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1998 Subaru Legacy GT Limited
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Discussion Starter · #62 · (Edited)
Are the old legacy ej20g rocker arm cam specs the same as impreza cop ej20gs?
They should be similar. I DO have cam specs, but early G/H had different specs.

EJ25D Cam Specs:
Intake opens 6° BDTC.
Intake closes 50° ABDC.
Exhaust opens 54°/30° BBDC.
Exhaust closes 10°/10° ATDC.
Overlap 16°.

EJ20G/H Cam Specs:
Intake opens 8° BDTC.
Intake closes 52° ABDC.
Exhaust opens 52° BBDC.
Exhaust closes 8° ATDC.
Overlap 16°.

EJ20K/R STi Cam Specs:
Intake opens 10° BDTC
Intake closes 56° ABDC
Exhaust opens 56° BBDC
Exhaust closes 12° ATDC
Overlap 22°

Final 3 are early EJ20G variants.

EJ20H 8.5:1 Cam Specs:
Intake opens 10° BDTC.
Intake closes 50° ABDC.
Exhaust opens 52° BBDC.
Exhaust closes 2° ATDC.
Overlap 12°.

EJ20G STi Cam Specs:
Intake opens 6° BDTC.
Intake closes 56° ABDC.
Exhaust opens 55° BBDC.
Exhaust closes 11° ATDC.
Overlap 17°.

EJ20D Cam Specs.
Intake opens 6°/4° BDTC
Intake closes 54°/56° ABDC
Exhaust opens 66°/36° BBDC
Exhaust closes 24°/16° ATDC
Overlap 30°/20°
 

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Discussion Starter · #63 ·
You must have notebooks full of information to just be typing it all out now.
I had a ton of information stored on backup hard drives, but 3/6 of them fried, and with them, much of my information. I still remember quite a bit, and I have much more left over on the final 3 hard drives.
 

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Just to add...

EJ25D Cam Specs:
Intake opens 6° BDTC.
Intake closes 50° ABDC.
Exhaust opens 54°/30° BBDC.
Exhaust closes 10°/10° ATDC.
Overlap 16°.

EJ20G Cam Specs:
Intake opens 8° BDTC.
Intake closes 52° ABDC.
Exhaust opens 52° BBDC.
Exhaust closes 8° ATDC.
Overlap 16°.

EJ20K STi Cam Specs:
Intake opens 10° BDTC
Intake closes 56° ABDC
Exhaust opens 56° BBDC
Exhaust closes 12° ATDC
Overlap 22°

The 25D cams and the 20K cams are like night and day different. The 25D cams die off approximately at 6500rpm, and they start to die off around 5800-6000rpm. The 20K cams carry all the way past 6500rpm, and die off at 7500rpm. The 20K ECU is limited to 8200rpm. The 20K cams are hotter all around.

Now, 25D cams are pretty much N/A mirrors of late EJ20G cams, the engines being massively identical in the head department. The EJ20G is NOT the EJ20K, even though late variants look the same. It is a far more tame, more civil version that was found in non-STi turbocharged cars.

It was WAY more common that the STi stuff. I call them "Common G's" because back when these were ordered into the USA by the truckload, there were far more of these than anything. They're also more reliable than the 20K because of their lack of aggression.

Another thing to note is that some of the Common G cams and the EJ20H cams ARE THE SAME, as are the EJ20K cams to the EJ20R cams, as EJ20H heads are Common G heads and EJ20R heads are EJ20K heads, both drilled and tapped for twin turbocharging.
so whats up with the exhaust lobes on the ej25d opening at differnt times. and is it not worth buying and installing ej20g cams in my heads?

my exhasut alwsy did sound oddly different than other turbo exhausts, mines more like a harley
 

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Discussion Starter · #65 ·
so whats up with the exhaust lobes on the ej25d opening at differnt times. and is it not worth buying and installing ej20g cams in my heads?

my exhasut alwsy did sound oddly different than other turbo exhausts, mines more like a harley
The 25D cams are more for exhaust scavenging/naturally aspirated format than they are for a boost application. The late 20G cams will be a direct drop in and will help a lot more with boost, although the 25D cams aren't exactly TOO bad. They are pointless with bigger power, though.
 

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1996 imp jdm ej20 NA dohc swap
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EJ20D Cam Specs.

Intake opens 6°/4° BDTC
Intake closes 54°/56° ABDC
Exhaust opens 66°/36° BBDC
Exhaust closes 24°/16° ATDC
Overlap 30°/20°

In case anyone doesn't know, EJ20D's came in 1st Gen Legacies in Japan and are outwardly similar to old school EJ20G/EJ25D's, but have higher compression ratios. However, that exhaust cam is amazingly bad for boost, it would seem. The intake cam is about spot-on the same as the STi 20G cam, which means that the swapping of exhaust cams between heads is a lot more important if you want to boost or stay N/A.
With these cam specs, you are talking about the ej20d na engine correct? I have a jdm legacy ej20D na engine in my 96 impreza wagon running off a 98 2.5 rs ecu with the 6500 redline.
 

