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Thread: Thinking about replacing your Clutch? LOOK HERE FIRST!!

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    Default Thinking about replacing your Clutch? LOOK HERE FIRST!!

    Just like suspension upgrades, clutch upgrades need to be chosen carefully.

    Hopefully this write up will help you make an informed decision


    There are a few reasons why SOA puts a certain type of clutch in your car:

    1. Comfort. The clutch needs to be light on the left foot and needs to engage easily. Not everyone who drives a subaru wants a beefy clutch or knows how to handle one.
    2. Reliability. The metals used in the OEM clutch are of decent qaulity are are cheap. Go figure.
    3. Protection. These 2.0/2.5 turbo motors can pack a mighty punch. The OEM clutch will slip before casuing transmission damage (usually). The last thing SOA wants is owners breaking transmission gears. It's harder to prove negligence on a car with a busted tranny then a car with scorched flywheel.

    With that being said....

    If you drive your subaru in a conservative manner and operate the shifting correctly your clutch will most likely last the lifetime of your ownership, usually up to 70k or more.

    For the rest of us who like to occasionally see how fast we can get to 60.... 80....(we won't go there) a clutch upgrade or replacement might be needed.



    How does a clutch work?

    Take a look at the picture below. It represents most clutches produced today


    As you can see there are 6 distinct parts

    1. Throw out fork
    2. Throw out bearing
    3. Clutch pressure plate assembly
    4. Clutch disk
    5. Flywheel
    6. Pilot bushing

    The majority of clutch problems come from the clutch disk and flywheel damaging each other.

    The Flywheel is a metal plate that 3 main functions
    1. It acts as balancing weight for the engine and reduces vibrations caused by the firing of the pistons
    2. It acts as the connecting plate between the engine and the transmission
    3. It also connects to the start motor (hence why your car needs to be in neutral when you start it!!)

    The clutch plate has 4, 6 or 8 friction disks on that when depressed against the flywheel make the tansmission move, which in turn sends power to the wheels.

    When you depress the clutch, the throw bearing releases the clutch plate from the flywheel and allows you change gears. When you engage the clutch it is pushed against the flywheel and the friction plates grab ahold of the already moving flywheel and sends power to the transmission.

    Why do Clutches go bad?

    There are few reasons why clutches go bad:

    1. Aggressive driving. Constant launching, quick power shifting or excessive down shifting will wear out your OEM clutch faster then Murphy20212 can drink IPA.
    2. Bad shifting habits. Riding the clutch, dogging the clutch, multiple bad uphill starts, teaching new drivers, ect ect.. All of these can cause a clutch to go bad.
    3. You get a bad clutch. It happens.... not very often.... but it does. Maybe the mechanis at SOA was hungover and put a bent fork or a damaged throwout bearing in your car. Maybe the metal was bad in the flywheel. Either way SOA should cover this if your car is under warranty.

    Generally... when a clutch slips it is caused by only a few things

    1. Worn clutch plate friction disks. This will happen in high mileage cars or heavily modded cars with high low end torque.
    2. Scorched Flywheel. This is caused by overheating the flywheel. This is usually accompanied with a worn clutch disk and is cause by aggressive driving. The intense heat changes the rigitity of the metal and renders the flywheel usless.
    3. Warped Flywheel. This also caused by overheating. A warped flywheel will ruin your clutch disk.

    In some cases, the flywheel and or the clutch plate can become so hot that they greande This can damage the engine,tranny or tranny casing.

    What causes me to not be able to shift, or make shifting hard?

    99.99% of the time it's a bad throw out bearing or fork. Both these parts are relatively cheap, but labor to install them will bite you in the arse.

    When my clutch goes bad do I need to replace everything?

    The easy answer to this is no. but... without opening up your clutch and actually looking at it there is no way to tell.

    If the flywheel is scorched, then your clutch plate will be bad too. if your clutch plate is raw, then your flywheel will be bad too.
    If you are a conservative driver you may get away with just replacing your clutch disk and having your flywheel resurfaced. IT IS IMPORTANT THAT IF YOU GO THIS ROUTE YOU GET YOUR FLYWHEEL INSPECTED AND RESURFACED!!!!

    If you upgrade your clutch to a non OEM version or size you will need:

    1. Throw out fork
    2. Throw out bearing
    3. Clutch pressure plate assembly
    4. Clutch disk
    5. Flywheel
    6. Pilot bushing

    Your best bet is to ask the vendor who is supplying the product what you will need.

