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Thread: Transmission Tuning Without Shift Pressures or Torque Management Tables?

  1. #1
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    Transmission Tuning Without Shift Pressures or Torque Management Tables?

    I have a Whipple SC'd 5.7L '13 Tundra. It has been tuned by a reputable tuner and runs great, but the transmission has always been a little clunky. When I say always, I mean ALWAYS - since the day I bought it new off the lot in 2013. It has been very reliable and tows and hauls often. But when trying to tweak the transmission a little bit, I've not been able to achieve satisfactory results. I've pretty much forum-stalked @SlowNStock for the last six months and have made perceptible changes to one of the tunes that I am able to modify, trying to follow his guidance.

    The stock tune that is pulled from the HP Tuners server is missing the Shift Pressures and Torque Management tabs in the Transmission settings.

    Basically, here is what I'm running in to: in order to achieve a smoother shifting experience, I can raise the RPM vs Accelerator Position under shift scheduling for each of the gears. But that makes the truck drive like it's working a little harder than it needs to as the RPMs start to level out and almost hang a little before shifting, or the transmission is being lazy and not shifting quickly. It does achieve a smoother shift as the motor RPM's aren't climbing as much under load when it does shift. But it feels lazy.

    In an effort to make the truck feel a little less labored and perhaps find a little better MPG in town, I've tried reducing the RPM vs Throttle angle tables (Throttle angle remains the same, RPM is reduced) by 5-10%. The shift points feel more natural, like the engine isn't revving more than necessary, but they get rougher and clunkier. I've also changed the lockup on 4th-6th to lockup a little sooner (4th doesn't usually lock up in normal driving, but it does in AI/Cruise, so I simply copied that shift schedule), but that doesn't affect gears 1-3. I've also played with the downshift tables but approximately the same percentage - 5-10% - but adjusting the Throttle Angle this time while the RPM remains constant.

    Several of the guys over on Tundras.com have been gracious enough to try and help me figure things out, but I though I would quit pestering them and bring some of my questions over the forum here. For reference, I've installed shift kits in several older Ford and GM vehicles and consider myself fairly mechanically inclined. Still, I understand that I don't know everything so I'm willing to learn.

    I also have a '15 Sequoia and have compared the stock files of two vehicles; they are nearly identical with two major exceptions - the throttle mapping (the sequoia is neutered and dull compared to the tundra) and the transmission tables that are missing on the tundra. Even before the SC, they drove like completely different vehicles. The tundra felt stronger and more truck like, the sequoia drove like a relaxed old man's car unless you REALLY put the pedal down. Shifting in the tundra is more positive - sometimes abusive at WOT - like your rowing gears in a manual with somewhere to be; the sequoia felt like a leisure drive, gently letting out the clutch and rev matching each gear.

    I guess my big questions are: how much can I really do without the Shift Pressures and Torque Management tables on the tundra? Am I really missing out by not having them? And ideas why they wouldn't include that with my ECM calibration? ECM is Denso 992k, OS 30CJ64 on the tundra. OS 30CG32 on the Sequoia, same ECM. Any help would be appreciated.
    Last edited by blenton; 6 Days Ago at 09:14 PM.

  2. #2
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    I had similar issues myself. Beyond not having the shift pressure and torque management tables available, I am also missing quite a few engine parameters (which everyone else in the HP Tuners-Tundra Universe seem to have). I did all of the things that you have outlined in your post and was at the same spot. While SlowNStock is undoubtedly the Master of Tundra Tuning, I have a hard time understanding and following their instructions, guides and advice. Ultimately what I did to understand the guides, advice and spreadsheets was download any tunes and logs anyone sent to SlowNStock that pertained to my tuning issues. After amassing a library of hpt and hpl files, I would open a log and the corresponding tune, then cross reference it with the related forum posts and instructions therein. A lot of effort and time, but it made everything plain as day.

    All that being said, my suggestion would be to check out and adjust your Ignition Efficiency and Ignition Efficiency Inverse tables. Post #42 of this thread: https://forum.hptuners.com/showthrea...l=1#post605500 , speaks directly to this issue. I read this post many times before I realized that was where my problem was. Hope this helps.

  3. #3
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    Thanks, RJ. Snivilous just suggested the same thing to me this morning - adjusting the Ignition Efficiency tables. He was a total stud and made the adjustments for me. I'll load the tune tonight and see how it runs.

    As much as it sounds like I'm complaining about the truck/transmission, the thing is absolute beast and has put up with some hard use for 11 years. But the Sequoia has started to sissify my in-cabin experience expectations.. even though it still doesn't hold a candle to the Whipple-charged awesomeness of the tundra.

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    From what I've seen across the forums, you're in good hands if Snivilous is lending his touch. I totally understand what you're saying about your Tundra. The electronic throttle and factory transmission tuning left a lot to be desired. Especially when I found out you could tune both of them. I'm saving up to buy a Whipple for my 2010 FFV Crewmax. I know Whipple doesn't offer a FFV version, but after crawling the forums and reading about what everyone else has done, coupled with the capabilities of HP Tuners...I'm pretty sure I can make it work. Let me know how the tune shakes out.

  5. #5
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    Just took it for a spin with the adjustments made to the Ignition Efficiency tables; made a subtle, but very noticeable difference. It accomplished almost EXACTLY what I was looking to do with the transmission tuning. It's still not like the sequoia, but actually feels better for me for this vehicle. Quick smooth shifts, power appears to transfer near seamlessly through the gears. Loving the change so far, just from the drive around the block. I've got a few miles to go tomorrow so I'll have seat time to better evaluate.

    The Whipple is awesome. Wish I would have done it a long time ago. Towing is unreal. Truck is crazy fun to drive. Wallet gets lighter and lighter... haha.

    As for being a FFV.. I'm not saying it's a totally proven route, but a forum member successfully swapped ECU's to a non-FFV in his 5.7 sequoia and made it play nice. Its only been a couple of weeks, but so far so good. He had been successfully running a SC for a long while before trying the ECU swap, but IIRC, he did it mostly to get rid of the ethanol content reading going haywire as they like to do. But either way, you should be able to make it happen. As far as I've seen, Black Friday is the best time to get a SC. Some retailers run a 10-15% discount on superchargers; Whipple ran 15% off directly through their website last year. Just in case you can fatten up the piggy bank enough by then...

  6. #6
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    Glad the tune is working for you. Thanks for the heads-up about when to buy