Instructions for custom tuning the truck with HPTuners.

Whats start up time mean?

 

That's how long it adds those extra RPMs before ramping down to 1200rpms as targeted in the Idle > RPM > Base Setpoint > Base P/N table. When the engine starts, it revs to 1400rpms, then after 3 seconds it ramps down to 1200.

 

Ah got it. Thanks

 

Something interesting I found. DTC's disabled in HPT still can be seen in techstream. So just because you uncheck them in HPT doesn't make them go away completely.

Techstream:



HPT:

 

Doesn’t mean they are viewable in emissions testing.

 

Agreed. Not saying that.

 

4th gear "lock" for dynoing:

Trans -> Shift Scheduling -> 4-3 Shifts

Adjust the table to a low number, so the truck will not want to downshift once it's in 4th. This can be done only in the Tow/Haul tables so that normal driving is fine, and then activate Tow/Haul during the dyno pull, then deactivate it and the truck is back to normal shifting. Following table shows the Normal 4-3 shift scheduling, and the second table is what my Tow/Haul and Tow/Haul Fault shift scheduling is. Those values are totally arbitrary, but on the highway I can floor it at 2000rpm (presumably much slower too) and it won't downshift. I did NOT change any of the other shift scheduling since I can use the shifter to limit the highest gear. Not sure what happens once the truck slows down to a stalling condition, and don't plan to test it.

 

There is also the width of the shaft, the TB plate is not a perfectly flat disk. 86* may make the valve the thinniest profile with the best aero vs purely 90*

 

Finally had some time today and got an initial "tune" into my truck. Still NA, but going to work on the transmission and TC first for fuel economy.

First up: if anyone has issues with the device not updating and connecting, try uninstalling the stable VCM suite and install Beta. I found this recommendation in the HPTuners forum and it worked perfectly. It also wouldn't allow me to write as the VIN locked to it had additional digits in the tuner file. Save file, uninstall suite, install Beta, then update and write. All good.

So far I've only done tire size (33's), speed limiter, and torque management. Drives just like normal but it seems to have ever so slightly better shift timing for rpm/speed.

Now I'm trying to figure out when I'm headed home to OR from a work assignment in AZ, so I can get a Harrop coming.

 

If you stay N/A, I can share a few things that were done to my 2018 on a dyno with my HP tuner just down the road in Eugene. Mine runs about a million times better than stock.

 

Yes, i'd love to hear what worked NA. It'll realistically be a couple months at minimum until I'm ready to SC.

 

Be careful with torque management. Reducing it to much can trash a transmission.

 

Can you elaborate on that point? What and how much would you say is safe for transmission longevity?

 

Torque management essentially reduces engine power during shifts. Saves wear and tear. I leave it alone on my vehicles. I do remove the partial slip on the converter and make it so the converter is either fully locked or unlocked which helps longevity. I also add 5-10% pressure to increase holding power and change which gears the converter locks in and how early it locks.

 

I'll clarify a bit, the "torque management" I mentioned adjusting is all electronic throttle torque/position limiting, my mistake. I have not done any changes to the transmission torque management section, but am interested to hear any of your experiences. Transmission and TC lockup tuning will be the next thing I plan to do.

 

Timing Changes:

Timing is very complicated, and I don't know much, but in the simplest form this is how to change timing, know it needs changing, and understanding the two variables that play a large part. I've been talking to SlowNStock on the HPT forum and he's spent a lot of time explaining to me how the timing works and I wanted to share it here since there's not much information on the internets. I will ignore the calculations to get to Actual Spark and the tweaking of things like exhaust timing variables, and just look at the basic level of "is my timing correct" and "how much do I adjust the timing".

To look at timing changes I datalog two variables, Knock Feedback and Knock Correct Learn and graph them against rpm/absolute load. This is an example of a Knock Feedback graph:



This is an example of a Knock Correct Learn graph:



These are the two primary graphs I use to adjust timing. The first graph (Knock Feedback) shows anywhere the truck is experiencing or anticipating knock, and the subsequent timing changes to prevent it. -3 shows there is no timing retard occurring due to knock, and anything below that is the amount of timing retard (relative to -3). For example at 4000rpm and 30% load, there is a cell of -4.5, that means -1.5deg of timing is being retarded to prevent knock (-4.5 is 1.5deg less than the base value of -3.0).

