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Old 12-29-2020, 04:53 PM   #1
riksk
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Member#: 518114
Join Date: Aug 2020
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11 WRX
Satin White Pearl

Default Flywheel step

Hi there!


I've noticed a difference between OEM flywheels and OEM replacement flywheels.


While the OEM flywheels have no step between the pressure plate mounting points and the friction surface of the flywheel, the OEM replacement ones do have a small step (most likely between a 1mm and 2mm, not sure)


Pics below.


The car is a 2011 WRX. EJ255 with the crystal weak 5 speed.


Why is there such difference? I'm asking because I'm currently changing my clutch, and the shop wants to machine a little step in the OEM flywheel, kinda to replicate the Exedy's flywheel.






Here's the OEM, sold by Subaru.




And here's the Exedy OEM replacement...


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Old 12-31-2020, 01:50 AM   #2
peerless
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I would want to see a picture of the flywheel that came off your car, then look up the exact replacement part number for your application.

For your reference your 2011 WRX takes factory Subaru Part Number: 12342AA090 ($370) or Exedy Part # TYF001 ($140, rallysportdirect.com)

I looked up your Flywheel on the factory Subaru parts catalog and it indeed has a step in it, so if yours is missing the step then you know someone else had it machined previously and machined the step off or replaced it with the wrong flywheel.

The picture you have shown of the flat flywheel is from a different model such as my 02 Legacy. (Exedy Part # FWSBL02FF)

SO, if we are going to play this game then you need to compare apples to apples, not apples to oranges.

So to explain that I will tell you what the step is for. The step sets the clutch cover height in relationship to the clutch disk. This takes into consideration clutch disk thickness, clamping pressure/force, clutch cover release and engagement and rate of engagement (ie. harsh or smooth engagement)

If I was you I would probably just purchase the proper flywheel, reason being this....
If the flywheel was previously machined, you don't know how much was removed from it prior. In addition to re-create the step your going to have to remove that much more material. Now if you drive gently there probably won't be much of a problem, but....

If you drive hard or have additional upgraded power on tap or a combination of both it is possible that flywheel will not be able to dissipate the heat generated which will glaze the flywheel surface, introduce heat checking and possible cracking. If the step is too tall then your going to likely have problems holding the power and slipping may occur thus see above.

Anyways, thats the long winded answer I got, hope it at least gives food for thought. Good Luck with it.
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Old 12-31-2020, 02:25 AM   #3
riksk
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Quote:
Originally Posted by peerless View Post
I would want to see a picture of the flywheel that came off your car, then look up the exact replacement part number for your application.

For your reference your 2011 WRX takes factory Subaru Part Number: 12342AA090 ($370) or Exedy Part # TYF001 ($140, rallysportdirect.com)

I looked up your Flywheel on the factory Subaru parts catalog and it indeed has a step in it, so if yours is missing the step then you know someone else had it machined previously and machined the step off or replaced it with the wrong flywheel.

The picture you have shown of the flat flywheel is from a different model such as my 02 Legacy. (Exedy Part # FWSBL02FF)

SO, if we are going to play this game then you need to compare apples to apples, not apples to oranges.

So to explain that I will tell you what the step is for. The step sets the clutch cover height in relationship to the clutch disk. This takes into consideration clutch disk thickness, clamping pressure/force, clutch cover release and engagement and rate of engagement (ie. harsh or smooth engagement)

If I was you I would probably just purchase the proper flywheel, reason being this....
If the flywheel was previously machined, you don't know how much was removed from it prior. In addition to re-create the step your going to have to remove that much more material. Now if you drive gently there probably won't be much of a problem, but....

If you drive hard or have additional upgraded power on tap or a combination of both it is possible that flywheel will not be able to dissipate the heat generated which will glaze the flywheel surface, introduce heat checking and possible cracking. If the step is too tall then your going to likely have problems holding the power and slipping may occur thus see above.

Anyways, thats the long winded answer I got, hope it at least gives food for thought. Good Luck with it.

Hi!


Well, figured it would be better to post pictures of my actual flywheel.


