Project GD Subaru STI, Checking out the Ultimate Streetable Clutch with XClutch.

The throwout bearing which is provided has clips to hold it in place.

The chrome-moly steel flywheel is 11.3 lbs vs the 19 lbs stock part.  This is decently light.  With Subarus, too light of a flywheel can trigger misfire check engine lights so this weight is a good compromise.

Although they look bolted on the lugs are CNC machined into the flywheel for strength.

The flywheel has lightning holes machined into the center and on its outer perimeter for less inertia.

With nearly double the torque capacity of the OEM clutch and its smooth and quiet action with a light pedal, the XClutch is going to be a winner for our Project STI!  Stay tuned for installation and driving impressions once we start putting it all together.




  1. Does the clutch/flywheel assembly need to be specially balanced? The lugs and lightening holes don’t look at all symmetrical.

    Looks like a well designed and made part. I really like the CNC’d lugs.

  2. Some really clever solutions to make this clutch the best of many worlds. Love seeing all the detail you provided in the article to explain why decisions were made. Looking forward to hearing some driving impressions!

    And surprisingly, I could actually get the same setup for my Volvo if I need a clutch to handle some big power. Not many companies support such an oddball chassis, so that’s kind of exciting.

  3. I was debating on a clutch setup for my Spec-B and I know from experience that the Exidy multiplate is OBNOXIOUS (but works well) I’ve been looking at the X-clutch for some time but after reading this analysis I’ve made up my mind! Now if only you guys hadn’t taken what seems to be the only one left in the country!

      1. Finally got my clutch in, 5 months from date of purchase. What an amazing piece, can’t wait to get going on my project again!

  4. Would you consider the unsprung version of this clutch would be manageable for a daily driven car? Could you kindly explain what differences in driving experience would running an unsprung version yield?

  5. I am so glad to have found this website! I’ve ben following you, Mike, since Sport Compact Car and that Nissan Performance web magazine you wrote for way way back. This clutch will most likely go into my bugeye once I destroy my current clutch

Leave a Reply

Your email address will not be published. Required fields are marked *