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Old 02-27-2021, 11:30 PM   #1
demid30
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Default Ej20x in 2014 WRX?

So after 173,000 miles cylinder 4 has 10psi compression and 90% leak down at valves and crankcase. Prime Motoring here in NJ are telling me it's cheaper to replace with used engine then to pull mine and find the problem and fix it the right way. They suggested either used ej25 or Ej20x. The Ej20x are half the price. They will professional tune it and it's still way cheaper then using the ej25. Any suggestions? Anyone running an Ej20x?
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Old 03-01-2021, 11:57 PM   #2
V10SNEK
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Originally Posted by demid30 View Post
So after 173,000 miles cylinder 4 has 10psi compression and 90% leak down at valves and crankcase. Prime Motoring here in NJ are telling me it's cheaper to replace with used engine then to pull mine and find the problem and fix it the right way. They suggested either used ej25 or Ej20x. The Ej20x are half the price. They will professional tune it and it's still way cheaper then using the ej25. Any suggestions? Anyone running an Ej20x?


Aren’t the ej20x engines open deck? As long as you’re not trying to get insane power levels, you’d be totally fine. The only issue between a used engine and a rebuild is that you don’t know the condition of the bearings, cam lobes, etc. If an engine ran low on oil pressure for just a few seconds, it would shorten the life of that motor drastically.

My advice is if you want to get it running and sell the car, slap a used engine in there. If you want to keep the car, spend the extra and rebuild the block with some decent bearings and rings. (Might as well upgrade anything else while it’s apart.
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Old 03-02-2021, 09:25 AM   #3
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If you decide to go cheap, do you plan to stay in that area ? I've heard that when issues pop up in the future, getting repairs done to a JDM engine can be tuff.

I did a OEM ej257 shortblock back in May 2012, that engine now has over 142,000 trouble free miles on it. Kept the ej257 stock, car has a vf52 dynoed at 21psi on stock fueling. I did have ARP heads studs installed in the ej257.
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Old 03-03-2021, 02:23 AM   #4
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I had an EJ20x in my 08 STi, they are definitely a very cheap alternative. There is nothing different from a EJ20x JDM motor to a EJ257 Dual AVCS USDM when it comes to replacement gaskets and parts. There is 2 different styles of EJ20x you can choose one with air injection system and one without. I don't know your smog regulations but your vehicle has an air injection system so if you want to maintain the system you can go with the EJ20x with the "U20" heads, or if you want to delete your air injection get the EJ20x with the "Z20" heads

Its a strong little motor and I was very impressed with it. I was running a UDSM STi turbo, stock injectors, with an Intake, Downpipe and Exhaust. I was revving the car to 7700RPM and running about 21 lbs of boost taper to 19psi at redline. You definitely have to watch the timing that is put in on the tune due to the higher compression ratio.

Just for comparison I had the EJ20x in my STi and my buddy had a 2012 WRX with intake, Downpipe, Muffler delete. He was set to 20PSi and taper to 16psi by redline and his car was running very well for a Stage 2 WRX and our cars were basically identical in speed from the roll races we did.
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Old 03-10-2021, 06:39 PM   #5
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Originally Posted by V10SNEK View Post
Aren’t the ej20x engines open deck? As long as you’re not trying to get insane power levels, you’d be totally fine. The only issue between a used engine and a rebuild is that you don’t know the condition of the bearings, cam lobes, etc. If an engine ran low on oil pressure for just a few seconds, it would shorten the life of that motor drastically.
My advice is if you want to get it running and sell the car, slap a used engine in there. If you want to keep the car, spend the extra and rebuild the block with some decent bearings and rings. (Might as well upgrade anything else while it’s apart.
Yes they're open deck, I'm not trying to get insane numbers. I just want it to be as quick or a little quicker then the stock setup. I found a place 10 minutes away that sells the Ej20x for $1050, which is a really good deal. A used ej255 is around 5k. The guys at prime said to pull the engine and do everything the right way rebuilding my engine would cost like 10k said and done. Im not looking to drop that much cash.
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Old 03-10-2021, 06:41 PM   #6
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Originally Posted by Max Capacity View Post
If you decide to go cheap, do you plan to stay in that area ? I've heard that when issues pop up in the future, getting repairs done to a JDM engine can be tuff.

