Clutch Slipping on stock A91 MT...

[Stvee]

Take it to any BMW shop, they can do it for like 30 bucks.

You basically remove the line, take the valve out, reinstall the line.

I know, I've done it plenty of times before. I just don't want to risk messing with a part that isn't available to order.

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[FuzzyRev]

I don't think anyone has checked yet but probably. I'd guess they are in the same spot as the G80.

It feels like it has one to me but I'm not going to remove it until that piece of hose is available to order from Toyota in case I were to mess something up.

Same, which is why I'm trying to work it up the chain with TMC, and I'll be calling them again tomorrow.

 

[AJRMKV]

I don't know, and I don't know much about the CDV in general, but I found this on the first site that came up on google and it sounds a lot like what @NitroYellowMKV is encountering:

A Clutch Delay Valve (CDV) is a one-way restrictor, located between the clutch slave and clutch master cylinders. It slows the engagement of the clutch, similar to a damped record player tone-arm, gently lowering the needle to the surface of a record.

Due to this factory device, the clutch engages the flywheel slowly, regardless of how quickly you lift off the clutch pedal. In theory, it reduces driveline shock, if an inexperienced driver dumps the clutch. In practice, it prematurely wears the clutch disc and transforms experienced drivers into novices, who cannot shift smoothly. During parallel parking, the delay can be infuriating, causing constant clutch slippage. During hard acceleration, the slippage shortens the life of your clutch. During normal driving, the first to second gear shift may be jerky, leading passengers to question your skill, as their heads bob back and forth!

Wouldn't this kind of thing lead to slippage when you shift quickly into the next gear because the clutch doesn't fully engage before you get on the gas? I am still in the break in period, so I haven't driven it hard enough to encounter this, but I do get the jerkiness in the 1-2 shift.

I know of atleast one shopcar supra that had it's CDV removed. The owner of the shop said it fixed the clutch issues they were having but should only be done if the objective is to use the vehicle as a track car.

 

[Sharocks]

I know of atleast one shopcar supra that had it's CDV removed. The owner of the shop said it fixed the clutch issues they were having but should only be done if the objective is to use the vehicle as a track car.

The purpose of the CDV is for noobs who don't know how to drive stick. It's literally there as a safety.

You can definitely drive a BMW without a CDV even easier on the street.

For example, my E39 M5 from the factory did not come with a CDV. One of the easiest manuals to use probably in the history of automobiles.

 

[NitroYellowMKV]

Hmm the CDV valve thing does sound right, almost as mine as failing or some other issue causing that slippage under hard 1-2-3 acceleration. I don’t know if I’d want to remove it as much try it working right first (if that is what is in fact happening)

 

[Evolution]

Hmm the CDV valve thing does sound right, almost as mine as failing or some other issue causing that slippage under hard 1-2-3 acceleration. I don’t know if I’d want to remove it as much try it working right first (if that is what is in fact happening)

Have you ever tested slow shifting? Like purposely shift slow, let the clutch fully engage and then go back ful throttle? Doing so (with no clutch slip results) would halfway point towards the valve.

 

[CortC]

Have not had any issues on mine, car shifts great and the clutch feels strong with no slipping whatsoever in any gear.

 

[UYCR]

Well another buddy of mine is having clutch issues but he is still at stock power. He was at an HPDE during the weekend and seems like the clutch overheated a bit by the end of the session causing him to slip in 6th gear during a straight.

 

[FLtrackdays]

Well another buddy of mine is having clutch issues but he is still at stock power. He was at an HPDE during the weekend and seems like the clutch overheated a bit by the end of the session causing him to slip in 6th gear during a straight.

That was my question. How it handles under an extreme track environment. I’ve seen Porsches and BMWs both with manual issues. It happens. One of my core reasons for going with the ZF this go round on mine. Being mainly a track car.

You’d think they’d have a fix for this quickly. Especially in the BMW part bins. Such as Turner Motorsports?

 

[NitroYellowMKV]

Well another buddy of mine is having clutch issues but he is still at stock power. He was at an HPDE during the weekend and seems like the clutch overheated a bit by the end of the session causing him to slip in 6th gear during a straight.

Ughhhh not a good sign… I just want a working car at stock power… that isn’t a lot to ask for

 

[UYCR]

That was my question. How it handles under an extreme track environment. I’ve seen Porsches and BMWs both with manual issues. It happens. One of my core reasons for going with the ZF this go round on mine. Being mainly a track car.

You’d think they’d have a fix for this quickly. Especially in the BMW part bins. Such as Turner Motorsports?

Toyota should have definitely used an M-spec clutch on these cars but I have also seen several manuals that have been getting tracked for months now without any issues. Makes me wonder if the clutch delay valve when combined with habits of certain driving styles makes these clutches more prone to failure.

After cooling down my buddy could still drive the car so at least is was a temporary failure but some damage has already been done unfortunately. He also has aftermarket wheels/tires in case that matters. I have some wheels and extremecontact force tires on their way but might end up sticking with stock for my free HPDE just to keep the clutch within its expected grip levels as I start abusing it.

 

[Stvee]

Toyota should have definitely used an M-spec clutch on these cars but I have also seen several manuals that have been getting tracked for months now without any issues. Makes me wonder if the clutch delay valve when combined with habits of certain driving styles makes these clutches more prone to failure.

After cooling down my buddy could still drive the car so at least is was a temporary failure but some damage has already been done unfortunately. He also has aftermarket wheels/tires in case that matters. I have some wheels and extremecontact force tires on their way but might end up sticking with stock for my free HPDE just to keep the clutch within its expected grip levels as I start abusing it.

Out of curiosity is his one of the early A91 cars or is it a regular A90?

 

[FuzzyRev]

@Stvee @NitroYellowMKV @Sharocks @UYCR @FLtrackdays

Success! I just placed an order with TMNA for the slave cylinder and the metal line that connects to it. Will get an ETA tomorrow..

 

[NitroYellowMKV]

@Stvee @NitroYellowMKV @Sharocks @UYCR @FLtrackdays

Success! I just placed an order with TMNA for the slave cylinder and the metal line that connects to it. Will get an ETA tomorrow..

Keep us updated !

 

[UYCR]

Out of curiosity is his one of the early A91 cars or is it a regular A90?

He has a Nitro Yellow A90. He took delivery of his car a few weeks after mine so that would be around the end of November of last year.

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