It's time to launch this project for real. Last time I was pondering this project was when I was fighting the slipping clutch issue back in April 2016. When Jag anteed up a non-slip replacement (T2R21165), the project went dormant. The newer clutches are exhibiting their own idiosyncrasies in the form of pressure plate failures instances of slippage. It's time to resolve this once and for all. While developing a clutch worthy of 475+ lb-ft of torque, I am also pondering the development of a lightened flywheel with replaceable friction surface. Much like my development of the short-shifter, some of the economic feasibility will come from a modest level of interest beyond my own. Shout out if you find either the clutch or flywheel to be of interest.
(Also let me know if you need a short-shifter).

 

Let me know when you start making cool stuff for the AT

 

I am a non-committal maybe. I will see if I manage to blow up third gen clutch with just normal use, if I do I will be in a good position to lemon the car. If it holds, then it is good enough to take beating.

 

Would be interested down the road, but I need to wait and see what the current 4th gen does that has been put in this month...

 

Ok. Have some background info to offer:


1st clutch (gen 1 clutch, gen 1 flywheel): Pressure plate exploded after 800 miles. Flywheel, clutchkit and throw-out cylinder all needed replacing.


2nd clutch (gen 1 clutch, gen 1 flywheel): Slipping from day 1. They finally agreed to replace under a TSB 7000 miles later. Again all 3 components replaced.


3rd clutch (gen 2 clutch, gen 2 flywheel): At 14,000 miles on new clutch, shifting into all gears becomes difficult when engine is running. Clutch, pressure plate and flywheel all burnt to a crisp. down to rivets on both sides of the clutch disc. Throw-out cylinder also to be replaced.


This is ridiculous. I have not been abusing this clutch and have pushed other cars much harder. I have never gotten less than 40k miles out of a clutch before, even when towing.


4th clutch: Jaguar Customer Service is claiming at this point, that the clutch is an ordinary wear item but is considering some kind of "financial assistance". The design and production of a high performance clutch and 2 piece lightened flywheel is underway, but the timing will require me to have the gen 4 clutch, gen 2 flywheel installed before the re-engineered parts are available.


5th clutch: The HiPerf parts will be tested as soon as clutch 4 fails (and we know it will).

 

Jaguar does not have much experience in the area of manual transmission cars of late, and I would imagine that is somewhat contributing to this problem. Some sort of design flaw either in the mechanism or the friction components themselves because this of course doesn't make sense.

BMW's 1 and 3/4 series models use virtually the same transmission in their I6 motors and those are practically bulletproof. I had mine at around 450-500 hp before the clutch started slipping under load... at 88k miles.

 

My experiences mirror Unhingd's. However, I am pushing my car more and have less patience with marginal components. My service manager also stands by the car a great deal more than what I hear happening elsewhere.

Gen 1 clutch, slipped like crazy. Replaced at 500 km along with an updated design flywheel.
Gen 2 clutch, did not slip at all. Destroyed differential at 10,000km (metal in oil) transmission at 15,000km (metal in oil). I paid for a new clutch and flywheel as the old one had scorching and glazing.
Gen 3 clutch - still in the car. I also upgraded gear oil to synthetic fluids to hopefully increase longevity.

I know there is now Gen 4 clutch available from JLR.

 

I think engineering choices might be: a) slip, b) destroy drive train in a hurry. There might not be an economical solution.

I feel that when the car is pushed, throttle by wire "hangs". If that was old physical linkage throttle, I'd say return spring went soft. I had numerous experiences where when shifting I completely let go off accelerator pedal but then when I push it into gear it would feel like some non-zero throttle input remained. So this effectively turns any shifting into bang-shifting, and that is very hard on the car. Especially if you do complicated inputs, such as applying hard braking while rev-match downshifting.

This means that any clutch would end up getting destroyed. In my mind, Gen 2 was as close to a racing clutch as they could have gotten. Hookup was rapid and immediate. If that setup ever slipped, like evident from the parts that I took out, then it had some help slipping. Also, Gen 3 clutch is softer. I think lack of damping combined with Gen 2 clutch is what killed both differential and transmission in my car.

Maybe VAP can investigate throttle issue, as Unhingd is a good customer?

I also suspect Unhingd will have hard time designing a solution that works only by replacing clutch and flywheel. I think custom drive shaft with MASSIVE flex disks or hardened racing LSD would be required.

 

I'll take this all on, one component at a time.

 

The Magellan of the Forum.

 

I don't believe this is a fuel delivery issue, but rather the result of the massively overweight dual mass flywheel. A standard design aluminum flywheel, should solve that issue, but will require greater launch and speed matching skills. Won't be well suited for the casual driver.

 

I hope you are wrong, as what you suspect is much harder to fix.

F-type MT is already a difficult car to drive well. I am not the best driver in the world, but picking up MT WRX reminded me that it doesn't have to be that much work.

 

Other than shifting slower, is there anything you can suggest to work with the current setup?

 

Shifting became much more effortless with the short-shifter. Resolving the drivetrain weakness will require further modifications: isolation discs on the driveshaft as you suspect, modifying the rear pumpkin to accept a Torsen and upgrading to an S6-53 transmission. With the current setup, driving it like a little old lady appears to be the only solution.

 

I suspected as much. Fundamentally, this isn't my problem unless I hang on to the car past warranty. I can't mod it in any way, as this will be used against me to deny warranty repair. I can't imagine JLR is happy about pulling parts from a production line and flying them over the pond to get my car going again.

 

My assessment is that the system is holding the throttle slightly under certain conditions. An example of when I most notice it is on my daily commute. If I want to accelerate quickly to cruising speed then coast in the next gear, the system acts dim-witted, like it can't figure things out fast enough.

The conditions:

1) Moderate to hard acceleration in 1st or 2nd to high RPM, but not to limit; perhaps 5K (approx)
2) Lift throttle and upshift. The car will actually surge forward momentarily instead of going straight to decel.

 

Sounds like we know why they didn’t put an mtx in the V8.

 

 

If so, maybe VAP can eliminate the effect. Jag has done this probably to prevent numbskulls from shock loading the drive train by lifting suddenly without depressing the clutch.

 

I remember by last manual sports car (400hp which was huge at the time), went with a much lighter flywheel and it made the car harder, but so much more fun to drive.

Good luck with this project!