Here's how it looked when we took it apart;


(PIC 1, for reference)



https://i.imgur.com/NrQ51EN.jpg




Then we had it resurfaced to clear the hotspots. It looked like this afterwards;


(PIC 2 for reference)


https://i.imgur.com/QiXgn6i.jpg


Then we had a 6 puck installed with that flywheel. Had issues with it slipping in the first test drive. Took it apart again, then had the flywheel resurfaced once again, but now they had added the missing "step". And installed it once again with another 6 puck (not the same from the first test), first test drive had some mild slipping in 3rd gear. But after a few miles it went away. Then had some ocassionaly slipping in 4th and 5th gear when coming into boost. Sometimes it grabs, sometimes it slips, randomly.
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Old 12-31-2020, 11:24 AM   #4
Samurai Jack
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Subaru OEM flywheel = Exedy flywheel.
Same goes for clutches.

Best thing to do is buy a proper flywheel ( Subaru or Exedy ) that is the exact replacement for your car.

The other best thing to do is buy a proper clutch.
Why do you think you need a 6 puck clutch? Totally unnecessary for a daily driver. Buy an Exedy organic replacement and you'll be better off.

If you want to buy it from the Dealer, you'll just pay more because it says Subaru.

Sounds like your shop is just hacking this issue to make it work instead of doing the right thing and giving you proper guidance.
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Old 12-31-2020, 04:34 PM   #5
riksk
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Quote:
Originally Posted by Samurai Jack View Post
Subaru OEM flywheel = Exedy flywheel.
Same goes for clutches.

Best thing to do is buy a proper flywheel ( Subaru or Exedy ) that is the exact replacement for your car.

The other best thing to do is buy a proper clutch.
Why do you think you need a 6 puck clutch? Totally unnecessary for a daily driver. Buy an Exedy organic replacement and you'll be better off.

If you want to buy it from the Dealer, you'll just pay more because it says Subaru.

Sounds like your shop is just hacking this issue to make it work instead of doing the right thing and giving you proper guidance.
It's only a weekend/track car. Not a DD. Also i'm running 360wtq. Stock clutch went bye-bye.


We don't have such options as just going to the dealer and buying a new part here. Closest dealership is about 700 miles away (doesn't matter cause I called them and they don't have the flywheel anyway hahah)


I will try to get an ACT kit next year with the Streetlite Flywheel and 6 puck disc and PP.



The thing over here is a bit extreme. This particular clutch kit gooes for like 900 USD right? But then we have shipping, import taxes, etc... ends up costing around 3000 USD for us. Not a real cost effective solution. That's why we service our flywheels, pressure plates, clutch discs.. almost everything we can resurface or reservice, it's done like so.


Anyway, thanks for the info about the flywheel. Now it makes sense why absolute nothing grips on that thing. Guess it's time to park it for a while.
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Old 01-02-2021, 09:27 PM   #6
peerless
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What pressure plate are you running?

The pressure plate is what provides the clamping force, whether your running the stock disk, 6 puck, 3 puck, doesn't matter if the pressure plate cannot give you the clamping force needed. And by looking at that first picture of your flywheel, you you got some major slippage there.

Also instead of parking the car, why don't you just turn down the boost and still enjoy the car with a lighter foot.

Also where are you located, I have a connection in the shipping business and might be able to get you a decent rate. I am assuming your in Australia because nothing hurts more then to have to pay shipping to Australia!
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Old 01-05-2021, 12:21 AM   #7
riksk
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Member#: 518114
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Location: BR
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11 WRX
Satin White Pearl

Default

Quote:
Originally Posted by peerless View Post
What pressure plate are you running?

The pressure plate is what provides the clamping force, whether your running the stock disk, 6 puck, 3 puck, doesn't matter if the pressure plate cannot give you the clamping force needed. And by looking at that first picture of your flywheel, you you got some major slippage there.

Also instead of parking the car, why don't you just turn down the boost and still enjoy the car with a lighter foot.

Also where are you located, I have a connection in the shipping business and might be able to get you a decent rate. I am assuming your in Australia because nothing hurts more then to have to pay shipping to Australia!

Running the stock pressure plate.


When i said park it I really mean it, cause it's track/weekend only car. Not a DD. I also have a NA GC8 and a Forester XT for DD :P So i'm not on foot in the meantime.


And I'm located in Brazil. God I would love to be in Australia xD, everything is so much cheaper.
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