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Thread: How does everyone stabilize Idle Torque and/or Timing at Idle?

  1. #41
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    I PM'd you with some additional info to try. But also, make sure you don't raise your peak torque table in the idle areas too much, especially if you drop the VT table in the idle area. You may actually need to lower peak torque in 1000 rpm and under. May or may not help you but it seems to affect Max Torque in that area when you change the Peak Torque table. Another thing, how much if at all did you change your Throttle Body Area scalar?
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  2. #42
    Advanced Tuner lt1z350's Avatar
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    Quote Originally Posted by TriPinTaZ View Post
    I PM'd you with some additional info to try. But also, make sure you don't raise your peak torque table in the idle areas too much, especially if you drop the VT table in the idle area. You may actually need to lower peak torque in 1000 rpm and under. May or may not help you but it seems to affect Max Torque in that area when you change the Peak Torque table. Another thing, how much if at all did you change your Throttle Body Area scalar?
    I have a ported 95mm zr1 throttle body so I was using a lot of the settings from the 2019 zr1 tune as it helped me a lot get timing back into it at idle when it was all bolt ons still. Since then I have tried to drop it back down some closer to stock setting just trying to force a change here. I think its 5000 right now 4750 ish stock and 5045 zr1 stock setting.
    Trying to wrap your head around changes. A car with a pd blower spinning the guts out of it 9.55 lower 2.45 upper at idle it should be making a lot of torque. So a lot more then stock per say. Then add a cam and better flowing heads and a cam with zero over lap (-0.5 to be exact) is it possible I have been trying to force all of this the wrong way as this is actually trying to make a lot of torque at idle? does this even make sense trying to think if it like this or a cam is a cam and its going to make less torque period? When I had the blower ported to the second version I did notice it lost kpa it was idleing closer to 0 on the boost gauge then It ever had due to the added flow I assume. That or the vve at that point was so bad I had a bunch of stuff out of wack? More air more torque I guess how it could be viewed unless you did a cam with a lot of overlap. If i lay on the throttle as I explained take it off idle torque over to axle the aimass will get into the .2s and kpa down to 60s damn near where it was with the new blower port. i never tried to run it on the old tune I just started changning things to accommodate for the cam and heads which may have been more worst mistake now talking this all out.
    First 9 second 6th gen lt4 zl1 stock blower SHC SBE boost only.

    2013 cadillac ats 2.0t Big turbo-gone
    2007 tahoe 5.3 lsa blower on 14 lbs boost 6l80e swap 2009 os
    2017 zl1 a10 big gulp/2 inch headers/ 9.55 lower/ e85/bigger hx /103mm tb / Synergy trunk tank and underhood kit/methanol injection with torqbyte controller and prometh pump / Jokerz performance R&D ported stock blower/ lme cnc heads /GP tuning custom cam. So far 9.30@150

  3. #43
    Advanced Tuner lt1z350's Avatar
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    ok so I think I found a problem that can cause issues. If you look at the stock vt tables and pull the values from airmass vrs map you will find they do corelate 100 precent to the stock car logs. Car idles at .20 cylinder airmass and about 45/50 kpa. go into the stock vt tables and look that the rpm rows on the airmass at .200 and then go to the map at 40/50 you will find they are with in a few lbs of torque of each other. So if you go in and raise only one or randomly rasie these and spread them apart from on another your going to get some really odd issues like the idle ok in say park and bad in drive. Im sure it will cause driving concenrns too. I found that making the tables tighter it will shift bettter and torque reduction will be much faster to recover. This is between -10 to 40 but now seeing what you do to airmass you better get it as close as possible on map. No wonder why so many cars do not run right after heavy mods as it too me a while to figure this all out. Now going to apply this and see how it works out. I had it back to running pretty good and about 3 degrees of timing in park and pulling it into drive it didnt surge and was ok. So I wanted more timing so went in and tried to lower the airmass only by 10 lbs and went to the map and saw it was a lot higher so started going crazy trying to balance it and it went back to surging in gear. I had been only adjusting the airmass up to that point and saw it was closer on that tune in the idle area vrs how I put it when started going to crap again. So really going to work on making it the same at idle in the .300/.400 as that is where my car idles and 70/80 kpa and see how this affects the idle. I also played with throttle body scalar and I have a 95mm it was good at 5000 so went to 4800 it got better then tried stock 4750 and it got bad. So then I went back to 5400 which is the stock zr1 value and it went back to being decent. But at 5400 throtttle response was better then at 4800 where it idles well. Im sure that value is changing how something is calculated and why it can swing one way or the other quickly. Seems there is no real right way to a lot of this but just to make it work best as possible. At least I am finding some direction on this and hope this helps others.
    First 9 second 6th gen lt4 zl1 stock blower SHC SBE boost only.

