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XClutch Twin Disk Sprung Organic Clutch: Unboxing, First Impressions, and Review
Hello Evom,
Due to the lack of information online regarding the Australian made XClutch twin disk, XKMI23522-2A, for the evo 8/9, I've decided to document and report my personal experience with this clutch to (hopefully) inform everyone of an additional, reliable, clutch option. It is no secret that once we make around 500ftlbs of torque on this platform, our clutch options shrink dramatically and our compromises begin. We get stuck in a circle of bad choices. You can either have a clutch that is quiet, grabby, but not daily driver friendly. Or you can have one that is chattery, grabby, and somewhat daily drivable. Or you can have one that is quiet, durable, and will NOT hold the power in the first place. Thankfully, with the relatively recent emergence of high power clutches that have the daily driver in mind, such as the ACT Mod Twin and the XClutch Twin, we might actually have a chance to forego some of these challenges all together.
My review of the XClutch Twin Disk will come based on owning and operating the following clutches in my own car throughout the years. I plan to give you my honest opinion on it and will not defend this clutch if it turns out to be a POS. I think that I speak for us all when I say that nobody wants a clutch that ruins the fun of their car for them. I will leave my short personal impression of each previously owned clutch so that you can decide for yourself if you agree or believe I'm being a little too harsh with my observations.
1. Stock Clutch
- We all secretly miss this one. Smooth and quiet. A real date night clutch with the best street manners.
2. ACT XTSS Street Disk
-Heavy pedal feel (at the time), but daily drivable. Held power very well, but would slip when launching on stock turbo, E85, and grippy tires. Did not chatter when clutch was pressed, but locked you out of your next gear above a certain RPM. I'm learning that this is more likely to happen if you have rev hang problems or older synchros.
3. Exedy Twin Disk
-Lighter pedal feel than the ACT XTSS, but heavier than stock. Held power very well. Chattered when clutch was pressed. Sounded like a dying whale if slipped when hot. Was, for better or worse, the best option for many years.
4. Exedy Triple Disk with AMS Hydraulic TOB - Pull to Push Conversion
-Lightest pedal feel, even lighter than the Exedy twin. Held most power and launched the car with no issues every time. Chattered so loudly it woke the dead and reving the car with the clutch pressed down made it sound like your car was broken. It was embarrassing to drive at the mall. Still made whale noises. Clutch pedal was not very adjustable because no matter what you did with the clutch pedal adjustment nut inside the car, the HTOB would self adjust to some extent.
5. ACT 6-Puck Sprung with Xtreme Pressure Plate (ran this until recently)
-Medium pedal feel, no chatter noise, and held power very well. The engagement window was very small and slipping it would cause a grinding noise when hot. Uphill traffic will destroy this clutch disk. Otherwise a very affordable and capable clutch.
Now, let's move on to unboxing this new XClutch twin disk:
Outside Box Cover Main Box Correct Part Number Technical Bulletins, Install instructions, and Decals Decals and pressure plate Steel alignment tool Included TOB Pressure plate Top Pressure plate Bottom First organic friction disk (hubless and floats) Floater plate Second organic friction disk with sprung hub Flywheel front Flywheel back Pressure plate bolt with sprung (conical) lock washer.
XClutch Twin Disk Specs taken from their catalog: XKMI23522-2A
Alignment Tool Included: Yes
Clamping Force % Increase: N/A
Clutch Disc Diameter: 9 1/16 in.
Disc Material: Organic
Disc Type Sprung Solid: Sprung
Flywheel Bolts Included: Yes
Flywheel Included: Yes
Flywheel Step: -0.768
Friction Surface Configuration: Recessed
Input Shaft Diameter: 1 in.
Input Spline Quantity: 23
Maximum Torque: 740 lb
Pilot Bushing Included: No
Pressure Plate Bolts Included: Yes
Recommended Use: High Power Street Use
Release Bearing Included: Yes
Spline Grease Included: Yes
One of the things that I liked about this clutch when compared to other similar clutches is that one of the friction disks is mounted permanently onto the sprung hub. This could potentially lead to greater strength and quieter operation. The sprung hub interfaces with the second friction disk using a keyed, circular, pattern which offers a lot more engagement/surface area contact than something like my Exedy triple did. The Exedy triple connected all three friction disks using a splined adapter hub that would pass through the very center of each clutch disk. This would wear out over time if your pedal was not adjusted perfectly and/or if you daily drive your car in traffic. The middle floater plate of the XClutch is keyed such that you cannot install it the wrong way or upside down. It does not have any metal spring tabs towards the outside like we see on the Exedy twin or ACT mod twin floater plates. Having the metal tabs, however, could aid in reducing clutch chatter/rattle noise. We will have to see how things fair on that end later. I am very interested to find out if it is better to have two detached sprung hub friction disks and spring tabs on the center floater plate or if it is better to have no spring tabs on the floater plate and only one detached sprung hub friction disk on a twin disk clutch.
