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Hi,

 

I just bought a new flywheel for my EJ25 but double checking the NAPA part number, it is for the EJ22.

 

Is there really a difference????

 

The product data for this flywheel also says it has 6 bolt holes (which it doesn't) :confused:

 

Steve

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Should all be the same - the EJ22's are 8 bolt at the crank.... which all Subaru engines are at least back to the EA71. In fact the only reason the EA's have a different bolt pattern is they made it asymetrical in order to insure there was only a single orientation for the flywheel-to-crank mating so the timing marks would line up. The EJ have no timing marks so they are a symetrical pattern but same number of bolts.

 

I doubt you will have any problems with it.

 

GD

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Should all be the same - the EJ22's are 8 bolt at the crank.... which all Subaru engines are at least back to the EA71. In fact the only reason the EA's have a different bolt pattern is they made it asymetrical in order to insure there was only a single orientation for the flywheel-to-crank mating so the timing marks would line up. The EJ have no timing marks so they are a symetrical pattern but same number of bolts.

 

I doubt you will have any problems with it.

 

GD

 

Cheers!

 

In it goes then :)

 

I had my old one re-surfaced btw - he mentioned that it was a "little" warped so I figured screw it, I'm gonna be safe and buy a new one.

 

Steve

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The auto flex plates are different sizes. Some of the flywheels had a little step in the flywheel so the clutch engaugement was slightly different.

 

It should be fine.

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Some of the flywheels had a little step in the flywheel so the clutch engaugement was slightly different.

 

A matter of a few thou - I'm not even sure why they bothered. But yeah I've seen that as well on some. I've also seen deeper steps worn into flywheels that weren't supposed to have them at all.

 

It should be fine.

 

I agree - shouldn't matter.

 

GD

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What about this. I am doing the EJ25 with EJ18 heads and EJ18 5sp tranny. Will EJ22 stage 1 clutch and EJ22 lightweight flywheel work for this? I am ordering parts tonight. So EJ18 tranny plus EJ25 block plus EJ18 heads. It works right with all EJ22 stuff? Thanks

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Yep - should work fine. All the EJ's use the same crank pattern, etc so the block you use doesn't matter. Pretty much all the non-turbo clutch and flywheel's are the same too so you shouldn't have any trouble with the Imp's transmission other than probably having more power than it will handle :rolleyes:.

 

GD

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other than probably having more power than it will handle :rolleyes:.

 

GD

 

Yeah, the simple math is scary (EJ25 - EJ18 = EJ7!) :lol:

 

EJ7 - That is quite a load you are putting on your tranny!

 

I heard that a lot of people had problems with their wrex's due to putting EJ25's on an EJ20?! tranny.

 

Steve

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Ok, I have a related question. I have a flywheel from a 1st gen legacy with an ej22. Also I have one from a non turbo ej25, I believe the car it came from was a 2.5RS coupe. The 2.5 flywheel is heavier. Is there any general rule of thumb when it comes to weights and what model of engine along with what model of car? Hope this question is not too confusing! Thanks, Spencer

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Typically - heavier flywheels are chosen for larger engines to make them idle smoother. Larger displacement = bigger BANG when a cylinder fires. More weight on the flywheel causes it to coast easier to the next cylinder in the fireing order. It also causes it to accelerate and decelerate slower given the same displacement - inertia is the key player here.

 

Lightweight flywheels are sold that will work with any of the EJ's - causing a rougher idle and a quicker throttle response and RPM drop between shifts.

 

The weight of the flywheel's is dependent on the displacement and application for sure - but it doesn't directly affect fitment or correct operation in the case of EJ25 vs. EJ22 (or even EJ18 for that matter). They are functionally equivelent.

 

Typically for an off-road wheeler you would want a heavy flywheel to maintain inertia and smooth clutch operation at low RPM, while for a street performance or racing application you would want a lighter one. Stock are usually on the heavy side for smooth idling and driveability reasons.

 

GD

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Yeah, the simple math is scary (EJ25 - EJ18 = EJ7!) :lol:

 

EJ7 - That is quite a load you are putting on your tranny!

 

I heard that a lot of people had problems with their wrex's due to putting EJ25's on an EJ20?! tranny.

 

Steve

 

People were breaking WRX trannies on test drives at dealerships when they first came out.