    Ready to buy?

    There are a few questions you need to ask yourself before you upgrade your clutch. These are VERY important to ask yourself before you spend hundreds of dollars.

    1. What kind of driver am I? Conservative, Average, Mildly Aggressive or Aggressive.

    If you answered Conservative, then a OEM replacement is probaly your best bet. If you plan on making a monster build or competing in Rally/auto-x/drag then you will need to upgrade.

    2. What is MY comfort level for a clutch.

    Upgrading your clutch will COMPLETELY change the feeling of your clutch pedal, your launching (power or slow) and NVH (noise/vibration/hardening). If you go from an OEM 4 puck to a drag racing 6 puck you will have to relearn your clutch.
    Clutch chatter, engine vibration and launch will be harder and the clutch engage faster and hold more power.

    Upgrading your Transmission mounts and Engine mounts will reduce NVH and are generally inexpensive.

    Many cluth packages offered are the virtualy the same as stock in weight and size but offer better metals and better qaulity. These are generally more expensive and will give you a closer to stock feel with added performance.

    3. How many puck? your car comes with a 4 puck, sort of it more of a friction disk then anything. If you upgrade to 6, 8 or hardened 4 you will feel a big difference come game day. 6 or 8 puck is not the best choice for daily driving and requires bit more rpms to catch.
    You will however gain a "sweet spot" that will be your bread and butter on race day

    4 puck




    6 puck



    4. What weight flywheel? your stocker is between 19lbs and 32lbs Some places offer as light as 11lbs.
    One thing to remember is that the flywheel acts a balance for your motor. If you go to light you throw off your engine and have a ton of problems. 14-20lbs should be fine. Remember also that a lighter flywheel = faster drop in RPM's between shifts.
    Multi Puck or Full Face? Be it the multi puck or a full face (OEM style) you will feel a difference after install. The multi puck disc will usually be a high performance upgrade. They have a more aggressive friction material and will wear the flywheel faster. Below are a few examples.

    4 puck
    These two discs appear different? That is because they have a huge difference! The Left disc is an unsprung hub design. Simply put this clutch is not a street clutch. It is the strongest in design. Lightest weight and THE most aggressive engagement. I Would Not Recommend this design on a daily drive kind of car.

    The disc to the right is a sprung hub. The design is a torsion damper. It absorbs twisting force from the engine and drivetrain during up shifting, down shifting, on to off throttle, take off etc. Pretty much any time you do anything, but don’t take that literal LOL.

    6 puck
    This Six puck below is just another example of a disc design. This clutch likely has a higher clamping load but really without being the manufacture I don’t know exactly why it is 6 puck vs 8 puck vs 4 puck.

    The key thing to remember is comfort. If the weight in the pedal increases by 5 pounds with your new clutch will you be comfortable in traffic? Also remember that gas mileage will suffer to because your shifts become stiffer and at higher reps. Stickier clutch = More load on the motor AND transmission. With a 6 or 8 puck clutch you can easily grind your tranny teeth down to the nub.... so launch carefully

    Installation

    1. Can I do this on my own? The easy answer is no. This is not an easy task by any means. Even experienced techs can find themselves cursing and screaming well into the night. I recommend you seek a professional who will warranty their work.

    2. Where's a good place to go? Your best bet is to have a professional do the install. A certified Subaru tech at a dealership or a certified tranny tech is your best bet.

    3.How long will it take? I would plan on renting a car many shops charge it as an 8 hour or more job. Whether they complete it in 8 hours or not that's what you will pay for.

    4. How much will it cost? Ever heard the old saying "you get what you pay for" well... you do. Expect to pay anywhere from $600-1600 for labor and anywhere from $100-$2000 for parts.

    I hope this helps you out!

    if you have any questions, please feel free to PM me or one our Vendors!
    Last edited by Bu11dogg2; 08-05-2010 at 02:31 PM. Reason: added nates stuff

  2. #2
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    I welcome any additions to this thread

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    Member #17... Jon's Avatar
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    3. How many puck? your car comes with a 4 puck, sort of it more of a friction disk then anything. If you upgrade to 6, 8 or hardened 4 you will feel a big difference come game day. 6 or 8 puck is not the best choice for daily driving and requires bit more rpms to catch.
    You will however gain a "sweet spot" that will be your bread and butter on race day

    the stock clutch i don't believe is a 4 puck, it's a full faced clutch. A 4 puck is a pretty aggressive race clutch if i'm not mistaken.

