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Old 08-16-2013, 09:30 AM   #376
Patrick Olsen
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Quote:
Originally Posted by squeaks6385 View Post
So the spacers dont give better mpg?
Nope.

Quote:
Originally Posted by schrek1991 View Post
I am currently rebuilding my ej251 and decided not to go the turbo route. I am doing many of the above mods including pnp, stage 2 cams, springs, titanium retainers, and .25 oversized pistons. Hopefully I can get some good numbers out of it.
Cool! Do you have an opportunity for some before/after comparisons (either dyno or 1/4mi)?
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Old 09-23-2013, 07:03 PM   #377
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Hey I got lost while reading posts, lost where I was and dont want to start over again so ill quickly ask my question. on a 05 2.5rs are the crank and/or rods forged. Or I guess are any 2.5 (STI or others) forged. Any info would be great. Even a title for me to search or link to a thread stating so. I did try to search but came up with nothing. But that could be bc I go brain dead wen I'm on the Internet.so for searches If it ain't obvious I won't find it unfortunately.
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Old 09-24-2013, 12:48 AM   #378
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So searching for "forged crank" or "forged rods" isn't obvious?
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Old 09-24-2013, 09:18 AM   #379
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I did try both but put ej253 in front and my built motor thread was first, i also tried "forged internals", "do ej253 have forged parts" i have tried a few but I have never been able to find anything. But then again I just saw a thread in the classifieds and the title was 02-07 impreza WRX/STI parts. And when I tried searching that title nothing showed but wen I put in "what parts are forged" then it would pull it up. Idk if I just don't understand the Internet or what but that little problem was confusing the hell out of me last night.
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Old 12-07-2013, 12:05 AM   #380
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So I have a few questions. In terms of swapping all the different subie engines, does anyone know all the parts that are interchangeable? Like will a 2.5 intake manifold fit a 2.2? or would it even increase the flow if it did? Also what about the intake spacer? Does that change over from 2.5 to 2.2? How about throttle bodys? Are they interchangeable, or would it make a difference? Are there any ignition coil upgrades for a 2.2? I have not seen any. Is a 2.5 coil higher output? Would these be interchangeable? Just some thoughts and questions as I have a 2.2 but dont want to swap to a 2.5. I like the reliability of my 2.2, at 260,000 it still has 185 psi in each cylinder, doesnt burn any oil, and has pretty good power. Although I do want some more Any thoughts or opinions are welcome.
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Old 03-22-2014, 01:08 PM   #381
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As a noob, I think this thread is in need of an update. Many of the products and companies listed are no longer exist. The theory behind the mods remains valid.
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Old 05-19-2014, 11:29 PM   #382
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Opinions on getting it chipped?
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Old 05-20-2014, 11:31 PM   #383
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Define "chipped"

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Old 05-21-2014, 02:43 AM   #384
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Define "chipped"

Reflashed?

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Old 05-21-2014, 02:53 AM   #385
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srs **** that was popular years ago. maybe you can find one used. there are a handful of piggy back chips. honestly the stock ecu can handle all but the most intrusive modifcations. I had a whole bolt on set and on a stock ecu and it ran well and fine. no codes

it wasnt till i got a vipec where i unlocked the potential ( christ i sound like a yugioh ***)
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Old 05-21-2014, 06:39 AM   #386
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You can try to find a PP6 piggyback ECU or use ROM Raider which is an open source software to tune.
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Old 05-21-2014, 10:19 AM   #387
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Tuning is always beneficial, even with NA.. and even stock. However, with a full exhaust, intake, maybe even cams or something, you're looking at some solid NA gains with piggyback ECUs and open source software.

Keep in mind, not anywhere around what a turbo model would gain, but still gains none-the-less.
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Old 05-22-2014, 06:42 AM   #388
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Quote:
Originally Posted by Clutch Dog View Post
srs **** that was popular years ago. maybe you can find one used. there are a handful of piggy back chips. honestly the stock ecu can handle all but the most intrusive modifcations. I had a whole bolt on set and on a stock ecu and it ran well and fine. no codes it wasnt till i got a vipec where i unlocked the potential ( christ i sound like a yugioh ***)
You do not need to go hunt down and old SRS tuned ECU. The tuner who was doing those reflashes is back at it on his own and no longer with Crawford. His company is Delicious Tuning. I have his stage 2 tune with delta 1500 cams in my '01 RS and it definitely woke the car up quite a bit especially over 4500rpm.
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Old 06-15-2014, 03:15 PM   #389
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You do not need to go hunt down and old SRS tuned ECU. The tuner who was doing those reflashes is back at it on his own and no longer with Crawford. His company is Delicious Tuning. I have his stage 2 tune with delta 1500 cams in my '01 RS and it definitely woke the car up quite a bit especially over 4500rpm.
I agree, delta 1500 cams gave my car a nice punch 4500 and up. Very happy with delta. For those with non tunable ecus (non jecs ecu 03 and 04) the aem fic works nicely contrary to others accounts. With full exhaust and cams stock ecu tries to add too much timing above 5000rpm. At red line I took out 7 degrees. These are facts! Also uel headers sound awesome with full exhaust and cams.
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Old 06-19-2014, 10:43 PM   #390
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I like this approach, building up an engine in steps. The full experience. I'm sure one learns a lot more doing it this way.
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Old 08-15-2014, 03:39 PM   #391
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Love this thread. lots of great info.

