Clutch Slipping on stock A91 MT...

[Isaleus]

Got some feedback on two Supras. Both are driven hard on street/ track with no issues so far. Milage is around 3000-4000. Both on stock power, however they upgraded thier brake fluids for track use. Since the brake and clutch fluids are shared in one reservoir, I am suspecting this could be the issue.

Maybe this and the cdv delete are the best solutions for now.

What brake fluid are they using?

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[Darth]

What brake fluid are they using?

SRF

 

[Sharocks]

SRF is the only brake fluid to run if the car sees actual track use.

The stock BMW brake fluid is decent and is still DOT 4 but I'm thinking of deleting the CDV from day 1.

 

[Eddy90]

No issues here… but those that are having issues, should remove your CDV. Remember these cars were abused by a ton of journalists prior to delivery, they were not easy on the manual.

those having issues, please post A video for everyone’s sake.

You and i do not drive the same car !
Do you have a build thread?

 

[STi_to_GRzupra]

Did you remove the CDV?

BTW, What exhaust set up you got?

It sounds great!

 

[6SPDA91]

So is the common consensus that the clutch delay valve removal fixes the potential of slipping clutches or that if it was properly broken in, that everything should be fine?

 

[FuzzyRev]

So is the common consensus that the clutch delay valve removal fixes the potential of slipping clutches or that if it was properly broken in, that everything should be fine?

We haven't confirmed that yet, but it's our main suspicion as of now.

 

[Brettandblue]

NOTE: I posted this on the other thread as well "A91-MT Clutch gone"

Hey folks, I'll add my 2 cents to this thread. I previously owned a Refraction* blue A91 Supra, purchased directly from Toyota, minus the rapid oil consumption I ran into no problems with that car. I sold that and purchased the A91-MT brand new in burnout clutch white in October (Paying $7k over sticker). My clutch is fried as of 3150 miles. I had no issues prior until a few miles before it became undrivable. I have a detailed description that I will post below. Upon inspection Toyota had noted heat marks on the flywheel as well as finding pieces of disintegrated clutch. I was left on the hook for a $1200 inspection fee and had to ultimately tow the car back to my house. I was quoted roughly $3800 to fix the car and a 6-7 month waiting period for parts. This is unacceptable. I reached out to corporate to either "good will" the parts or buy back the vehicle and both options were rejected. Their stance is that they "believe" the damage is due to abuse. That is not the case, and unfortunately trying to "disprove" abuse is not an easy task. I plan on having the car sent to an independent Toyota approved shop to look into everything more extensively. I am unsure if the car records the driving records like some Porsches, but if it does I'd love to access those records to send to Toyota as well.

Please Note: There has been no track use, no canyoning, no donuts, no burnouts, let alone me even approaching the redline on the car. The car itself is completely stock and has been my daily going to and from the gym/groceries/etc. I have a Lotus Evora GT that I use to let loose on the more "aggressive" style driving. The car was also completely babied beyond the engine/clutch break in period.


This is what I informed Toyota-


"As I drove the car down the road, I couldn't help but notice that something felt off. No matter my gear, it seemed like the clutch would slip if I applied more than 50 percent throttle. This was particularly noticeable when I was driving at highway speeds of around 65 miles per hour, and my RPMs were relatively low. There would also be the occasional smell of a burnt clutch and no indication of driver error while driving, so the smell of clutch would follow a small acceleration and then the clutch would slip indicating there is a clutch issue. Even the slightest amount of throttle that was over the 50 percent mark would cause the clutch to slip, and the car would accelerate at a painfully slow rate, especially given its impressive power-to-weight ratio."




I'm looking to gather and connect with anyone else running into slipping issues/clutch failure. I have numerous friends who are stock MT owners that are experiencing slipping issues, especially in 4th-6th gear. Any guidance is welcomed and I hope that we can squash this issue for everyone's sake. If you are running into these issues please feel free to contact me

[email protected] or DM me.

Thankyou all for your time reading this, hope everyone is having a wonderful spring!

-Brett

 

[robotvoice]

I have numerous friends who are stock MT owners that are experiencing slipping issues, especially in 4th-6th gear.

I'm sorry, you have numerous friends....all of which have the MT Supra...all of which are completely stock.......all of which are having supposed clutch slipping issues....in the same driving situations...

I find this a bit hard to believe. Sorry but this sounds like FUD to me.

 

[Eddy90]

... No matter my gear, it seemed like the clutch would slip if I applied more than 50 percent throttle. This was particularly noticeable when I was driving at highway speeds of around 65 miles per hour, and my RPMs were relatively low. There would also be the occasional smell of a burnt clutch and no indication of driver error while driving, so the smell of clutch would follow a small acceleration and...