I did a OEM ej257 shortblock back in May 2012, that engine now has over 142,000 trouble free miles on it. Kept the ej257 stock, car has a vf52 dynoed at 21psi on stock fueling. I did have ARP heads studs installed in the ej257.
Yea I don't plan on leaving the area, and I don't think prime motoring is either. So I'm sure they'll be able to help me out. I can do a lot of work myself, if I have the time.
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Old 03-10-2021, 06:44 PM   #7
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Originally Posted by SlammedSix View Post
I had an EJ20x in my 08 STi, they are definitely a very cheap alternative. There is nothing different from a EJ20x JDM motor to a EJ257 Dual AVCS USDM when it comes to replacement gaskets and parts. There is 2 different styles of EJ20x you can choose one with air injection system and one without. I don't know your smog regulations but your vehicle has an air injection system so if you want to maintain the system you can go with the EJ20x with the "U20" heads, or if you want to delete your air injection get the EJ20x with the "Z20" heads

Its a strong little motor and I was very impressed with it. I was running a UDSM STi turbo, stock injectors, with an Intake, Downpipe and Exhaust. I was revving the car to 7700RPM and running about 21 lbs of boost taper to 19psi at redline. You definitely have to watch the timing that is put in on the tune due to the higher compression ratio.

Just for comparison I had the EJ20x in my STi and my buddy had a 2012 WRX with intake, Downpipe, Muffler delete. He was set to 20PSi and taper to 16psi by redline and his car was running very well for a Stage 2 WRX and our cars were basically identical in speed from the roll races we did.
Thanks for all the information! I'm glad to hear you ran the Ej20x and liked it! Yes I know about the 2 different versions and that I have the secondary air pump. I am going to get the right one with the secondary air pump. You think I should run the Ej20x headers and turbo and what not with the Ej20x down pipe? Or use my turbo and headers with my down pipe?
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Old 03-16-2021, 10:40 AM   #8
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. ..You think I should run the Ej20x headers and turbo and what not with the Ej20x down pipe? Or use my turbo and headers with my down pipe?
A little different situation, but I just swapped a EJ20X into my 08 WRX. I really wanted to try and keep the twin scroll VF44 that came on the engine, but sourcing an inter-cooler and down pipe to fit became the hardest part of the build. I finally just splurged on an AVO Liberty GT inter-cooler and DP bellmouth, and fabricated a downpipe to fit. The final results after a conservative tune are a very broad and linear powerband that I am quite please with.

Last edited by tredmeister; 03-16-2021 at 02:54 PM.
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Old 05-17-2021, 02:14 PM   #9
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so i have the ej20x in my 2012 wrx and i feel slow until 4k rpm. im assuming because of the exhaust cam being parked in a position where low rpm exhaust flow is restricted. im using the vf52 off of the original ej25 as i couldnt source a DP for the twin scroll that came on the 2.0. found the thread about programming arduino to run the avcs but he used custom 3d printed cases and mounting solutions i wouldnt have access to. I have seen posts about adjusting the ex cams in the u20 heads and heard 2 teeth is ok and whatnot. has anyone else done this in a single avcs chassis 2011+. thought about possibly getting a standalone to run it all together but that wouldnt be very cost effective for what the car is. (daily commuter and grocery getter). i really liked that arduino post from NSFW but if there is a simpler solution im all ears.
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Old 05-17-2021, 02:29 PM   #10
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Originally Posted by Aynoz View Post
so i have the ej20x in my 2012 wrx and i feel slow until 4k rpm. im assuming because of the exhaust cam being parked in a position where low rpm exhaust flow is restricted. im using the vf52 off of the original ej25 as i couldnt source a DP for the twin scroll that came on the 2.0. found the thread about programming arduino to run the avcs but he used custom 3d printed cases and mounting solutions i wouldnt have access to. I have seen posts about adjusting the ex cams in the u20 heads and heard 2 teeth is ok and whatnot. has anyone else done this in a single avcs chassis 2011+. thought about possibly getting a standalone to run it all together but that wouldnt be very cost effective for what the car is. (daily commuter and grocery getter). i really liked that arduino post from NSFW but if there is a simpler solution im all ears.
You feel slow before you spool because youre running a VF turbo on a 2.0 w/o running AVCS. Spool is expected around 4k with that config.