What the truck WANTS to do, is to advance the timing across the board as far as possible, this is where Knock Correct Learn comes into play. KCL is part of the timing calculation, and is the broad correction of timing for the vehicle. So if you put in higher or lower octane fuel, KCL changes to compensate and shifts the entire timing because of that. KCL is the gross correction of timing, and Knock Feedback is the fine correction (similar to long term and short term fuel trims kind of). The truck wants Knock Correct Learn to max out, that is then the maximum timing the truck is capable of. This value is found in Engine -> Spark -> Retard -> Knock Adaptive Learning -> Learn Max.

If the truck has not learned to the max, then it will be trying to advance the timing, which may then cause Knock Feedback. Knock Feedback can stop or reduce Knock Correct Learn and limit it. So you'll end up in a cycle of KCL advances timing -> Knock Feedback triggered -> KCL retards -> Knock Feedback stops -> KCL advances timing again -> repeat. Obviously there is more to it than that, but that is the simple gist. This results in KCL setting in at a value, in the above table that is 18.1deg. Without modifying the values in the Knock Retard tables, the truck wants a KCL of 18-19deg. Once it gets into that range it will stop trying to advance timing. If KCL has reached 18+ and there is no knock feedback happening then the truck is as advanced as possible.

If KCL is BELOW 18 then look where there's Knock Feedback occurring and retard those cells by the amount of Knock Feedback occurring PLUS the difference from KCL to the 18deg max. ie if you have KCL of 17deg, and Knock Feedback of -4.5, then KCL can increase by 1deg and Knock Feedback is retarding by 1.5deg (-4.5 vs -3 which is the normal value)--so you want to retard that cell by 2.5 deg (1.5deg for the current amount of knock retard happening, and another 1deg because once KCL increases the timing will go up by 1deg, which would trigger knock retard again).

There are different methodologies to determine how much knock retard is effectively happening. At the top left of the graph there are the symbols " + - A L C ", these can be used to adjust what data you're seeing. In the following screenshots the " - " is selected to display the lowest value (ie the worst knock feedback measured) and then " A " is selected to display the average of all the knock feedback readings.





As you can see, those are drastically different numbers, and if you selected the " + " symbol everything would show -3. Each cell is logged multiple times, just because a knock event occurs doesn't mean it's always knocking and doesn't necessarily mean it should be retarded just because random knock event occurs. In the above pictures, the average values are almost universally -3 to -3.2 so on average those cells have no knock or extremely low, and rare events trigger knock but it's probably not worth retarding that cell. At 4400rpm there are a few cells that their average value is lower, so I may want to retard those cells since knock appears to be more common or there are more severe knock events occurring. It is your call how far you want to adjust your timing.

Here is a comparison against my personal truck, this shows the average values, and as you can see there are only six cells where there was any knock detected at all and it averaged out to nothing anyways. Is this timing table better than the above graph? The above is tickling on knock in a few spots, but the majority of the time it's fine with that slightly more advanced timing. Is my graph below too conservative since there's essentially no "random knock events" occurring? I don't know the answer.



Personally I like to retard the timing until there's essentially no knock anywhere ever, I don't think the 0.5-1deg timing difference is enough to make a difference but the truck will overall be safer and if conditions become less than ideal (extremely hot weather, bad fuel, elevation change, etc.) then the trucks base tune will at least be safe and further help the truck when the conditions go south and give it more room to retard the timing as needed.


Timing Tables

There are three "primary" timing tables: Base Spark, High Octane (HO) Spark, and Low Octane (LO) Spark. These tables are a little weird, and there is differences in how different people do them. The simplest approach is use the tables you already have, and make any changes to all three tables. Now personally, and I'm not saying this is correct but works for me, I have Base Spark and HO Spark completely identical (just copy them to each other), and LO spark I copy the same table over and then do -5deg across the board.




After you make your timing table changes and flash the new tune onto your truck, the truck will start at a lower Knock Correct Learn value (Learn Init, which is usually 14-15deg) and the truck will have increase the KCL value as it advances timing, there's ways to speed this up, or just drive the truck like normal and get it into the normal operating range and it will do its thing.

Since you corrected the knock feedback from before, the truck will advance the timing to the same spot, see that there's no feedback occurring and continue to advance the timing until it hits the next set of knock feedback areas which will most likely be at other cells that weren't advanced enough before to be triggered. Do this until KCL has hit the max value, and now all of timing will be as advanced as possible and will have been retarded where needed to prevent knock feedback and allow all timing cells across the board to be advanced to their highest potential.

