2.4litre stroker (2336cc) engine 2.3(2329)

[Lunatech]

Hello all,

I have been wondering for sometime what EXACTLY is needed to create a
2.4litre stroker (2336cc) engine.

Here is what I believe is needed,

EJ22 crank case
EJ22 pistons
EJ25 crankshaft with center thrust bearing
EJ25 connecting rods

My questions are regarding main bearings and pistons.

1. I read somewhere that the main bearings had to be modified, if so, in what way?
Which bearings should be used EJ22 or EJ25? Does it matter?

2. I also read somewhere that compression ratio calculates to about 8.3:1.Is this correct?
How does this compare to the stock EJ22 N/A compression ratio?

[evolutionmovement]

Stock CR is 9.5 on N/A, 8.0 on turbo. Sounds like a nice boat motor.

Steve

[Lunatech]

I wonder how much closer a set of 10.5:1 pistons (if there is such a thing) would bring it to stock.

Like stock is even a consideration once you've gone as far as to build a stroker.

However, does your 8.0:1 EJ22T/ N/A have good drivability, Steve? I mean as far as torque is concerned?

Has anyone done the dyno test on a stroked EJ22? Got numbers? If not that, then does anyone have a first hand report on the drivability and other characteristics of one? By other characteristics I mean fuel consumption and anything else worthy of note.

[evolutionmovement]

I've observed no apparent loss of torque, however, HP is definitely down. Acceleration from a stand still is greatly reduced. I've gone from 0-60 in a little over 8 secs. to a little over 10. In gear and cornering acceleration seems unchanged, though. My guess is I've gone from ~140 CHP to 125. I've also dropped gas mileage by about 15%.

Custom 10.5 pistons on a stroker with some valve work to roller rocker or DOHC heads would be a good way to go. While there I'd try to get stronger lighter rods to go with the pistons and match the assembled weights as best as possible. Eliminating the rev limiter would be nice so it could rev to 7500 or so and make more peak HP. Add headers and you're talking money, but could maybe hit 200 CHP and get decent gas mileage. It wouldn't be a racer, but it would definitely be fun. It's a thought I've been tossing around about my spare engine, but I can't afford it with my turbo build. I'd also get the block cryo-treated. I think this would be a blast in the right boat, too. Allright I've gone on enough.

Steve

[-K-]

Is there a good reason for this on a N/A? I mean you can get a 2.5 that is a real good engine and won't cost nearly as much as a custom pistoned 2.2 stroker.
Not to say it wouldn't be cool....

[evolutionmovement]

Less piston slap concerns and higher rpm potential, but, yes, a 2.5 would be much cheaper.

Steve

[Lunatech]

Less piston slap concerns and higher rpm potential, but, yes, a 2.5 would be much cheaper.

Steve

It would be much cheaper than what?

I still don’t know how much it will cost.

I just did an online search for a ’98 EJ25. In the northwest there were a number of them ranging in price from $1400 to $2300. There were also quite a few that did not list the price but I didn’t call any of them.

Now, let’s say I already have the crankcase and crankshaft and possibly the main bearings, that is if the EJ22 bearings are suitable. By my reckoning I still need the connecting rods, rod bearings and a set of pistons.

Pistons. Pistons.

I could get stock pistons pretty cheap, thereby making a compression ratio of about 8.6, if I recall correctly, or I could try to find a set of high compression slugs for the EJ22 and do the math to figure out the resulting compression ratio with longer stroke and shorter connecting rod. I’m actually leaning toward stock at this point, but I just don’t know what the torque or horsepower numbers are. I want to make an informed decision not one based on blind opinion or emotion.

That’s why I’m here to seek knowledge.

Who out there knows?

[THAWA]

technically it would be a 2.3l

[Lunatech]

technically it would be a 2.3l :)

Actually technically it would be a 2336 cc. See the Topic title.

But thats not why I'm here. I need solid, usefull, helpful information.

[scottzg]

Not very useful- 2.33 is about 1/2 way between 130 and 166. a 2.2 is rated at 130 and a 2.5 is rated at 166. Theoretical hp gain would be 18hp, totalling 148hp. I'm pretty sure the 2.5 is 10:1 comp ratio. Is 18hp worth all that work? To top it off, you dont have the convienence of a factory tuned ecu, etc.

Me, I'd stick with a factory 2.2 (which i intend to do) or turbo my 2.2 for 8 intercooled psi with megasquirt, giving a considerably larger gain for less money.

[Lunatech]

Me, I'd stick with a factory 2.2 (which i intend to do) or turbo my 2.2 for 8 intercooled psi with megasquirt, giving a considerably larger gain for less money.

