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Old 10-28-2010, 09:22 AM   #1
cdnsigop
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Default EJ25D Cams with Boost 10-20+ psi

I have searched everywhere and am asking for help. I have nearly completed my budget build EJ25. Donor is a 99 Legacy Outback.

Build is a Phase 2 EJ25 block and crank, with EJ257 oem rods and pistons, Phase 1 EJ25D shim over bucket heads, an AVO 2.5 RS kit GT25 turbo and uppipe with an ebay Borla rep. dual port N/A header... I have the N/A EJ25D cams with the offset exhaust lobes...

What I want to know is how the stock cams will deal with big boost, as much as 20+ psi. It would be nice to hear from someone who has actually done this, as I do understand that N/A cams arent ideal for this...
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Old 10-28-2010, 01:43 PM   #2
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i know i havent turbo charged my car yet but that seems sketchy cause my friends 06 wrx that has quite a a bit of work and he only runs 16psi to 18psi so not positive but i wounldt try it
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Old 10-28-2010, 03:15 PM   #3
07ImprezaMB
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You would never get away running that much boost on stock heads with stock cams. You would only be able to run 10-12 psi with upgraded pistons. In order for you your heads to run more boost you would need to upgrade your cams and valvetrain.
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Old 10-28-2010, 04:39 PM   #4
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Quote:
Originally Posted by 07ImprezaMB View Post
You would never get away running that much boost on stock heads with stock cams. You would only be able to run 10-12 psi with upgraded pistons. In order for you your heads to run more boost you would need to upgrade your cams and valvetrain.
You can run 12+ boost with stock heads, subies out there running 20+ boost, and I am going to run soon 18psi on my SOHC heads, the limiting factor is pistons, NA pistons just don't cut it for boost.
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Old 10-29-2010, 08:57 AM   #5
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Its not a question of whether Its possible or not. I have been running 17+ psi with water injection on an otherwise stock 1998 EJ22E. My question is how the EJ25D cams are with boost, lots of it, up to the 6500 RPM limit of the corresponding ecu...

No offence, but I dont care for the canned response of what the EJ engines can take boost wise, stock. Especially from people who have not done it. Because so far Ive proven those theories to be horse*****... Along with many other members on the board. Its just not a valid theory anymore.

Thanks anyway for the responses!
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Old 10-29-2010, 09:41 AM   #6
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I havent done it, but looking at the lift and duration of them I would estimate that not much power would be made. Better to drop some wrx cams in there perhaps?
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Old 10-29-2010, 09:50 AM   #7
07ImprezaMB
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it has been proven that our stock heads experience valve float past 6k rpms when boosted without upgraded valvetrain.
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Old 10-29-2010, 01:02 PM   #8
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i floated a valve with just cams and no boost before i got my springs and retainers.
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Old 10-29-2010, 01:07 PM   #9
07ImprezaMB
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Quote:
Originally Posted by olsen726 View Post
i floated a valve with just cams and no boost before i got my springs and retainers.

Thanks for the back up olsen! lol
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Old 10-29-2010, 01:14 PM   #10
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The D heads are very similar to 20k/eg33 heads, and are pretty awesome. With port work, they will be able to flow very very well.

I think your primary issue will be the cam profiles- they have a little too much overlap for my tastes at a high pressure level. It is preference.

Another observation is that the cheap headers are very likely to crack with high EGTs. The Chinese replicas are 409 stainless if I recall, and that is not much better than mild steel as far as heat to strenght ratio. So expect to reweld them at the flanges at the least
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Old 10-29-2010, 06:53 PM   #11
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i will agree on having the replica headers crack. i have had mine on my car for well over 60k miles, (probably about 5k boosted) and i noticed that my turbo was taking forever to spool up... anyways long story short my borla rep's were cracked at one of the welds... but if you have anyone that can tig weld, it was a really easy 5 minute fix job.... and i have had my headers on my car for a long ass time ( not to mention i have bottomed them out on the road enough to dent the bottom of them) and they are holding most of the pressure from my heavy ass turbo.
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Old 10-29-2010, 08:20 PM   #12
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Thank you very much for the thought out rather than canned responses. I really appreciate it. As far as the ebay header, I was thinking that I might be better off with a stock dual port exhaust manifold, but Im going to try this ebay header anyway... The ports arent overly large. I might even wrap the header and uppipe. Im trying to keep costs down, lol.

