Any and All Modding Q&A's

[Grimmrican]

Hey guys I figured that it would be a good idea to make this thread to help any and all fellow sli-ers and guests with some modding questions. I believe it would also help pinpoint during the search.


So to start it off I have a few questions but will just start with one for now.

Is there any benefit in putting ej25D heads on a ej251/3 phase 2 block? Is it compatible?

[GTDrifter]

from searching the forum I found this thread. Yes it'll work but use the 25d crank gear and 25d ecu. Also thicker head gaskets.
https://sl-i.net/FORUM/viewtopic.php?f=11&t=26594&hilit=ej25d+heads+on+ej251

[harrymaneuvers]

^this. You would need to retain all the wiring, sensors and intake from the EJ25D.

Basically only sounds like it would be worth it if you already had a subaru with the EJ25D and needed to replace the short block.

[pleaidestar]

Hey guys I figured that it would be a good idea to make this thread to help any and all fellow sli-ers and guests with some modding questions. I believe it would also help pinpoint during the search.


So to start it off I have a few questions but will just start with one for now.

Is there any benefit in putting ej25D heads on a ej251/3 phase 2 block? Is it compatible?

Yes it will raise your compression a bit, would use 25d gaskets or get the Cometic ultra thin 25d gaskets and will give you. 001 less clearance to bump compression further.

[pleaidestar]

I have a question too if anyone knows the ej18e at all I have heard that the cams have more duration and lift (spicier grind) to make up for the lack of displacement the 22e has...that would be a good n/a upgrade for anybody with a 22e. Is there any truth to that....and I know the 1.8 is not a favorable motor for Subaru fans, but I want to use some parts of one and do a high compression build with a 22e block 18e heads.

[GTDrifter]

I have a question too if anyone knows the ej18e at all I have heard that the cams have more duration and lift (spicier grind) to make up for the lack of displacement the 22e has...that would be a good n/a upgrade for anybody with a 22e. Is there any truth to that....and I know the 1.8 is not a favorable motor for Subaru fans, but I want to use some parts of one and do a high compression build with a 22e block 18e heads.
My cousin swapped 18 heads onto his 22e. Higher compression so if you have plans to turbo than don't do it. Plus they're dual port so you can get headers cheap and easy

[Grimmrican]

Hmm I'm pretty sure I can gather all those parts for cheap. Should be an interesting build.

Now lets say in my 00 legacy I wanted to convert my trans to a 5mt. Which wrx trans should I go with? Are they all the same or does it change thru out the years? I hear the r160 is a good one but not too sure as to what year

[GTDrifter]

Hmm I'm pretty sure I can gather all those parts for cheap. Should be an interesting build.

Now lets say in my 00 legacy I wanted to convert my trans to a 5mt. Which wrx trans should I go with? Are they all the same or does it change thru out the years? I hear the r160 is a good one but not too sure as to what year
I heard that the 02-05 wrx transmissions were all complete junk

[rkrenicki]

That could be, but then again the transmission may be junk with a 226hp Turboed-EJ20 attached to it.. may be perfectly fine with a 165hp NA-EJ25..

[Grimmrican]

^true story. I'm not gonna go boost I'm going to stick to NA

[GTDrifter]

That could be, but then again the transmission may be junk with a 226hp Turboed-EJ20 attached to it.. may be perfectly fine with a 165hp NA-EJ25..
Also look at it this way, if its from a wrx the owner will want a ton for it unless they actually know how bad they are. If you just want a 5 speed get something from an rs or any other 5 speed car, you'll pay lessand probably have a better trans.

Also remember it is a ton of work, I've done a 5 speed swap to my buddies impreza. Removed the entire interrupt to swap wiring and ecu, entire rear subframe was removed. And the trans and drive shafts were removed.

Just a wrecked or cheap 5 speed on craigslist and you'll have everything you need

[pleaidestar]

I have a question too if anyone knows the ej18e at all I have heard that the cams have more duration and lift (spicier grind) to make up for the lack of displacement the 22e has...that would be a good n/a upgrade for anybody with a 22e. Is there any truth to that....and I know the 1.8 is not a favorable motor for Subaru fans, but I want to use some parts of one and do a high compression build with a 22e block 18e heads.

That's exactly what I wanted to do since I have a spare 22e to put in a first gen wagon. Do you know about reliability and compression numbers on his build? Id like to know if its a worth while build for daily use. I'm tossing that idea and another with a 222 block and 22e heads for a small compression bump. Got a gently used block for $220 a few months ago.

