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Thread: Torque Converter Settings - Need Advice

  1. #1
    Tuner breal5825's Avatar
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    Question Torque Converter Settings - Need Advice

    There was another thread going that I jumped on for information on this but I wanted to start another one because I'm not 100% sure I'm having the same issue as the other person. Besides, I would also like to better understand what's happening in this portion of the TCM tuning so... here we go.

    I have a 392 with a cam. I think I've adjusted the idle RPM and airflow as much as I can. When I'm at stop lights, in gear and foot on the break, the car will sometimes do a little bit of jerking. It's worse when the engine is still warming up but it's still there even after driving around for 10+ minutes or so. It's pretty minor but it's still noticeable enough that I will sometimes put the car in neutral just so I don't feel like I'm being shaken up while I'm waiting for the light to change.

    Is there anyway to adjust the Torque Converter settings so that when I'm at 0% throttle, idle conditions, 0mph / 0 rpms on the transmission exit shaft, the TC is really loose? I mean, when I let off the gas, I still want to idle forward slightly. That's standard behavior but when I put my foot on the gas, even just 5% throttle, it returns to normal operation like it is now?

    Otherwise, the car performs great. If I could just get it to not shake me up while sitting at a stop sign, I'd be golden.

  2. #2
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    https://forum.hptuners.com/showthrea...=zf8+converter

    Read that.

    Log TCC lock status and I think you will find that it's unlocked already when you're stopped.
    Last edited by spoolboy; 11-19-2019 at 02:24 PM.

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    Take cam out, put blower on...problem solved and it will go faster.

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    Tuner breal5825's Avatar
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    Quote Originally Posted by Hemituna View Post
    Take cam out, put blower on...problem solved and it will go faster.
    If I would have known that this would be the situation with the cam, I probably would have done exactly this. This is the first car I've ever had that one would actually want to put money into for performance and the Stage 1 cam & headers package was $6,200 and the Stage 2 supercharger package was a little over $10k. I figured, 600hp at the crank is plenty for me and I can more easily afford $6k so... there we go. I'm smarter now. Heck, even if I had a manual transmission, I wouldn't have this issue but the Chargers only come with automatics. Oh well... live and learn.
    Last edited by breal5825; 11-20-2019 at 08:15 AM.

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    Tuner breal5825's Avatar
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    Quote Originally Posted by spoolboy View Post
    https://forum.hptuners.com/showthrea...=zf8+converter

    Read that.

    Log TCC lock status and I think you will find that it's unlocked already when you're stopped.
    Dang it... so when I look at the TCC mappings, at 0 output shaft RPMs in 1st gear, which would be stopped, the state of the TCC should be open/unlocked which I have to believe that's true. How can that be? If the clutch is totally disengaged, as the post you linked to states, how is there any energy being transferred from the engine to the transmission at all? If there was no power getting from the engine to the transmission, then the jerking would be impossible.

    However, I know that this situation that I described would also be impossible because if that was true, how would you ever get the car moving at all? If you had zero clutch engagement while stopped and no power was getting from the engine to the transmission at all and the PCM was looking for a transmission output shaft speed of 440 rpms to get from unlocked to slip, that could never happen.

    This is just so frustrating. The deeper I dive into this, it basically sounds like this is an issue that's unsolvable unless I upgrade my Torque Converter and even then, how do I know that dropping that money will solve it? I honestly wish I would have been more informed before I went ahead with this Stage 1 package. If I would have known this was going to be the outcome, I would have just kept saving, waited a year or two and got a Hellcat.

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    Live and learn.

    And/Or keep working trying to fix it, if it is truly even a "problem" to begin with.

    You have a large displacement, heavily modified engine. Did you honestly believe it would still drive like a stock car?

    The torque converter isn't a clutch. But it has a clutch. The car will work perfectly fine leaving the converter NEVER "locked" and as a matter of fact, if you drive with MDS mode functioning, it won't lock any time MDS is active.

    Google how torque converters work to see what I'm talking about.

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    Tuner breal5825's Avatar
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    Quote Originally Posted by spoolboy View Post
    Live and learn.

    And/Or keep working trying to fix it, if it is truly even a "problem" to begin with.

    You have a large displacement, heavily modified engine. Did you honestly believe it would still drive like a stock car?

    The torque converter isn't a clutch. But it has a clutch. The car will work perfectly fine leaving the converter NEVER "locked" and as a matter of fact, if you drive with MDS mode functioning, it won't lock any time MDS is active.

