Tuning Facts - Understand Your Truck Like We Do at CAMTuning

[JayTech]

Session 5:
Shift Schedules: RPM vs Output Shaft Speed (And Why Your Truck Feels the Way It Does)
If you’ve ever thought “this truck should’ve shifted already” or “why did it short-shift there?” — this post is for you.
Most people assume automatic transmissions shift purely based on engine RPM.
In reality, modern Toyota transmissions care much more about Output Shaft Speed (OSS).
What’s the difference?

• Engine RPM tells you how fast the engine is spinning.
• Output Shaft Speed tells the transmission how fast the vehicle is actually moving through the gears.

OSS accounts for:

• Gear ratio
• Torque converter behavior
• Tire size
• Load
• Throttle input

That makes it a far more reliable signal for deciding when to shift.
Why this matters for drivability
Because shift schedules are often based on OSS:

• Two pulls to the same RPM can shift at different road speeds
• The truck may hold a gear longer under load, even at the same RPM
• Light throttle can cause earlier, smoother shifts
• Heavy throttle can delay shifts without increasing RPM targets

This is why changing engine power alone doesn’t always change how the truck feels to drive.
What tuning can (and can’t) influence
A refined calibration aligns:

• Torque delivery
• Throttle behavior
• Shift timing

When these agree with the OSS-based strategy, the result is:

• Fewer “busy” shifts
• More predictable downshifts
• Better part-throttle smoothness
• A transmission that feels like it’s anticipating your intent

Discussion encouraged:
Have you noticed situations where the truck feels like it “should’ve shifted” but didn’t—or shifted when you didn’t expect it to?

One thing I have seen a few people mention is how the transmission "feels like a cvt" when it shifts under throttle and holds a specific RPM range when I would imagine that is just the transmission trying to stay within the torque curve for optimal acceleration. Or are there other factors at play?

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[CAMTuning]

One thing I have seen a few people mention is how the transmission "feels like a cvt" when it shifts under throttle and holds a specific RPM range when I would imagine that is just the transmission trying to stay within the torque curve for optimal acceleration. Or are there other factors at play?

I have noticed the same on my truck when it had the OEM calibration. I offer a few variations of TCM mapping, and have my customers try a couple if they want to experience the difference.

The shift schedule is indexed by accelerator pedal position (driver demand) vs. output shaft speed(which can be translated to vehicle speed). That’s why it can feel like it’s “holding” a band — it’s following a driver-demand based map, not reacting to RPM alone.

Up shift and downshift have their own schedules, per gear, and per drive mode.
Normal vs Sport changes which set of maps/strategies it’s using (and how aggressive it is about holding gears and commanding downshifts), so the same pedal input at the same speed can result in a different gear choice.

 

[CAMTuning]

Session 6: Rotating Weight: Why Bigger Tires Feel Like Lost Power (and How Tuning Gets It Back)

Let’s take a quick break from sensors, trims, and tables and talk about something you can feel immediately behind the wheel: rotating weight.

Earlier this week I had a Tacoma on the dyno running significantly heavier tire and wheel combo than stock. No engine changes. Same truck. Same dyno. The only variable was rotating mass.
(These tires are ~65lbs each, on factory wheels)
The baseline result was exactly what you’d expect:

• Lower measured power
• Slower acceleration
• A drivetrain that had to work harder to do the same job

But here’s the part most people miss.

That “lost power” isn’t gone — it’s being used.

Why rotating weight matters more than vehicle weight

Rotating mass (tires, wheels, driveshafts) doesn’t just need to be moved forward — it has to be spun. That means:

• More torque required to accelerate
• More load on the engine and transmission
• Slower rate of RPM change
• Heavier demand during shifts

This is why trucks often feel:

• Sluggish after tire upgrades
• Lazy to downshift
• Less responsive at part throttle

What the dyno showed

Despite the heavier setup, once calibrated correctly:

• Torque gains were equal to—or better than—stock-tire trucks
• Throttle response improved noticeably
• The power curve became smoother and more usable

The tune didn’t “add magic horsepower.”
It reclaimed efficiency that the stock calibration wasn’t designed to preserve with heavier rotating mass.


OEM calibrations are built for factory tires.
Once you change that equation, the strategy needs to change too.

The takeaway

Big tires don’t ruin performance — unaddressed calibration does.

When torque delivery, throttle behavior, and shift strategy are aligned for the added rotating mass, the truck stops feeling heavy and starts feeling intentional again.

 

[CAMTuning]

Day late this time around. Just spent the last several days with the Cobb crew at the King of the Hammers. I've never been to that event but it's something you have to experience to understand!
Easy reading this week!

Session 7: Throttle ≠ Power


Not every throttle input needs full power. A lot of what people describe as “lag” or “soft response” is really just factory pedal mapping trying to cover every possible driver and condition.


A proper ECU calibration focuses on making small pedal inputs smooth and predictable. That’s what keeps the truck from feeling jumpy around town or hard to modulate off-road. The goal isn’t to make the truck aggressive—it’s to make it easy to drive.


