Recommendations for a turbo prepped EJ25 block?

Digital_Boy · 10-21-2000, 01:22 AM

As you might have guessed from my post on the classifieds, I am cutting the BS and getting the ball rolling.
What would constitute a turbo prepped shortblock?
I know that forged pistons and forged con rods are a necessity, but what about the crankshaft? Is the stocker forged, and will it hold up to a high boost street engine?

What about rings? Gapless? How much would a pre-prepped block run? Would the cost differential of kit vs pre assembled be great enough to warrant me putting the pieces together? I do have experience pulling engines apart and putting them back together, so I could conceivably do the assembly on my own.

I want to know the score before I commit a large sum of money to engine, internals, turbo, ECU, and so forth. I want to get everything up front so I don't end up dragging it out and blowing the budget because I had to do a half assed job to get it running, and go back and do a portion of the build over again.

* Registered users of the site do not see these ads.

TMR Impreza · 10-21-2000, 01:24 AM

ISR is building my motor. Ed has some tricks up his sleeve. Should be a nice motor.
www.autocarsubaru.com

Joel Gat, 1.8L · 10-21-2000, 02:54 AM

Hello,

Trey Cobb can also prep an engine. He works over the blocks, seals the deck, adds the piston backside oil-squirters, bores and hones the block to 100mm (if you want), has forged pistons, 8.5:1 or whatever custom CR you want, etc.

www.cobbtuning.com

Joel

legacyGT00 · 10-21-2000, 07:50 AM

TMR, there was a typo in your link http://www.autocaresubaru.com.

Anyway, I checked it out. Are you getting a turbo? Which?

Tim Prudence · 10-21-2000, 10:25 AM

What is your target horsepower/torque?

Digital_Boy · 10-21-2000, 10:46 AM

Tim, my target is in the 350-400 range, possibly 450. I've seen that it can be done reliably (by that I mean 100K mile reliably) if you select the right components and follow good assembly guidelines.

markus · 10-21-2000, 10:36 PM

IIRC, the EJ25 crank is a cast piece. Not sure if you can get 100k reliability at those sort of HP levels.

However, that point may be moot since it appears that a lot of people that are going FI on their EJ25's are having tranny problems long before engine reliability problems.

My 2cents

Digital_Boy · 10-21-2000, 11:51 PM

Markus,
I am *well* aware of the stock RS transmissions tendency to grind 2nd gear to mulch under spirited driving with a turbo. I have contacted a company that makes 450HP capable *HELICAL* (i.e. synchromesh capable) gearsets for the Subaru. So, no dog box in my future.

Jay_UK · 10-22-2000, 01:10 PM

Ideally:

Crank
Rods
Pistons
Uprated main bearings

For that power you wont need to brace the block or go closed deck.

I might even go as far as saying the stock crank would be ok.. but will need balancing...relieving...etc..

But definately do the rods and pistons..

As for compression... I would go for 9.5'ish.. but will depend on fuel and final boost..(simply put)

J.

ps - Ready to be corrected..as per usual

MikeYOX · 12-19-2000, 01:46 PM

What company is that digital_boy? How much are the gears?

stimpy · 12-19-2000, 02:41 PM

You might also want to inquire about this sort of thing to www.b-specusa.com .

Turk · 12-19-2000, 02:54 PM

Beat me to it Stimpy

www.b-specusa.com has a stronger crank and other goodies and www.cobbtuning.com has everything else you need.

Oh yeah please share the knowledge about the transmission.

Turk

Marquis · 12-20-2000, 05:47 AM

Digital_Boy, I can't recommend you building the shortblock yourself. The rest you can probably do without really hampering engine reliability(though you may want to have someone assemble the heads, too), but unless you consider yourself an expert engine builder let someone else do it. You're talking about a lot of horsepower out of an engine you expect to last for awhile. In this respect, there is no substitute for an extremely profesionally built shortblock.

10-21-2000, 01:22 AM	#1
Digital_Boy Scooby Specialist Member#: 730 Join Date: Jan 2000	Recommendations for a turbo prepped EJ25 block? As you might have guessed from my post on the classifieds, I am cutting the BS and getting the ball rolling. What would constitute a turbo prepped shortblock? I know that forged pistons and forged con rods are a necessity, but what about the crankshaft? Is the stocker forged, and will it hold up to a high boost street engine? What about rings? Gapless? How much would a pre-prepped block run? Would the cost differential of kit vs pre assembled be great enough to warrant me putting the pieces together? I do have experience pulling engines apart and putting them back together, so I could conceivably do the assembly on my own. I want to know the score before I commit a large sum of money to engine, internals, turbo, ECU, and so forth. I want to get everything up front so I don't end up dragging it out and blowing the budget because I had to do a half assed job to get it running, and go back and do a portion of the build over again. * Registered users of the site do not see these ads.

