Ej207 block Ej205 heads hybrid
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This is a discussion on Ej207 block Ej205 heads hybrid within the Engine Modifications forums, part of the Tech & Modifying & General Repairs category; Hey guys, I am looking for advice, suggestions, recommendations etc about an Ej207 block ej205 head hybrid. I own a ...

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    Ej207 block Ej205 heads hybrid

    Hey guys, I am looking for advice, suggestions, recommendations etc about an Ej207 block ej205 head hybrid.

    I own a 2005 Wrx with Cobb intake/box/post maf, Perrin turbo inlet, Samco IC hoses, Cobb up, Cobb dp, Cobb AP stage2 93 oct. Stock Ej205 with 126k miles, probably 100k miles as "stage 2".

    I am looking replace/build the block before going stage 3 with Sti Vf__ turbo (and all supporting mods).

    I would prefer to stay 2.0l and non avcs for now. I do not want to go Ej25_ or any avcs heads. As close to stock ej205 compression as possible would be preferred.

    So, I was thinking up tracking down a good Ej207 (v7 or v8???) and keeping the stock non-avcs ej205 heads.

    What is the best way to go about this as far as strength/reliability go? Stock v7 ej207 short block with stock ej205 heads? Stock v8 ej207 short block with stock 205 heads? v7 207 block with v8 or 205 pistons? v8 block with v7 or 205 pistons?

    I know there is no power "gains" by going ej207 and 205 heads, just stronger bottom end (block), which is EXACTLY what I want. But not sure the best way to go about this. Would stock 207 block with stock 205 heads work with my 2005 Wrx ecu (with appropriate ots map)? Or would the compression be too high meaning custom tune? Would 205 pistons in a 207 block work with my ecu with appropriate ots map? Or are 207 pistons much stronger than 205 pistons making that pointless? Plz help me on this.

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    Pro Manscaper Mikie13's Avatar
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    I think the starting question is...WHY do you want to replace/build the block before going with an STI turbo?
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    Strength and reliability.

    Is there any way to swap in an Ej207 block and keep my usdm 205 heads and ecu?
    I do not want a 2.5 or avcs.

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    Pro Manscaper Mikie13's Avatar
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    Yeah you can do that fine. Just need to make sure the heads are matched to flow correctly to the block (may not be an issue like it is with a 2.5L)

    I'd just start with a compression test on your current 2.0L block. If it's holding fine within spec, no need to spend a ton of extra money for a block swap. You're not exactly pushing a ton of power with any VF series turbo. The stock 2.0L if healthy, will handle a VF** perfectly fine (properly tuned and with necessary fuel upgrades of course).
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    Quote Originally Posted by Mikie13 View Post
    Yeah you can do that fine. Just need to make sure the heads are matched to flow correctly to the block (may not be an issue like it is with a 2.5L)

    I'd just start with a compression test on your current 2.0L block. If it's holding fine within spec, no need to spend a ton of extra money for a block swap. You're not exactly pushing a ton of power with any VF series turbo. The stock 2.0L if healthy, will handle a VF** perfectly fine (properly tuned and with necessary fuel upgrades of course).

    I would just really hate if I spend over $1000 on an Sti Vf turbo, Sti tmic, injectors, fuel pump etc, flash the stage 3 map and blow my ej205 within a year.

    What exactly is better about the ej207 than the ej205? Just the semi closed deck? Rods?
    I read that the 2004-05 ej205 had a better oiling crank than the earlier 205, like the 207 crank?
    Are the 205 pistons as strong as the 207 pistons? I do not want an increase in compression or displacement, but a little confused here :S

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    Supposedly the Ej205 has 8.0:1 Cr, as well as the Ej207 with 8:1 cr. But, they have different heads, correct?

    Will my 2005 usdm Wrx ej205 heads on an ej207 v7 block raise, or lower the compression? Or would it somehow stay the same even though the heads are different?

    Has anybody here run a v7 ej207 and usdm ej205 heads?

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    Pro Manscaper Mikie13's Avatar
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    But unless you have an unhealthy engine to begin with or you beat the ever living piss out of it, you won't blow your engine within a year if you're just running a VF30/VF34/VF39/VF43/VF48.

    All honesty though, I'd skip an OTS map and STI TMIC and go with a protune of some sort and a good aftermarket TMIC such as Processwest. You'll get better cooling efficiency out of that, and you will ensure the tune is working specifically better for your car.

    I believe the ej207 heads are different in that they have AVCS, depending on which year/version STI they came off of. I don't recall when they began utilizing that technology. But in the grand scheme of things, it won't make all that much difference with a 0.1 increase in compression. You could probably utilize a thicker headgasket to offset that anyway. The difference between a semi-closed and an open deck block at your potential power levels also won't make a difference. The open deck 2.0L block is plenty stout.

    I don't know enough about the internals to tell you which is better, but I do know enough to say that you don't have to worry about spending all that money to put in a different block, when the block you have will be fine (as long as it checks out with a compression or leakdown test, like I mentioned).
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    I understand that people have run vf3x turbos at around 300hp/tq on a completely stock ej205, and still going strong, which is cool as hell. But, I still want another block. Maybe to throw in "before stage 3", or possibly keep in my garage untill it's needed.

    Just wondering if anyone know's if/how the compression will change, and also trying to find others that have put the ej207 block under their usdm ej205 heads. I'm not looking to MAKE more power with the new block, I just want a block that can hold way more power than I have.

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    Subaru Newb MainFrame's Avatar
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    Quote Originally Posted by 4eat05 View Post
    I would just really hate if I spend over $1000 on an Sti Vf turbo, Sti tmic, injectors, fuel pump etc, flash the stage 3 map and blow my ej205 within a year.

    That's going to be your problem.. it doesn't matter what shortblock you use, if you have a crap tune on the car it's only going to be a matter of time. Replacing a stock block with another stock block isn't going to make your engine any stronger. There's no reason to build the engine for a VF turbo.. in fact, I expect you will a lot more likely to have engine troubles if you change things out, rather than leaving it how it is. There's really no point to what you're wanting to do, the ej207 short block won't be any stronger, and you're introducing a lot of new things to go wrong.

    You're going to have a hard time finding someone running that combo, because there's no point to doing it.



    IF you really want a block that "can hold way more power than I have".. then you need to build the engine (forged rods/pistons/etc). Of course you should realize that built engines last significantly shorter than OEM engines. You can build your block to handle 600whp, but it's not going to last more than 30k-50k miles (at most).

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    Subaru Newb MainFrame's Avatar
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    To reiterate, the more power you build your engine to handle, the less reliable it will be. If you're worried about reliability, first thing you need to do is stay away from ****ty OTS maps and get a real tune.

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    This is silly.

    The main strength of the EJ207 motor over the EJ205 IS the heads. The bottom-end is stronger, but you can just build the EJ205 block.

    Other than that, the physical blocks are very similar in strength.

    I really think you ought to do a bit more research.
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