High RPM Clutch Hang Up

[StigsBaldBrother]

I was at Sebring this weekend for the beast's second track outing and experienced a peculiar issue. When shifting at high rpm, around 7500 to 8000, the clutch wouldn't reengage when the clutch pedal would release. It seemed as if the pressure plate, and the clutch pedal too, were stuck for about half a second, then it would reengage like normal. My wife experienced the same thing, so it wasn't my driving style or releasing of the pedal.

I did change the stock clutch pedal spring for the Steeda one. However, Steeda happened to be at the event and I spoke with Dario, the owner, who said it was just a function of the pressure plate at high RPM and the pedal spring had no effect. I'll take that with a grain of salt seeing that it's his product and I don't know how much testing they did on a GT350, if they tested it at all.

Have any of you experienced something similar with the stock pedal spring?

 

[VoodooBoss]

Wait, first you let your wife drive your car on track? You're a lucky guy. My wife won't even go to the track with me.

And I was just commenting to a friend how trouble free the Gt350 TP and R have been on track. @Moto had his R on track this weekend and @Black Boss has a bunch of track days on his R. I know Moto has the Steeda Spring on his car but I'm not sure about BB. I have the Steeda Spring sitting on my work bench ready to be installed but I doubt it's causing the problem.

 

[StigsBaldBrother]

Wait, first you let your wife drive your car on track? You're a lucky guy. My wife won't even go to the track with me.

And I was just commenting to a friend how trouble free the Gt350 TP and R have been on track. @Moto had his R on track this weekend and @Black Boss has a bunch of track days on his R. I know Moto has the Steeda Spring on his car but I'm not sure about BB. I have the Steeda Spring sitting on my work bench ready to be installed but I doubt it's causing the problem.

You got it backwards. My wife let me drive her car on the track. We did have to sell her beloved 03 Cobra to get it. The track sessions are my payment, or I guess reward, for doing all of the maintenance and modifications. She's the one doing the Track Attack and 302S day at Ford Racing School in another 2 weeks.

Other than that, the car was amazing this weekend. We had back to back run groups and the car didn't skip a beat.

Back on topic: I would tend to agree with you that the spring isn't the issue, if the pedal wasn't stuck to the floor. But then again, it is a hydraulic clutch and the pressure plate should have enough spring force to handle returning to engagement at high RPM. Hopefully some other track junkies will chime in.

 

[VoodooBoss]

Cool. The pedal sticking was very aggregating in the Boss and I sure hope we don't have widespread issues in the GT350.

 

[Flyboygsxr]

Here we go again...Could be due to the fact that you were running back to back run groups so I'm assuming 40 minutes or so without a cool down? That's a long time in the summer to run without a cool down.

 

[moto]

And I was just commenting to a friend how trouble free the Gt350 TP and R have been on track. @Moto had his R on track this weekend and @Black Boss has a bunch of track days on his R. I know Moto has the Steeda Spring on his car but I'm not sure about BB. I have the Steeda Spring sitting on my work bench ready to be installed but I doubt it's causing the problem.

Yep. No problem with high rpm shifting like the boss. Steeda spring felt very good. Clutch engages/disengages slightly higher than I like, but no issues on the track.

 

[TMSBOSS]

Yep. No problem with high rpm shifting like the boss. Steeda spring felt very good. Clutch engages/disengages slightly higher than I like, but no issues on the track.

Is there adjustment in the clutch linkage under the dash?

 

[moto]

Is there adjustment in the clutch linkage under the dash?

Not that I know of. Just the spring(double actually) that was initially way too light for my taste and now after replacing with the lighter single spring, results in a stiffer, more linear, feel. The engagement point appears to not be adjustable.

 

[Black Boss]

Doubt it's the spring. I have 10+ track days and about 1,400 track miles with no issues on the Stock set-up

 

[StigsBaldBrother]

Argh. We'll I'm certainly not going to take it back to the dealer and ask them to try to recreate the problem. I'll try to do some more diagnosing at the next event. Thanks guys.

 

[8250RPM]

Could it be the brake fluid temps? I never understood why they did away with a stand alone clutch cylinder. I actually rather have the cable actuated clutch back.


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[StigsBaldBrother]

Could it be the brake fluid temps? I never understood why they did away with a stand alone clutch cylinder. I actually rather have the cable actuated clutch back.


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It didn't seem to be temperature dependent as it hesitated the first session out. I didn't know that this was an issue on the Boss. I know the Cobras didn't have this issue, but you also needed to be a weightlifter to depress the clutch. Being able to adjust the release point was amazing too.

 

[k98dave]

Could it be the brake fluid temps? I never understood why they did away with a stand alone clutch cylinder. I actually rather have the cable actuated clutch back.


From what I have read here and other sites the issue on the Boss (and GT's also) appears to be the springs in the friction disc hat failing. Its doubtful hyd. fluid temp has anything to do with it.

 

[YellowJacketBoss302]

please give us an update. Are you still having this issue?

 

[StigsBaldBrother]

Not really sure yet to be honest. I put the stock clutch spring back into it as a test, but I haven't been to a track that I was familiar with enough to get my shift points that high. I was supposed to go back to Sebring in 2 weeks to find out, but they just canceled the event.

 

[Froggy47]

Just came across this. My 2004 z06 (and a lot of other z06 cars) have this well known issue. Clutch pedal sticks down after high rpm shift, will not pop up to reengaged clutch. Many different approaches to fix such as:

Different (performace) clutch
Different clutch master and/or slave
Helper spring to pull pedal back up (I have this)
High(er) temp clutch fluid (I have this)
Change clutch fluid when it darkens (Ranger turkey baster method) I do this.
The ones I do have fixed my problem, I am still on all stock components @ 60k miles.

My personal opinion is that at extreme/repeated high rpm/heat conditions the design of the clutch itself allows a momentary (and damn annoying if not dangerous) hang up of the parts at disengaged position. Sometimes it stays there for a while. You would think the engineers would account for this in design, but what do I know, just a customer. I think the engineers cave in to other "market research" folks who insist that the few remaining stick drivers want a light, easy to push down pedal, and that nobody REALLY shifts at the red line. SIGH.

 

[StigsBaldBrother]

Just came across this. My 2004 z06 (and a lot of other z06 cars) have this well known issue. Clutch pedal sticks down after high rpm shift, will not pop up to reengaged clutch. Many different approaches to fix such as:

Different (performace) clutch
Different clutch master and/or slave
Helper spring to pull pedal back up (I have this)
High(er) temp clutch fluid (I have this)
Change clutch fluid when it darkens (Ranger turkey baster method) I do this.
The ones I do have fixed my problem, I am still on all stock components @ 60k miles.

My personal opinion is that at extreme/repeated high rpm/heat conditions the design of the clutch itself allows a momentary (and damn annoying if not dangerous) hang up of the parts at disengaged position. Sometimes it stays there for a while. You would think the engineers would account for this in design, but what do I know, just a customer. I think the engineers cave in to other "market research" folks who insist that the few remaining stick drivers want a light, easy to push down pedal, and that nobody REALLY shifts at the red line. SIGH.

Thanks Froggy. It's only an annoyance right now, but I hope that it doesn't get worse as the clutch wears. Been too hot for any decent track events, but I should know more soon.

 

[v8 snake]

i have the same issue on my 2018 gt350...

 

[racer01]

My car did this with the Steeda spring. Figured it was all in my mind and the spring couldn't really be the cause. Put stock spring back in and full throttle redline shifts were normal again. Try going back to stock. Some folks don't appear to have issues. I did. Mine was installed correctly as well...double checked.