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10-21-2000, 01:24 AM	#2
TMR Impreza Scooby Specialist Member#: 168 Join Date: Aug 1999 Chapter/Region: SCIC Location: San Pedro Vehicle: 2011 M3 and STI white	ISR is building my motor. Ed has some tricks up his sleeve. Should be a nice motor. www.autocarsubaru.com

10-21-2000, 02:54 AM	#3
Joel Gat, 1.8L Scooby Specialist Member#: 32 Join Date: Jun 1999	Hello, Trey Cobb can also prep an engine. He works over the blocks, seals the deck, adds the piston backside oil-squirters, bores and hones the block to 100mm (if you want), has forged pistons, 8.5:1 or whatever custom CR you want, etc. www.cobbtuning.com Joel

10-21-2000, 07:50 AM	#4
legacyGT00 Scooby Newbie Member#: 2052 Join Date: Aug 2000 Location: Baltimore, MD	TMR, there was a typo in your link http://www.autocaresubaru.com. Anyway, I checked it out. Are you getting a turbo? Which?

10-21-2000, 10:25 AM	#5
Tim Prudence Scooby Specialist Member#: 216 Join Date: Aug 1999 Location: san diego, ca USA	What is your target horsepower/torque?

10-21-2000, 10:46 AM	#6
Digital_Boy Scooby Specialist Member#: 730 Join Date: Jan 2000	Tim, my target is in the 350-400 range, possibly 450. I've seen that it can be done reliably (by that I mean 100K mile reliably) if you select the right components and follow good assembly guidelines.

10-21-2000, 10:36 PM	#7
markus Scooby Specialist Member#: 438 Join Date: Oct 1999 Chapter/Region: W. Canada Location: St. Albert, AB, Canada Vehicle: 2004 STi White on Gold	IIRC, the EJ25 crank is a cast piece. Not sure if you can get 100k reliability at those sort of HP levels. However, that point may be moot since it appears that a lot of people that are going FI on their EJ25's are having tranny problems long before engine reliability problems. My 2cents

10-21-2000, 11:51 PM	#8
Digital_Boy Scooby Specialist Member#: 730 Join Date: Jan 2000	Markus, I am well aware of the stock RS transmissions tendency to grind 2nd gear to mulch under spirited driving with a turbo. I have contacted a company that makes 450HP capable HELICAL (i.e. synchromesh capable) gearsets for the Subaru. So, no dog box in my future.

10-22-2000, 01:10 PM	#9
Jay_UK Scooby Specialist Member#: 296 Join Date: Sep 1999 Location: Derby, Derbyshire, England	Ideally: Crank Rods Pistons Uprated main bearings For that power you wont need to brace the block or go closed deck. I might even go as far as saying the stock crank would be ok.. but will need balancing...relieving...etc.. But definately do the rods and pistons.. As for compression... I would go for 9.5'ish.. but will depend on fuel and final boost..(simply put) J. ps - Ready to be corrected..as per usual

12-19-2000, 01:46 PM	#10
MikeYOX Scooby Specialist Member#: 1754 Join Date: Jun 2000 Location: West Boemfugk, Egypt Vehicle: 2002 S4 Nogaro Blue	What company is that digital_boy? How much are the gears?

12-19-2000, 02:41 PM	#11
stimpy Homicidal Maniac Moderator Member#: 1612 Join Date: Jun 2000 Location: Austin, TX Vehicle: 2008 STI	You might also want to inquire about this sort of thing to www.b-specusa.com .

12-19-2000, 02:54 PM	#12
Turk Scooby Specialist Member#: 1888 Join Date: Jul 2000 Chapter/Region: South East Location: Charlotte, NC	Beat me to it Stimpy www.b-specusa.com has a stronger crank and other goodies and www.cobbtuning.com has everything else you need. Oh yeah please share the knowledge about the transmission. Turk

12-20-2000, 05:47 AM	#13
Marquis Scooby Newbie Member#: 64 Join Date: Jul 1999 Location: Lansing, MI Vehicle: 1999 Impreza 2.5RS Rally Blue Pearl	Digital_Boy, I can't recommend you building the shortblock yourself. The rest you can probably do without really hampering engine reliability(though you may want to have someone assemble the heads, too), but unless you consider yourself an expert engine builder let someone else do it. You're talking about a lot of horsepower out of an engine you expect to last for awhile. In this respect, there is no substitute for an extremely profesionally built shortblock.