Page 1 of 3 123 LastLast
Results 1 to 20 of 41

Thread: Please Explain WOT VVT Values

  1. #1
    Advanced Tuner WS6HUMMER's Avatar
    Join Date
    Feb 2006
    Location
    Pineville La. US
    Posts
    771

    Please Explain WOT VVT Values

    I'm trying to understand how these numbers relate to timing and if advancing or retarding will help squeeze out a little extra power. Any help is much appreciated, couldn't find much searching.
    99 T/A WS6, original LS1 turbo

  2. #2
    Senior Tuner Higgs Boson's Avatar
    Join Date
    Mar 2010
    Location
    Texas Hill Country
    Posts
    3,299
    As far as I know the numbers are ICL and ECL and together make LSA.....I have a 2014 Wrangler and the stock WOT settings make for a race cam LSA number.....Seems strange.

  3. #3
    Advanced Tuner
    Join Date
    Feb 2016
    Posts
    431
    Yep, ICL and ECL are the numbers, creating LSA (which is fixed on the single cammers). Pretty basic cam tech really.

    Have you changed the Pentastar's cam timing? They really appreciate it.



    Quote Originally Posted by Higgs Boson View Post
    As far as I know the numbers are ICL and ECL and together make LSA.....I have a 2014 Wrangler and the stock WOT settings make for a race cam LSA number.....Seems strange.

  4. #4
    Senior Tuner
    Join Date
    May 2015
    Posts
    1,907
    I personally never understood why they even give you the option to advance and retard both the intake and exhaust, they move together no matter what, advancing one doesn't retard the other.
    Last edited by 06300CSRT8; 10-28-2016 at 03:34 PM.

  5. #5
    Advanced Tuner WS6HUMMER's Avatar
    Join Date
    Feb 2006
    Location
    Pineville La. US
    Posts
    771
    Quote Originally Posted by 06300CSRT8 View Post
    I personally never understood why they even give you the option to advance and retard both the intake and exhaust, they move together no matter what, advancing one retards the other.
    Yeah that's what I was thinking, just one cam so you change one you change both. Thanks for the explanation, so there's not really anything to be gained from changing this on a stock 5.7?
    99 T/A WS6, original LS1 turbo

  6. #6
    Senior Tuner Higgs Boson's Avatar
    Join Date
    Mar 2010
    Location
    Texas Hill Country
    Posts
    3,299
    on a single cam you either advance or retard the whole cam....how do you figure advancing the intake retards the exhaust? if you are advancing the intake and the whole cam advances, how is that retarding the exhaust?

    the tables are there for both ICL and ECL for the DOHC applications, same thing with the GM configs except GM goes by degrees rather than actual CL values.

  7. #7
    Advanced Tuner WS6HUMMER's Avatar
    Join Date
    Feb 2006
    Location
    Pineville La. US
    Posts
    771
    Quote Originally Posted by Higgs Boson View Post
    on a single cam you either advance or retard the whole cam....how do you figure advancing the intake retards the exhaust? if you are advancing the intake and the whole cam advances, how is that retarding the exhaust?

    the tables are there for both ICL and ECL for the DOHC applications, same thing with the GM configs except GM goes by degrees rather than actual CL values.
    Yeah that's how I understood it, if I advanced one table it would advance the whole thing. Is there much to gain from advancing or retarding the VVT timing? Also the lock pin is set on 120* does that mean 120 is as far as you could go on the whole table?
    99 T/A WS6, original LS1 turbo

  8. #8
    Senior Tuner
    Join Date
    May 2015
    Posts
    1,907
    Quote Originally Posted by Higgs Boson View Post
    on a single cam you either advance or retard the whole cam....how do you figure advancing the intake retards the exhaust? if you are advancing the intake and the whole cam advances, how is that retarding the exhaust?

    the tables are there for both ICL and ECL for the DOHC applications, same thing with the GM configs except GM goes by degrees rather than actual CL values.
    LOL small word missing from my post "doesn't" but thanks for clarifying. I would agree with your statement on the DOHC purpose except that the various calibrations certainly have varying intake and exhaust advances, indicating they were originally programmed as though they can move independently. My thinking would tell me you should see the same exact overlap at all points in the rpm range, which is certainly not that case.