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    The amount of pucks often times has to do with inertia of the disc. Less pucks less weight. Help with disc cooling a little too.

    Most clutchs have a full face. You should make a little write up on here about sprung and unsprung hubs. THAT is my opinion is the biggest deal breaker of anything. Unsprung hubs are a bitch to drive in most cases. They are either ON or OFF. For a daily drive an unsprung hub is crazy to have I think.
    rubber baby buggy bumpers!

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    Quote Originally Posted by Jon View Post
    3. How many puck? your car comes with a 4 puck, sort of it more of a friction disk then anything. If you upgrade to 6, 8 or hardened 4 you will feel a big difference come game day. 6 or 8 puck is not the best choice for daily driving and requires bit more rpms to catch.
    You will however gain a "sweet spot" that will be your bread and butter on race day

    the stock clutch i don't believe is a 4 puck, it's a full faced clutch. A 4 puck is a pretty aggressive race clutch if i'm not mistaken.

    3. How many puck? your car comes with a 4 puck, sort of it more of a friction disk then anything

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    Quote Originally Posted by Nate8409 View Post
    The amount of pucks often times has to do with inertia of the disc. Less pucks less weight. Help with disc cooling a little too.

    Most clutchs have a full face. You should make a little write up on here about sprung and unsprung hubs. THAT is my opinion is the biggest deal breaker of anything. Unsprung hubs are a bitch to drive in most cases. They are either ON or OFF. For a daily drive an unsprung hub is crazy to have I think.

    can you right up something for this?

    I'll delete the above posts and make it in order

  7. #7
    Member #17... Jon's Avatar
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    Randy, are you saying that my car comes stock with a 4 puck? It sounds like thats what your saying. You might want to reword the post to make it more noob friendly so they don't go running around telling everyone there car comes stock with a 4 puck race clutch. The stock clutch is a full face disk.

  8. #8
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    Just like suspension upgrades, clutch upgrades need to be chosen carefully.

    Hopefully this write up will help you make an informed decision


    There are a few reasons why SOA puts a certain type of clutch in your car:

    1. Comfort. The clutch needs to be light on the left foot and needs to engage easily. Not everyone who drives a subaru wants a beefy clutch or knows how to handle one.
    2. Reliability. The metals used in the OEM clutch are of decent quality arecheap. Go figure.
    3. Protection. These 2.0/2.5 turbo motors can pack a mighty punch. The OEM clutch will slip before causing transmission damage (usually). The last thing SOA wants is owners breaking transmission gears. It's harder to prove negligence on a car with a busted tranny then a car with scorched flywheel.

    With that being said....

    If you drive your subaru in a conservative manner and operate the shifting correctly your clutch will most likely last the lifetime of your ownership, usually up to 70k or more.

    For the rest of us who like to occasionally see how fast we can get to 60.... 80....(we won't go there) a clutch upgrade or replacement might be needed.



    How does a clutch work?

    Take a look at the picture below. It represents most clutches produced today


    As you can see there are 6 distinct parts

    1. Throw out fork
    2. Throw out bearing
    3. Clutch pressure plate assembly
    4. Clutch disk
    5. Flywheel
    6. Pilot bushing

    The majority of clutch problems come from the clutch disk and flywheel damaging each other.

    The Flywheel is a metal plate that 3 main functions
    1. It acts as balancing weight for the engine and reduces vibrations caused by the firing of the pistons
    2. It acts as the connecting plate between the engine and the transmission
    3. It also connects to the start motor (hence why your car needs to be in neutral when you start it!!)

    The clutch disc is a friction disk/s that when depressed against the flywheel connect make the tansmission move, which in turn sends power to the wheels.

    When you depress the clutch, the release bearing releases the clutch disc from the flywheel and allows you change gears. When you engage the clutch it is pushed against the flywheel and the friction plates grab ahold of the already moving flywheel and sends power to the transmission.

    Why do Clutches go bad?

    There are few reasons why clutches go bad:

    1. Aggressive driving. Constant launching, quick power shifting or excessive down shifting will wear out your OEM clutch faster then Murphy20212 can drink IPA.

