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Thread: What to tune first? MAF, VVE, TIMING- Does it matter?

  1. #1
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    What to tune first? MAF, VVE, TIMING- Does it matter?

    as stated in the title. is there a preference for tuning? MAF, VVE, TIMING?

    scenario-

    ive got the MAF dialed in with the help from GHuggins. if i wanted to bump up the timing, would i need to go back and re-tune the MAF? i feel this is going to be a "yes" answer but in order to keep from having to tweak this tweak that redo this then tweak again. is there a preferred order to tuning a NA car?

    Thanks in advance!

  2. #2
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    Changing ignition timing won't change the engine's airflow. If the MAF calibration is good, you can use that to help get the VVE close. I'd do timing last although that will have the greatest impact on power. Get the airflow and fueling right, then sneak up on timing.

  3. #3
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    Well, depends on how "off" the timing is. Such as where we had yours REALLY low for you to dial in your MAF. Once you increase timing at that point it will actually change scavenging into the cylinder by how much faster the engine is revving and not only that but by how much cleaner the fuel is burning. SOooo in that scenario yes timing can change your MAF and VE curves. I personally like to back calculate and tune VVE the same time I'm doing MAF, add the timing in and "tweak" or rather "fine tune" the MAF curve when dialing in final timing... The vve I won't hardly touch any more after it gets really close and is only changing a number or two log to log...
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    ~Greg Huggins~
    Remote Tuning Available at gh[email protected]
    Mobile Tuning Available for North Georgia and WNC

  4. #4
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    ghuggins- thanks for chiming in. my timing tables haven't been dialed in yet. that "tune" when sent to me, was, let's say, less than stellar lol so i do know that i will need to adjust all of them. only thing i have done to them was took 3 degrees out of the LOW OCTANE table and guesstimated the IDLE SPARK ADVANCE.

    Also, just to let you know, i tried reading up on that link you sent about back calculating VVE while doing MAF. honestly, i cannot wrap my head around it yet. i will have to re-read it to see if i can begin to understand it.

  5. #5
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    I use this - (([50041.223]*(273.15+[50011.241]) * (1000/[50030.91]))

    Uses cylinder airmass which is only partially going off of some of the MAF and then MAP and IAT. I find it works best for me. You'll need to log cyl air, map and iat for it to work then set up the "math" parameter in your scanner yourself. Unfortunately the scanner isn't 100% user friendly - you can highlight and copy the above with simple highlight then right click "copy". As far as the scanner side goes you have to "control v" to paste it into the expression function of the math creation table... Since it's using cyl air it also requires your injector data to be as spot on as possible as this will control your cylinder air readings, so that could be a downside of it...

    I am kind of curious how GM calculates it since it seems like they only get accurate data under 3000ish rpms...

    AND yes, that "tune" was super safe for dialing in your MAF on your NA platform while keeping it out of PE...
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    ~Greg Huggins~
    Remote Tuning Available at gh[email protected]
    Mobile Tuning Available for North Georgia and WNC

  6. #6
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    so where do you put the custom math equation? in the filtering function? also, do i need to skip the "parameter" field? VVE.PNG
    Last edited by LS ROB; 01-10-2022 at 06:54 PM.

  7. #7
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    top left corner go into ''tools'' and u will see math parameters in there, then once that is setup in the table as u have named search it as parameter and down the bottom in maths

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    thank you!

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    Ghugginsmsd.PNG i know we made some progress on the MAF but should i adjust my Dynamic Airflow Manifold Volume based on this information from Holley? also, now that i have my scanner set up with the equation you suggested, do i need to disable anything in order to start tuning?

  10. #10
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    Yes manifold volume will save A LOT of transient tuning fuss, but if you have a cam you'll still need to tweak it a touch after all said and done most likely. Nothing to change or disable other than reactivating your PE settings. Put the timing back in it then you can clean up MAF and VVE as you go. Keep in mind to post into the VVE table open and closed sections then hand select and smooth selections. Also don't be afraid to multiply sections missed and then smooth big sections out before calculating coefficients. Just keep at it until your happy with it.
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    ~Greg Huggins~
    Remote Tuning Available at gh[email protected]
    Mobile Tuning Available for North Georgia and WNC

  11. #11
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    cool. sounds great man! im going to give it a go and see what happens! Thanks again!!