This is also where ECU tuning differs from pedal-commander–type devices. Those only change how quickly the throttle opens for a given pedal input. They can make the truck feel more responsive, but they don’t change torque management, cam timing, fueling, or how the engine and transmission actually work together.


With real tuning, pedal mapping is just one part of a bigger picture. When everything is aligned, you end up with more usable power, not just sharper tip-in.


That’s the difference between a truck that feels quick when you touch the pedal and one that feels right everywhere.

 

[CAMTuning]

Session 8: Pulling these concepts together, and what to monitor on your Cobb Accessport

If you’re running a tuned 4th Gen Tacoma / T24 truck, your dash should give you context, not anxiety. Here’s the clean setup I recommend:


1. KCLV (Knock Correction Learn Value)
This is your long-term knock learning value.

It shows how the ECU is adapting over time based on fuel quality and operating conditions.

You’re not chasing a perfect number — you’re watching for stability.
If it lives in a consistent range and behaves predictably, that’s healthy.

Sudden sustained changes are what matter.

2. Knock Correction Angle
This is real-time knock response.

You will see small corrections. That’s normal closed-loop strategy.

Important reminder that:
-3° = effectively 0.
Seeing -3 doesn’t mean you’re “losing 3 degrees.” It’s essentially baseline behavior.

What you’re watching for isn’t small blips — it’s repeated, large corrections under steady load.

Trends > single events.

3. Boost
Keep it simple. Just boost.

Know what your truck normally makes in:

• 3rd gear
• 4th gear
• Typical temps

Toyota torque targeting means boost isn’t just a “max PSI” number — it changes based on load and conditions.

If you know what’s normal for your truck, you’ll instantly spot when something is off.

4. Charge Air Temp (Post-Intercooler)
Not generic intake temp — charge temp.

This is the temperature of the air the engine is actually ingesting after compression and intercooling.

This directly affects:

• Ignition timing
• Knock sensitivity
• Torque consistency

If charge temps climb, the truck may feel softer — even if nothing is wrong mechanically.

5. Long Term Fuel Trim
This is one of the most underrated parameters.

Stable trims = sealed system, healthy airflow modeling.
Sudden swing = possible boost leak, vacuum issue, or MAF contamination.

It’s an early warning system.

What I don’t recommend:

• Staring at AFR constantly
• Chasing peak boost numbers
• Turning the Accessport into a stress device

The goal isn’t constant monitoring.
It’s knowing what’s normal.
Once you understand your truck’s patterns, you’ll recognize changes early.

What are you running on your dash?

 

[Will721]

Random shower thought I had the other day, I've been told these trucks run dual injection. A hybrid so to speak of manifold and direct injection. My understanding is the only pro of direct injection is better (slightly) fuel atomization which in gas engines is primarily for emissions unlike diesels.

That said, a common complaint about these trucks is the noise from the direct injection. It's so prominent that even automotive review publications have noted it. Personally, I haven't really pushed my truck hard yet as I'm still in my first oil change cycle. Meaning I haven't really noticed the direct injection "rattle" outside of initial warm up. So the question I have is, do the mpfi injectors have enough flow to support the engines by themselves and could the direct injection cycle be disabled? Are there set parameters which trigger direct injection outside of warm up? If there is a need would it be possible to disable it only at initial start up?

 

[CAMTuning]

Random shower thought I had the other day, I've been told these trucks run dual injection. A hybrid so to speak of manifold and direct injection. My understanding is the only pro of direct injection is better (slightly) fuel atomization which in gas engines is primarily for emissions unlike diesels.

That said, a common complaint about these trucks is the noise from the direct injection. It's so prominent that even automotive review publications have noted it. Personally, I haven't really pushed my truck hard yet as I'm still in my first oil change cycle. Meaning I haven't really noticed the direct injection "rattle" outside of initial warm up. So the question I have is, do the mpfi injectors have enough flow to support the engines by themselves and could the direct injection cycle be disabled? Are there set parameters which trigger direct injection outside of warm up? If there is a need would it be possible to disable it only at initial start up?

Yes, these are dual injection (DI + port).
One thing to clear up first: direct injection isn’t just there for emissions. On a turbo engine especially, it’s a performance advantage.

DI helps with knock resistance because of the charge cooling effect — when fuel is injected directly into the cylinder, it cools the intake charge as it evaporates. That effectively increases octane under load. It also allows more precise fuel delivery at high cylinder pressures and helps improve low-RPM torque and combustion stability.

And keep in mind, this engine is 11:1 compression from the factory. That’s relatively high for a turbocharged engine. The cooling effect from DI is a big part of how Toyota can safely run that compression ratio with boost on pump fuel without constantly riding the knock sensors. It’s not just an emissions strategy — it’s one of the reasons the engine works as well as it does.

Could the engine run on port injection alone? At very light load, probably. But under boost and higher torque demand, DI is doing important work. Removing it would effectively lower knock resistance under load, which would mean less timing, potentially less boost, and ultimately less efficiency and power.

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