GR Yaris If u know how hot ur Gr Yaris transfer case can get, u will never drive ur Gr Yaris in same way

Diyman25

Totally Hooked
Jan 7, 2023
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I never understood why Toyota give green light on this design , or they are pretty comfortable Gr Yaris transfer case strength
Which will run over 170-180c even with GRMN panel install just 2lap of serious track driving from 82/82 (75/140 gear oil ) which is crazy
I have to use gear oil of 75/250 that design for drag car to kind da control temperature around 150c
As u can see gearbox oil in very normal operating temperatures

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My friend designed and tested the Xshift and it should be a bit better (gear can not get stuck and have the trans oil conection) but both are superior. They use to be one company Kaps trans here in Czech but split some time ago.
 
I don’t think the standard gr yaris transfer case had a design brief to be able to cope with serious track work, on 295 semi slick tires with a lot of extra downforce. You should upgrade it to your use case and not blame the OEM, imho.
 
Even in stander power trim , the transfer case is still very hot , transfer case can go over 150C if use in track condion ( been monitor it since day 1 )
 
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Even in stander power trim , the transfer case is still very hot , transfer case can go over 150C if use in track condion ( been monitor it since day 1 )
Do you have photos of the temp sensor installation and plumbing of the cooling lines?
 
What is THE best oil and grade for the transfer box?..that will cope better with high track temps?..
 
Bolt on like intake , down pipe and hks power editor
Wide high performance tire
So not standard.

Toyota will have done a lot of testing and it’s not something people are experiencing in the use that Toyota designed it for so I’d say they’ve done a good job.

As you’re modifying (and I’d say the extreme end of that) you’re finding the limits of the parts, I wonder what the super taikyu or rally2 cars are doing to keep the temps down?
 
So not standard.

Toyota will have done a lot of testing and it’s not something people are experiencing in the use that Toyota designed it for so I’d say they’ve done a good job.

As you’re modifying (and I’d say the extreme end of that) you’re finding the limits of the parts, I wonder what the super taikyu or rally2 cars are doing to keep the temps down?
More like GRMN , so pretty standard
Trust me , this transfer case go very hot in track use , if u did not mentor it please don’t say Is good job 🤣
U can check my other thread about the tranmission
 
So not standard.

Toyota will have done a lot of testing and it’s not something people are experiencing in the use that Toyota designed it for so I’d say they’ve done a good job.

As you’re modifying (and I’d say the extreme end of that) you’re finding the limits of the parts, I wonder what the super taikyu or rally2 cars are doing to keep the temps down?
Exactly, Toyota tested the GR Yaris on several track both in Japan and Europe prior to its release. And they tested at least with stock ps4s tires and cup 2, so I’d say for an occasional track day, the car is fine.

Another thing is this is a dedicated track day that does 90% of its miles on the Ring or another circuit for that matter. Then, you probably need to updgrade a good few things to get proper reliability.