    So then the question is, can the cam actually adjust during the overlap phase of the intake and exhaust lobes, so that theoretically it is barely changing the intake advance and adjusting the exhaust advance just prior to the valve opening and so it can act like a DOHC? I cant get my head around the rest of the motor and cam timing, as even though this makes sense for one cylinder, certainly there is another cylinder at the opposite phase (coming up on the intake valve opening vs another cylinder coming up on the exhaust valve opening) and therefore for one cylinder you are retarding the exhaust but on another cylinder are retarding the intake.

  9. #9
    Senior Tuner Higgs Boson's Avatar
    Join Date
    Mar 2010
    Location
    Texas Hill Country
    Posts
    3,299
    just think in terms of one cylinder, remember all the other cylinders have separate valves, they don't all open at the same time, which is why the cam(s) have independent lobes. cylinder to cylinder timing is ground into the cam so if you set one, you have set them all.

    if you have one cam (OHV) then the whole cam moves together and overlap is fixed. DOHC applications can adjust overlap. however, I do think the viper has or had the ability to adjust intake and exhaust independently with an in block camshaft, but I've never tuned a viper.

    the pentastar V6 is a small and low revving engine which is why it surprised me to have such aggressive values at WOT, like a 9000 RPM small block race motor....the values at part throttle make sense but seem to go backwards, maybe for emissions purposes.

    the good thing is, the valve event info is googleable so you know where you are opening the intake and where you are closing the exhaust, which is what controls overlap and you also know where you are closing the intake, which is the most important valve event.

  10. #10
    Advanced Tuner WS6HUMMER's Avatar
    Join Date
    Feb 2006
    Location
    Pineville La. US
    Posts
    771
    Thanks everyone for the explanations, is there anything to be gained from advancing this or retarding this on a stock cam hemi?
    99 T/A WS6, original LS1 turbo

  11. #11
    Senior Tuner
    Join Date
    May 2015
    Posts
    1,907
    Quote Originally Posted by Higgs Boson View Post
    just think in terms of one cylinder, remember all the other cylinders have separate valves, they don't all open at the same time, which is why the cam(s) have independent lobes. cylinder to cylinder timing is ground into the cam so if you set one, you have set them all.

    if you have one cam (OHV) then the whole cam moves together and overlap is fixed. DOHC applications can adjust overlap. however, I do think the viper has or had the ability to adjust intake and exhaust independently with an in block camshaft, but I've never tuned a viper.

    the pentastar V6 is a small and low revving engine which is why it surprised me to have such aggressive values at WOT, like a 9000 RPM small block race motor....the values at part throttle make sense but seem to go backwards, maybe for emissions purposes.

    the good thing is, the valve event info is googleable so you know where you are opening the intake and where you are closing the exhaust, which is what controls overlap and you also know where you are closing the intake, which is the most important valve event.
    One thing I guess now I am understanding is the values are degrees from the CENTERLINE. if you are looking at the cam as a 360*, the centerline (spot exactly in the middle of the intake and exhaust lobe centerlines) as 0* then it makes sense for the tables to move opposite each other. So if the intake centerline is 110 and the exhaust centerline is 110, moving the intake to 112 would result in the exhaust being 108, but in both cases you are advancing both 2*, you moved the intake 2* further ahead of centerline but moved the exhaust 2* closer. I realize the centerline ALSO moves, but if you think of the centerline as a predefined location the PCM knows and measures back against regardless of where the cam is.

    Is this correct?

  12. #12
    Senior Tuner Higgs Boson's Avatar
    Join Date
    Mar 2010
    Location
    Texas Hill Country
    Posts
    3,299
    For a fixed overlap OHV cam yes, that's true.

