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Rebuilding my engine for boost - EJ251 with sti internals + vf39

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20K views 62 replies 16 participants last post by  JededaiahSoup  
J
#1 · (Edited)
Well, some of you I have talked to about me turboing my car. it's been in the calendar for over a year now. From my first part that I bought for my build - STI pistons - to being only a couple months away from when i am going to start.

Ideally what I want - Good boosted, reliable ej251 engine controlled by Greddy E-manage Ultimate making decent power. (decent I mean nothing over 300whp)

My parts:

• STI Stock Pistons with new oil rings AND wrist pins - $52 – Brand new
• ‘05 STI VF39 Turbo - $290 – 7500 Miles
• GReddy E-manage Ultimate with harness + boost sensor and harness - $350
• 2005 USDM STi 10mm oil pump - $52 – 1k miles
• 2006 WRX TMIC - $40 –
• ACL Race main and rod bearings - $100 – NEW
• JDM STi pink top feed injectors (565cc) – $185 – Under 10k miles
• STi head gasket set - $60 – NEW
• Walbro 255lph Fuel pump - $89 – NEW
• V2 Catback exhaust system 3” - $185 - NEW

Going to get:
-STI header
-ARP Head studs
-STI downpipe
-Grimmspeed EWG kit 38mm tial
-ACT Street performance clutch
-Turbo water pump
GASKETS: - 3 oil pump seals (1 for oil pump, 2 for oil passages in block ) – Big orange seal (water block) between blocks – O-rings on top of the block for water pipe, crossover waterpipe o-rings, intake manifold gaskets, rear main seal, cam seals, front oil seal.
-Gauges
-Coolant/oil lines for turbo
-intercooler piping
-BOV


I'm going t notch the crossmember.

TIME PERIOD:

November 6th-November 7th: Pull engine, take apart. once taken apart, bring to machine shop to get hot tanked. Any suggestions on what else to do here?

November 13th-November 15th: Rebuild engine and TRIPLE chck all specs! Any suggestions/tips on this part?

November 20th-November 22nd: Put engine back in, take time and make sure everything is going smoothly. BEGIN with turbo related stuff (ie- exhaust stuff)

November 25th-November 29th. Final steps! Put all turbo related parts on. Triple check everything. Sunday (or maybe earlier! Helpfully not later!) As of now will be start up day!

Is this a reasonable time frame? And suggestions? Thanks!



This thread is mainly for me to keep track of, add to my list (note I may have forgotten some stuff) and to ask questions.

-Questions for now:
I need to search about taping the oil pan for oil feed/return for turbo and coolant lines. Not knowledgable on this subject.

When everythings set and done, what oil should I use? How long should I use it? When i change what should I start using after that first oil change?

I'm running the E-manage Ultiame. Going to get a frend to help me put it in. If I get a good base map, Will I have to fool around with everything until I get it tuned? WILL get it professionally tuned.

Does anyone have a good base map for my set-up?



Will be adding. Thanks in advance!

ANY tips/advice/comments are welcome!
 
K
#8 · (Edited)
Here are a few tricks to help you keep it alive:
Parallel fuel mod: Current system on the Impreza runs in series, mod will convert to parallel and the 3 rd cylinder will not run lean http://www.northursalia.com/modifications/drivetrain/fuelrail/fuelrail.html

Throttle body coolant bypass: Decrease your intake temperature and also help fight off detonation better http://www.northursalia.com/modifications/drivetrain/bypass/bypass.html

And a couple suggestions:
Ditch the WRX TMIC and run a FMIC
I’d also just get a 02-03 WRX X-member I found it easier just to swap the X member than hacking and trial fitting for clearance and lame guess work (why re invent the wheel?) and they’re only like $100-$150
I’ve been curious about the Greddy E-manage unit in a RS-T I thought about using one when I had my RS-T but I blew the tranny and bought a 05 STi parts car scrapped everything RS and will never regret the choice 
Have you researched ways of making the Block semi closed? Or just going with a STi block? The open cylinder walls ARE going to be a problem

I think your time frames are fine but just remember to take your time and finish it right.

On to your questions:
Oil return
You can get a bung welded onto the passenger side valve cover (I ran this and it worked fine) however it my not be the best flowing option because of positive pressure in the valve cover
OR…
I know there are kits to tap and seal your oil pan without any welding the Honda guys do this often however if you can weld get a weld in fitting and go that route this forum should have a few threads on the subject you could also Google it

Oil? Well, Mobil One 5-30 seems to work nicely and Subaru Factory filters are the best for our cars

E-manage a good tool for tuning… make damn sure your friend knows what they are doing if you hack your wiring harness and it’s wrong GAME OVER the reliability goes right out the window this is what happened to my RS and one more reason to swap!

Have you talked to Element tuning http://www.elementtuning.com/main.htm about maybe using a Hydra? I know they’re kind of pricy but you’ll have an EMS that will be more than capable of handling your build and future mods and plugs into your car also they can send it out with a base map so your car will start once you plug it in

I hope you get a few ideas out of this!

Good luck!
Kincaid
 
2
#23 ·
Do you know the rod length of your motor? There are two rod lengths for the EJ251 motor - 131.6 mm and 131.25 mm. If the factory STI piston has a similar compression height compared to its Wiseco counterpart (30.7 mm), then there will not be enough quench clearance.

What is the condition of the rod and main bearings? It seems like you have the block out.

Also what is the condition of the bores? Are you ready for an overbore?
 
#25 ·
He's probably asking about bore size because you are using stock sti pistons and you may have to bore your block to make sure its nice and round. You may need larger than oem size pistons depending on how much the block needs to be bored. Now if its within tolerance and just needs honing that would be great.

Do you know the diameter of the sti pistons versus the original non turbo pistons that were in the block?
 
J
#26 ·
Boring wil not be needed. Just re-honing of the cylinders which I will get done for $9 a hole (ALOT cheaper than I thought it would be..)
And I dont not know they diameter sizes. But they are the same.. I'm using STI pistons with STI rods. Now if I were using STI pistons with stock rods, then I would ahve a problem.
 
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