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ChadBird 08-28-2011 03:05 AM

Need Help! 04 RS EJ255 swap AVCS or no AVCS?
Customer walks in to my speed shop and wants over 400-650hp in his suby and hands me 10k cash on the spot and says there is more $.

So i found a few complete low mile USDM EJ255s for around 1700-3000$ before i go and purchase the best engine i had a few questions to ask.
But first here is some info on the project...

My target car is a US 04 Impreza SOHC 5 speed 2.5RS or 2.5TS.

As far i can research i have only one short block option avalable and three long block options EJ255, EJ257 and all EJ55/7s 05' and later equipped with (AVCS) & (CAN).

(Active Valve Control System) & (Controlled Area Network)

The difference between the 55 and 57 short block to me is obsolete because im going to install 100mm pistons H beam rods and re sleeve the block. So my two long block options are a (AVCS) equipped or non (AVCS). I would prefer a AVCS engine for its ability to adjust timing on the fly and make more use of wilder cams.

So my question is can this factory RS SOHC engine harness be modded for the (AVCS) and (CAN)? Or should i put in a factory 05 or later EJ harness?

Also in order to function properly & take advantage/tune the (AVCS) will i need to have a factory (SI Drive) Coupled to it or is there after market programmers available?
Or can it be tuned by a simple reflash of the ECU?

I allready have a Cobbs Stage 2 Access Port ECU reprogrammer with full exhaust priced out. But im reading that a piggy back unit from Apexi or Greddy has more tune options what do you recommend?

As far as HP projections i plain on having the rotating assy capable of withstanding 900hp/Bulletproof! I only plain on splitting the Jugs one time. After i get off the fence on this (AVCS) i can start pricing out camshafts and valvetrain. i would like to drop the motor in knowing the internals will hold whatever boost and fuel the customer can throw at it.
But after spending around 6-7k of a customers money just on a long block i will prob just throw 1000cc inj in it and toss a Walbro 255 fuel pump in swap factory turbo for a GT3076R and hopefully be pushing around 450-500HP and see if he can handle that for a while and break in the engine. And if he can handle that prob get a full turbo kit and turn the boost up. Customer is only 18 yo he just inherited around 210k from his mother passing away few years back .

So hey thanks allot! For your time, knowledge, opinions and information i greatly appreciate it im just really looking for a second opinion from someone else who knows subys before i drop down all this cash.

mosc 08-28-2011 03:53 AM

I think if you want a full EJ255/7 longblock you'd need to rip out the entire harness. You also have DBW vs DBC issues dealing with an EJ255/EJ257. Unless you want to get really serious, you're going to want to also get the heads and ecu from an 02-05 WRX specifically (16-bit ECU) and only the shortblock from the 2.5L (EJ255 and EJ257 have the same short block). That way you can stay drive by cable. AVCS on a "hybrid" is beyond my expertise but I'm sure it's been done. Basically, the EJ205 is the swap you need to make and if you want to do a hybrid 2.5L build on top of that you can do that too.

If he wants fancy heads, would be cheaper to sell the RS and buy a factory turbo'd DBW platform to start with... That'd be 06+ WRX and 04+ STi

ChadBird 08-28-2011 11:25 AM

Hey thanks for the info Mose greatly appreciate it! And beautiful Sti by the way.

And ya we are always serious! At Northern Lites Customs... You Dream It And We Build It!

So I really would like to install this particular EJ255 engine because its newer, more HP and more advanced also very easy and inexpensive engine/donor car to acquire & comes factory in more popular models than just a WRX like: Foresters, Legacy/Outbacks and Baja's.

I did a search for a 04 WRX and came up with only a hand full of high mile beat to crap missing part engines in the whole country for around 4K. I'm assuming in less than 5 years they will be impossible to find parts for.

When i search for a EJ255 i can find literally hundreds! I can acquire a 07 Legacy rollover with only 44K ECU, Engine harness and throttle for around 3K only 55 Miles from my shop by Monday. And from the looks of it they will be in the yards and on shelfs for years to come.

I'm also Keeping in mind it is a interference engine that is being pushed to its limits driven daily in Wi year around.