Going standalone is costly as you said but certainly has its benefits.
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Old 05-17-2021, 02:46 PM   #11
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so i have the ej20x in my 2012 wrx and i feel slow until 4k rpm. im assuming because of the exhaust cam being parked in a position where low rpm exhaust flow is restricted. im using the vf52 off of the original ej25 as i couldnt source a DP for the twin scroll that came on the 2.0. found the thread about programming arduino to run the avcs but he used custom 3d printed cases and mounting solutions i wouldnt have access to. I have seen posts about adjusting the ex cams in the u20 heads and heard 2 teeth is ok and whatnot. has anyone else done this in a single avcs chassis 2011+. thought about possibly getting a standalone to run it all together but that wouldnt be very cost effective for what the car is. (daily commuter and grocery getter). i really liked that arduino post from NSFW but if there is a simpler solution im all ears.


Are you using your intake AVCS? What supporting mods?

I can't speak for clocking the ex cams, but you should be spooking faster than that with the VF52. It's not a huge turbo and single AVCS 2.0 on a VF48 that's been tuned properly with supporting mods sees full boost in the low 3000 range. Hell, my 20g XTR on a 207 sees 19psi by 3900 with a slow slow increase to 21psi by 4200 for a more linear feel. I could've had the full 21 by 3800 according to the tuner. So I'd look for leaks or at your list of mods to see if maybe the tuner held back for some reason. And this maybe the case considering fuel quality in the US and your engine having 9.5:1 CR from the factory.
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Old 05-17-2021, 05:24 PM   #12
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Are you using your intake AVCS? What supporting mods?

I can't speak for clocking the ex cams, but you should be spooking faster than that with the VF52. It's not a huge turbo and single AVCS 2.0 on a VF48 that's been tuned properly with supporting mods sees full boost in the low 3000 range. Hell, my 20g XTR on a 207 sees 19psi by 3900 with a slow slow increase to 21psi by 4200 for a more linear feel. I could've had the full 21 by 3800 according to the tuner. So I'd look for leaks or at your list of mods to see if maybe the tuner held back for some reason. And this maybe the case considering fuel quality in the US and your engine having 9.5:1 CR from the factory.
i am using intake AVCS. Have an Injen high flow catted DP and cobb intake. no other mods that would hinder or enhance engine performance. i use accesstuner to modify engine parameters and all i can see is very slow boost buildup to about 3750 when she gets spinning and it pulls nice and strong to 7k i run low boost levels around here for heat management (17 psi taper to 15) and elevation as well as we only have 91 here. i would just like the power to come on alot sooner than it is. when i put that engine in i did a smoke test for leaks and found none. i was able to pressurize the system to 10 psi no problem. i think it has to do with the parked ex cams as thats the only common denominator i can think of thats. i notice down bottm on the throttle i get a bit of a chuggle then once ovr 2.5k she slowly creeps up to full power at close to 4k where my boost pegs the set limit and tapers like programmed.
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Old 05-17-2021, 05:36 PM   #13
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Originally Posted by Aynoz View Post
i am using intake AVCS. Have an Injen high flow catted DP and cobb intake. no other mods that would hinder or enhance engine performance. i use accesstuner to modify engine parameters and all i can see is very slow boost buildup to about 3750 when she gets spinning and it pulls nice and strong to 7k i run low boost levels around here for heat management (17 psi taper to 15) and elevation as well as we only have 91 here. i would just like the power to come on alot sooner than it is. when i put that engine in i did a smoke test for leaks and found none. i was able to pressurize the system to 10 psi no problem. i think it has to do with the parked ex cams as thats the only common denominator i can think of thats. i notice down bottm on the throttle i get a bit of a chuggle then once ovr 2.5k she slowly creeps up to full power at close to 4k where my boost pegs the set limit and tapers like programmed.

