down leaving fuel trims on datalogging the errors. Copy and paste to both open and closed VVE by 1/2. With headers it will never trim idle proplerly. Ill attach my tune file please look at my closed loop VVE youll see a slight spike. I simply using my wideband did my histogram multiplied by percent 1/2 till idle was beatiful regardless of trims. Meaning it must start good idle good and have no flaws even during first 60 seconds. Now please do not forget before and after flash in vcm scanner reset fuel trims.finished6 high ve12 maf.hpt dont forget to reset fuel trims in vcm scanner as they can carry over.
    Attached Images Attached Images
    Last edited by jpierro79; 10-28-2018 at 10:23 PM.

  13. #33
    Advanced Tuner HawkZ28's Avatar
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    LTFT boundaries define FTC......I have LTFT turned off, so that's probably why I am having the bouncing and odd readings. I turned them off when I first tuned by STFT before I got my wideband.

    Here's what I've been running for a filter. I have been viewing it with both <14 and <15 to see how much difference. It on average has accounted for a +/- .3 max difference in values in a long log (20-30 miles). Between tuning OLSD and OLMAF this way I've gotten CL Blended to run at -.250 to -.750 STFT only.

    [50090.156.slope(200)]<2 AND [50090.156.slope(-200)]<2 AND [6310]<15

    Great find- I had looked all over for an actual table like that. Your google fu is strong!
    Hawk

  14. #34
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    Quote Originally Posted by jpierro79 View Post
    Here's the reason i tune maf second.Its that there is chart that is called intake valve temperature multiplier and it has to to due with the intake valve temps at x rpm and you can have 2 different rpm values and two different intake valve airflow multipliers so if you tune maf first its not correct only making your vve harder to tune.
    Example say at 3200 your intake valve temp read 285 degrees with a multiplier of 1.1 and you have 1/8 throttle but at 2200 rpm 1/4 throttle your intake valve temps are 245 with a multiplier of 1.2 you can have the same exact airflow with about 10 percent difference in required fuel. its just a persay example but airflow DOES NOT DICTATE CORRECT AFR you have to take into account heat and other factors. WOT yes TUNE away with maf but part throttle try to touch it as least as possible and I assure you it takes longer is more complicated but with factory like results. Also heres other thing that stinks is any time you change injectors your intake air temp multiplier is changed and so many shops tunes during summer can run lean or rich during winter. There is no simple way to tune but if you just car about max power ignore me if you want a factory drivable car please listen
    shush with your non sense. get over the fact that you can do maf first and its prefered maf first to get PE wot all set.