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1996 imp jdm ej20 NA dohc swap
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This may be a bit off topic, but what about this set up:

02-05 wrx ej20 block with 79mm stroke crank, sti 0.027" head gasket and 97-98 ej25D na heads with pistons to make it 11.5:1 since there is some overlap in the cams dropping the static compression a bit.
 

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ej204 has 11.5 compression

almost 200hp, revs to 7500, cheap and can probably be made to work with newer 2.5i avcs ecus
 

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Not sure if anyone has any info on this, and the OP hasn't been on in a while.

I screwed up and bought 96 heads. I originally was going to bolt them on my EJ22E.

I may be able to get a EJ257 short block for a good price.

I know the stock bore is 99mm and stroke is 77mm on the EJ257.

So will the 96 heads work on that block?

I have searched, only 97-99 are mentioned..
 

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96 heads will be fine on a 257 block, be about 8.2" compression. with the thinner gaskets

and its a 99.5mm bore and 79mm stroke
 

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and while were here. I made another ej22D.

95 block, 2013 sti rods, stock 95 pistons, 05 wrx heads and 9856PT ej22t gaskets.

8.4:1 compression and going for 350whp
 

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Discussion Starter · #73 ·
and while were here. I made another ej22D.

95 block, 2013 sti rods, stock 95 pistons, 05 wrx heads and 9856PT ej22t gaskets.

8.4:1 compression and going for 350whp
Using 205 heads on a 22E block? Those kinds of 22D's are referred to as EJ225's and are more potent when it comes to power, but you still have to look out for your pistons. And the 3rd position crank bearing will show its ass with too many hard launches.
 

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No problem! I've been building these engines for years, so I know how to go about it, especially when it comes to USDM Phase 1 parts. There aren't many combos one can do with Phase 1. If anyone needs the compression ratios to the Phase 1 EJ25 hybrids, I'm in the middle of doing the math and combos now. The finished equations will be up in a bit.
Hey man I have a quick question. So I have a manual 99 Impreza and I’m looking at an ej22 off of a 97 auto Impreza. My plans with the 97 ej22 if I get it, is to put wrx ej25 Heads, manifold, exhaust, turbo,etc. so my question is will it fit my 99 manual trans? If yes, will there be any modifications I’d have to do?
 

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A quick review of this thread didn't seem to address ECUs much.... and not much activity (thanks to FB) here.

My question: Any (dis)advantage to running the '97-'98 EJ25D ECU on a '96 EJ25D? I know Subaru specs Premium fuel for only the '96 version.

Thanks
 

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Did you search on facebook? 😂 I ran a 97 or 98 ECU on my 96 LSI without issue, running 87 octane. I believe your ECU has to match the transmission type, at least it did on my 99 SUS.
 

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Did you search on facebook? 😂 I ran a 97 or 98 ECU on my 96 LSI without issue, running 87 octane. I believe your ECU has to match the transmission type, at least it did on my 99 SUS.
Hey Mike ..Hope you're well.
Good to hear about the ol' LSi.
The '99 was the odd transistion year and the ECU was changed (I tried to run a '99 ECU on a '96 Project - no go), but I'm 99% sure the trans didn't matter on the '95 - '98 models - ECU/ ECM would run either. There was PIN on the ECU that looked for the AT's TCM/TCU to determine what was connected. Kinda like the SS/TW's ECUs ran both transmissions, I'd guess.
 

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There was PIN on the ECU that looked for the AT's TCM/TCU to determine what was connected. Kinda like the SS/TW's ECUs ran both transmissions, I'd guess.
Wait a minute, are you saying the SS/TW ecu's can run either trans and you're guessing on the similarity of other ecu's? That's good news for me, I gotta replace an ECU in a 93 legacy manual, all I can find are auto ecu's. Hopefully all the first gen ecu's play nice, not just the SS and TW!
 

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Wait a minute, are you saying the SS/TW ecu's can run either trans and you're guessing on the similarity of other ecu's? That's good news for me, I gotta replace an ECU in a 93 legacy manual, all I can find are auto ecu's. Hopefully all the first gen ecu's play nice, not just the SS and TW!
100% YES on the Legacy SS/TW. See this PINOUT: 1990-1994 Subaru Legacy EJ22/EJ22T ECU Connectors
B48.20 is the Transmission ID.
I 'think' the '92-'94 comply too...LegacyCentral likely covers this.

If you have Cruise Control, I had to swap the cruise computer (by the passenger footwell) when I did an Auto>5-speed swap in a '90, but that 'might' me unnecessary in a '93?

And not 'guessing' on the '95-'98 EJ22/EJ25 equipped cars (or @ least only 1% unsure) as I swapped a few of those w/out issue.
 
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