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Old 11-23-2012, 10:05 PM   #1
mrchyes
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Default throwing it out there!

Just going to throw this out here to the N/A forum of NASIOC and see what anybody here thinks. First off, I am not a useless 17 year old kid who has no experience and no common sense while driving or installing/fabricating things.

I know there will be some skeptical people posting in here, and I know i don't have all the answers, im going out on a limb and posting this to hopefully get some more info.

ON TO THE REASON I MADE THE THREAD!

My plans for my EJ251 are as follows.
a E85 fuel setup
Ported and Polished Aluminum Intake Manifold - already bought
850cc (havn't checked into size too much yet) injectors
possibly fuel rail upgrade?
CAI intake
EL headers, catless custom catback

In the future: Possibly... ( i have almost 0 knowledge on the below )\/\/
built block with higher compression (up to 13:1 or so)
maybe bored out to 2.7?
custom pistons/cams/anything else?

please dont focus too much on the building the block and what not, that is for later when i have a much larger budget.

What is anyones thoughts on how this N/A engine will be, reliability, fuel econ, whp, wtq, anything else? just trying to get some information. Any Help Is Appreciated! thanks
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Old 11-24-2012, 01:16 AM   #2
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What do you want from this build?

E85 is a nice idea. To get the most from this fuel type, you should make an attempt to take advantage of the octane and very excellent knock resistance. In order to do this, you need to increase static compression. This requires new pistons. The highest compression off the shelf is 11.2:1 which is good for 91 octane with stock cams. Aftermarket cams would allow higher static compression. E85 can take advantage of static compression much higher. Timing, from what I've read is similar to gasoline meaning you can't really optimize the fuel through timing alone past a certain point. This means you must step to higher compression to really gain serious torque gains.

Note, torque does not necessarily equal HP. HP is dependent on where the torque is located in the power band. The cams, heads, exhaust manifold, and intake manifold influence where this power band is located in the rpm range. The biggest factor is whatever is located closest to the combustion event, i.e. cams and heads mainly. Then along with these the intake manifold and exhaust manifold play their role in air flow speed along with the head ports and cams in how that air moves in and out of the combustion chamber. As you move farther away from the combustion process, you have less and less influence on the actual combustion event.

I will give an example of what I was thinking about (if I ever had $10k to blow on a motor for no good reason). 2.7L setup is nice. More stroke will make more power (and does so more than rpm will get you from destroking). There really is no replacement for displacement. There's only so much rpm you can make use of until the engine blows up. For a 2.7L stroker, 8.5k rpm should be very doable.

With E85, you will likely run higher compression than you think. Now it depends on the cams as the cams will influence the dynamic compression during operation. To get HP you need rpm and torque up high in the power band. To do this you need race cams with very long duration. This long duration will in turn reduce dynamic compression so your 13:1 pistons may end up only around 9.5:1 dynamic which could run on pump gas just fine. It's the burden of using hot cams. Your fix is higher compression pistons. From what I could find looking around the web and from some engine simulation software, you can run QUITE high static compression, think more like 16:1 and dynamic compression will drop down to more around 12.5:1 once cams come into play.

IF you don't get the torque up, peak HP will still be very low for the amount of money you put into the engine.

When I was toying with engine simulation software, it hinted that the intake manifold is seriously not tuned for high rpm efficiency. The long runners will create a bottleneck. However, I don't know how significantly this translates into real world operation. Both your intake and exhaust primary runner length and diameter will be sized depending on what rpm you're shooting for and the cfm flow level the engine will flow through. In this sense, upgrading the intake manifold is just as important as upgrading the exhaust manifold. There are nice exhaust manifolds to buy, but there really are not any aftermarket intake manifolds made. It would be custom work.
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Old 11-24-2012, 01:27 AM   #3
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I learned a lot reading that ^^^. Good and detailed advice there.

Good luck OP, N/A Subaru engines aren't exactly easy to squeeze power out of. The easiest thing I [and many others] have found to increase power is reground cams. That's all I've done, and I don't plan on doing any more except maybe an exhaust if I have money to burn. To me, the cost of building an N/A engine vs. the benefits is prohibitive, but that's obviously not an issue with you.

Anyways, good luck.
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Old 11-24-2012, 01:46 AM   #4
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Oh man...

Quote:
Originally Posted by mrchyes View Post
i got a rather large wreckless driving ticket :/ lame, i was going to get my headgaskets done... but i will have them done before the summer is out probably.
Way to go! It's a good thing you're not just another useless 17 year old who has no experience and no common sense while driving!

Your car looks nice though, I hope you learned from your ticket.
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Old 11-24-2012, 02:21 AM   #5
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I've sort of looked into this myself for a while, so I have some ideas. The downside is cost and gains. Frankly, for the same value, you can much more easily drop in a a EG33 and make more power much easier. That's pretty much the biggest shortcoming of looking at a build for this engine size. You look at, can make power, then look at the bigger offerings and realize you can get a lot more power through displacement.