    Google how torque converters work to see what I'm talking about.
    It's not the driving like a stock car that I'm after. It doesn't drive like a stock car and that's what I like about it. It's just this jerking at idle. Before I did any of this, I asked the shop about what adding a cam to the idle would do and they told me that it would idle rough and I asked what that meant and they're explanation was that the car would shake because the motor won't just be sitting still under the hood anymore. I was OK with that. I've sat in cars that are cammed before too so that part was all expected. What I didn't expect was this jerking back and forth at stop lights. I just wish I could solve this issue. If I could solve this, the car would be perfect in my eyes.

    I know how a Torque Converter works. When this issue first came to light, upgrading it was the very first suggestion I had for my shop. They said they believed they could tune the issue out and I wouldn't need a higher rated TC. To their credit, the tuning they've done has really minimized the issue but it's still there. Now I'm back to thinking that an upgraded TC is the only way to solve this. I'm just scared to death that I'll spend $1,400 on an upgraded TC and once it's installed, the issue will still be there. Then I'm really gunna be unhappy.

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    A looser converter will be better with that cam.

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    Quote Originally Posted by Hemituna View Post
    A looser converter will be better with that cam.
    Any suggestions on a brand and stall speed?

  10. #10
    generally you need to figure that out. Stall speed should be 500-700 RPM below the engine RPM at peak torque.
    https://revmaxconverters.com/part-un...lancing%20act.

  11. #11
    Off topic but what cam did you go with?

  12. #12
    Advanced Tuner f.creek-ranch's Avatar
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    Have you fixed it ?
    I would play around with the tcc slip at rpm...
    I set my TCC Slip under sport mode at 200-250 for hard acceleration and add an oil cooler.
    So I bring up the rpm and the power a little faster.

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    Quote Originally Posted by [email protected] View Post
    generally you need to figure that out. Stall speed should be 500-700 RPM below the engine RPM at peak torque.
    https://revmaxconverters.com/part-un...lancing%20act.
    Revmax makes a good solid converter
    04 GTX........ 8.91@151mph 392Ci G3Hemi NA 3600lbs 2.6HP/CI Naturally Aspirated
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    What are the cam specs? Good chance your cam is too big to play nice with the stock torque converter.
    Cam specs will be needed before anyone can give a recommendation on stall speed

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    Advanced Tuner PurpleRam's Avatar
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    Quote Originally Posted by white1 View Post
    What are the cam specs? Good chance your cam is too big to play nice with the stock torque converter.
    Cam specs will be needed before anyone can give a recommendation on stall speed
    I don't think we'll find out, he hasn't been a round since late 2019, being a "stage 1 package" it's probably ,214/222 .582/.582 115cl , or 218/223 .585/585 114 , that seems to be the stage 1 flavors of most of the aftermarket shops.

    I know I've seen very few aftermarket cams that can go in to a 6.4 and not need at least a 2800 stall.
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    Quote Originally Posted by PurpleRam View Post
    I don't think we'll find out, he hasn't been a round since late 2019, being a "stage 1 package" it's probably ,214/222 .582/.582 115cl , or 218/223 .585/585 114 , that seems to be the stage 1 flavors of most of the aftermarket shops.

    I know I've seen very few aftermarket cams that can go in to a 6.4 and not need at least a 2800 stall.
    We have had mixed results with something a little larger than that. We do see some lurching or pushing through brakes generally but several customers dont even notice.
    I must have missed where he stated stage 1. That 214/228 is smaller than stock iirc

  17. #17
    Advanced Tuner PurpleRam's Avatar
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    Quote Originally Posted by white1 View Post
    We have had mixed results with something a little larger than that. We do see some lurching or pushing through brakes generally but several customers dont even notice.
    I must have missed where he stated stage 1. That 214/228 is smaller than stock iirc

    post #5 last Paragraph, ...............I think Elevation plays bigger role in how some of these Idle in gear . My 2014 ram when I had the 428CI in it I had Comps cams it was one below the 274 , I remember the @ 50 was 216/224 or 218/226, 116 CL here at Sea Level it was fine , but out the other end of PA out where Elevation was 2200 ft , that thing would lightly surge at a light,...not a two foot brake pedal surge but enough to notice.

    I play around mostly with 04/05 rams and I've noticed that depending on where the truck was sold originally some of the PE charts are different , and startup inj Pw startup base(table 34000) can be different also
    Last edited by PurpleRam; 06-14-2021 at 04:01 PM.
    04 GTX........ 8.91@151mph 392Ci G3Hemi NA 3600lbs 2.6HP/CI Naturally Aspirated
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