GR Yaris I Broke my third Transmission at track 。this time GRMN close gear set

[Onehp]

@Onehp Mabe is tide track of my home course it get 23 turn

I had see Some Japanese Gymkana GR Yaris brake front transfer case early on , so is the course lay out ?



Even though my Dyno read only 460nm at wheel
But
Different Dyno read differently
The mainline Dyno I use is know to be heart braking Dyno because it will always read lower then other brand ,
and that is close 500nm at engine , where I come from I only take reading from wheel

I still find hard to believe light weight flywheel can create more harm then dual mass

Ok, 460 "wheel Nm" (whp/engine rpm) can be a lot more at flywheel, and a lot more than 500Nm, maybe 550Nm+. I remember writing when you had 600+ with Motec at first and I predicted expected broken driveline... Obviously need to reduce that torque more.

I remembered an IG with single flywheel and the vibration sound in gearbox was terrible...

 

[Yaris146]

Gearbox is rated to 400nm at least that’s the limiting factor for lotus. I think that’s the strongest transverse box aisin sell which was pretty good when it came out.

 

[Michael Knight]

Gearbox is rated to 400nm at least that’s the limiting factor for lotus. I think that’s the strongest transverse box aisin sell which was pretty good when it came out.

its Toyota Version EA6X of Aisin BG6

List of Toyota transmissions - Wikipedia

en.wikipedia.org

EA67F​

• 2020- Toyota GR Yaris with G16E-GTS engine
• 2023- Toyota GR Corolla with G16E-GTS engine

Torsen Limited Slip Differential Optional

Gear	1st	2nd	3rd	4th	5th	6th	Reverse	Final 1-4	Final 5-6-R
Ratio	3.538	2.238	1.535	1.162	1.081	0.902	3.831	3.941 (Yaris) 4.058 (Corolla)	3.350 (Yaris) 3.450 (Corolla)
Synchromesh	Triple	Double	Single

EA68F​

• 2023- Toyota GR Corolla Morizo Edition with G16E-GTS engine

Torsen Limited Slip Differential Equipped

Gear	1st	2nd	3rd	4th	5th	6th	Reverse	Final 1-4	Final 5-6-R
Ratio	3.214	2.238	1.592	1.162	1.081	0.902	3.557	4.250	3.578
Synchromesh	Triple	Double	Single

​

BG6 listed also in this torque chart from Aisin though rather rough scale.

 

[Diyman25]

Great information Michael knight
That really show , my theory if u push over 460NM on wheel , and use it on track with super wide tire
u are risk of damage transmission 。
Is pitty G16E-GTS engine can do so much more ……

 

[Onehp]

That chart is for flywheel torque for sure.

Is it wheel or hub dyno @Diyman25 ?

 

[Diyman25]

That chart is for flywheel torque for sure.

Is it wheel or hub dyno @Diyman25

I think gr Yaris gear itself can withstand more TQ
But not on Syncro hub ,
this will explain why i am and other
serious track user are braking it

My
460nm wheel on front wheel is roughly 500nm

 

[Onehp]

I think gr Yaris gear itself can withstand more TQ
But not on Syncro hub ,
this will explain why i am and other
serious track user are braking it

My
460nm wheel on front wheel is roughly 500nm

Ok, hub dyno then. Just to get an idea of flywheel torques.

 

[HammeredSole]

Thank you for the command, yes my point is always
To let people know what happened if u push this far at track , not just Dyno or street car
Wish u the best on ur GRC project, keep ur ftransmission cool , if u are using it as serious track machine , I just can’t imagine how the transmission can last with 200 kg more weight and even more tire !!!

That's exactly what I am wondering as well. As we already know the GRC shares the exact same engine code with the GRY, but the motors have different pistons, cams, exhaust valves, valve springs, turbo, HPFP, oil cooler; to name a few. I'm very curious what sort of internal revisions were done to the transmissions, if any.

 

[Diyman25]

That's exactly what I am wondering as well. As we already know the GRC shares the exact same engine code with the GRY, but the motors have different pistons, cams, exhaust valves, valve springs, turbo, HPFP, oil cooler; to name a few. I'm very curious what sort of internal revisions were done to the transmissions, if any.

I don’t think they will do at transmission revision
After all they are super reliable at stock level and bolt on level to track ~ I did a 12-15 plus event in first year of GR Yaris ownership
No issue even with 295 tire ,

 

[HammeredSole]

I don’t think they will do at transmission revision
After all they are super reliable at stock level and bolt on level to track ~ I did a 12-15 plus event in first year of GR Yaris ownership
No issue even with 295 tire ,

You're probably right. Hopefully, Albins or PPG will offer a helical synchronized gear set option, or even a helical dogbox. Straight gears are just too loud outside of first or second gear for street driving.

 

[Diyman25]

EA60 transmission
Was first introduced all the way back at 2005
And use on a lot of FWD car back them

• Toyota Avensis, Toyota Corolla, Toyota RAV4, Mazda6, Mazda5, Mitsubishi Eclipse, Mitsubishi Grandis, Jeep Compass, Jeep Patriot, Dodge Caliber, Dodge Journey, Lotus Exige, Lotus Evora

u don’t see any high TQ car like in 202x

So even Gr Yaris come better material for transmission component, it can hold stockish TQ for track very well
but still is not a transmission for Hight TQ condition for Track if u are fast enough

I am testing some reinforcement Syncro hub this year , will keep u guys update

 

[Diyman25]

Is been almost 2 mo since my transmission issue
Face some more problems, for some reason Toyota refuses to sell me a replacement part , they want me to order complete kit again , I was none sense , this is race part install for competition and it will brake ,when it brake I need part to be replace
Not buying whole thing , and clearly there is individual part number that mean u can order individual part to be replacement

My contact Japan try almost 2 mo to convince Toyota to sell the replacement,

Finally some good news , look like some how he manage to convince Toyota part department

Look like my car should be back to action in July

Some update 6/13
Look like part will be ship out shortly, bought enough part to fix my spare stock transmission
And yeah , Toyota stock part is super cheap
Cost way less then GRMN part

 

[Diyman25]

Some thing new in the market

 

[Diyman25]

Acoording to neat box testing
And some thing I found on line
Gr Yaris Syncro hub is definitely on soft side and is a
Weak link if u are pushing the limit

 

[Diyman25]

My replacement transmission part had arrive
Will test out gear stiffness before install

 

[Diyman25]

Hopefully I can finish the transmission rebuild
At mid July , the part with red dot is GRMN part
The package look 90% stock
So I have put a sticker for shop to put it on easier
Install
And I might take it to metal lab to test the stiffness

 

[Diyman25]

Test GR Yaris stock fifth gear clutch hub and GRMN
Different at Friend’s Lab

Not Suprisely stock GR Yaris is pretty soft

 

[Diyman25]

Japanese drivetrain specialist Cusco
Is making reinforcement gear hub too

 

[Onehp]

For reference, what gearbox oil are you using?

 

[Diyman25]

For reference, what gearbox oil are you using?

I have ATS Carbon LSD , it need special oil
Monty’ M409 80/250