    2. Bad shifting habits. Riding the clutch, dogging the clutch, multiple bad uphill starts, teaching new drivers, ect ect.. All of these can cause a clutch to go bad.

    3. You get a bad clutch. It happens.... not very often.... but it does. Maybe the mechanic at SOA was hungover and put a bent fork or a damaged release bearing in your car. Maybe the metal was bad in the flywheel. Either way SOA should cover this if your car is under warranty.

    Generally... when a clutch slips it is rarely a defect but just common wear.

    1. Worn clutch plate friction disk/s. This will happen in high mileage cars or heavily modded cars with torque exceeding the pressure plates clamping load. As the disc wears the clamping load decreases.
    2. Scorched Flywheel. This is caused by overheating the flywheel. This is usually accompanied with a worn clutch disk and is caused by aggressive driving. The intense heat changes the rigidity of the metal and renders the flywheel useless without resurfacing.
    3. Warped Flywheel. This also caused by overheating. A warped flywheel will ruin your clutch disk.

    In some cases, the flywheel and or the clutch plate can become so hot that they explode This will damage the engine, tranny or You. Just imagine something metal spinning at a few thousand revolutions a minute. Tie a little rock to the end of a string and spin it as fast as you can. You might be able to spin it a few hundred revolutions per minute. Now stop the rock with your hand. Exactly.

    What causes me to not be able to shift, or make shifting hard?

    99.99% of the time it's a bad throw out bearing or fork. Both these parts are relatively cheap, but labor to install them will bite you in the arse.

    When my clutch goes bad do I need to replace everything?

    The easy answer to this is no. but... without opening up your clutch and actually looking at it there is no way to tell.

    If the flywheel is scorched, then your clutch plate will be bad too. They wear to each others shapes. If you smoke you clutch while beating the car you might as well expect a toasted flywheel. Most normal driving will not wear a flywheel out. Yes it wears but typically will not fail unless something has made it fail such as an oil or something leaking into the housing. Driving you car hard will not smoke a clutch. Poor shifting technique will make both the clutch and flywheels lives short. Combined with poor technique and hard driving. Get your wallet out.


    If you upgrade your clutch to a non-OEM version or you usually need:

    1. Alignment Tool
    2. Release bearing
    3. Clutch pressure plate assembly
    4. Clutch disk
    5. Pilot bushing

    Your best bet is to ask the vendor who is supplying the product what you will need although most aftermarket clutch kits have all these in them anyway. The cases where this is wrong are with special clutches. Like compact multi disc clutches that have an intergrated flywheel for super low inertia and super high clamping loads.

    Ready to buy?

    There are a few questions you need to ask yourself before you upgrade your clutch. These are VERY important to ask yourself before you spend hundreds of dollars.

    1. What kind of driver am I? Conservative, Average, Mildly Aggressive or Aggressive.

    If you answered Conservative, then an OEM replacement is probably your best bet. If you plan on making a monster build or competing in Rally/auto-x/drag then you should upgrade.

    2. What is MY comfort level for a Clutch.
    Some clutches can down right suck to drive normally on the street. These usually are not really street daily driver clutches anyway. For the comfort level you can usually determine it by a couple of things. The design of the clutch disc and the clamping load that the manufacturer specifies for that “kit.” As the clamping load gets higher the clutch will get harder to depress with your foot and likely harder to control the engagement.


    Multi Puck or Full Face? Be it the multi puck or a full face (OEM style) you will feel a difference after install. The multi puck disc will usually be a high performance upgrade. They have a more aggressive friction material and will wear the flywheel faster. Below are a few examples.

    4 puck
    These two discs appear different? That is because they have a huge difference! The Left disc is an unsprung hub design. Simply put this clutch is not a street clutch. It is the strongest in design. Lightest weight and THE most aggressive engagement. I Would Not Recommend this design on a daily drive kind of car.

    The disc to the right is a sprung hub. The design is a torsion damper. It absorbs twisting force from the engine and drivetrain during up shifting, down shifting, on to off throttle, take off etc. Pretty much any time you do anything, but don’t take that literal LOL.




    6 puck
    This Six puck below is just another example of a disc design. This clutch likely has a higher clamping load but really without being the manufacture I don’t know exactly why it is 6 puck vs 8 puck vs 4 puck.



    4. What weight flywheel? your stocker is between 19lbs and 32lbs Some places offer as light as 11lbs.
    One thing to remember is that the flywheel acts a balance for your motor. If you go to light you throw off your engine and have a ton of problems. 14-20lbs should be fine. Remember also that a lighter flywheel = faster drop in RPM's between shifts.

