Choosing an engine upgrade for a 94 Legacy. No turbos here.

VRoman · Post by **VRoman** » Wed Mar 21, 2007 5:13 am

I decided to modefy my engine to get more power out of it, but I can't deside what to do:
1) stay with 2.2 engine, get new cams, pnp heads, try to find higher compression pistons;
2) build a 2.5 engine with my current 2.2 heads, cams and heads done as well;
3) get a 2.5 Phase2 engine and work with it.
So what are exactly the benefits of each setup? How difficult is it to wire the 2.5 engine? Can the stock ECU be tuned for the new setup, or is it too old for that and I will need to get a stand alone?

Splinter · Post by **Splinter** » Wed Mar 21, 2007 5:33 am

Get one of the new Tribeca 3.6L engines

206er · Post by **206er** » Wed Mar 21, 2007 6:57 am

1 dont bother given that you can do #2(lol)
2 would be the easiest way
3 could get more power with the better heads but a little more
ecu should be able to learn quite a bit but for best power some sort of tunable efi would be better.
I did #2 and would not do it again. save money for a turbo setup even a low boost tdo4 setup on your ej22e. 2.2/2.5 has underwhelming power at 5000' and heavy car. but, it has decent pull in 1st/2nd gear, I get 24-27mpg runs like a top and it never gives me trouble.

n2x4 · Post by **n2x4** » Wed Mar 21, 2007 12:53 pm

Subysport mag. did their 2.5L build. They had like 10 grand in the motor to keep it NA, and last time I read about it, they only had 220HP. It might be more now, but still, bummer.

VRoman · Post by **VRoman** » Wed Mar 21, 2007 4:51 pm

So, how much better are the 2.5 heads comparing to 2.2 heads? If it's only 10hp, then I'll keep the old ones. What size valves can I use with 2.2 heads? Well, assuming that I get new valve springs and PnP done. I'd rather keep 2.2 heads after the idler pulley broke on me last fall. They saved the engine, literally. Will the new cams push the valves far enough to interfere with pistons, so it won't be worth keeping the old heads?

206er Is your engine running out of air above 5000?

Are you using stock cams?

3.6 or turbocharger won't look stock.

206er · Post by **206er** » Wed Mar 21, 2007 5:46 pm

i guess thats one way of putting it

. 5000' elevation the air gets quite a bit thinner than sea level and I do spend a good amount of time at 10,000+ so NA cars are hurting. I take the car to redline almost every day and it does fall off slightly towards 5500rpm or so.
yes i have stock cams which I would say its a must to do the delta cams while you are doing the 2.5 block because doing cams requires either pulling a head or pulling the engine. they supposedly wake up the top end a good bit.
the 2.5 heads have excellent flow, on cobb tuning's website there is a flow sheet of various subaru heads.
I'm not sure what the actual gains of going to sohc2.5 heads would be other than that you can rev them to the moon in stock form and they flow a lot better.
btw converting to a ej25 top end should not be super difficult to retain the stock ej22 EM.

Matt Monson · Post by **Matt Monson** » Wed Mar 21, 2007 11:50 pm

n2x4 wrote:Subysport mag. did their 2.5L build. They had like 10 grand in the motor to keep it NA, and last time I read about it, they only had 220HP. It might be more now, but still, bummer.

Don't take everything you read in the magazines at face value. There's some real issues with their build that I am not at liberty to discuss. But trust me, that engine has issues. Do a search for my Ej25 thread here in this forum. I put about $7500 less into my engine than Subiesports put into theirs and got nearly equal numbers. They were kind of embarassed about it all on NASIOC...

Matt Monson · Post by **Matt Monson** » Wed Mar 21, 2007 11:53 pm

http://bbs.legacycentral.org/viewtopic. ... light=ej25

made it easy for you...

Murphy · Post by **Murphy** » Thu Mar 22, 2007 3:09 am

how much bigger is the 3.6L than the EZ30, an EZ30R barely fits into the engine compartment, but it bolts to the EJ mounting brackets and fits about 2-3 inches from the radiator

Edit: crap, i just read about it, its not an H at all, in fact its a V6, its blasphemy, i wouldn't put it in my car if it did fit and i had the money

Splinter · Post by **Splinter** » Thu Mar 22, 2007 4:06 am

What are you talking about?

The 3.6 is a flat 6

Its exactly the same physical dimensions as the 3.0, they used some kooky rod design to get extra stroke out of it

Basically, what it boils down to, is that Subaru is really bad at building naturally aspirated engines. They suck. Bigtime.