With those mods, the spool seems fairly normal.
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Old 05-18-2021, 01:03 AM   #14
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so i have the ej20x in my 2012 wrx and i feel slow until 4k rpm. im assuming because of the exhaust cam being parked in a position where low rpm exhaust flow is restricted. im using the vf52 off of the original ej25 as i couldnt source a DP for the twin scroll that came on the 2.0. found the thread about programming arduino to run the avcs but he used custom 3d printed cases and mounting solutions i wouldnt have access to. I have seen posts about adjusting the ex cams in the u20 heads and heard 2 teeth is ok and whatnot. has anyone else done this in a single avcs chassis 2011+. thought about possibly getting a standalone to run it all together but that wouldnt be very cost effective for what the car is. (daily commuter and grocery getter). i really liked that arduino post from NSFW but if there is a simpler solution im all ears.
An EJ20x with a VF52/39/43/48 will spool around 4250-4500 RPM in stock form. Obviously the more mods in air flow (Intake, Turbo inlet, Headers, Downpipe, Exhaust) you can drop that full spool time. But its very unlikely to get a VF52 to spool on a EJ20 sooner than 3500rpm.

I ran my EJ20x with a VF48 turbo and the Exhaust AVCS turned off and left at 0 degrees and i was able to still have the car spool just fine and never noticed any performance loss.

I think you are just noticing the spool difference from a 2.0 to 2.5 liter engine. In stock form a 2.5 will spool that VF52 at like 3500rpm a 2.0 will do it about 4500.
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Old 05-19-2021, 07:47 PM   #15
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Originally Posted by SlammedSix View Post
An EJ20x with a VF52/39/43/48 will spool around 4250-4500 RPM in stock form. Obviously the more mods in air flow (Intake, Turbo inlet, Headers, Downpipe, Exhaust) you can drop that full spool time. But its very unlikely to get a VF52 to spool on a EJ20 sooner than 3500rpm.

I ran my EJ20x with a VF48 turbo and the Exhaust AVCS turned off and left at 0 degrees and i was able to still have the car spool just fine and never noticed any performance loss.

I think you are just noticing the spool difference from a 2.0 to 2.5 liter engine. In stock form a 2.5 will spool that VF52 at like 3500rpm a 2.0 will do it about 4500.
i just feel a big difference in the bottom half of the RPM range compared to my old 2.5. my butt dyno doesn't lie and even my daughter says it feels slower...lol maybe a fresh tune on the rollers can improve a bit of the bottom end sluggishness. (is that a word?) I'm still going to build my original engine anyways I was just wondering if its possible to extract some more out of the exhaust flow by clocking the cams a bit on the ex side. if not well im still enjoying my 28-33 MPGs the 2.5 gave me 23 at best and 17 on the lower side. thanks for yalls input!
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Old 05-19-2021, 08:01 PM   #16
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i just feel a big difference in the bottom half of the RPM range compared to my old 2.5. my butt dyno doesn't lie and even my daughter says it feels slower...lol maybe a fresh tune on the rollers can improve a bit of the bottom end sluggishness. (is that a word?) I'm still going to build my original engine anyways I was just wondering if its possible to extract some more out of the exhaust flow by clocking the cams a bit on the ex side. if not well im still enjoying my 28-33 MPGs the 2.5 gave me 23 at best and 17 on the lower side. thanks for yalls input!
The reason why you feel a big difference is because there IS. If you look at airflow at just that CFM. (I'm using general numbers) if a 2.5 can output 500 cfm at 3500 and thats what is needed to start to spool the turbo a 2.0 cannot hit 500 cfm flow until 4500. That is why the turbo spool is dependent on the amount of airflow output of the motor, which generally is based on size of motor.

So outside of boost the 2.0 is essentially always making less hp than the 2.5 in your specific situation. Thats why the gas mileage is better because less fuel is less hp.

But from personally experience that 2.0 can still get down when its under boost.
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Old 05-21-2021, 09:59 PM   #17
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I’ve managed to improve my spool about four hundred RPM by playing with my AVCS intake advance. I advance it to 28 degrees while trying to build boost. Maybe try some changes to intake AVCS…
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