  12. #12
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    I like to go back and forth between MAF and VVE a few times until they are both right. You can also do a quick histogram to compare your VVE vs MAF measurements of airflow. If they are both reading the same Lb/Hr value over the whole of your MAP/RPM range then you have tuned them to match. If you are running in SD mode only and your AFR is good, your MAF tune is also good if its saying its reading the same amount of airflow.

  13. #13
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    thanks andrewquant. ive not had a chance to do much tuning right now between the weather and work..i should be good to go once i get some free time.

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    cold to op idle.hpl disabledtip-in.hptwould someone take a look at my VVE graph, to make sure i have it set up correctly before i start? My intentions are to tune VVE without having to disable a bunch of stuff. As for my injector data, im not sure if it is correct or not but i do have stock ls7 injectors. AC DELCO 217-2425. Thanks!

  15. #15
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    I didn't check the tune itself, just looked at the log and a quick glance at your VE table. Your running on straight MAF and your MAF at idle is dang good dialed in. Best I've seen in awhile honestly. Your VE still needs to be dialed in, but isn't far out - looks like 100ish points at idle. A couple of drive cycles should have it really close while logging the cyl air equation. Just keep your graph smoothed while making corrections. I should also mention that you don't want to log while cranking - just while driving and doing good easy driving to keep transients and what nots out of the equation.
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    ~Greg Huggins~
    Remote Tuning Available at gh[email protected]
    Mobile Tuning Available for North Georgia and WNC

  16. #16
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    Thanks Greg! i had some help with that so now, do i adjust my Dynamic Air so that it doesnt use MAF and do the whole VVE table or should i set it to where i want MAF to take over and just tune VVE up to that point? What is the best practice here? Also, not sure as i type this but if i remember correctly i believe my LTFT are turned off, should i enable those as well? when posting to the VVE table do i "paste-special multiply by % half or paste special-multiply by %?"

  17. #17
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    Quote Originally Posted by LS ROB View Post
    as stated in the title. is there a preference for tuning? MAF, VVE, TIMING?

    scenario-

    ive got the MAF dialed in with the help from GHuggins. if i wanted to bump up the timing, would i need to go back and re-tune the MAF? i feel this is going to be a "yes" answer but in order to keep from having to tweak this tweak that redo this then tweak again. is there a preferred order to tuning a NA car?

    Thanks in advance!
    I am new to tuning and am still learning. I have struggled with the VVE table for a while. However, this last week I have been using the info in this thread. I had to read it completely a few times, as others have chimed in to provide clarifications and updates. After doing a few logs and updating as needed, this has been a tremendous improvement to how the car feels in the off idle tip in and as well as getting the fuel trims in check. Of course part of the magic is in the filtering to keep the junk out of the good data.

    https://forum.hptuners.com/showthrea...ation-for-gen4
    Last edited by Cringer; 02-06-2022 at 12:54 PM.

  18. #18
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    To add to that, when making corrections off of equations that are calculating your VVE numbers for you, you don't have to multiply anything... Just paste in the new numbers, hand smooth between the empty cells, smooth large sections of the table, calculate and then flash and restart. Fuel trims are up to you. I would just make sure to put ltft's back in before your done. Run in 100% maf until your done with your VVE and then set to something like 2000 full maf enable.
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    ~Greg Huggins~
    Remote Tuning Available at gh[email protected]
    Mobile Tuning Available for North Georgia and WNC

  19. #19
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    thank you for the link. i have not attempted VVE yet but am going to try soon. i'm sure ill be needing to read up on all the info i can get regarding the subject.

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    awesome! i think im ready to get started then! i wanted to make sure how to copy and paste because i would have definitely messed that up with the multiply percent option. once i copy and paste. how can i tell that i am going in the right direction? i pasted into the VVE table and done a rough estimation that at idle, the VVE is out around 28 percent. does this seem common?
    Last edited by LS ROB; 02-06-2022 at 01:10 PM.