The cams....Im trying to "run what you brung". Back in my Honda days, I used to run big boost on the N/A cams all the time... DOHC ZC's and SOHC D16A6's. They made really good power for their size, and with 20+ psi I never noticed any problems with power falling off at the top..The only thing that really throws me off is those offset exhaust lobes on the EJ25D cams...
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Old 11-01-2010, 10:47 AM   #13
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cdn... are the block and piston from an N/A or turbo car? u shouldn't run over 7psi on stock N/A block and pistons.
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Old 11-01-2010, 05:33 PM   #14
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Quote:
Originally Posted by PA-Outback2000 View Post
cdn... are the block and piston from an N/A or turbo car? u shouldn't run over 7psi on stock N/A block and pistons.
The block is Phase 2 EJ25, with EJ257 pistons and rods.
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Old 11-02-2010, 09:44 AM   #15
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so N/A?
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Old 11-02-2010, 09:50 AM   #16
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LOL the bare block halves are N/A, but the EJ257 is the factory turbo 2.5 in the 2004- STi. So factory turbo pistons and rods. How do you get to be a Scooby Specialist without knowing what an EJ257 is??
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Old 11-02-2010, 04:20 PM   #17
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it is based on # of posts i think, but i know enough. i get the EJ25x's mixed up sometimes. cams should be fine, but the heads may limit flow if they aren't done right or at all. u should think about different pistons depending how much over 20psi u plan to go.
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Old 11-02-2010, 08:25 PM   #18
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Quote:
Originally Posted by PA-Outback2000 View Post
it is based on # of posts i think, but i know enough. i get the EJ25x's mixed up sometimes. cams should be fine, but the heads may limit flow if they aren't done right or at all. u should think about different pistons depending how much over 20psi u plan to go.
lol man sorry, I was just busting your chops... I will be limited by my turbo, which is the AVO 320 GT25 (or GT28?) I believe (From the 2.5 RS kit). I will be leaving the heads bone stock but serviceable, except for new valve seals and resurface... I have been looking for the cams from an EJ20G/EJ20K, but not sure if the difference in power will be worth the money spent. I will be keeping the 6500 RPM limit, the GT25/28 turbo, the oem 2004 WRX TMIC, and the stock MAF. My exhaust is currently made up of an oem single port manifold to turbo (to be replaced with the borla rep dual port header), 2.5" downpipe to an oem 2004 WRX cat, to an ebay 3" catback, to a 2.25" reducer at the axle, to an oem 2005 STi axle back. My concern is that I dont truly have the flow on the exhaust side to let any cam really sing in the top end. Combined with my smallish turbo, and the WRX TMIC, and the low redline, this car is going to be more of a torque monster than it already is...

See where Im coming from with my question?
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Old 11-02-2010, 10:25 PM   #19
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Quote:
Originally Posted by WagonMafioso View Post
You can run 12+ boost with stock heads, subies out there running 20+ boost, and I am going to run soon 18psi on my SOHC heads, the limiting factor is pistons, NA pistons just don't cut it for boost.
^ This , I have done a 255 case w/ Sti internals, N.A heads & ran over 20 P.S.I. The cams kinda choke after 5 k tho
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Old 11-05-2010, 10:20 AM   #20
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Quote:
Originally Posted by 07ImprezaMB View Post
it has been proven that our stock heads experience valve float past 6k rpms when boosted without upgraded valvetrain.
Can you site your facts cause I am running up to 6500 RPMs and I am not experiencing valve float (running about 15+ psi boost).
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Old 11-07-2010, 04:40 PM   #21
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i dont mean to hijack, but im looking to do the SAME thing

except, i was planning on getting Delta cam grinds for my SOHC, and i was going to use the stock EJ257 springs and retainers in my SOHC heads for a 7k RPM rev limit?

from what i gather from this thread tho, i should also machine my heads for bigger valve openings?

@ cdnsigop: i was wondering what type of ECU u were using. u said u wanted to keep costs down, and so do i (lol)
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Old 11-07-2010, 11:07 PM   #22
cdnsigop
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Quote:
Originally Posted by stallion91 View Post
@ cdnsigop: i was wondering what type of ECU u were using. u said u wanted to keep costs down, and so do i (lol)
I am using a 99 Legacy Outback 2.5 DOHC ECU, with a Greddy Emanage blue...
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Old 11-07-2010, 11:17 PM   #23
cdnsigop
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Quote:
Originally Posted by 2milehi View Post
Can you site your facts cause I am running up to 6500 RPMs and I am not experiencing valve float (running about 15+ psi boost).
+1 for this... I ran a max of 20 psi with my EJ22e all stock, and no apparent float...

Either way, I am running these cams, got the shortblock assembled with the left side head, valves and cams installed. I used Cometic gaskets sprayed with Permatex copper gasket. Gotta tap the oil return boss on the right head before I can complete this build...
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Old 11-10-2010, 12:24 AM   #24
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I would not use the stock STI pistons if you can afford the $450 for some forged ones. I have gone through enough of them to actually be taught a lesson hahahahahah.

In fact, as long as the tune is good, the only weak point is the pistons at less than 350-400 whp....
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Old 11-10-2010, 10:30 AM   #25
cdnsigop
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Thanks!!

I am sticking to the STi pistons, as thats what I have, and thats what has been installed... I will continue using my water/meth injection, with a pretty conservative tune...

Reddevil, how did your setups run with the EJ25D cams??
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