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Old 06-23-2012, 01:56 PM   #1
Buurma
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Default Physical differences between ej207 and ej205

hey everyone i usually dont post on this site, usually looking. havent found anything on here about this nor have i found any reliable info on the rest of the interwebs.
so what i'm looking for is the physical differences between the jdm ej207 vs the usdm ej205

i know the 207 runs smoother, comes with a bigger turbo, revs to 8250 rpm and puts out way more power. and is pretty much a better engine in every way than the 205 but why,

is it all forged internals? less stroke/bigger bore allowing it to rev higher?
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Old 06-23-2012, 08:51 PM   #2
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Search and you shall be rewarded. The biggest differences are found in the heads, JDM big ports flow way more air than any other EJ head.

here is a little taste
http://forums.nasioc.com/forums/show....php?t=1455775
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Old 06-23-2012, 09:16 PM   #3
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He asked for 205 vs 207, not 257 vs 207..
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Old 06-23-2012, 10:31 PM   #4
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i've searched, like i said i cant find any info on nasioc about it. wiki has some information but not what i'm looking for either. i did see that they flow more, some numbers would be helpful. i know this info is somewhere i just havent found it..

and for once and for alll i wanna know if our usdm ej205 has forged internals, have had a lot of mixed opinions there. tuning shop says they are, subi tech's say they're just cast.
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Old 06-23-2012, 10:45 PM   #5
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stay away from that tuning shop if they say the 205 has forged internals
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Old 06-23-2012, 11:17 PM   #6
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lol thats why i havent said any names.
so NONE of the 205's internals are forged?
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Old 06-23-2012, 11:21 PM   #7
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nope...unless you put them there.
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Old 06-23-2012, 11:25 PM   #8
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no they are not forged

I've heard (speculation) the 207 has forged rods and pistons. Also the crank oiling holes are different on the 03 and under ej205 and the 04+ ej205 all have the same "style" crank oiling holes as on the ej207. Basically the older cranks are **** for high rpm builds, the 04+ ones are the better ones.

As for heads, not sure on the flow differences (changes depending on version) but they do have shorter duration cams with more lift and also shimless buckets in the valvetrain. The ej207 also has 2 cam sensors for AVCS. One in the normal ej205 location and one at the back of one of the heads, I think both on the driver side (unsure).
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Old 06-23-2012, 11:58 PM   #9
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All subaru cranks are forged, all oem subaru pistons are cast. Can't say for certain on the rods, i've read conflicting info on multiple sites...


~Josh~
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Old 06-24-2012, 12:03 AM   #10
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Quote:
Originally Posted by Buurma
hey everyone i usually dont post on this site, usually looking. havent found anything on here about this nor have i found any reliable info on the rest of the interwebs.
so what i'm looking for is the physical differences between the jdm ej207 vs the usdm ej205

i know the 207 runs smoother, comes with a bigger turbo, revs to 8250 rpm and puts out way more power. and is pretty much a better engine in every way than the 205 but why,

is it all forged internals? less stroke/bigger bore allowing it to rev higher?
There's an ej207 owners club thread in the factory 2.0l tech section. Read that.
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Old 06-24-2012, 01:48 AM   #11
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205 - fully open deck block, pretty standard in every way

207-R - Fully closed deck like the EJ22T, has oil squirters to lube the cylinders.

207-G - Semi closed deck like the USDM 257

the 207 spins higher RPM due to better oiling, and heavy duty valve springs.

In a nut shell..... thats the best part of a 207. None of it is forged like people claim. The parts are cast just as any other EJ engine. The block its Self is stronger and has more potential for power and reliability.

If the stroke and bore were different than a 205 then that would bump the Liter size to something like a 2.2L or 2.5L so no.... you need to think at question over again.
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Old 06-24-2012, 01:23 PM   #12
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Quote:
Originally Posted by UK-Wagon View Post
205 - fully open deck block, pretty standard in every way

207-R - Fully closed deck like the EJ22T, has oil squirters to lube the cylinders.

207-G - Semi closed deck like the USDM 257

the 207 spins higher RPM due to better oiling, and heavy duty valve springs.

In a nut shell..... thats the best part of a 207. None of it is forged like people claim. The parts are cast just as any other EJ engine. The block its Self is stronger and has more potential for power and reliability.

If the stroke and bore were different than a 205 then that would bump the Liter size to something like a 2.2L or 2.5L so no.... you need to think at question over again.
So the bore and stroke are the same as the 205's ? You could have more bore and less stroke to achieve the same displacement AND let it rev higher. is why i asked.
also, so if nothing is forged in it why does it handle more boost, bigger turbos so much better? the closed deck block alone is what makes the difference? so, saying this then you can just get a jdm ej207 block, throw your ej 205's internals in there and there is no difference there?