Last edited by Back Road Runner; 11-24-2012 at 03:11 AM.
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Old 11-24-2012, 08:02 AM   #6
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Quote:
Originally Posted by tibug View Post
I learned a lot reading that ^^^. Good and detailed advice there.
+1, and easy to understand, cheers.
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Old 11-24-2012, 09:11 AM   #7
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thanks for that information back road runner. that was very helpful, im sure ill read through it a lot!

tibug, i did learn from that ticket. it was one of the stupidest things ive ever done. i regret every thought about it. Funny thing is, all i was trying to do was play in the mud.

back road runner.

My plans for this engine As of Now. are to just get a little more power out of it. hence the intake manifold and exhaust. i Dont think ill get into the 2.7 stroker/internal work until i can really afford to be imaginative with the engine. So, For Now, all im looking at doing is getting the most power i can (which i know my tuner is capable of doing) with just small things outside of the combustion chamber itself.

if all i would need to make higher compression is pistons, then maybe that is in the ballpark. but i would need to talk to quite a few people before i dropped IDK how much on 16:1 compression pistons.

What you were saying is a very clear description of whats going on and whats in play here. i thank you so much for that.
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Old 11-24-2012, 12:24 PM   #8
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Back road runner kind of touched this subject but how much can the stock heads flow? You can only pump as much air as the weakest link can handle. I'm sure you understand that but to me it seems like you won't get much benifit until you match the intake manifold with the port size, cam and exhaust manifold and tune of course. Simply slapping on a new intake and exhaust manifolds in a $/hp gain isn't going to be worth while IMO. Not to mention if you don't have a strong grasp on intake velocity and how you are effecting that you may actually reduce power in some rpm ranges.

I've read through the NA power threads and essentially regardless of what some people think you can not get much added power out of NAs with bolt ons. I commend your efforts but being on a limited budget as it sounds, you should be sure you are focusing your money on the right things. NA power builds are not cheap, and the last thing you want is to spend thousands building up an NA motor only to have your neighbor blow you out of the water with his $2000 turbo motor swap.
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Old 11-24-2012, 12:37 PM   #9
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what your saying makes sense Jhop. Makes me think about what im doing even more.

So, as you've all probably noticed, i change my mind a lot. mostly because of new information that i didnt know before being presented to me.

I think i did get a very good buy on this intake manifold though, it is a very nice manifold and it can be used for more than just my N/A application.

So i think im looking at a more mild build. can't really call it a build honeslty, ill just be tuning and changing out parts. I guess i just don't see it as "wasted" money, it makes me very very happy.

as a 17 year old kid, about to turn 18, I get very excited when a new part, even of the smallest proportion comes to my house for me to install. or spending my time on my car. Maybe its because i havn't done enough to any car to be bored of it, but i think i really do just love it, and thats why im heading into the automotive field. I dont care if i make barely enough to feed myself.. if i love doing it, youll find me doing it

thanks for the info once again
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Old 11-24-2012, 10:09 PM   #10
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Here's a huge thread if you want to read about getting power from a N/A. It's a bit disheartening when you realize how there's very little you can do to extract more power from these engines without modifying the internals. That said, it is nice that they are not bottlenecked from the factory. I wonder how much of a difference your intake manifold will make.

http://www.rs25.com/forums/f5/t2912-...-bolt-ons.html
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Old 11-24-2012, 10:12 PM   #11
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ive read and posted in that thread already, read through it more than once haha...

its a good read, but kinda wanders. And we will find out man! haha, ill be getting it pretty soon, might just figure out how to put it on just for now because ill port it and get on the E85 juice around next year when i move down to where the fuel is..
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Old 11-25-2012, 03:04 AM   #12
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Good luck OP, started to type a response questioning your priorities since this does sound like a lengthy build for such a young one- however we all have been there and I've sunk more than I would want to admit in cars at a younger age, where when younger it seemed like one of the bigger priorities in my life. The pitfalls of trying to modify your EJ in such a way is that, come school time, if at any time something goes wrong, or something takes longer than expected to install or tune, then you will encounter additional stresses which will impact your education.

And that reckless driving ticket for playing around in the mud.. straight depressing- that officer probably was having a bad day and you were in the wrong place at the wrong time!

I'd keep the unequal length headers option open too
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Old 11-25-2012, 11:35 AM   #13
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I would like the UEL headers because i simply adore the noise they make.. but it seems like a useless endeavor because of the added stress it puts on the other two cylinders, and the fact that i lose much sought after power.

yes, it was completely my fault i got that ticket though, went in for round 1 looking for a good spot to get muddy so i could impress everyone at the autox... then went back for round 2, and shortly after, they got me... the muddy tracks actually led right to my car haha.

but that is in the past, ive learned my lessons... next time my car gets that dirty it will be having fun in a rallyx..

