Choosing the right Clutch featuring XClutch - Part 3!

To wrap up the last part of our segment with XClutch we will be going over reasons why we choose to use XClutch for my build and review some of the most common questions Steve gets asked by the community. If you like what you are seeing/reading then this company might be a great fit for your application but, if not we will be covering other clutch companies later in the year as well so you can be sure to have all the options explained to find the perfect fit for your application. 

One of the main questions that XClutch gets asked is "Can I send my clutch in to be rebuilt?" Steve's answer was a "yes and no" meaning you are absolutely able to get support through walking through what your clutch will need to be rebuilt but, because they're a smaller shop they will most likely not do the actual rebuilding. Your clutch can be sent in for evaluation to get guidance on what you will need, or you can also just email them pictures/videos at [email protected].

XClutch will be able to help tell you what the thickness of the disc should be or what the diaphragm spring height should be as well as evaluate any other wear concerns such as heat checking or identifying signs of a slipping clutch. It is to be noted the single plate clutches will likely be recommended to be replaced which means buying a new disc and pressure plate as a set. However, remember that usually the fly wheel can be remachined a few times so at least you could save some money by not having to buy a new one right away as well. 

For the twin discs like mine or any other multi plates, there are actual service kits offered. If you have been following along on IG or YouTube you probably already heard Steve and I cover that part but, for the newer readers these service kits are elite. They have everything you will need to do the rebuild including actual instructions that you can scan the QR code that is on there and it will take you to a YouTube video explaining things further. Some of us just learn better actually seeing how to do it rather than read, so for me that is a huge win. The instructions also cover information about machining the flywheel and the step height etc. The service kits also come with any discs, intermediate plates, bearings, alignment tools that you would need.

The next question we had from some of you for Steve was "What's the best way to test if my clutch is slipping"? When the clutch is worn out because of wear, you will first see it happening in higher gears where the transmission has a lower gear ratio causing more load on the clutch. For street cars this can be seen when driving on the highway and as you start to get on throttle a bit in 5th or 6th, you will be able to notice a slippage. If your clutch is an organic, you will also be able to smell it happening - can confirm. If your clutch is a ceramic and you smell it, she gone. The most obvious sign for a slipping clutch though is when you're applying throttle and the RPMs go up but, you're not going any faster - also can confirm. If you're curious on how to tell if the clutch was slipped when you have it taken apart- refer to our previous article and/or video where we break that down as well. 

Third question we had for Steve was "Do I need a pedal stop"? The answer is, it depends but it is not typical. For a car like mine with the twin disc it is not needed. Pedal stops can help if you feel like the clutch is engaging too high and you don't have a clutch pedal adjustment available in your car. It helps more with full motorsport-oriented cars that have triples because they can then potentially be over stroked.  

The intermediate or floater plate is also telling the same story as the pressure plate. We see the heat checking from regular clutch engagement and the heat discoloration from the slipping. The role of the intermediate plate is to ensure each disc on either side can grip uniformly without jolting. The intermediate or floater plate "floats" when the clutch pressure is released and this the rattling sound you hear when the clutch pedal is down. 

Which leads us into the next question, "What is the break in procedure for your XClutch and why do I have to break it in"? Steve had the perfect analogy to explain why you would have to break in your clutch, as he mentioned one wouldn't go out on track and send it with new brakes without bedding them, so it's the similar reasoning when you think about the clutch. If you don't break in the clutch there's a good possibility that you can get it too hot which would cause the friction discs to glaze over, which can be seen in my video of my slipped clutch break down. Having the discs get too hot takes away from the friction coefficient on the disc which shortens the life of your clutch - or if you have a ceramic, you run the risk of welding it together. So, to properly break in your clutch before you should go race with it is to break it in on the street for about 600-1000 miles, this means stop and go city miles. When we say stop and go, we mean stop and go using the clutch, letting the car engine break, let a little bit of rpm slip happen to make the clutch slip and work to allow everything to bed in.

If you have a car like mine where it is street legal but, it's not going to be driven for 600 city miles, Steve recommends to try to get it out for as much stop and go as you can so that way you allow the clutch to get some heat into it but, let it cool down and repeat to ensure the bedding of the material to the steel surfaces. This also helps the friction material on the friction discs be flat, right out of the box the friction discs have high and low spots so without allowing the clutch to heat and cool, you'll only be engage the steels through the high spots rather than the whole disc - so breaking it in with the stop and go city miles allows the friction discs to be broken in so they're flat and function at its optimal performance. It is noted the organic disc like mine will break in a bit quicker due to the materials being softer compared to the ceramics since they can tolerate a lot more heat. If you have a ceramic and are not street driving it, you can break it in on the dyno by running them through the gears up and down a few times, but ensure you're heat cycling it. You could also break it in on track, go out for a test or practice session and spend a session not giving it full power and running up and down through the gears a few times, and follow similar instructions to how to break it in on the street before full sending it. This is probably one of the most important things to remember to ensure optimal performance, wear, and service life.

Another install question we received is "Do I need to use Loctite on the bolts"? Some of the bolts that are supplied come pre Loctite, and the service/new kits also come with the proper Loctite to use. Flywheel bolts can have some 272 red Loctite on them and for pressure plate bolts it's recommended to have a medium blue. 

The second most asked question is "How are XClutch’ s rated and how do I pick one for my car"? All of XClutch’ s torque ratings are at the engine and are calculated by the clamp load variable, friction coefficient of the material, and the surface area of the disc. This provides a recommendation of where the clutch should be rated - a fun fact to remember is as the clutch wears for the first half of its life, it will be at the highest clamp load and arguably performing at its peak and hold just a bit more power. The clutch rating however is for when it's new to keep the clutches rated by the calculations they can prove, keeping the ratings consistent and within the proper powerband. Some of the biggest things to consider when choosing a clutch are, what are you using the car for, what is your current power level and the weight of the vehicle (heavier vehicles will be harder on a clutch since it has to slip more to get moving). With so many different variables to consider Steve recommends just contacting them at [email protected] or giving them a call so they can go over your build and accurately recommend the correct clutch for your application. Before ending our Q&A session, Steve wanted to add one more point to this is - do not put a clutch that is rated for more power than you have in your stock car. When you put a higher clamp load, you're also putting more aggressive friction materials and it'll wear quicker. Especially if you have a really light flywheel and you have a twin or multi plate clutch, you're slipping the clutch more and revving it up more to get it to engage but, it's also causing a lot of wear that could be avoided if you have the proper clutch for your application. Stock applications require a more stock solution, race applications require a more motorsport solution and for those of you who are like me and in the middle with a stockish street race car, there's a middle solution that Steve and the team can help guide you to.

All Photo Credit Goes To The Respected Owners!