Quote:
Originally Posted by sorrowfulkiller View Post
no they are not forged

I've heard (speculation) the 207 has forged rods and pistons. Also the crank oiling holes are different on the 03 and under ej205 and the 04+ ej205 all have the same "style" crank oiling holes as on the ej207. Basically the older cranks are **** for high rpm builds, the 04+ ones are the better ones.

As for heads, not sure on the flow differences (changes depending on version) but they do have shorter duration cams with more lift and also shimless buckets in the valvetrain. The ej207 also has 2 cam sensors for AVCS. One in the normal ej205 location and one at the back of one of the heads, I think both on the driver side (unsure).
i like the info about the oiling differences between 03 and 04. good stuff!
I remember reading stuff about the cam spec was different depending on what version 207 you got.

Quote:
Originally Posted by ballitch View Post
All subaru cranks are forged, all oem subaru pistons are cast. Can't say for certain on the rods, i've read conflicting info on multiple sites...


~Josh~
i've read so much conflicting info thats why i wanted all of this debated info on one thread. some say a thick casting line is forged and a thin line would be cast. but then you go here and people tell you that they're ALL just cast
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Old 06-24-2012, 01:29 PM   #13
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Quote:
Originally Posted by Psychoreo View Post
There's an ej207 owners club thread in the factory 2.0l tech section. Read that.

i read that thread, got bore 5 pages in when i started reading about peoples builds or turbo sizes. no real info there (that i saw) just speculation
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Old 06-24-2012, 01:50 PM   #14
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Gonna do this all with the search button
The specs for all the EJ turbo motors are summarized here http://forums.nasioc.com/forums/show....php?t=1667168



Here is info about why the heads are so much better
http://forums.nasioc.com/forums/show....php?t=1455790



Detailed flow numbers for all the subaru head castings
http://forums.nasioc.com/forums/show....php?t=2034555

A comparison of dyno data from the 205, 207, 257 with the same turbos
http://forums.nasioc.com/forums/show....php?t=2367119

Here is a detailed tech report by Tomei on the 2.5L and they compare to the JDM 2.0L, its more than a page long so you might get bored.
http://www.tomei-p.co.jp/news/Report-EJ25-V1.html


My 207 spins out to 8500 RPM with ease, why on earth would you want a shorter stroke than 75mm?

One single year had forged pistons in the 207, the JDM V7 motor. They are not like aftermarket forged pistons and only marginally tougher than the hypereutectic pistons that replaced them, but the hypereutectic pistons have better heat transfer properties.

The USDM STI cams have more lift and less duration than the JDM cams for a narrower powerband. I have a friend measuring a set of JDM V9 STI cams to compare to the JDM v8 STI Spec-C cams he has and we already have the measurements for the USDM STI cams. The JDM valve springs are much stiffer than the US cams for better high RPM performance.

Cam height
Intake:
USDM STi - 9.58mm 256
JDM STI spec-C - 8.88mm 270

Exhaust:
USDM STi - 9.80mm 256
JDM STI spec-C - 9.58mm 270

All of this I have learned on these forums and the net so don't try and say the info is not out there. You just can't be lazy when doing research and stop after reading 5 pages.

Last edited by lukeskywrx; 06-24-2012 at 02:05 PM.
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Old 06-24-2012, 02:00 PM   #15
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i see you're giving me more stuff on the 255 vs the 257.
dont care;
i'm again, asking about the differences between the ej205 and the ej207. i care about the ej257 or the 255. at all. really dont.

Dont care about hp numbers either. all i want to know is the physical differences between the 205 and 207 are. looks like that too hard of a question to ask around here.
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Old 06-24-2012, 02:17 PM   #16
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Quote:
Originally Posted by Buurma View Post
i see you're giving me more stuff on the 255 vs the 257.
dont care;
i'm again, asking about the differences between the ej205 and the ej207. i care about the ej257 or the 255. at all. really dont.

Dont care about hp numbers either. all i want to know is the physical differences between the 205 and 207 are. looks like that too hard of a question to ask around here.
The head ports are the same on the 255/257/205 vs the 207 so those physical differences hold true

The table I posted shows all the engine PHYSICAL DIFFERENCES

205 block is open deck, 207 block is semi-closed

rods are the same, crank is the same, pistons have less dish. The heads are very different.

Rather than asking vaguely what are the physical differences, ask an intelligent specific question.

For example, "How are the blocks different?", "What are the main differences in the heads/cams/pistons ect."

People are answering your question however its so open its just not exactly what you want to hear.

Direct question-direct answer
open vague question-random vague answer

I have a 207 in my car and an opened up 205 on my engine stand, I can likely answer any question you have but you have to be SPECIFIC.
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Old 06-24-2012, 02:27 PM   #17
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Quote:
Originally Posted by ballitch View Post
All subaru cranks are forged, all oem subaru pistons are cast. Can't say for certain on the rods, i've read conflicting info on multiple sites...