    LSA is the average of ICL and ECL so let's get old school and say you have a stock cam that is @ .050 210/210 with a 118 LSA and no ground in advance meaning it is straight up and you install it straight up then:
    IVO: 13 ATDC (-13)
    IVC: 43 ABDC
    EVO: 43 BBDC
    EVC: 13 BTDC (-13)

    So if Intake Opens 13 degrees After TDC and Exhaust Closes 13 degrees Before TDC then it's -26 degrees of overlap @ .050 lift.

    LSA is 118 and ICL is 118 (no advance) so then ECL must also be 118....since (ICL+ECL)/2 = LSA

    So with a cam that controls both intake and exhaust (like a pushrod motor or SOHC motor) advancing the cam 4 degrees will move ICL to 114 but LSA is ground into the cam profile so it is still 118.

    So (114 + X)/2 = 118
    then X = 122 ECL

  13. #13
    Senior Tuner Higgs Boson's Avatar
    Join Date
    Mar 2010
    Location
    Texas Hill Country
    Posts
    3,299
    So then when you advance the whole cam 4 degrees IVO moves to 9 ATDC and EVC moves to 17 BTDC and 17+9 is still of course 26 (-26 technically).

    The cool thing about DOHC is that you can move the cams separately and depending on the application and range, go from -26 overlap at idle for fresh smells and smoothness to say, 20 degrees of lumpy overlap at WOT for power, and anything in between, because now you can advance the intake and retard the exhaust at the same time.

    Check this out:
    Cam Timing and LSA Change Effects

  14. #14
    Advanced Tuner
    Join Date
    Aug 2004
    Location
    Franklin,OH
    Posts
    215
    So in the case of these mopars, where is camshaft zero or parked?

  15. #15
    Senior Tuner Higgs Boson's Avatar
    Join Date
    Mar 2010
    Location
    Texas Hill Country
    Posts
    3,299
    It appears at full retard based on what it says in the tune.

    Hopefully someone who has had a motor apart or degreed the cams can confirm or deny.
    Last edited by Higgs Boson; 10-30-2016 at 09:54 PM.

  16. #16
    Senior Tuner
    Join Date
    May 2016
    Posts
    1,134
    So what I'm missing looking at the tune for my 392 is where you guys make WOT adjustments? I see all kinds of part throttle tables but nothing for WOT.

  17. #17
    Senior Tuner SultanHassanMasTuning's Avatar
    Join Date
    Nov 2009
    Location
    All Around
    Posts
    3,149
    ^ no power gains, change your cam to a after market and then you will see some gains
    Follow @MASTUNING visit www.mastuned.com
    Remote Tuning [email protected]
    Contact/Whatsapp +966555366161

  18. #18
    Senior Tuner Higgs Boson's Avatar
    Join Date
    Mar 2010
    Location
    Texas Hill Country
    Posts
    3,299
    Quote Originally Posted by SultanHassanMasTuning View Post
    ^ no power gains, change your cam to a after market and then you will see some gains
    can you confirm all the above stated info?

  19. #19
    Advanced Tuner WS6HUMMER's Avatar
    Join Date
    Feb 2006
    Location
    Pineville La. US
    Posts
    771
    Quote Originally Posted by SultanHassanMasTuning View Post
    ^ no power gains, change your cam to a after market and then you will see some gains
    Quote Originally Posted by Higgs Boson View Post
    can you confirm all the above stated info?

    This is what I've been wanting to know all along.
    99 T/A WS6, original LS1 turbo

  20. #20
    Senior Tuner SultanHassanMasTuning's Avatar
    Join Date
    Nov 2009
    Location
    All Around
    Posts
    3,149
    all you can technically do it exhaust advance/retard thats it.

    i have done testing on both 5.7 and 6.4 with no gains
    Follow @MASTUNING visit www.mastuned.com
    Remote Tuning [email protected]
    Contact/Whatsapp +966555366161