206er · Post by **206er** » Thu Mar 22, 2007 4:34 am

Splinter wrote:
Basically, what it boils down to, is that Subaru is really bad at building naturally aspirated engines. They suck. Bigtime.

uuuhh no?
ea81-reliable enough that it is among the industry standards for homebuilt airplanes
ea82-yeah, they suck balls
ej22e-dead nuts reliable and torquey as hell for what it is
eg33-silky smooth torquey amazing sounding engine
ej25's-have some SERIOUSLY good ports from the factory and SOHC has an extremely light valvetrain, so what if they pop head gaskets after 60k? run MLS's.
pound for pound(and I mean that quite literally) there arent many NA 4 bangers out there that can match the EJ. well under 300lbs ready to run?

555BCTurbo · Post by **555BCTurbo** » Thu Mar 22, 2007 4:50 am

Splinter wrote:

Basically, what it boils down to, is that Subaru is really bad at building naturally aspirated engines. They suck. Bigtime.

Completely dumbass statement...

That's probably the reason there are so many 250k mile EJ22E's running around...

+1 to what Jeremy said...

Murphy · Post by **Murphy** » Thu Mar 22, 2007 4:52 am

Splinter wrote:What are you talking about?

The 3.6 is a flat 6

Its exactly the same physical dimensions as the 3.0, they used some kooky rod design to get extra stroke out of it
.

V6 is what i read on AutoBlog, maybe they were confused but thats what it says

VRoman · Post by **VRoman** » Thu Mar 22, 2007 6:11 am

206er Yeah, I've noticed that my rans out of power at high elevations, above 7000' it is reallly noticable. Oh well, it's NA...
I couldn't find the flow chart on 2.2 and 2.5 heads. I remember that I've seen it on cobb's web site like a year a two ago...

Matt Monson Thanks for the link. I've read first page last week, but I didn't pay attention to the second page.

It looks like I will be building an engine pretty much like yours, but I will spend more money into the heads. I do need 7500rpm red line, and I'll probably move torque and power up by 1000rpm or so. PS. The description of your cams says that torque and power should be moved up a little, but on the graph torque curve looks like stock or stage1 cams.

So... now I am thinking about getting a 2.5 SOHC for my car, unless someone thinks I should go with DOHC. How difficult is it to wire EJ25 to the stock ECU?

555BCTurbo · Post by **555BCTurbo** » Thu Mar 22, 2007 6:25 am

There is a guy on this board who did a SOHC EJ25 with 2.2 management...and it works fine...

206er · Post by **206er** » Thu Mar 22, 2007 6:42 am

also you can do dohc just fine.

Manarius · Post by **Manarius** » Thu Mar 22, 2007 4:11 pm

Could always be daring and put an EG33 in. 230HP stock..just a little heavy...

Matt Monson · Post by **Matt Monson** » Thu Mar 22, 2007 7:15 pm

Vroman,
Do some digging for stock RS charts. You will find peak HP is 500-600 lower than mine. And good luck finding cams with a higher peak power for those heads without going with a custom grind and spending a shitton on them. I will try to say this without being rude. Don't try and reinvent the wheel. There's a bunch of guys over on NASIOC who keep thinking they can better what I have done here. So far, without spending 5 figures on a build, noone has done it. As my soccer coach used to say, keep is simple, stupid!

When you get into raising redlines and all that, everything gets WAAAAYY more complicated. You will need a standalone. You will also need upgraded valvetrain. You will also want to blueprint your bottom end. etc. etc. etc. So, the question I leave you with is this: Are you ready to spend 4-5 times the value of the car to build an engine that might put out 5-10 more HP than mine? Or spend a couple grand following a known and prooven formula and have something that is reliable, driveable and still one monster of a sleeper...

aspect · Post by **aspect** » Thu Mar 22, 2007 8:48 pm

Why not just buy a usdm WRX motor for a couple thousand and drop that in? Exhaust + tune gets you ~270hp and you pretty much have OEM stock reliablity.

Yup, the N/A build is probably smoother to drive and it's pretty cool too, but I think matt did the right thing by calling it a finished build at the point he did. 149whp on a dyno dynamics unit is definately in the WRX range, and he didn't actually spend that much money or time on the motor...if he had built a turbo kit for the same price, it would be pretty crappy and risky on that motor.

Once you get into expensive headwork and fiddling with the bottom end to keep up with your new high rpm valvetrain, imo you are just wasting money and spending twice as much to get that last 10%. If you went with a turbo setup you could take that $5k or whatever your budget is and make more power, have more reliability, and do less work.

"But what about turbo lag???11??oneone?"

If you look at matt's dyno in the other thread, his motor gets a big fat torque boost from teh cams around 4k rpm. A stock WRX turbo with a little P+P is going to be making full boost at 3k rpm. Yeah, I know, its not exactly the same, but keep in mind that getting max power out of an N/A setup usually means the car is just as useless below 4k rpm as a wrx with a huge turbo.