[GTDrifter]

I have a question too if anyone knows the ej18e at all I have heard that the cams have more duration and lift (spicier grind) to make up for the lack of displacement the 22e has...that would be a good n/a upgrade for anybody with a 22e. Is there any truth to that....and I know the 1.8 is not a favorable motor for Subaru fans, but I want to use some parts of one and do a high compression build with a 22e block 18e heads.

That's exactly what I wanted to do since I have a spare 22e to put in a first gen wagon. Do you know about reliability and compression numbers on his build? Id like to know if its a worth while build for daily use. I'm tossing that idea and another with a 222 block and 22e heads for a small compression bump. Got a gently used block for $220 a few months ago.
He daily drives his impreza, even goes for long trips and I've never heard him have an issue. Sadly idk what his compression is. Maybe look at his build. t3hwit on rs25

[Grimmrican]

Now what's the real diff between a wrx trans and a rs?? Obviously one is turbo and one is not. But is the gear ratio different? And what about the driveshaft and pumpkin?

[GTDrifter]

Now what's the real diff between a wrx trans and a rs?? Obviously one is turbo and one is not. But is the gear ratio different? And what about the driveshaft and pumpkin?
Not sure about wrx but rs trans from a gc has a 4.11 rear diff, if its a 98 than it also had an lsd. Wrx I believe has the lsd but I'm guessing 3.70 or 3.90 rear diff. Don't take my word for it though

[pleaidestar]

Alright never been to the sight, cool thanks feel a little better about it.

[Grimmrican]

Well 4.11 is what the 2gen ob had right? So if I can manage to get a 98 gc diff with 4.11s? What trans does the 4.11 come in other than the 2gen legacy

[Subafreak]

The 02 and up wrx used a transfer gear reduction. The rear end was the same ratio used in the SVX. I think a 3:45 or 3:54. (I'm number dyslexic)
But the front diff was still a 3:90.

It's always a good idea to match the tranny and rearend. Unless your absolutely sure what tranny you got.

[pleaidestar]

Just checked his build out briefly, there is a lot of info...'preciate it gtDrifter

[Grimmrican]

Well in my old bk I had the 4.11s so I'd like to go back to that if possible. And I'd like to match the trans gr to the diffs gr. no sense in screwing both up and starting all over again.

[GTDrifter]

Well in my old bk I had the 4.11s so I'd like to go back to that if possible. And I'd like to match the trans gr to the diffs gr. no sense in screwing both up and starting all over again.
Some automatics came with a 4.11 open diff. The rs came with a 4.11 closed diff

And I know, his build is huge but he knows a ton

[Grimmrican]

My old Bk was 5mt sorry didn't specify. But yea I'd like to convert to 5mt and make sure the trans and diff do match gr

[Garrison]

Is there any benefit in putting ej25D heads on a ej251/3 phase 2 block? Is it compatible?

You can stick STi pistons/rods on the oem crank for way less $$ than an Sti block.

[Grimmrican]

Is there any benefit in putting ej25D heads on a ej251/3 phase 2 block? Is it compatible?

You can stick STi pistons/rods on the oem crank for way less $$ than an Sti block.im planning on using my stock phase 2 2.5 NA ej251 block and installing the ej25d heads on it. But if I put the sti pistons in wouldn't that drop my compression seeing that the sti was turbo??

[Garrison]

Is there any benefit in putting ej25D heads on a ej251/3 phase 2 block? Is it compatible?

You can stick STi pistons/rods on the oem crank for way less $$ than an Sti block.im planning on using my stock phase 2 2.5 NA ej251 block and installing the ej25d heads on it. But if I put the sti pistons in wouldn't that drop my compression seeing that the sti was turbo??
Yes, it would. That free's you up to 1) use a turbo 2) keep 2.5L of displacement = better spool, more power, etc

Turbo 2.5 hybrid is king in all respects except TT3.0 H6 :grin: :twisted:

[1996Battlewagon]

The 251 block isn't that special though. It's by no means any more tough than the 25D block and putting dual cam heads on a single cam block is more trouble than it's worth.

If you already have a 251, stick with what you have if you want to do a "NA build". Delta Camshaft does regrinds much more often and cheaper for the single cam engines than for the dual cam ones. In the end, your wallet and patience will benefit greatly just by staying true to your engine.

