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2000 Impreza 2.5RS BRP Coupe
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Discussion Starter #1
I did a search...

I want to run the Stage 4 Delicious and the JE 314344 pistons.

And NO-ONE in 17 years has a post about it?
 

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I ❤ BOOBIES
99 Coupe
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17,006 Posts
Honestly its because swaps have gotten really cheap, and for the money you cant beat it. You can do a high compression build with cams and head work and the whole nine yards, it costs more than a swap but you've built a motor that has a ceiling, you cant go any farther than that. You "might" get 230-240whp out of all that stuff, throwing in a stock EJ20 with a TD04 will get you that with a reflash, for less money, but you can then swap around turbos and injectors, have free opensource tuning and not have to take your ECU apart and mail your chip to a company while not having a car to drive for two weeks.

Thats why.
 

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The subaru of many acronyms
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I don't like that you have to use a 251 length rod. It would be really nice and easy it had the same compression height as the 257/255/205 etc so those rods could be used, but no. Also go project lambda and tune it better.
 

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1998 JDM Impreza STi v4 GF8
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46 Posts
Interesting!

Also go project lambda and tune it better.
Someone here in Vancouver posted about Project Lambda in a different Subaru forum. I'm a Subaru newb and I've never heard of this service before. This is the apparent list of supported cars/engines...

https://lambdatuning.com/support/supported-vehicles/

I find this a little confusing, as it lists the '98 JDM Impreza STi with a different engine than the EJ20K that mine has. I'll have to contact them to see what's up (and it's fortunate that they're local to me), but do you know anything more about this Project Lambda that you could share?
 

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2000 Impreza 2.5RS BRP Coupe
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1,772 Posts
Discussion Starter #6
I am not sure why I did not get updates from this thread... hmm

The reason I ask is that this engine is for Stage Rally and RallyX (and if I am lucky fit it into some obscure classing at AutoX)

You "might" get 230-240whp out of all that stuff
I would have a heart attack if I even hit 200Hp.... that would be amazing...
 

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2000 Impreza 2.5RS BRP Coupe
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1,772 Posts
Discussion Starter #7
I have 3 other engines I plan to assemble as well that are turbo, so I won't be missing out on the action ;)

But I have 2 complete RS drivetrains that I want to prep for Rally.

Then I have an EJ22 Closed Deck I am working with (finding the right machinist is my biggest issue currently)

Then I have a EJ20 that I am going to do a 2.1 stroker and FP Blue. (This is my current project outside of getting RallyX car ready)
 

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The subaru of many acronyms
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You have been sitting on that ej22 for what 5 years? and you want to talk building some engines for an actual motorsport? keep it simple. stock bottom ends with MLS gaskets and cams at most for an OL car.
 

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2000 Impreza 2.5RS BRP Coupe
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1,772 Posts
Discussion Starter #9 (Edited)
You have been sitting on that ej22 for what 5 years? and you want to talk building some engines for an actual motorsport? keep it simple. stock bottom ends with MLS gaskets and cams at most for an OL car.
Buying a house and travelling is expensive. Wanted to get that out of the way first.

But fair enough.

I figured since I had a spare engine out of the car I would build it.
 

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Cams are more important than compression.
Compression makes power but it is sort of "secondary benefit" - but it does go hand in hand with cam selection.

If you have the specs of those Stage4 cams please post them...
For making power keep it simple and "benchmark" other cars. Engines are engines on a basic level and "combos" that work well for one can be applied to another.

My "other car" is an old Porsche 944...there was a variant with a 2.5L DOHC inline 4 from 1987-1988. Engine dimensions 100mm bore x 78.9mm stroke (almost identical to EJ25).

They had great heads, but otherwise pretty mild camshafts, intake and exhaust were optimized for idle-4000 rpm cruising torque before the cams kicked in from 4000-7000 - peak HP at 6000.