    2013 cadillac ats 2.0t Big turbo-gone
    2007 tahoe 5.3 lsa blower on 14 lbs boost 6l80e swap 2009 os
    2017 zl1 a10 big gulp/2 inch headers/ 9.55 lower/ e85/bigger hx /103mm tb / Synergy trunk tank and underhood kit/methanol injection with torqbyte controller and prometh pump / Jokerz performance R&D ported stock blower/ lme cnc heads /GP tuning custom cam. So far 9.30@150

  4. #44
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    As we were discussing in PM, the Scalar directly affects torque calculations from my findings. If you adjust the scalar too far from stock you might have to adjust the entire VT table to things back in line. With a bigger cam you make less torque at idle, but then add the blower and now you're making less torque at a higher airmass down low but that quickly changes off throttle to higher airmass with more torque, especially when you cross in to positive boost.
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    Owner/GM Calibrator
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  5. #45
    Advanced Tuner lt1z350's Avatar
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    Quote Originally Posted by TriPinTaZ View Post
    As we were discussing in PM, the Scalar directly affects torque calculations from my findings. If you adjust the scalar too far from stock you might have to adjust the entire VT table to things back in line. With a bigger cam you make less torque at idle, but then add the blower and now you're making less torque at a higher airmass down low but that quickly changes off throttle to higher airmass with more torque, especially when you cross in to positive boost.
    I did tune my vve with the stock zr1 scalar values as it did drive better that way with the 95mm tb and when had bolt ons. So after playing with it I went back to the value I had when I did my SD tuning just so that was not off. I had used a few of the zr1 settings as it made sense to try them as I used the same throttle body. Currently redoing all virtaul torque to line up airmass and map to reflect what the car is acutally seeing vrs stock now. The one adjustment I tried helped a lot so this is the correct direction.
    First 9 second 6th gen lt4 zl1 stock blower SHC SBE boost only.

    2013 cadillac ats 2.0t Big turbo-gone
    2007 tahoe 5.3 lsa blower on 14 lbs boost 6l80e swap 2009 os
    2017 zl1 a10 big gulp/2 inch headers/ 9.55 lower/ e85/bigger hx /103mm tb / Synergy trunk tank and underhood kit/methanol injection with torqbyte controller and prometh pump / Jokerz performance R&D ported stock blower/ lme cnc heads /GP tuning custom cam. So far 9.30@150

  6. #46
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    Interested to see your results this evening from your findings and changes you told me about in PM.
    [email protected]
    Owner/GM Calibrator
    Gen V Specialist - C7 Corvette, Gen6 Camaro & CTS-V3

  7. #47
    Advanced Tuner lt1z350's Avatar
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    A must read if fighting idle

    So finally got back out to the car and after all that work on the vt tables it still had a slight surge in park and got worse in drive but it got stable more often then trying to stall or go over 1200. I let it run for a few min to get temps up and saw stft was -12 so I trimmed both the maf and vve a touch at idle and that nailed it. I could see on the log it looked to be dipping lower then my commanded in the virtual torque tables and noticed that it was going really lean on the wideband like over correcting for it being rich. So by pulling out 5 percent on the maf and on the vve the timing came up and throttle closed down and idle is right around my commanded 675 in park and 700 in gear. I couldnt ever get it to idle with this much timing in the past until I made the airmass and virtual torque more in sync. Once I looked at my log and saw .30 cylinder airmass and 75 kpa I went in to the vt and made sure that in the idle it was very close to each other doing that getting the fueling correct brought the idle timing up and closed the throttle. It seems when they are not close and more on stock settings that it wants to use one or the other to try to achieve commanded torque in that area it idles. Every single time before I was getting the throttle to close down but was also pulling timing out to get to the torque values. the odd thing is it is idleing with near zero zero pedal torque so I might be able to come up on it a little Im going to play with it some and try to learn more. I am not near the values in the external load table I could put 20 in that and it would be fine how it is idling now. I also had a slight swing when went into gear so lowered my speed control reserve down some and that made the idle more steady in gear. Throttle response is incredible too with the tables set up this way. Not the lazy gen v throttle response at all. I even see a little boost now when I nail in park. SO It is commanding more throttle for the first time when not in gear. this all just show how important the torque coeff tables really are on this platform. I feel with enough work on it I can get it to command a true 100 percent when not in gear but I am worried it might mess with how it drives so it sounds and feels good now so if drives as good like it had on my older vt tables Ill leave it and be happy with how it is now. Seeing my methanol trigger in park when I floor it means its making at least 4 psi on a quick stab and that is night and day to how its been in the past and didnt have to rape the driver demand table to do it. Everything revolves around this model being as close as possible. I feel now the virtual torque is more important then the vve being correct but they do work together and will probably have to re address my vve again just to double check it.
    The one thing that bothers me is that I can still force it with a little throttle input to idle with lower kpa and timing. the more timing its adding the lower my kpa is due to making more torque. I can actually make it idle with .24 cyl/air and 60 kpa if the timing is at least 20 and throttle is down around 9 percent. So it can get even better then I have it now. But what that will do it off set the vt tables yet again as I have them currently at .30-.40 and 70/80 kpa the torque values are lined up more to that. So in testing I may try to off set it to what I see if I give it 12 percent of pedal input on the throttle just to see if it will then try to get the same results while it is at a true idle with out me leaning on the pedal a touch.
    But I promise you this is key set up your torque tables to what you see on your log make sure its not too rich and over correcting and it will idle so much better. I am attaching a log to show where it is now and you can go back and see on an older post how it was in the past.
    First 9 second 6th gen lt4 zl1 stock blower SHC SBE boost only.