I think for right now anyways, when this manifold comes in a few days, im just going to try and install it on my car, maybe relocate a few things, and make it easily accessible to take in and out to test.

thanks for all input, once more
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Old 11-25-2012, 04:34 PM   #14
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What manifold did you get? There isn't really much out there for our motors, and nothing (designed) for NA use.

850cc injectors won't be needed for E85. WRX injectors are 440 and plenty big enough given the 280cc rating of the stock NA stuff.

Good luck on the build. You can build some fun stuff without breaking the bank. The out and out numbers won't be great, but the car will still be a hoot!

Jay
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Old 11-25-2012, 04:45 PM   #15
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I got an aluminum polished intake manifold from a 03 RS... i don't think it is the stock manifold for that car, so i dont know much about it.

and yes, 850cc may have been a bit high.. but we will see

I just tore the AC out and am working on figuring out how to move the alternator over to the AC condensers spot. some may say thats stupid. but i dont think so lol. I dont want that ugly distributor sitting on top of my manifold, so im going to figure out how to relocate it. also i didn't once use my AC this summer... roll down the windows and im happy happy happy.

Thats what im looking forward to more than anything, just getting the time in on my own car, getting the experience. It is exciting to say the least.
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Old 11-25-2012, 05:17 PM   #16
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yea A/C is overrated! just to avoid confusion I don't believe your car has a distributor. The block on top of the manifold is the coil pack. You will be limited on where you can relocate it because of the length of the plug wires. The JDM ej25 motors (like mine) had their coil packs on the passenger back side of the manifold. I threw my bracket out but maybe you can find a local who is willing to part with their JDM bracket and wires because you'll need the longer ones for the drivers side cylinders. This will likely mean switching coil packs because the only north american car I could find with the same plug wire fittings was the forester so JDM plug wires won't match your current coil pack fittings so you'll either have to swap to a forester coil pack or a JDM one to match the JDM wires

OR you could by a plug wire kit and transfer your fittings onto custom length wires


edit; sorry that may have sounded more confusing than it is. essentially you won't be able to move your stock coil pack around much due to plug wire length. The JDM setup might be more what you are looking for but you will need JDM wires, a bracket (i think) and either a forester coil pack or the JDM coil pack due to fittings differences.

Last edited by J-hop; 11-25-2012 at 05:26 PM.
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Old 11-25-2012, 05:38 PM   #17
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wow! thanks so much J-hop! i might see what i can fab up seeing how i just put on new NGK spark wires... and yeah, i didn't know if that was a distributor, coil pack sounds right haha...

i will look around, maybe i can work something out with my tuner, he just picked up a spec c with a jdm ej205

EDIT: wouldnt i be able to keep my coil pack and just either work with the length wires i have and somehow secure it down, or just get longer wires?

Last edited by mrchyes; 11-25-2012 at 05:48 PM.
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Old 11-25-2012, 05:59 PM   #18
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yes you could get custom plug wire lengths made (or make them yourself). The only issue will be making sure you have the right fittings on the wires to match your existing coil pack.

edit it looks like not ALL JDM motors have the coil pack on the back passenger side of the manifold but all of the ones I have seen do.


most JDM:

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Old 11-25-2012, 06:06 PM   #19
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hmm well ill probably try and see what i can do with my coilpack and wires first... then maybe look into longer wires.. hopefully i can get my money back out of those new wires i just put on lol.
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Old 11-25-2012, 07:23 PM   #20
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just talked to a guy from my local club and it looks like i found my solution to relocating the alternator ! should have it fabbed up in a week or less with my new manifold on

EDIT: also now looking into getting Delta 2000 reground cams

Last edited by mrchyes; 11-25-2012 at 10:36 PM.
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Old 11-25-2012, 10:59 PM   #21
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I am new to the subaru forum scene.
I am in a similar situation as you. I want to stick with a 2.5 "short block" for now.
I have an extra engine for my car.
I'm looking for the best "bolt on" n/a "mods".
But I don't want to convert to e85...
I am looking for a ported and polished intake for n/a 2.5
I'm trying to figure out what to with my heads and cams
I think I want borla header/random tech cat/stromung cat-back
I am very lost and any help would be greatly appreciated.
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Old 11-25-2012, 11:00 PM   #22
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i think your on the right track.. id advise you to start your own thread though because you do have different concerns..

ill post there with any help i can give you
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Old 11-25-2012, 11:06 PM   #23
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I still need 3 "legitimate" posts before I can start my own thread...
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Old 11-26-2012, 08:10 PM   #24
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my intake manifold will be coming in tomorrow night won't have time to mess with it much because i work :/
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Old 11-26-2012, 09:36 PM   #25
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STOP posting in my THREADS. seriously if you have an issue with me posting add 3% fees.. then do the math yourself. Take the price something is listed for and add 3% fees yourself. Are you going to complain to 1million other forum users about them asking for you to add 3% paypal fees to their asking prices? Grow up. Kids like you are problems with forums.

Your build is stupid. Do more research.
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