I know people like to be original but sometimes the road less travelled is less travelled for a reason.

If having a high-revving, peak-hp style N/A engine really floats your boat, perhaps a subaru is the wrong choice of car?

Matt Monson · Post by **Matt Monson** » Thu Mar 22, 2007 9:24 pm

If it's about being unique and different, do the build on the Ej22 block. Get custom high compression pistons made and design the thing to rev to 9000 rpms. Then use some DOHC Ej20 heads outfitted with some really agressive cams and port the shit out of them. Basically, do something like the Ej20R but do it with 2.2l instead. At least that's what I would do if I was going to go to all the trouble to really build an NA engine for the legacy...

Post by **DLC** » Thu Mar 22, 2007 9:34 pm

I like this kind of conversation, especially in this forum. I'd love to have more power, but I don't think a turbo is for me because 1) that's too much temptation 2) I really like the NA feel and 3) I like having a car that gets 25+MPG.

I don't trust my current engine one bit, but I think there might be an EJ257 block with high compression pistons and SOHC heads in the distant future. Maybe not...

VRoman · Post by **VRoman** » Thu Mar 22, 2007 9:43 pm

Well, as far as where I want the power I still haven't decided. All I want is to be able to stay in 1st gear as long as possible without having to shift. I need that for autocross. Peak power may be at 6000, but I still want to have red line at 7500-8000. I'm not looking for max power, I want torque, instant response, and good gas mileage for daily driving
Matt Monson I probably am trying to reinvent the wheel... I just want to make sure I understand everything what I am doing and why this way is better for me than another. That's why I am here, to learn possible mistakes before I do something stupid.
I'll definately get an upgraded valvetrain. That's why I said that my engine will look like yours eccept for the higher rev. Now, can't Delta grind any custom cams? 0.5" lift or so...

150whp is enough for me, 6500rpm red line is not. My dream is 200-220chp and 8000 red line. Let's see how much money it will take to get there.

Then I'll make up my mind whether I want to spend that money or not.

perhaps a subaru is the wrong choice of car?

No, it is the right car. No other car can do every single racing stile and be daily driver, all at the same time. Only Subaru can servive my spirited driving. Jump 2 feet in the air every time I go to work, racing at the track every month, creating new offroad trails and so on. 5 years of fun, there is no way I'll change this car.

Splinter · Post by **Splinter** » Thu Mar 22, 2007 10:44 pm

Honda 1.6: 160hp, 111ft-lbs of Torque
Subaru 1.8L 110hp, 110ft-lbs of torque

Nissan 2.0L: 150 hp, 148ft-lbs
Subaru 2.5L: 160hp, 163ft-lbs

Nissan 3.0L: 240 hp, 227ft-lbs
Subaru 3.0L: 245hp, 215ft-lbs

Thats just as far as stock goes... as far as potential goes, Hondas and Nissans have been proven time and time again to have massive NA potential.

evolutionmovement · Post by **evolutionmovement** » Thu Mar 22, 2007 11:59 pm

Torque curve vs. torque curve is more important than peak number. I also think some manufacturers approximate the amount of work done by their engines as compared to number of ponies. In real life, I've found Subaru engines to have more muscle than cars with engines boasting same or a little more numbers. A 160HP Honda Civic Si hatch (same approximate weight also) only pulled on my low compression 2.2 when I ran out of rpm somewhere around 80mph. I'm not saying these engines are best in class, but they are far from worst.

aspect · Post by **aspect** » Fri Mar 23, 2007 1:11 am

VRoman wrote:
perhaps a subaru is the wrong choice of car?
No, it is the right car. No other car can do every single racing stile and be daily driver, all at the same time. Only Subaru can servive my spirited driving. Jump 2 feet in the air every time I go to work, racing at the track every month, creating new offroad trails and so on. 5 years of fun, there is no way I'll change this car.

Well said! New sig.

Something to possibly consider if you are looking to stay in 1st a little longer is going to a slightly longer final drive ratio. This might end up being more difficult then just making your engine rev a lot higher though.

Perhaps there's a supercharger system that would meet your needs...I don't really know what the market is like. Typically superchargers offer faster response and better low-end power than turbo applications. Also keep in mind that a well ported, ball bearing turbo will spool up extremely quickly.

The torque curve on a turbo engine is largely dependant on the tuning as well. A good auto-x tune should provide you with much better response and torque than a stock turbo motor would provide. Again, I don't know if getting a tuneable ECU or reflashing a WRX ecu is within your budget.

EDIT: nevermind, I can't fit the quote into my sig

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Choosing an engine upgrade for a 94 Legacy. No turbos here.

Choosing an engine upgrade for a 94 Legacy. No turbos here.