There it is again, a reference to cost.

How much does it cost for pistons, rods and bearings.
I think I have everything else. Everything I have cost me around $300. Stock type pistons are around $100 to $125. Connecting rods I have yet to check into.

How much does it cost to turbo, intercool, and “megasqirt”? (NOS?)

While 18 more horsepower is pretty cool, I am actually more interested in the torque numbers. If anyone has such information please let us know.

[scottzg]

140lb/ft +165lb/ft /2= 153lb/ft.

A 13lb/ft gain, about 10%. Yay.

megasquirt is a diy engine managment program. Runs ~200$.

I'd say that on a 15 year old car with 182000 miles, cost is definately a factor. The car just isn't worth much. If you're going to completely rebuild the engine- new rings, pumps, seals, and gaskets, and pistons, then maybe its a perfect excuse to give yourself a slight performance boost. But after you've replaced all that junk, haven't you just about paid for a low miles ej25? And if you're not going to replace stuff, why tear into an engine that you might be in again in another 20k? It just doesn't make sense.

For tq, even 2.5L is fairly small, and turboes are a pain in the butt. I'd say your best bet, if price is no object, is a svx engine.

If you want to do a pile of work for relatively little benefit, go ahead, and ill applaud and support you, but personally, i wouldn't waste my time. My 2.2 takes me where i want to go.

[Lunatech]

Well if price was no object I might try an SVX engine IN MY FERRARI, But probably not.

Price is a huge object and my engine is on its way out.
I was able to obtain a free ’91 EJ22 that had a knocking sound. I tore into it and discovered the number one rod bearing and journal were destroyed. I called around to machine shops and nobody will even consider working on a Subaru crank. I ordered a reground crank (EJ22) $150 the parts guys accidentally sent me the EJ25 crank, I didn’t notice this until after the 30 day warranty period was up. They won’t take it back, I figure what the heck. I’ve been slowly doing this project anyway since my old engine does work well. It just uses a lot of oil. Since I spend so much time in the car, generally 3 to 9 hours a day, typically 100 to 400 miles, I really don’t want a new, low mileage rig that will just be ran into the ground. I like this car and I am kind of stuck with the engine parts that I have, so, I mean to make the best of it.

I could go and reorder another crankshaft and just go ahead with a standard 2.2 rebuild, but unless I could sell the other crankshaft first I would not be able to afford to do that. Plus a used engine from a wrecking yard would cost upwards of $900 with a 30-day warranty, what shape is it really in? I don’t know.

I’m into this thing for about $300 now and still have pistons and connecting rods to go. I doubt they will cost $600. Even if they do I will know exactly what is going into it.

[scottzg]

Well if price was no object I might try an SVX engine IN MY FERRARI, But probably not.

I suggest you keep your ferrari engine in your ferrari.

Ok, now your position makes more sense. The ej24 plan that you hear of occasionally is a turbo application. They use a 2.2t block and the 25 crank you've got, basically doing what you intend to do. In the turbo motor, it makes sense to keep the low compression, but usually it has forged pistons and whatnot anyway. More information herehttp://wac.addr.com/auto/obs/turbo/ejcalcs.html

In your case, 8.3:1 cr with 2.35L will produce about the same power output as the 2.2L with marginally worse economy. It would be a good basis for a torquey turbo motor.

I think custom pistons might sink the good ship 'Worthwhile,' as I have not heard of an inexpensive cast piston in that size (not to say it doesnt exist!) and forged units run upwards of 600$ and are unnecessary.

You could mill down the heads a touch, put on a thinner hg, and prolly sneak away with something close...

That's really all the info i can provide, im sure as hell no subie engine expert.

[greg donovan]

if you can find a phase II ej25 shortblock put the ej22 heads on it will yield a CR of around 11:1. i was going to do this but now am in the process of getting a legacy turbo.

there is a guy on 2.5RS forum that did this about a year ago w/good results.

[-K-]

Well your question doesn't seem so out there now. Unless you figure out the CR problem I don't think you will get much if any power increase. I know there are some places that will make just about any custom pistons you want. I have no idea how much it would cost.
Oh almost forgot. What 2.5 crank do you have? Phase I or II
I think only one will work but don't remember exactly.

[Lunatech]

I’m not sure how to tell the difference between phases one and two.
When I plastigauged it I put the thrust bearing in the center. Everything went together OK.
Does that mean phase one?

It gauged at .04” with EJ22 bearings and Haynes (LOL) says main bearing oil clearance should be .0004”. That is the reason I wonder if I should get EJ25 bearings. Haynes is not clear if there is a difference between the two. It only states a slight difference in main bearing journal diameter size for ’90 thru “94 and ’95 thru ’98. I guess that means all the 2.2 and 2.5 from ’95 thru ’98 are the same?