Interesting... I just did a 200 mile trip (mostly highway cruising) this past weekend. Monday morning, I noticed my clutch definitely felt funky, and had almost no "grabby/jerky" or "bite" feeling. The shifts were just way too buttery, if that makes any sense?
While on the 200 mile highway trip, I did something similar; at 65 MPH or so, I would leave the car in 6th and use the torque to speed up to 80~90, instead of downshifting. I once heard someone say this method of accelerating in a high gear at low RPM, puts more torque thru the clutch, but i always thought it was bs considering the pressure plate has already locked the clutch in (there should be no slip right?)... i was probably wrong..

Soon after some city driving in the next few days, the normal clutch behavior was back...
My car is at 750 miles or so. Still breaking it in, but for a day or so, I sure felt like the glazed the clutch after that highway drive..

EDIT : Not trying to create any hysteria. Just noting down my experience. Worst case if the clutch does go, ill just pay for an aftermarket one... you gotta pay to play i guess.

 

[Lonestar_Nomad]

Y'all have me extremely concerned to leave my garage, especially since I'm pretty green on a manual transmission.

Would anyone mind sharing their thoughts on a "proper" break-in for the clutch?

 

[AJRMKV]

I’m picking up mine on Saturday.
Annoyed as hell reading this

 

[mdpalmer]

Remember these cars were abused by a ton of journalists prior to delivery, they were not easy on the manual.

Right, I've seen what I believe is the same strat blue MT car in a number of videos (same Texas plate?). Would be nice to know how it's holding up.

https://youtube.com/clip/UgkxtIOrKPW2swYtfSrYw_Rx3x7MQ5nVUuqa

 

[6SPDA91]

Y'all have me extremely concerned to leave my garage, especially since I'm pretty green on a manual transmission.

Would anyone mind sharing their thoughts on a "proper" break-in for the clutch?

Typically on a clutch break in, you want to vary RPM as much as possible. Break in usually depends on the clutch but 1000 miles seems to be pretty standard when you do a mix of highway and city driving. If you can do 500 miles of stop and go that would also suffice. If mainly highway, it's typically around 1500 or so miles because the clutch should be fully engaged at that point.

If you're on the highway, sitting in the same gear at the same rpm for long periods doesn't actually count towards the miles (ex. If 200 miles are done on the highway at roughly the same speed in the same gear, only county about 50 miles).

I believe coming to a stop you don't really want to row down through the gears, rather, stay in your gear, let the RPMs drop down then shift into neutral. After completely stopping re-engage first or reverse and drive. If you are going to downshift, you should avoid rev matching if possible (I believe it allows the surfaces to mate like bedding in brakes). That being said, I did some rev matching, especially if I had a little highway driving, just to allow a change in rpm.

Those first 1000 miles should be light. Nothing wrong with a brief lighter acceleration, but typically you want to be gentle. I would say stay below 4500 in any given gear (I believe that's the engine break in spec as well).

It feels like a lot and it is, but if you can break in your friction materials properly then they should last. I'm around 5k, numerous road trips so far.

I've used a number of aftermarket clutches in my time and might have the break in procedure for one in my house for the last one I had installed back in July on my daily. I'll post pictures of that if I can find it when I get home.

That's my typical process for breaking them in at least. I think the lack of "fun" for the first 1000 miles is worth the longevity of the properly broken in equipment.

 

[kern417]

"As I drove the car down the road, I couldn't help but notice that something felt off. No matter my gear, it seemed like the clutch would slip if I applied more than 50 percent throttle. This was particularly noticeable when I was driving at highway speeds of around 65 miles per hour, and my RPMs were relatively low. There would also be the occasional smell of a burnt clutch and no indication of driver error while driving, so the smell of clutch would follow a small acceleration and then the clutch would slip indicating there is a clutch issue. Even the slightest amount of throttle that was over the 50 percent mark would cause the clutch to slip, and the car would accelerate at a painfully slow rate, especially given its impressive power-to-weight ratio."

Being the devil's advocate - how low are the rpms? Accelerating in High Gear/Low RPM scenarios is a recipe for a bad time. It's almost always better to downshift. 5th gear is 1:1.

Y'all have me extremely concerned to leave my garage, especially since I'm pretty green on a manual transmission.

Would anyone mind sharing their thoughts on a "proper" break-in for the clutch?

The goal is to slip the clutch a bit to wear away any high points so that the materials have as much contact surface area as possible. Do a lot of city driving so you're going through the gears as much as possible. It happens quicker than a lot of people think, but if most of your driving is highway then it'll take more miles then just driving some laps through the city on a weekend (that's what I did, I think it ended up being like 40-50 miles). Not full throttle pulls, no fast shifts. The clutch engagement is what wears the materials down sot hey mate together perfectly.

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