For anything more, you might as well go for boost and that's a whole different argument and thread. Although, I do agree with Garrison: hybrid is the way to go.

[Garrison]

I would even go so far as to say that the phase 1 block is -stronger- than the phase 2, thanks to the thicker casting. But the phase 2 can use sti rods/pistons (and crank, but that's a waste of money, IMO), whereas the phase 1 would need custom rods and pistons (or skully's use of wrx pistons with custom rods) to withstand much boost reliably.

Good call on keeping the ej251 by itself. A simple cam-grind (~$50-75) would net you HUGE gains up top and with a td05-16g that thing would be singing all the way to redline.

[pleaidestar]

The phase 2 blocks are a tad wimpier, but the yield higher compression numbers with phase one heads. Maybe you can just get pistons and rods from a phase two and slap them in a phase 1 block but it may be a lot of work for a slight compression raise.

Personally I want a 251 block with 22e heads and a moderate cam grind but I'm of belief that I would have to port match the intake and heads, a little throttle body and intake runner polish because of the 22e ridiculous bottleneck. Or would a 3 angle on the heads be more beneficial?

[Garrison]

The phase 2 blocks are a tad wimpier, but the yield higher compression numbers with phase one heads. Maybe you can just get pistons and rods from a phase two and slap them in a phase 1 block but it may be a lot of work for a slight compression raise.

Personally I want a 251 block with 22e heads and a moderate cam grind but I'm of belief that I would have to port match the intake and heads, a little throttle body and intake runner polish because of the 22e ridiculous bottleneck. Or would a 3 angle on the heads be more beneficial?
Tons of work actually; The crank has a different thrust bearing position.

[pleaidestar]

Oh yeeeeaahh, forgot about that one garrison, what do you think about the polishing though, have no experience with that on flat motors.

[Garrison]

I've heard that you can blueprint it out and remove a TON of material. You'll make it rev stupid quick, but my bet is you'd have trouble as a daily driver and probably lots of CEL's.
Polishing the crank is, to my knowledge, a very good waste of money. Save it for the race car.

LW flywheel all the way for something like that. You'll feel the increase and not lose streetability. I run 11lbs.

[pleaidestar]

I imagine with a high compression set up and a pnp it would be that much worse as far as daily use. Unfortunately my sedan has a 4eat, but I do have a kartboy lw crank pulley, my wagon is going to get far more mods when its all said and done, what lw flywheel would you vouch for? I have a perrin crank pulley for it too but I heard running both lwfw and lwcp might employ some crank trigger issues but idk, it is a first gen so I'm not sure how different electronics and sensors are between gens.

[Grimmrican]

Thank u guys for all ur input. I do want to keep this car as my daily so I don't wanna go super crazy n everything. I'd like to boost but that's not until the far future. I do have a stage 3 clutch that I was supposed to use on my old bk but never got around to it. Supposedly it should fit my Be as well but we'll see about that. I was planning to get a lwfw but wasn't sure which weight would be beneficial. And I just started looking into cams. So I'll still do my homework on that. Do any of u know where I can get a tuned stage 1 ecu for my car??

On another note what are some average numbers for an rs 5mt tranny, xmember, ds, and pumpkin?? I know a few guys here in ct who have some parts but I'm not sure what's a good price for them

[1996Battlewagon]

Thank u guys for all ur input. I do want to keep this car as my daily so I don't wanna go super crazy n everything. I'd like to boost but that's not until the far future. I do have a stage 3 clutch that I was supposed to use on my old bk but never got around to it. Supposedly it should fit my Be as well but we'll see about that. I was planning to get a lwfw but wasn't sure which weight would be beneficial. And I just started looking into cams. So I'll still do my homework on that. Do any of u know where I can get a tuned stage 1 ecu for my car??

On another note what are some average numbers for an rs 5mt tranny, xmember, ds, and pumpkin?? I know a few guys here in ct who have some parts but I'm not sure what's a good price for them

I'd say the average 5mt in good order will run you between $350 and $500. You could go cheaper if you found a junkyard score. The rest of the drivetrain and crossmember, I'm not sure but a manual swap would probably run you right under $1,000 including everything.

A "tuned stage 1 ecu" doesn't really exist. Tuning an NA Subaru ECU is flat out a headache. It's possible (check out Cardoc's Supercharged H6 - he cracked the factory ECU) but you're better off running piggyback or standalone.

