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Premium Member
Drag 00 Impreza 2.5 RSTI
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1,525 Posts
Discussion Starter · #1 ·
Well,
found out that the 2000 Impreza 2.5rs I bought doesn’t have a EJ257 in it like I was told it did. Wow. Really pissed! Too bad Craigslist isn’t like eBay and I can complain and get some money back...

Anyways, it seems to be holding up to the punishment that I have been putting it through. Have been running a stock EJ251 at 10lbs of boost for over 5 months and still have full compression. Vishnu turbo kitted.

Does anyone know how much punishment these stock pistons and rods can take? Can I tune it for any higher boost (more than 10psi) without it blowing up or snapping a rod? Doing a EJ257 and STI swap in the winter but for now, I want to get as much outta this car as I can.

Any thoughts?

Ben
 

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Premium Member
2002 2.5 RS-T
Joined
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2,960 Posts
Well,
found out that the 2000 Impreza 2.5rs I bought doesn’t have a EJ257 in it like I was told it did. Wow. Really pissed! Too bad Craigslist isn’t like eBay and I can complain and get some money back...

Anyways, it seems to be holding up to the punishment that I have been putting it through. Have been running a stock EJ251 at 10lbs of boost for over 5 months and still have full compression. Vishnu turbo kitted.

Does anyone know how much punishment these stock pistons and rods can take? Can I tune it for any higher boost (more than 10psi) without it blowing up or snapping a rod? Doing a EJ257 and STI swap in the winter but for now, I want to get as much outta this car as I can.

Any thoughts?

Ben
umm if you rely on the car for a DD then turn the boost down..RIGHT NOW.....u can handle 7 lbs, maybe 8 top with stock ej251..but 10psi is just asking for it...
 

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Boxer rumble FTW!
2005 Subaru Impreza 2.5 RS
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621 Posts
yeah i would do as Jeff said and turn it down till you swap with sti. then you can save or sell your old lump maybe.
 

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4 please, to go.
Ver 7 STi GC, elderly L
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3,623 Posts
+1 for turning down the boost, it's not so much the engine i'd be worried about it's the tranny, boosted high comp EJ251's love to blow trannies
 

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Registered
1997 impreza L, w/ ej251 swap.
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3 Posts
i have an ej25. the previous owner says they swappd it(ej25 jdm) in the 99' , because the orignal ej22 blew.. so how can i identify what kind of ej25 i have? this guy makes me scared... i hope i have an ej257 like the one the poster wants so much.
 

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Premium Member
2002 2.5 RS-T
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2,960 Posts
i have an ej25. the previous owner says they swappd it(ej25 jdm) in the 99' , because the orignal ej22 blew.. so how can i identify what kind of ej25 i have? this guy makes me scared... i hope i have an ej257 like the one the poster wants so much.
well for usdm stuff this is about the only way i can think of to tell right now:

ok on the top of the block, towards the back of the passenger side theres a breather that goes to the pcv system.....the ej251 only has this breather....and ej257 will have another one about 6" to the right (center of the block)...it'll most likely be blocked off.

but hopefully someone knows more than i do and chimes in.
 

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1998 Forester on Orange 57F
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4,129 Posts
^^^ that would be the easiest way to tell.

The original poster could even have STI internals in a RS case. How do we know this is not a ej257.

And the guy that has the "JDM ej25" Why would you want a ej257 in a NA car? And it is unlikely the ej25 is a ej257. There was only one JDM car that has the ej257 I beleive. The USDM stuff is what you want.
 

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01 stm sedan w/v4 sugar
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3,499 Posts
The original poster could even have STI internals in a RS case. How do we know this is not a ej257.
Sorry to re-hash this, but I was thinking: Is it Vishnu that makes the bolt on turbo kit for NA 251's?

If so, I'm not surprised that the engine is a 251. No one in their right mind would put a bolt on turbo kit on a 257 motor, when it's already equipped with a legit setup.
 

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Registered
2000 Impreza++
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66 Posts
yeah I blew my phase 2 ej25 QUICK around 9psi. dunt do it!!!!!!!! keep it low until you either swap or rebuild with some forged aluminum and powdered metal. or find out how long the top ring lands can last in the combustion chamber.
 

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Premium Member
2002 2.5 RS-T
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2,960 Posts
Sorry to re-hash this, but I was thinking: Is it Vishnu that makes the bolt on turbo kit for NA 251's?

If so, I'm not surprised that the engine is a 251. No one in their right mind would put a bolt on turbo kit on a 257 motor, when it's already equipped with a legit setup.
im thinking he means ej257 shortblock with everything else a la ej251...
 

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1998 2.5RS Coupe
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20 Posts
Yea but it could simply be an EJ257 shortblock... alot of peeps that have a turbo SOHC have been known to build that way.
 

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Premium Member
overdeveloped beater
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8,335 Posts
The original poster could even have STI internals in a RS case. How do we know this is not a ej257.
Quoted for good reason. The EJ257 internals drop right into the phase II EJ25 block. The motor very well could be essentially an EJ257 without the extra ribbing between the cylinders of the real deal.
 

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Premium Member
overdeveloped beater
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8,335 Posts
I would leave it alone. Delta can make you the cam you want if you wanna go that route. Swapping to DOHC heads will do nothing but cost you money.
 
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