    The key thing to remember is comfort. If the weight in the pedal increases by 5 pounds with your new clutch will you be comfortable in traffic? Also remember that gas mileage will suffer to because your shifts become stiffer and at higher reps. Stickier clutch = More load on the motor AND transmission. With a 6 or 8 puck clutch you can easily grind your tranny teeth down to the nub.... so launch carefully

    Installation

    1. Can I do this on my own? The easy answer in no. This is not an easy task by any means. Even experienced techs can find themselves cursing and screaming well into the night. I recommend you seek a professional who will warranty their work.

    2. Where's a good place to go? Your best bet is to have a professional do the install. A certified Subaru tech at a dealership or a certified tranny tech is your best bet.

    3.How long will it take? I would plan on renting a car many shops charge it as an 8 hour or more job. Whether they complete it in 8 hours or not that's what you will pay for.

    4. How much will it cost? Ever heard the old saying "you get what you pay for" well... you do. Expect to pay anywhere from $600-1600 for labor and anywhere from $100-$2000 for parts.

    I hope this helps you out!

    if you have any questions, please feel free to PM me or one our Vendors!
    rubber baby buggy bumpers!

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    I changed some stuff but that is all I have time for right now.
    rubber baby buggy bumpers!

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    thanks nate!

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    Its good to see posts like this on the site. I have some comments.


    -Lots of aggressive driving and slipping the clutch at high RPM launchs can cause the clutch to heat glaze. Basically it makes the surface of the friction disk glazed over and it will cause the clutch to slip. (dumping the clutch at high RPMs breaks drivetrain parts so take you pick.)

    -Sometimes you can clean the glaze off with some mild daily driving for about 100 miles.

    -Sometimes people try just replacing the friction disk but that is a horrible idea because if you heat glaze the disk the flywheel and pressure plate are probably warped.

    -Nobody has mentioned that a warped pressure plate, broken pressure plate fingers, backed out flywheel bolts, worn or leaking master and slave cylinders, and misadjusted clutch rods can also be to blame.

    1. Can I do this on my own? The easy answer in no.

    Expect to pay anywhere from $600-1600 for labor
    I disagree. I've done four clutchs on my race car this year and one on my buddy's for only $100 and an reverse HJ.

    The Flywheel is a metal plate that 3 main functions
    1. It acts as balancing weight for the engine and reduces vibrations caused by the firing of the pistons
    2. It acts as the connecting plate between the engine and the transmission
    3. It also connects to the start motor (hence why your car needs to be in neutral when you start it!!)
    -The flywheel doesn't balance your engine. The crank is suppost to be balanced by it self. The weight of the flywheel keeps the engine rotating easier because of the momentum of the flywheel. Thus the heavier the flywheel the greater the momentum.

    -The car doesn't have to be in neutral but it is a good idea to have the clutch disengaged if it isn't

    -As far as a clutch recommendation. Nobody on this forum should get an unsprung disk. I would recommend everybody on the forum to find something that has a full face disk. They are good places to spend money and dump places to spend money. Spend you money on a pressure plate with a lot of clamping force not on these crazy ass puck clutches!

    -Puck clutches are like on/off switches if you drive your car on the street than this is not the clutch for you.

    -I went 10.8 sec. in the 1/4 mile at trap speeds of over 133MPH on a full face disk with a 2600 pound pressure plate and a bone stock drivetrain. Until you have an mid 11 second heavy ass car stay with a full face disk and a sprung hub!

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    yup I'm going with an act full face disk with the heaviest pressure plate they make.
    when that doesn't work I will step to a dual or triple plate carbon exedy or tilton clutch.

  13. #13
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    Quote Originally Posted by silverwrx666 View Post
    yup I'm going with an act full face disk with the heaviest pressure plate they make.
    when that doesn't work I will step to a dual or triple plate carbon exedy or tilton clutch.
    Spoken like a champion!

    -I also forgot to mention that you can have a flywheel resurfaced for around $60 it you are replacing the clutch but don't have money for a new flywheel its not a bad idea.

    exedy and tilton are serious money but they don't make better clutches.

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    I mentioned that.

    It's not very often that you see a slipping clutch that has a flywheel that nots either glazed, warped or to thin.

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