    2013 cadillac ats 2.0t Big turbo-gone
    2007 tahoe 5.3 lsa blower on 14 lbs boost 6l80e swap 2009 os
    2017 zl1 a10 big gulp/2 inch headers/ 9.55 lower/ e85/bigger hx /103mm tb / Synergy trunk tank and underhood kit/methanol injection with torqbyte controller and prometh pump / Jokerz performance R&D ported stock blower/ lme cnc heads /GP tuning custom cam. So far 9.30@150

  8. #48
    Advanced Tuner lt1z350's Avatar
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    With further adjustment I got it up to 20-30 degrees of timing now at idle but its swinging I cant figure out how to make it more stable and closer to flat. The idle isnt hunting but timing is all over the place aas low as 6 and high as 30. I lowered the peak torque some and timing came up more but it still has the oscillation though rpm is pretty steady. if it was 20-30 id be ok with it but dropping to 6 is making the car shake quite a bit and though I have tried to change a lot of stuff yet to figure this one out. Pulling it into gear is gets more steady and loses some of the timing so adding load to it helps this time. Posting a log maybe someone has an idea I havent tried yet. Zero pedal torque is pretty low still and delivered is low but its swinging with the timing
    Attached Files Attached Files
    First 9 second 6th gen lt4 zl1 stock blower SHC SBE boost only.

    2013 cadillac ats 2.0t Big turbo-gone
    2007 tahoe 5.3 lsa blower on 14 lbs boost 6l80e swap 2009 os
    2017 zl1 a10 big gulp/2 inch headers/ 9.55 lower/ e85/bigger hx /103mm tb / Synergy trunk tank and underhood kit/methanol injection with torqbyte controller and prometh pump / Jokerz performance R&D ported stock blower/ lme cnc heads /GP tuning custom cam. So far 9.30@150

  9. #49
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    Quote Originally Posted by lt1z350 View Post
    With further adjustment I got it up to 20-30 degrees of timing now at idle but its swinging I cant figure out how to make it more stable and closer to flat. The idle isnt hunting but timing is all over the place aas low as 6 and high as 30. I lowered the peak torque some and timing came up more but it still has the oscillation though rpm is pretty steady. if it was 20-30 id be ok with it but dropping to 6 is making the car shake quite a bit and though I have tried to change a lot of stuff yet to figure this one out. Pulling it into gear is gets more steady and loses some of the timing so adding load to it helps this time. Posting a log maybe someone has an idea I havent tried yet. Zero pedal torque is pretty low still and delivered is low but its swinging with the timing
    Drop it in open loop and throw some fuel at it and see what happens. Might just be lean. I had this issue when my wideband and my narrows weren't agreeing.

  10. #50
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    I hurt inside reading this entire thread!

    Quote Originally Posted by sevinn View Post
    Drop it in open loop and throw some fuel at it and see what happens. Might just be lean. I had this issue when my wideband and my narrows weren't agreeing.

  11. #51
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    I'm no expert but I've had 3 of these models with 6.0 and they all seem to need about 100 to 150rpm on idle. Helps alternator and helps me.