The XClutch twin disk kit included a steel clutch alignment tool (this is the first time I've seen that), a new throw out bearing, and new flywheel bolts. I did not see any included transmission spline grease. I have plenty of extra spline grease, but if I did not that would **** me off. Based on tried and true methods, I will be using new OEM flywheel bolts and a new OEM throw out bearing, so I won't be testing that part of the kit. I am on the fence about reusing my ACT Monolock collar on this clutch because it made it hell to release my old TOB from my old pressure plate when the transmission was still in the car. I guess that's the point of it after all?
Even though I won't be using it, the included throw out bearing looked VERY OEM like. When I compared it to an actual OEM Mitsubishi TOB, the markings were nearly identical, the only difference being an additional letter "A" on the top. The included XClutch TOB and the OEM TOB both had "Japan" written on them. Overall things looked very high quality and the clutch arrived balanced as well as marked for installation in one particular arrangement using white paint lines. The pressure plate uses 9 bolts with sprung locking washers. Factory torque specs were recommended for this clutch. 98 ft lbs for flywheel and 13ft lbs for pressure plate. My expectations for this clutch is that it will last me between 40,000 to 50,000 miles, have a light to medium pressure feel, and be more quiet than the Exedy Twin Disk. Having the greatest street manners while holding as much power as possible is my new goal now.
I will do my best to install the clutch and factory 5 speed back into my car for testing by the end of this month. Stay tuned for results!
Nice write up!
Did you happen to notice if the floater plate and pressure plate are individually balanced also?
Thanks man,
The floater plate and pressure plate both had markings, but I cannot confirm if they were individually balanced prior to the entire clutch assembly being balanced together. I'm expecting good results with this setup, but if vibrations increase once I install it we will know there is a problem.
Update! I had some time today to mount the clutch onto the engine. Everything was straight forward with no surprises, but I need to correct a few details that I posted above.
1. The final torque spec for the pressure plate bolts for this clutch is 32Nm or 23.6 ftlbs. The stock pressure bolt spec is 13 ft lbs.
2. The center floater plate is keyed so that it cannot go on upside down, but you can still rotate it amongst the different flywheel legs when it is facing the right way.
That's it. I expect the new transmission parts to arrive this week so I should have the car back on it's wheels by Sunday.
Folks, the car is back together. I still need to perform a 500 mile break in before I can test high rpm shifts, but here are my first impressions of the x clutch twin disk after the first 20 miles. I used Amsoil MTG 75W90 API GL-4.
The clutch is doing it's job. The pedal feel is about 1/3 softer than the ACT 6 puck sprung (xtreme pressure plate). Shifts are smooth and slipping the clutch in uphill traffic is easy. The slip window is MUCH bigger and more forgiving. No noise has been heard during slipping this clutch thus far.
The twin plate rattle noise is present when you press the clutch in, but it's very subdued. I use a very quiet exhaust (tanabe touring medallion) so noises like that bother me over time. This clutch's rattle seems to be only half as loud as the rattle heard in the exedy twin. This pleases me and I expect it will get even quieter after break in. I'm going to drive the car much more frequently now and will report progress along the way. I'll post a drive and noise video after break in is complete.
Do you know how to do a clutch drag test before you start performing high rpm shifts?
The way that I do it is to place the the car on jack stands with all four wheels in the air. Then with the car in first gear, slowly release the clutch pedal to engage the drivetrain. There should be about 2 to 3 inches of clutch travel before the clutch starts to engage. When pressing the clutch in again, the wheels should stop completely at the same engagement disengagement point.
The second method is to find a very flat/level road with nobody around, place the car in first gear and rev the car to 6 or 7k rpm with the clutch pedal pressed in and e brake down. The car should not show any signs of moving at all. If it does, then the clutch rod needs to be adjusted or the pressure plate, flywheel, and/or clutch disk is not working properly. This could be due to warping, exposed rivets, imbalances, etc.
The second method is to find a very flat/level road with nobody around, place the car in first gear and rev the car to 6 or 7k rpm with the clutch pedal pressed in and e brake down. The car should not show any signs of moving at all. If it does, then the clutch rod needs to be adjusted or the pressure plate, flywheel, and/or clutch disk is not working properly. This could be due to warping, exposed rivets, imbalances, etc.
This one - but go to redline and with the handbrake (e-brake) off.
If the car moves, you've got clutch drag.
My current unit is fine at 6000 and 7000rpm, it starts dragging at 7200. So go right to redline (rev limit).
I just hit 300 miles on this clutch and things are looking good so far. The clutch engagement remains consistent and it is still easy to slip. The clutch still starts to engage with the clutch pedal about 3" off the floor. No abnormal noise is heard or shaking felt during engagement and slipping of the clutch. The twin plate rattle noise is still present, but has gone down slightly. Now you can only hear it when you pull into a garage or park next to other cars. It remains very subdued. I look forward to being done with break in so that I could slam gears and see how the clutch does.
I am now at 650 miles on this clutch. After ripping the car last night and performing 7000 rpm shifts I experienced no lockout and no added noises. The clutch just works and the street manners did not change with some heat in the clutch. You can still softly pull into the driveway or bang gears on straight roads. I have not launched on it yet, but if it's true to rating then it should not slip. Overall I am still very pleased with this clutch kit. I am not using the ACT monoloc collar, but I am using the radium clutch fork stopper. I'll pop back in from time to time to report on anything that comes up.
Jan 8, 2023, 10:13 PM