I'm in the early building .. late planning phase of my motor build .

I do Rally racing, I started off with a production FWD Impreza for several years, and then did an AWD Conversion. How ever i was racing under a limiting rule set. i won't bother to explain what the CRS GT ruleset was, but it was quite limiting.

I had a stock RS 2.5 motor with ECU (98 block & heads with 01 intake manifold). 01 ECU Delta cams 1500 grind . Stock exhaust manifold with a custom Exhaust . 2.25" 1 Hi flow Racing Cat, and i was using my old STI Muffler.

My "big" mod was The Gorilla hood scoop air intake kit.
actually gained 12 Whp
~~ 4500 feet elevation but i think they tried to altitude correct?

(my car ran a little rich from 3.5-4k rpms with the gorilla air intake, suggesting the gains would be even bigger if i had control over my AFRs)

My car was fun to drive and reasonably quick at the regional level, But was missing some very attainable Hp gains. and then i blew up my motor. fist sized hole in the block.

oh well, I'm now going to focus on Open light rules. Basically anything goes!! 2.7L max, no forced air, no NOX.


So for my next motor build I want more power of course ,I want enough to where it would be really hard for a competitor to have a real (meaningful) Hp advantage over me. a number high enough its highly unlikely someone will out do me by say 10% .

I'm not sure what that number would be though. Reading about the + 50 hp from stock as what seems Reasonably doable , i believe that should be my goal. Its beatable, but its very likely someone with that kind of money will go and play in the Open "wallet" class.

So I'm trying to stick mostly to the established formula, but as a few have posted (newer mods out, more mods tested) what's on post #1 may not be the absolute best route ..


My plan (chime in, any advice to make more power or not to waste money )
  • 8k red line
  • 05 STI short block with 11.7 : 1 compression pistons (Done! )
  • Z25 cast heads (still searching for)
  • +1 valves 8k rpm supporting springs, retainers, etc
  • Intake manifold port matching & polishing
  • Head port matching & polishing
  • 06 Intake manifold (the one that got 300 CFM in the bench flow DB)
  • Delta Racing cams.
  • bigger throttle body

I am still very clueless on these items
  • Tuning solution ? (piggy back or stand alone)
  • Exhaust Headers ??
  • THROTTLE BODY SPACER??

so I have Borla UEL Replicate headers (came with my 2.5 motor, but i could not use them under the CRS:GT rules) But I'm thinking i should switch to EL headers ?

and what should i do for ECU / Tuning? Help. My shell is a 93 so i can claim ODB-1 and do the tail pipe sniff test . (Reno,NV) i'm not sure how my car is gonna Idle and if that will cause a fail . My car does have the ODB-2 port , and that may be easier , however i'm using a 95 gas tank with that 01 ECU, so i have codes for missing fuel temp and missing evap sensors.

Also i have a preference to an ODB-2 solution , in the event that i crash my rally car and have to re-shell , i would like to leave the option of finding 96+ shells as well..

my drive-train (if relevant) is an 02 outback transmission with an OBX Torsen front, 20kg center diff (still need to buy) , and a plated rear LSD. and a 4.44 FD swap for good measure.

Gearing / MPH chartwith an 8K red line my car will still be geared for to high of a top end (IMO) but i don't think i can (cheaply) do anything about that.


please advise me on areas i could improve. I'll definitely dyno when i'm done .
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Old 08-17-2014, 02:09 AM   #392
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Default N/A power white paper, long, please critique.

Since it looks like you're running an ej25 go get the rally sport racing UEL headers! Those add horsepower

Also grimmspeed makes an intake manifold spacer that is supposed to decrease the temp of intake air. That may be useful in this case.

