VF Tuner ECU/TCU Tuning for the GX550 (2 Viewers)
- Thread starter VF Tuner
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if they wanted to keep the stock Transmission programming.
The original TCU tune was more for shift points and towing. It was not meant to address the clunky shifting that Lexus is trying to fix. I'm assuming that once VF Tuner has a hold of the new flash, they will see what Lexus did and possibly add their own twist to it.
That is why I am patiently waiting for someone to send an updated Read file to them. I don't have time to drop of my GX at the dealer for their shenanigans
The original TCU tune was more for shift points and towing. It was not meant to address the clunky shifting that Lexus is trying to fix. I'm assuming that once VF Tuner has a hold of the new flash, they will see what Lexus did and possibly add their own twist to it.
That is why I am patiently waiting for someone to send an updated Read file to them. I don't have time to drop of my GX at the dealer for their shenanigans
- Thread starter
- #383
Good Evening everyone.
We are working on a new updated tune for everybody. We have the "TSB" reflash along with the newer version (there is a version newer than that shipping on some vehicles).
It looks like Lexus has introduced new load limiters onto these new calibration versions that limit power. We are working on that now.
Thank you
We are working on a new updated tune for everybody. We have the "TSB" reflash along with the newer version (there is a version newer than that shipping on some vehicles).
It looks like Lexus has introduced new load limiters onto these new calibration versions that limit power. We are working on that now.
Thank you
Thanks for your hard work. Really excited to get the new tune, I was waiting since I didn't want to go through the flash process again.
What exactly does a load limiter mean in regards to power ?
awesome news. Can't wait for the updated tunes. How's the timeline for being able to use VF Tuner from Iphones?
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I ordered the GX550 Vf tuner kit but it didn’t come with the CAN CONNECT cable. Is that not included?
Thanks, it’s otw now.
Hello everyone..I live here in San Diego..does anyone know which Lexus dealership is equipped with the software update for the transmission issues of GX550 issues? I have been checking with my Lexus tech but they dont have it yet..Thanks
Would you be willing to share if the new calibrations are purely ECM changes (i.e. changing macro characteristics like shift logic & timing)? Or does it also include a TCU calibration (things like fill time, clutch apply speed)?
I'm curious to better understand what Toyota sees as the root cause. Is it just adjusting engine torque and picking smarter timing for when to downshift? Or are they trying to improve the mechanical & hydraulic behavior in the trans like changing TCC / clutch apply and release speeds or changing line pressure targets?
I also might be asking the wrong question; sorry if it's confusing. Having never seen Toyota's ECU / TCU logic, I'm making the assumption that the ECU handles shift requests, while the TCU handles mechatronic / valve body adaptation.
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- Thread starter
- #392
Stay tuned as we release pre-order (discounted) pricing on our Tundra/ GX550 700 Horsepower package.
World exclusive release from VF Tuner.
VF Tuners "STG1 700" Power Package is available for PRE-ORDERING.
(est. ship late January / February 2026)
Pre order pricing and save off Retail
Package includes:
VF Tuners STG1 Kit ECM/TCM Tune (if you ALREADY have our tune kit and want this please email us)
VF Tuners BOLT-ON Upgraded Turbochargers
VF Tuners 700+ HP Package - 3.5L Tundra/GX550
NOTE: We are limiting this to 15 Packages.
5 Packages are already sold.
10 left.
Also, a big tune update is set to release end of this week as well.
- updated boost tuning / ignition strategy / fueling strategy / TCU tune.
World exclusive release from VF Tuner.
- OEM Like response / Torque
- 700+ Horsepower capable, with 570+ WHEEL Horsepower Possible on PUMP GAS.
- Extensively tested on our 2024 Tundra, through the most brutal conditions for thousands of miles.
VF Tuners "STG1 700" Power Package is available for PRE-ORDERING.
(est. ship late January / February 2026)
Pre order pricing and save off Retail
Package includes:
VF Tuners STG1 Kit ECM/TCM Tune (if you ALREADY have our tune kit and want this please email us)
VF Tuners BOLT-ON Upgraded Turbochargers
VF Tuners 700+ HP Package - 3.5L Tundra/GX550
NOTE: We are limiting this to 15 Packages.
5 Packages are already sold.
10 left.
Also, a big tune update is set to release end of this week as well.
- updated boost tuning / ignition strategy / fueling strategy / TCU tune.
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Can you post a pic of the tundra engine bay with the kit?
Where are the links to the other parts?
I can’t find the site that sells these Magnuson parts
POWER GAINS 700+ Possible:
700+ Possible WITH REQUIRED UPGRADES BELOW (sold separately)
I can’t find the site that sells these Magnuson parts
POWER GAINS 700+ Possible:
700+ Possible WITH REQUIRED UPGRADES BELOW (sold separately)
- Magnuson / aftermarket intakes
- Magnuson Intercooler
- Aftermarket Exhaust
I am not a tuning expert, so somebody please correct me wherever I'm wrong.
I imagine our engine, like most modern turbo engines, are tuned to request a certain amount of torque per accelerator pedal % and rpm, rather than the old school way of requesting a certain amount of throttle opening / air, like older cars. This helps compensate for things like air density, humidity, fuel quality, oil / coolant temps, and gives a super consistent amount of shove every time you push the throttle pedal (and to help simplify the hundreds / thousands of parameters that determine engine output).
Brief aside -that's why aftermarket air filters kinda don't do anything these days, unless you get a tune (or if your intake moves the MAF sensor to read an inaccurate amount of air, which is sketchy). The engine doesn't care how much air it can get - it will compensate and close the throttle body slightly to produce its requested torque value.
Transmission torque limiters, to my understanding, establish a maximum safe torque (and maybe a maximum rate of change? like the mathematical derivative of torque) for an engine to produce to protect transmission & drivetrain longevity. It's almost certainly not a singular value, but a multidimensional map based on many different parameters. When the engine reaches one of those limits, the TCU asks the ECU to reduce torque output to a known safe value to protect the built in safety margins.
It means no matter how much power you tune your engine to produce - even if your engine can make 2000hp - the TCU can step in and ask the engine to reduce power down to its torque limited value. So if you want to make meaningfully more power, you've got to adjust those values - and accept the potential extra stress & wear on your drivetrain.
I would guess what VF Tuner means when they say "introduced new load limiters" - is that Toyota added even more parameters and maps into the TCU load limiter mapping, making it harder to bypass or increase torque limits.
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Any update on the revised GX550 tune?
Hoping this comes this week as i really dont want the dealership to determine that my truck needs the update based on what they think
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