Depending on what you want out of your build, a GReddy eManage Ultimate could easily do the trick. An older PerfectPower piggyback could be okay too.

[Garrison]

I imagine with a high compression set up and a pnp it would be that much worse as far as daily use. Unfortunately my sedan has a 4eat, but I do have a kartboy lw crank pulley, my wagon is going to get far more mods when its all said and done, what lw flywheel would you vouch for? I have a perrin crank pulley for it too but I heard running both lwfw and lwcp might employ some crank trigger issues but idk, it is a first gen so I'm not sure how different electronics and sensors are between gens.
I've got an unorthodox racing flywheel from nasioc, and I think I payed $75 for it, or so. Plus resurfacing was another $20. It's a dual mass one, where the center housing bolts into the flywheel itself; this is so you can swap out when worn.

I don't know that I would vouch for anyone over the other, but I have heard nothing but good things about exedy. I assume because they make JDM/OEM parts as well as aftermarket.


Grimm,
A stage 3 clutch will murder your leg in a daily, and likely your hydraulic clutch cylinder as well. Which according to this (http://www.rs25.com/forums/f7/t139473-b ... guide.html (http://www.rs25.com/forums/f7/t139473-boosting-1990-2002-usdm-subarus-chronological-guide.html)) #10, is a $300 part.

[Garrison]

Question for you all.

Can anyone give me any downsides to this mix of parts? It's what I've hypothesized for my next build:

EJ251 w/ sti rods/pistons
EJ25D heads
TMIC/FMIC (no sure which yet - feel free to input)
TD05-16g
Piggy back controller

-Here's where I'm confused-
What do I do about injectors? nissan s240 injectors?

[86bratman]

for your injectors you can use any side feed subaru injectors with adequate flow

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[86bratman]

The phase 2 blocks are a tad wimpier, but the yield higher compression numbers with phase one heads. Maybe you can just get pistons and rods from a phase two and slap them in a phase 1 block but it may be a lot of work for a slight compression raise.


this is also completely incorrect, the phase 2 ej25 has the standard 52mm rod journals, phase 1 ej25 had 48mm because they did an offset grind on an ej22 crank to stroke it out. The phase 2 has the revised thrust bearing location as mentioned earlier.

you also cannot put phase 2 pistons in the phase 1 ej25 because they will stick out further than the existing pistons already do, and you can't use the phase 2 rods because of the rod journals. Can't just throw the whole rotating assembly in because of the thrust bearing location.

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[Grimmrican]

Hey guys. I'm planning on doing a 5mt swap and I really don't want to throw my money away buying any tranny. Will a 2nd gen 5mt ok to get for a 00 legacy 3rd gen. 2.5? Also if the trans is compatible does it matter if it's from a 2.2 or 2.5??


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[1996Battlewagon]

All EJ trannys will bolt up any EJ engine. You have to match the trans gear with the final drive of the rear diff.

What car is the trans out of? An Outback or Legacy - they had different final drives.

[pleaidestar]

The phase 2 trannys have different electronics, but the 5mt/4eat will run on the same ecu apparently, not so sure you could run a phase 1 tcm with phase two motor though...I would try to find a salvage vehicle of the same year and spend the day taking everything out...I just wonder if the tcm and ecus are they're own entity or the vss's are the same between phases.

[Grimmrican]

I'm aware of the final drive and gear ratios. And that's y I'm looking for an entire car because it'll be cheaper for me rather than buying the tcm, pedals, slave cylinder, clutch, flywheel, trans, diff, shaft, axles, xmember.

Also at this point idc if it's the legacy or the outback. As long as it's 5mt and I can clutch kick and shift again then I'll be content lol


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[1996Battlewagon]

Also at this point idc if it's the legacy or the outback. As long as it's 5mt and I can clutch kick and shift again then I'll be content lol



Ha! I know what you mean man. I axed my H6 for many reasons and the 4EAT was one really really really boring one.

[Grimmrican]

sup guys me again. and this time i actually bought my old 95 bk 2.2 single... block has a very cute hole in it so im salvaging quite the parts. the heads i took off are still in good condition and are non-interference (thank god) i pulled them off earlier today and im curious how these heads will work on a ej251 block? what gaskets should i use? what kind of compression will i see? if it seems like everything is good to go then ill be porting and polishing the heads before i decide to install them. also will the timing belt need to be changed in length? any and all vital info will be needed and appreciated. thanx guys for ur future input