So i guess I'm just going to swap everything over from the 07 legacy. Does anyone know if this has been done before or if i will have any problems during the swap?


brfatal 08-28-2011 11:30 AM

You need to start with an STI, not an RS. It will cost waaaaay more than $10k to do what he wants. How much more money is there that he's talking about? I just spent $8k on an engine build with parts at cost and extreme discounts on labor, and the build is slightly more tame than what you're talking about. What budget is there for the car itself, the built transmission, the suspension, all the other go-fast and support mods needed, and labor? He's going to need to triple what's he's given you.

psinuse 08-28-2011 11:59 AM

Well do you want the good news or the bad news? Bad news first, for about $30k you'd be able to give him that much power coming from a ej25. It's going to cost at least 10k to build the motor to be able to handle that kind of power, let alone trans, and other supporting mods and the tuning. So many parts I can;t even begin to list them all.......
The good news is if you do it for the person you could make a butt load of cash of the labor..

ChadBird 08-28-2011 01:39 PM

I don't see how its so hard to pull out the SOHC engine, Wire Harness and ECU and drop a 3500$ EJ255 turbo in and install the forester ECU and harness and gas pedal/sensor. Sounds pretty simple and fun to me. I have done Engine,ECU,Harness swaps on tons of cars just not this particular model. whats so hard about it?

And 30k where is all this money being spent? for around 15k i can get a Cosworth long block good past 600hp and theres another 15k to spend? all i plain on doing b4 dropping the used mystery junkyard motor right in is installing a Billet Crank, re sleeve, rods and pistons and race bearings.

Thats a little over 3500$ for parts on the rotating assy and sleeves good to 900hp.

As for the heads install after market race cams for 800$ Titanium Valve Springs & Retainer Set for 400$ and re surface the valves and valve seats for free purchase some good head gaskets and head bolts and pop the heads on the block.

Thats around 1500$ in cylinder heads.

Average of 5000$ in the Long block.

So you think i will spend $25,000 on after market bolt ons and tuning to reach 450-600hp? i don't think so.

Besides with all do respect i was not really asking about the $ thats not really a factor i was asking if the engine will bolt in without any troubles like clearance issues exc.

Please note: I'm picking up the whole forester front clip for 3500$
And all my machine shop work is done for free.

And yes i am aware that the stock RS chassis trans diffs and suspension will not hold up at 600hp everything will be upgraded to WRX or name brand parts as soon as i can find a power plant worth installing.

Agian thanks for the input guys.

newtothegame 08-28-2011 01:46 PM

A WRX transmission will not hold near that power for an FYI. If you do by chance get the WRX drivetrain, you will have to upgrade diffs (w/e you feel like spending on them), a build 5spd, my gears were about $6500, a new clutch, flywheel, and then labor for that. So in the transmission alone there is 10K pretty easy. It does sound fun, and wish you the best of luck with the build. You did come to a great forum with a wealth of knowledge, I hope it helps you.

ChadBird 08-28-2011 01:51 PM

And brfatal he dropped me 10k just to get the engine and start ordering internals and begin tear down on the engine & told me to call whenever i need more.

ChadBird 08-28-2011 02:19 PM

How much HP will a factory WRX trans with a good after market clutch hold up to?

and [B]new to the game[/B] how much about did you spend on hard parts for your transmission upgrade and where did you get them

psinuse 08-28-2011 03:55 PM

Well right around 300-320whp is roughly what most will hold. No offense, but this project sounds more complicated than it's worth. Best of luck and hope everything works out for you.

turmic 08-28-2011 04:25 PM

Its not complicated if you like to strip a car down to its it and then put it back together. But, it is a more unique approach to making a older subie fast. Sounds like the guy doing the work is trying his hardest to do it right the first time. Good luck. !Thumbs Up

newtothegame 08-29-2011 07:08 PM

[quote=ChadBird;266808]How much HP will a factory WRX trans with a good after market clutch hold up to?

and [B]new to the game[/B] how much about did you spend on hard parts for your transmission upgrade and where did you get them[/quote]

Like I said most of it is up to the buyer/builder as far as diff, clutch, and flywheel. Contact the guys at andrewtech as that is where my gears came from. I dont have the sheet in front f me, but Im pretty sure I paid right at 10K for transmission, clutch, flywheel, pads, rotors, lines, fluid, gauges, pod and wiring/install. That was my last leg of my build.

mosc 08-29-2011 11:03 PM

It's going to take you ~100 hours to pull the engine, harness, and everything down the the friggin gas pedal, swap it with an 06+ WRX drivetrain, and put it all back together. When you're done, you'll have ruined an RS. An expert might be able to do it 3/4 or maybe even 1/2 that time but you've clearly never done this before on a Subaru. What a colossal waste of time when they sell perfectly good WRX's for cheap.

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