There are numbers stamped on the crank itself. If I were to get those could some one cross reference them?

[THAWA]

technically it would be a 2.3l

Actually technically it would be a 2336 cc. See the Topic title.

But thats not why I'm here. I need solid, usefull, helpful information.

Hey lets get real techincal. First of all it wouldn't be 2336cc's, it would be 2329 cc's. Dont believe me let me solve it for you

bore: 9.69cm
stroke: 7.9cm
cylinders: 4

The equation to find the area of a cylinder is: A = pi*r^2*h
Multiply that whole thing by 4 to find the displacement of all 4 cyls and there's your real displacement.

so D = 4(pi*r^2*h)
d would be displacement
pi would be rounded to 2 sig figs or 3.14
r would be 9.69/2 or 4.845
h would be 7.9

D = 4(pi*4.845^2*7.9)
D = 4(pi*23.474025*7.9)
D = 4(pi*185.4447975)
D = 4(3.14*185.4447975)
D = 4(582.29666415)
D = 2329.1866566

Now lets talk about the liter aspect. anything 50cc's or greater is rounded up to the nearest liter. Anything 49cc's or lesser is rounded down to the nearest liter. So your 2329cc engine is a 2.3l, even if it were 2336cc it would still be a 2.3l. Yes I realize using a longer version of pi yields a different answer, but even rounding to the 30th decimal only ups the ccs tp 2330.

[Lunatech]

Whether it’s 2.3, 2.4, 2336, or 2339, doesn’t really matter as far as I’m concerned. Call it what you will. I am BORED with picking knits.

Although I think I figured out the main bearing issue as I typed my most previous post. One thing I still don’t know is which phase of crankshaft I have or if it even matters.

[-K-]

Phase II has the thrust bearing in a different location.
So if it fit I think it's the right one.

Call someone who would know, Crawford comes to mind and they make custom pistons for just about anything.

Some of us are a little familiar with the idea but I don't think anyone here has done it. Let us know what you find out and I don't think anyone here is trying to be a smart ass to you.

[THAWA]

What type of heads did the ej25 have? If it had DOHC it was a phase I, if it had SOHC it was a phase II. Or what year and model was it from? IIRC 99+ impreza and forester are Phase II, and 00+ legacy and outback are Phase II

[Lunatech]

Scott- I totally missed your post with the link to the CR calculation page. There is a lot of good info there. Thanks, and I think the Ferrari engine is in no real danger of being replaced.

-K- I suppose you are right, I should speak someone who would know. In my travels I occasionally go past a repair shop that specializes in Subaru. I have stopped in to ask questions before, but the guy either A: doesn’t know much about modifying these things, or B: figures he’ll never make any money from giving advice, so doesn’t say much. Which ever is the case I can’t really blame him? Maybe I’ll stop by there again for have a chat with him, and bring coffee and doughnuts.

THAWA- I wish I knew how the engine the crank came from was configured. But I went to the counter at Quality parts to order it and pick it up, it was in a box.

Thanks to all for the responses and the concern.

[Penguin]

Um i know it is kinda old now but....... the svx engine won't fit in a 90-94 leg, well it will but can't fit the radiator in there.

(I have personally tried this.., in real life. Some major engine bay moding is needed OR like i wanted to do but my boss said no, you could put the rad on the roof rafe and still keep the fans underneath. I mean talk about cooling power!!!)

and lunatech when you get the 2.3?l stuff figued out PLEASE post it. I would love to do the same with my 22t

[ballitch]

has anyone thought about taking a stroll over to nasioc and searching there? im sure ive seen the info on that site before.


~Josh~

[93forestpearl]

My Wiseco pistons and eagle rods ran about $800. The thing is, with the Wisecos, you need to bore the cylinders .020 or .040 over, which pretty much eats up the difference in cost from custom pistons. You would still need bearings and seals, and while you had it torn apart, it would be foolish to not replace the water pump, oil pump and timing set. I hope you are starting to see how this stuff gets real expensive real quick.

Generally, with NA motors, getting power out of them focuses alot on the heads and rev limit. Neither is a cheap endevour. Just upping your displacement, along with lets say intake and exhaust plumbing, won't get you a whole lot for how much money you have invested. You still need to get the gases in and out of the cylinders better.

Personally, my feelings on subarus is that the best way to make power is with a turbo motor, and the cheapest way to make power is with a turbo motor. Whether you want big power, or just a little grin factor, the most economical way is with a factory turbo motor. If you know where to look, you can get an ej22t for cheap(Mine was $250).