What sparks are you running? Going to guess ngk platinum? Also grab their spark wire set. I noticed increase in performance with this setup.
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Old 08-17-2014, 02:10 AM   #393
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Since it looks like you're running an ej25 go get the rally sport racing UEL headers! Those add horsepower
They do, but not very much at all.
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Old 08-17-2014, 02:13 AM   #394
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They do, but not very much at all.

Oh, I thought they did help with gains.
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Old 08-17-2014, 02:14 AM   #395
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Oh, I thought they did help with gains.
They do make more power than the stock header, just not a lot more. They don't make nearly as much as the TWE headers do.
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Old 08-18-2014, 02:07 PM   #396
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yes ngk platinum, how did you know? And i'm not sure what brand my spark plug wires are ... i replaced those on my 1.8L 08 with what ever was in stock at Kragen (O'reilly) , but I think when i got my EJ251 we went with what ever spark plug wires came with it. Doh! rather dumb that i never thought about that over 2 seasons,

So the logic behind the spacers is pretty straight forward. less heat transfer into the IM, so intake air temps stay a bit lower, air stays denser, more O2 to combust!

there's a Side affect of changing the length of your intake system .. could be good or could be bad (probably helps either low or top end at the expense of the other) ?

But my big question is How long will the intake remain cooler compared to a motor with out the spacer? A common Scenario in rally is that you Transit for 15+ minutes, shut your car off for 10, start it back up Idle for 5, and then take off down a 12 minute stage.

Is my Intake going to get heat soaked either way Or will the spacer work fine in those conditions?

Am i safe to assume i can grind (dremel) down the spacer if needed to match with the intake to block port matching?

I still need to search the forums for the "best" set of headers. early research has me leaning Towards the TWE , for as much as i love the boxer rumble, i love trophies even more! LoL (thanks Williaty)..
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Old 08-18-2014, 02:23 PM   #397
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So the logic behind the spacers is pretty straight forward. less heat transfer into the IM, so intake air temps stay a bit lower, air stays denser, more O2 to combust!
Without tremendous other work, they don't really do anything. The spacers just block conduction from the block to the IM. The problem with that is that the IM also receives TREMENDOUS heat input via radiation and convection. I've placed thermocouples on the IM and some other stuff with and without different spacers and other cooling mods. Nothing made an improvement if you heat soak the car by shutting it down before a stage (or pass or lap or whatever) or by idling it for more than a few seconds. The only thing I was ever able to see reliable reductions in temperature from was increasing the outside airflow through the engine bay. Of course, that only works when the car is moving/

Quote:
there's a Side affect of changing the length of your intake system .. could be good or could be bad (probably helps either low or top end at the expense of the other) ?
Lengthening the runner makes the low end better and the top end worse. In reality, you can't lengthen the runners enough with a spacer to make the effect measurable outside the lab.

Quote:
Is my Intake going to get heat soaked either way
Yeah, you're going to overwhelm the supposed benefit of the spacers by all the other sources of heat.

Quote:
I still need to search the forums for the "best" set of headers. early research has me leaning Towards the TWE , for as much as i love the boxer rumble, i love trophies even more! LoL (thanks Williaty)..
I have now owned and had on the dyno every single (yes, really) header made of the EJ25 NA except that old MRT design that kept the right and left banks separate all the way to back behind the tranny. UEL designs make a tiny bit of power. The "normal" EL designs make a little bit more. The TWE 4-2-1 EL HO headers make more than all the other ones I tested put together.

If you want to win, you've really got no alternative to the TWE headers.


Edited to Add: If you're really serious about this, you should switch to the 05-07 intake manifold. You have the older, smaller, more restrictive one on an older car like that. The 05-07 flows CONSIDERABLY better. The downside is you'll have to custom fabricate some stuff since the 05-07 IM was designed for DBW and EGR. Not hard to work around though.
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Old 08-18-2014, 10:47 PM   #398
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good to know about that spacer. totally what i was thinking so maybe i'll skip that on my build.

and yes my current motor has the smaller IM, but I have the 05-07 intake manifold at my crew chiefs house , along with my completed short block. and it has much larger runners and a massive plenum . the air intake connection is also appears to be in the same post as before, though it looks low on the actual IM. (if that makes sense) i can post a pic of what i have in a few.
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Old 08-19-2014, 01:18 AM   #399
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"yes ngk platinum, how did you know?"

Haha well what other brand goes well in the ej25? None I say! That's what I run on my commuter car. That's a rally mechanic recommended to me.

Glad you're getting this all sorted out!
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