Intake manifold runners are very close in length to those of an EJ25. Exhaust was a simple 4-2-1 as found on many inline-4 engines, pairing cylinders 1/4 and 2/3 with a very short collector before merging into a single ~2" ID exhaust with cat and non-straight-through muffler. Compression is 10.9:1

Breathing through the old Bosch AFM (flapper door) and with a very emissions-oriented tune they made 190 crank hp, stock...simply by swapping to a free-breathing MAF setup and slightly tweaking the tune, 200hp is easy on all stock engine parts with a hugely improved low/mid range.

944S camshafts used hydraulic flat tappets and cam specs were approximately:

Intake 216 degrees at 1mm (0.039")
Intake peak lift 11mm
Exhaust 212 degrees at 1mm (0.039")
Exhaust peak lift 10mm

Looking at some info I found for EJ251 heads (assuming that's what you have) the EJ251 flows a bit less than the Porsche heads (about 250cfm vs 270 at 0.400" lift) but if your cams are hot enough I could see 200hp coming around easy. You are further "ahead" simply by having the excellent Subaru roller-rocker cam followers which lets you go nuts with cam profile...

I think the real key thing is getting a good exhaust on your EJ - if your budget permits (and your ears, too) an EL header would be optimal...
 

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97 Brighton, 04 2.5RS, 07 Foz
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34 Posts
I've got an 04 RS with JE 314345 and, I believe 1.25mm, Cometic heasgaskets for a 11.44:1 CR. Stock engine otherwise, with a custom intake and catback, UEL header and stock cats. No tuning and it runs fine on 87, but I usually run 93. Feels better than stock but I can't wait to get it tuned! Once I do I'll be rebuilding some heads with Delta regrinds and a bit of port work. Stock STi head gaskets would've put my motor at 12.62:1 CR so I may bump up to 12:1 as long as there's not much knock when I get to log my current setup. No E85 in Maine or I'd try the STi gaskets

Sent from my Z753G using Tapatalk
 

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2001 Impreza RS - Black
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227 Posts
I'll chime in and add that I rebuilt the motor in my 01 RS with 11.5:1 Wiseco pistons, Delta 2000 cams, sti crank, sti rods, and the Delicious Stage 4 reflashed ecu.

I got it running last November, but right away I found a pretty significant oil leak and that was right when I was moving between states. So it's been sitting since. I should have a bit of time coming up that I can dedicate to it and get her running properly.
So I can't really comment on how it runs as I've only taken it around the block twice for a grand total of 1 mile on the rebuild so far, but that should change soon.
 

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1996 imp jdm ej20 NA dohc swap
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400 Posts
I'll chime in and add that I rebuilt the motor in my 01 RS with 11.5:1 Wiseco pistons, Delta 2000 cams, sti crank, sti rods, and the Delicious Stage 4 reflashed ecu.

I got it running last November, but right away I found a pretty significant oil leak and that was right when I was moving between states. So it's been sitting since. I should have a bit of time coming up that I can dedicate to it and get her running properly.
So I can't really comment on how it runs as I've only taken it around the block twice for a grand total of 1 mile on the rebuild so far, but that should change soon.
Update?
 

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In the process of building an engine for my '01 2.5rs that is based on 257 case halves, new Sti crank, King bearings, JE 11.5:1 pistons and correct length K1 rods. Case halves and pistons and are boxed up and about to go to Larry's in CT. The heads are a set from Tom at TWE that have been extensively ported and have his old Stage 3 NA cams and valvetrain. Plan to use JE Proseal .039 thickness head gaskets and a custom intake manifold setup I have devised myself utilizing a 2005 big plenum/ long runner manifold and DW 440 injectors. Will either tune with Lamda or a Haltech standalone. This is a long term project that I will be taking my time with so don't expect numerous updates, just thought I'd put it out there that someone is doing it. I will report back but it probably won't be anytime soon. Any advice, criticism or questions are also welcome.

[
 

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Hoopty King
2000 BRP 2.5RS/1994 Legacy SS
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875 Posts
I'm finally getting around to starting this build for my old coupe. Just got the valvetrain parts I needed last weekend, already have the pistons kicking around, and already have Delta 2000s in the motor.
 
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