Clutch Problems

[bazza1440]

Hi All,

A bit of advice please -

I have a 2015 2WD Yeti 100 BHP but mapped to 190 BHP. I am starting to get Clutch slip (at least that's what I think it is) at around 2,500 rpm in 4th &5th gear if I accelerate hard. 

So far it hasn't slipped when I tow my Caravan - but accelerate sensibly.

 

Assume the clutch is on it's way out and wondered the following:-

 

1. Is it worth changing to a single mass flywheel?

2. Can I fit an uprated clutch to the same DMF or a replacement DMF? 

3. If I chose 3. then do I need to change the DMF?

 

Any help appreciated

 

Cheers

BAzza

[J.R.]

Cant help re the choice of clutch or flywheel but it does sound like clutch slip under max torque.

 

I have the same vehicle & engine and had intended to have the same remap but CV19 has hampered my travel, can I ask you for your experiences of it, where did you have it done & did the clutch start to fail soon afterwards? How many mile on the clock etc? And any other info you think of interest.

 

Thanks & good luck.

[bazza1440]

Hi, 

well its the second yeti i have had done but the first was a 4WD with 112,000 on the clock this was absolutely fine. The power was great and better delivered with the 4WD. Never any problems over the 40,000 miles that i had it for. I miss the 6 speed box of the 4WD the 2WD is just 5 speed and isn't quite the same. 

For this car the increase in power was good but i did start to notice a bit of clutch slip after about 15-17k miles after having it done i guess. I can still drive the car steadily and i dont get any clutch slip but it does it briefly if I welly it.  The previous owner had put around 27k miles on it so I don't know how much of a Legacy i inherited. 

 

Barry

[J.R.]

I wonder if the 4WD has a stronger clutch because of the power that can be put down from a standing start? - Anyone?

 

Who has done your remaps please?

[logiclee]

6 minutes ago, J.R. said:

I wonder if the 4WD has a stronger clutch because of the power that can be put down from a standing start? - Anyone?

 

Who has done your remaps please?

 

5 speed box is only rated for 250NM of torque, the 6 speed is 350NM. 4WD versions also get uprated clutch on the 6 speed I believe.

 

 

[J.R.]

Thankyou for that

 

It gives me some confidence.

[Austin 7]

Hi

 

If you fit a single mass flywheel, the gearbox will be subjected to higher peak torque as the cyclic fluctuations aren't smoothed out.  So even if you are prepared to put up with the increased noise and vibration, the gear teeth might not.  Remapping will increase torque, which will further eat into any margin of strength the gearbox might have.

[J.R.]

An interesting theory, do you really believe it?

[Urrell]

13 hours ago, Austin 7 said:

If you fit a single mass flywheel, the gearbox will be subjected to higher peak torque as the cyclic fluctuations aren't smoothed out. 

The clutch would be the first in line to suffer with the low down firing pulses not being smoothed as well.

[logiclee]

11 hours ago, J.R. said:

An interesting theory, do you really believe it?

 

Some autoboxes had a similar issue.

 

Jeep used the same gearbox on the big 5.7V8 Petrols and the 2.8 diesels. The petrol pushed out more torque and considerably more power but the gearbox was failing on the diesel. 

 

This was found to be the pulse loading from the 4 pot diesel that would shred the lockup clutch and destroy the torque converter splines.  V8 with more power and torque no problems.

 

On subsequent boxes they fitted a "Torsional Damper" basically a DMF that the lockup clutch mated to to protect the lockup clutch, torque converter and splines.

 

On a manual it's whatever is the weakest, clutch or gears? If you fit a SMF in place of the DMF and fit an upgraded clutch then the gears will see that pulse load.  The 5 speed box is weak to begin with, I wouldn't fancy it's chances with a remapped engine, SMF and upgraded clutch.

[J.R.]

But its the  much stronger 6 speed box that has failed in some instances when a SMF has been fitted.

 

My theory, and that all it is, I am not confidently advocating it as fact, is that its gear chatter and occurs at low RPM's when vibration is evident if a DMF is not functioning or has been replaced by a SMF, I dont believe the gearbox failures have been full load torque failures but fatigue failures.

 

I think we agree that replacing a DMF is going to cause undesirable torsional loadings on the crankshaft and to a lesser degree the drivetrain, I would really like to understand what it is about the 6 speed gearbox that makes it susceptible to damage in these instances when the weaker 5 speed box does not seem to suffer.

[bazza1440]

Thanks guys some interesting replies - 

Regards

Bazza