There are some peculiarities to note:
-Knock Correct Learn is broken into zones, even though each cell is graphed as having a specific value. In this example all the zones are at the same value to make it easy, but as you can see there are a few cells that are acting like they're at a different KCL--this is not the case, those cells just haven't had their value updated in awhile and the true KCL is what the surrounding cells are at. The abrupt changing of zones can also cause knock feedback at transition lines, for instance above 2800rpm is a transition so if the 3200rpm KCL is at 17 and 2800rpm is at 19, there may be Knock Feedback occurring there and get into this weird area. In my experience for the most part everything hovers within a close value and the transitions aren't noticeable or an issue.
-At the top of the datalog graph there is "+-ALC", these buttons allow you to adjust what values you see. + is max, - is min, A is average, etc. I use the minimum display for Knock Feedback so you see the lowest value that was datalogged for that cell. A cell may only get knock feedback during one event and be fine as the truck revs through that rpm for instance, in which case max or average will display a higher (numerically) feedback value, and I like to use the worst case value the truck experienced for my adjustments. Likewise for KCL you can play with those, usually max seems like a good indicator since the truck is slow to learn to a higher KCL and won't go higher unless there's minimal/no feedback, so max is usually what the truck's value actually was at when the truck turned off.

Knock Feedback and Knock Correct Learn work together to set the timing. There are lots of timing variables and calculations, but those two are easy to understand: KCL is universal corrections, but can only advance if feedback is eliminated. If there is feedback, KCL will stop prematurely, so one or a couple cells may stop other cells from reaching their full spark advance potential. Hopefully this simplified post will give some understanding and guidance on what to datalog, what to change, and how much to change timing.

 

Fuck ya dude! Thanks for doing this! SNS has been coaching me on figuring out my starting issue. Now when I want to start learning about timing, I can bother you!

 

Yea I've been following along on those posts too. He may be the only person that truly understands (or as close to an understanding as possible) how the Tundra ECU works, so I usually just message him directly when I don't understand something.

 

How does he know so much? Is he a Toyota or HPT engineer?

 

I've wondered the same thing. I don't think he's either though. Maybe he is/was associated with another manufacturer, but certainly very engine management software engineer savvy. It's his word choices, like calibration vs. tune. His calling one of the tables a "transfer table" and explaining it as kind of a generic term for what it does; very software centric.

 

Slightly off topic>

now that HPT has cracked the Corvettes, I'm guessing some big ass numbers are gonna happen.

https://www.youtube.com/watch?v=SOzt3IvIRb0&ab_channel=AlexPeitz

 

You guys are just the worst…

HP Tuners MPVI3 ordered. This should be fun.

 

You think we're bad now? Wait till you start playing with that thing and you wind up balls deep in a rabbit hole... It's a little addictive...
I've got mine 99% where I want it, with just a couple fine tune tweaks left to go as I dial it in the rest of the way.

 

Mind sharing some of your transmission adjustments? PM is fine. My HP Tuner just showed up but I’ve been watching a few HewToobers getting to know the basics. Stock tire size and gears for now…

 

The trans tuning is going to be very subjective, as we all like things a little different.

Tune points that I have been working on:

TCC release points. I hate that the TCC releases all the time, even on small overpasses. I’ve fixed that.

I’ve got it holding gears longer, but not to the extent like Tow/Haul does. It’s smoother.

I’ve adjusted the ACIS engage point. So many things!!!


The best advice I can give is to register on HP Tuners forum and read everything that SlowNStock has to say. He has been a huge help with dialing this in. He’s very giving with the info to the community.

 

Forum stalking SlowNStock right now...

TCC unlocking on small overpass drives me bonkers.

 

Or not... first post I read on the HP forums... 'Guys, I flashed my tundra yesterday and bricked the ECU..."

 

Yea... Try not to do that

Good battery, put it on a trickle charger ideally, good internet connection (I hot spot off my phone), a laptop that doesn't suck, and then I usually close most programs, hit flash and don't touch anything until it's done. Make sure the cord is solidly plugged in beforehand too so it won't fall out.

 

Nailed it. I’ll flash at home in my garage because signal is solid AF. Anywhere else, including three campgrounds this month, I hotspot with the phone.

Make sure truck and laptop both have solid batteries. I’ve not used a charger though…

I roll the windows down and set the steering wheel up high and out da way before I get into it. No drinks, no snacks. Climate control off. Laptop on center console, and get comfy. Once I click “Write”, I’m sitting there for a few minutes. Doing nothing…. Just watching the progress and listening to the beeps.


It’s scary the first couple times, but very few people have troubles. Do it right, and you should be good!

 

Read through the thread I was active on regarding trans and torque management. Most of the stuff I fiddled with is in there!

If you get into ACIS tuning, you may need to turn that channel on in the VCM Scanner. Mine wasn’t on at first so I couldn’t see if ACIS was active during logging.