Originally Posted by
Chad D.
Seems I accidentally deleted my message.
Following this for same answers. I?ve got my engine running great and am tuned for my 5.29 gears and tire diameter.
Looking to get my TCC to stay locked more while using cruise. It unlocks on small rolling hills, only when using cruise.
With a 19 mile commute on a quiet highway, I use cruise daily.
There are a couple things in play.
The Load Limit tables (Engine -> Airflow -> Electronic Throttle -> Limits -> Torque Based -> Low/High Load) will dictate throttle behavior during cruise.
If the max throttle angle for a given requested torque is too high, it will unlock the converter and/or downshift - the tricky part is that if the throttle angle is too low it can fail to hold speed or requested torque can increase until converter unlock or downshift can meet the target (often overshooting). Ideally, this is where we would make the correction since manual inputs behave well - unfortunately, because we can't directly log requested torque, nor which table is being referenced at a given time, so it's difficult and frustrating to tune.
The other option is to simply increase the throttle required for TCC unlock. In this case, under Trans -> Torque Converter -> Lock Apply/Release, you would increase the Accelerator Pedal Position (by clicking on the underlined axis) for your cruise RPM by a nominal percentage for the appropriate gear.
For example, if we are cruising in 6th at ~2000 RPM without Tow/Haul on, we would find the axis cell in Trans -> Torque Converter -> Lock Apply/Release -> Output Speed vs. Throttle -> Normal -> 6th Rel corresponding to 2000 / 0.588 = ~3400 Output Shaft RPM, then iteratively increase it by, say, 5% until you get the lockup behavior you like. Just an FYI: the Pedal Position axis is doubled for converter lock tables in HPT, so 200% on the axis is 100% in reality.
To shortcut the process, you can pick a value that would force it to downshift prior to unlocking - we can look up the corresponding 6-5 downshift pedal position from Trans -> Shift Scheduling, look up our Output Shaft RPM, halve the pedal position value, paste that in our Rel axis, then add a nominal amount (5-10%) to that value to ensure that it will always downshift prior to unlocking the converter.
As a matter of personal preference, I like to allow for some converter unlock prior to downshift in my Normal tables as a brief unlock is a bit "nicer" than a full downshift (especially with cruise control), and it helps ensure that the TCC is unlocked prior to downshift. In Tow/Haul, I'll force a downshift prior to TCC unlock, or have TCC unlock very slightly before. The reason is fairly simple: if we're actually towing, we're not going to be using 6th (and, possibly, 5th), so 6th in Tow/Haul is effectively an intentional, dedicated selection, which means holding the converter longer isn't otherwise an issue for drivability.
There is one additional trick you can use if you haven't already, which is to lower ACIS activation and cheat more torque for lower pedal positions. Log to find the TPS required to cruise on flat ground at the highest speed you typically drive in less-than-favorable conditions (hot, humid), then set the value in Engine -> Airflow -> Charge Motion Device -> ACIS -> Zone Boundaries -> High TPS a little (2-3 degrees) higher. This will ensure that we're not cruising down the highway with it constantly active and taking the associated fuel economy penalty, but will let it activate on any hill of significance.
Originally Posted by
M_RED
Soo...
Thus far I have only played with the engine maps on my Sequoia. I'm pretty happy with where I landed with AFRs, a little timing advance and light touches to cam phasing...
I'm now trying to understand how an automatic transmission works within the toyota,,, and to be honest, I'm clueless...
I've read through the other documentation here, but I'm curious about where & what you would start tweaking first.... A little snappy shifts,,, a little more torque convertor lockup (I assume some mpgs to be had there??) and getting rid of any more electronic nannies would be nice...
@SlowNStock, is your guide written in an order of what to tackle first??
The bit of the guide that covers trans stuff is just informational, not instructional.
In very general terms, two common steps you can take on basically anything:
1) Correcting WOT shift points.
Log a WOT pull, determine the actual WOT shift point, then adjust the appropriate cells it to match your desired target, using the below formula:
Correction Factor = Desired Shift RPM / Logged Shift RPM
So, if we logged a shift at 5800 RPM, but we want the shift to occur at 6200 RPM, we would multiply output shaft speed in the cells corresponding to WOT TPS by:
6200 / 5800 = ~1.07
2) Adjusting Shift Pressures (if available).
The stock pressure curves have some dips at moderate pressure, and bringing them up a bit gives a little crisper shift for more aggressive (but less than WOT) driving. The factory cal for later trucks (2019+) does just that for 1st and 2nd, but the same approach can be applied to other gears.
Don't go overboard, too much pressure just makes things clunky and harsh rather than meaningfully improving shifts. Personally, I prefer to leave max pressure alone.
Engine -> Torque Model -> Torque Calculation -> Optimum Torque Trans also affects shift firmness, so you can make small changes there for specific RPM/Throttle Angles.
For converter lock/unlock, you can follow the above guidelines regarding tuning via Pedal Position axis. I would start with Release as there's usually more room for improvement there and it's more forgiving all around. Fine tuning Apply can be a bit more finnicky because there are more, competing conditions where we may or may not want to enter converter lock for a given RPM/TPS combination, and we don't have some of the advantages that, say, an 8HP or 10R equipped vehicle does when it comes to the strategy of locking up early and often - using converter multiplication is a bit more valuable for us and the tradeoff of fuel economy for drivability is more favorable.
RE: Torque Management:
While popular, ditching a bunch of Torque Management (TM), especially on upshifts, isn't especially productive - I actually increase it in quite a few places along with allowing for more timing to be pulled (Engine -> Spark -> Advance -> Minimum Spark -> Min Final/Base), in part to offset the increased line pressure per above - but the stock tables certainly leave room for improvement.
How noticeable TM is will depend in part on the shift schedule: the more that output shaft torque changes across the shift, the more it's noticeable. If output shaft torque is held constant across the shift, we're really just using TM to help slow down the engine, so we have the opportunity for some very smooth shifts without appreciably sacrificing acceleration - that's a big part of why I reference targeting 100% output shaft torque retention for much of the shift schedule in some of my other posts.
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