GR Yaris I Broke my third Transmission at track 。this time GRMN close gear set
- Thread starter Diyman25
- Start date
Very rarely does a car get its own gearbox... It's Toyota part bin used on the large engines, also used by Lotus for their (Toyota) V6 models...
Some really great information you are sharing, that is likely to help push the boundaries even further. On the image of the stress riser analysis, it seems there are 2 different parts. Has Toyota superceded the failing part, is this a newer 5th gear synchro ring for the GR Corolla? What exactly are we seeing?
I am starting down the slow build path of my GR Corolla, and I am addressing drivetrain and cooling issues before I even touch the engine. There are aftermarket gearsets and transmissions available, but I am looking to make stealth power for street/track use, so I am not interested in a noisy dogbox or sequential transmission. I wish Albins or PPG offered a strong helical gear set.
I think it’s the BG6 out of the Evora and obviously lots of other stuff. They had a few failures on the early cars I but it’s over ten years ago. I believe recently they have been fairly reliable. I know lotus changed the gear sets on one of the shafts but I don’t know if it was weakness or just different ratios. I would imagine the new emira has the same box although not seen one yet.
Michael Knight
Totally Hooked
fun to see how GRC manages the heat and driveline part as its heavier car.
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 !!!
Shop have time to tear down the transmission
Not Suprisly same part fail
This time just GRMN Syncro hub
And this time 5th gear get damage too
What d diaster , is pitty great car let fown by weak faulty design
Not Suprisly same part fail
This time just GRMN Syncro hub
And this time 5th gear get damage too
What d diaster , is pitty great car let fown by weak faulty design
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Do you have lightweight flywheel? The micro vibrations caused by removing the dual mass flywheel (or actually by 2nd order vibrations due to 3-cyl with offset) can cause failure on gearbox due to cyclic load that much increases fatigue stress.
That is very long shot of Syncro hub failure
If we are talking about endurance race like 12Hr or 24hr , I think is possible
But one lap time attack using high performance street tire
Man
Yeah it seems improbable but not impossible either..That is very long shot of Syncro hub failure
If we are talking about endurance race like 12Hr or 24hr , I think is possible
But one lap time attack using high performance street tire
Man
If the harmonics and flywheel play a role it will actually be worse at low loads when the vibrations, several times per revolution for each cylinder, will reverse loads.That is very long shot of Syncro hub failure
If we are talking about endurance race like 12Hr or 24hr , I think is possible
But one lap time attack using high performance street tire
Man
If you can put back the dual mass flywheel, it's easy to test the hypothesis...
The other way around, is there any coincidence of having the single flywheel and gearboxes failing? Because some people are running similar torque as you without any immediate gearbox failures as far as I know, and you have three in a short period of time... and sticky tyres don't work well as an explanation in 4th and 5th gear where traction loss (limiting torque on driveline) on normal tyres isn't a thing either...
Could of course be something else, just one possible theory...
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Damage this time
GRMN part
2gear 5th gear Syncro hub
3 gear 4 gear
OE part
Syncro , oe hub , 6th gear
Damage are pretty bad compare to my last 2 transmission
GRMN part
2gear 5th gear Syncro hub
3 gear 4 gear
OE part
Syncro , oe hub , 6th gear
Damage are pretty bad compare to my last 2 transmission
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Michael Knight
Totally Hooked
Gear damage due to debris?
Engine unbalance is a source of failure, there is a reason for dual mass flywheels, crank shaft dampers, balance shafts exist. Performance engines have pistons etc weighed and matched to the gram...
Anyone anywhere heard of similar damages at less than 500Nm? Seems very odd you get so quick failures, the forums should be flooded with broken gearboxes if it's just the torque, tyres and gearboxes fault... any other mods?
Yep
After seeing this , I am going to sequential
Enough is enough
Yeah 5th Syncro hub get throw into gear cause damage , Suprisely i stlll manage to finish my personal best at the week after
there is lots failure on 5 Syncro hub
I had heard more then 10 case , they just don’t post how and when and why of failure ,
and they are all serious track car
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Kudos to you for sharing. Still wondering why we don't hear more from it, there must be hundreds tuned Yarii tracking quite seriously and just you broke three, the last one very quickly with only 460Nm...
Michael Knight
Totally Hooked
In today's IG world bet it would get more hits to put broken stuff content than just shiny cars. .
@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
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
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