 

Putting 7 more EJs:lol: of power on the EJ18 tranny should be fine if driven properly.

 

Jacob

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Putting 7 more EJs:lol: of power on the EJ18 tranny should be fine if driven properly.

 

Jacob

 

Yeah i planned on breaking the tranny. Just gonna run it til it breaks then find a 2.2 tranny.

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Yup, 2.5l flywheels are quite a bit heavier I've found. There's less of a hollow cast into the back between the ring gear and the crank surfaces on the 2.5's. I've used them on 2.2l's because I lug the engines down all the time offroad. Functionally, their the same and interchangeable, the average driver won't notice. But if you have 2 side by side and you want to pick which best suits your application, there you are.

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hi im just wondering i have a 01 gc8 impreza its an ej20 non turbo 4wd , im trying to find a lightnd flywheel for it , but i can only find ones for an ej25, im just wondering wil the flywheel from an ej25 fit and work fine in my ej20 n/a?

 

thanks

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Any EJ flywheel will fit on any EJ engine. The only real difference between them being weight. You want lightweight so any EJ lightweight flywheel should do.

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Everything in this thread is wrong. Cars that came with a 2.5 have a larger diameter clutch than 2.2 cars, so they take a different flywheel.

 

However you can interchange the cpmplete flywheel/disc/pressure plate between them if you use all 3 together.

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Everything in this thread is wrong. Cars that came with a 2.5 have a larger diameter clutch than 2.2 cars, so they take a different flywheel.

 

However you can interchange the cpmplete flywheel/disc/pressure plate between them if you use all 3 together.

 

Every parts listing I have seen says the 2.5 and 2.2 clutch disc are the same size. I haven't seen dimensions for the pressure plate, other than a few that list clamping force, which is higher for the 2.5 plate.

 

 

The dual mass flywheel is quite different, and so is the pull type pressure plate used with it. That setup is larger, but only available on the STI as far as I know.

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Every parts listing I have seen says the 2.5 and 2.2 clutch disc are the same size. I haven't seen dimensions for the pressure plate, other than a few that list clamping force, which is higher for the 2.5 plate.

 

 

The dual mass flywheel is quite different, and so is the pull type pressure plate used with it. That setup is larger, but only available on the STI as far as I know.

 

They aren't. Try and bolt one on, it's an inch bigger.

 

Wrong again, the wrx has a dual mass flywheel with a bolt on weight on the back. The sti does as well, but it's a larger diameter.

 

This whole thread should just be deleted so somebody doesn't find it in the future and get bad info.

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Hhhmmm - I'm going to check this out immediately and post pictures if that's the case. I thought they were the same also. I happen to have an EJ25D flywheel in the garage from a recent clutch job as well as a '96 OBW with the transmission removed for replacement (and clutch job as well). I will compare and measure. Stay tuned.

 

GD

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if one flywheel is bigger, wouldn't you have to change the starter? or does the trans housing make up the difference?

 

different part numbers : (click on usage)

 

ej25

http://opposedforces.com/parts/info/12310AA210/

 

 

ej22 (ej18)

http://opposedforces.com/parts/info/12310AA091/

Edited by johnceggleston

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if one flywheel is bigger, wouldn't you have to change the starter? or does the trans housing make up the difference?

 

I think they are thicker rather than bigger in diameter.

 

Steve

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hi dat impreza i have is 00 gc8 2.0 4wd! , if i was to convert it to a ej20 turbo , what do i need, engine, turbo, gbox, do i need a loom and ecu or will my loom fit it?

 

what exactly do i need?,

 

thanks.

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I've swapped a 5 speed from a 2003 turbo WRX (EJ20) with pull type clutch into a 2003 Baja (EJ25). Original equipment was 5 speed with push type clutch. I had to also change the flywheel and clutch master cylinder to match. As I recall, the bolt pattern and size of the pressure plates were different.

 

FYI: I used a lightweight flywheel and the entire experience sucked. Low RPM operation became horribly rough and inclined starts were tough. This resulted in failure of the replacement clutch after only 100k miles. I have it torn down now and will be replacing the flywheel with an OEM version (heavy) from an Impreza (EJ25). The only difference I have noted seems to relate to the clutch type, push or pull.

 

Will get this together and see where it goes from the current 270,000 miles.

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