~Josh~
Wrong. V7 had forged pistons.
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Old 06-24-2012, 02:31 PM   #18
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Quote:
Originally Posted by lukeskywrx View Post

I have a 207 in my car and an opened up 205 on my engine stand, I can likely answer any question you have but you have to be SPECIFIC.

are the casting marks on the 205 rods the same thickness as the casting marks on the rods on your 207?


i know the 207 makes way more torque, hp, revs higher, smoother. just wanting to know why. magic subaru dust?

more specifically, the short block, if i bolt on 207 stuff to my 205 i.e. heads, turbo, intake manifold, intercooler. willl i be as reliable as the jdm spec 207 or what? if the internal components are the same as a 205 then i should be able to. right?
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Old 06-24-2012, 02:45 PM   #19
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Quote:
Originally Posted by Buurma View Post
are the casting marks on the 205 rods the same thickness as the casting marks on the rods on your 207?


i know the 207 makes way more torque, hp, revs higher, smoother. just wanting to know why. magic subaru dust?

more specifically, the short block, if i bolt on 207 stuff to my 205 i.e. heads, turbo, intake manifold, intercooler. willl i be as reliable as the jdm spec 207 or what? if the internal components are the same as a 205 then i should be able to. right?
The rods are the exact same, part numbers match 205 to 207.

The 205 heads suck, they cannot flow nearly as much air as the 207 heads. Putting a 207 shortblock on 205 heads will give you the same power as a 205, the 205 heads are the limiting component. The 207 SB is stronger but you need the heads to make the power

JDM 207 heads flow 283 CFM
USDM 205 heads flow 250 CFM

If you put a 207 big port head on a 205 shortblock you would make 207 power levels. Like I said before all the power comes from the heads and the huge airflow increase. AVCS also helps to make more torque on the 207 vs 205

The 207 also has a better oil pump (12mm) vs the 205 (8-9mm cant remember off hand) so it is much better oiled at high RPM.

Last edited by lukeskywrx; 06-24-2012 at 02:51 PM.
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Old 06-24-2012, 02:57 PM   #20
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Quote:
Originally Posted by Buurma View Post
looks like that too hard of a question to ask around here.
Bissh, dont come here asking for help and then be a douchebag about it when someone helps you with more info than what you wanted. He was simply posting the specs of a 207. The 255 spces just happen to be there also, ignore those and compare the 207 to current 205 specs that can be found just bout anywhere. Search for the 205 specs if you dont know them, were NOT youre personal Army!

Wait that post didnt have answers? go look at the bore, & stroke numbers in that post. Those are "physical differences"...........
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Old 06-24-2012, 03:08 PM   #21
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Quote:
Originally Posted by UK-Wagon View Post
Bissh, dont come here asking for help and then be a douchebag about it when someone helps you with more info than what you wanted. He was simply posting the specs of a 207. The 255 spces just happen to be there also, ignore those and compare the 207 to current 205 specs that can be found just bout anywhere. Search for the 205 specs if you dont know them, were NOT youre personal Army!

Wait that post didnt have answers? go look at the bore, & stroke numbers in that post. Those are "physical differences"...........
I would usually charge 50-100+$/hr for technical research, going rate for an engineering doctorate. Where should I send his bill
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Old 06-24-2012, 03:33 PM   #22
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Quote:
Originally Posted by Buurma View Post


i know the 207 makes way more torque, hp, revs higher, smoother. just wanting to know why. magic subaru dust?
The larger turbos, twin scroll setups and AVCS probably go a long way towards making more torque and power with the 207.
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Old 06-24-2012, 05:31 PM   #23
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Originally Posted by kpluiten View Post
The larger turbos, twin scroll setups and AVCS probably go a long way towards making more torque and power with the 207.

But remember people that have tried the TS VF37s on the 205 have found them generally laggy and slightly disappointing. The heads simply do not flow enough up top.
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Old 06-24-2012, 05:56 PM   #24
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Originally Posted by lukeskywrx View Post
But remember people that have tried the TS VF37s on the 205 have found them generally laggy and slightly disappointing. The heads simply do not flow enough up top.

this is good info. thank you.

and to all the other nonsense posters, this is why i hate posting on this forum.
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Old 06-24-2012, 06:05 PM   #25
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to all the other nonsense posters, this is why i hate posting on this forum.
Its not nonsense! Simple rules apply to every forum. Ask questions, get answers! Dont like 1 or 2 answers?? just wait for other responses or ignore. The FACT is, the guy did help you with a question! You were just to stupid to realize it...... then, you acted like a dick.

Dont expect too much more help here, I was going to post more info that is ACTUAL fact with links but Ill just keep it to my self at this rate of ass-hattery you continue with. You hate it here because likely all youre threads go this way. Go to youre local forum where you might get 2 b.s. responses to a topic like this!

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