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Old 06-21-2005, 03:00 AM   #1
josh...just josh
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Default why not more super powered N/A Subies?

so this is just one of the things I think about when I get bored. I got a kick to look into Hondas and bit and I've come away with some food for thought...I cant get over how generic and uninspired hondas look but the thing is I am honestly impressed with their power figures.. close to 200hp with a N/A 2.2L, that is really something. You dont many really powerfull N/A subarus out there though....and almost never any that spin 8500-10000rpm like the hondas do, and why not? I know that big H cars are big bore really short stroke/ rod ratio type machines and that subies really arent but I have always wondered what it would be like to have a high horse, high rpm, screaming little n/a suby. has anyone really set out to build such a machine? am I missing out on whats been done already? I'm not sure what engine would have the smallest rod ratio (they all have very simalar strokes right) or if the stuff is even available for suby owners (honda guys get all the stuff), but I would love to see a dry sump ej22 with ported ej18 heads, hotter cams, and stronger rods turning nine thousand times a minute and pulling 250+ hp...someone build that
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Old 06-21-2005, 10:44 AM   #2
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those high hp screaming honda engine have no torque and have to rev that high just so they can get moving. Plus the fact that hondas are lighter that they don't really have to worry about torque as much. Also, honda engines are inline 4 cylinders which is really easy to make them rev easy while we get the boxer engine that is harder to make it rev. While it's doable, it'll take alot of money to make a subaru engine that can rev as safely as a Honda. Besides Subaru engine are WRC tested and all the rally engine are turbocharge, so it's easier for us to follow what works and stick with it. People have built 250+ hp N/A subaru engine, but they don't go as fast as their turbocharged brothers.
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Old 06-21-2005, 02:40 PM   #3
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I think Fuji Heavy Industry has the mentallity "If it ain't broke, why fix it?"
They stick with what they got that works. WRX and STI redlines at 7000 I think. Not bad, but I think they can go even higher, safely and cost effectively if they went back to the drawing board instead of improving on what they have.

I believe Porche redlines somewhere up there too, but they have a lot less drivetrain loss.
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Old 06-21-2005, 03:50 PM   #4
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Well,
If one is talking about the Ej25, a big problem is that the engine is oversquare. As such, it's dwell time at TDC makes it hard to get a complete burn. This effectively limits how high you can rev that engine. On Irish Mike's NA car, which is supposedly 290hp, TWE made him some special domed pistons to make that kind of power. And he does quite well in the Touring Class races he does. I say it is BS that the NA cars are slower than their turbo charged brothers of equal power. The 2.5 NA's make more peak torque and more power under the curve than their 2.0l turbo charged brethren.

Funny this came up because Diz and I were talking about such things last night. Now if one were to do this, the Ej22E block would be a good place to start. But you are never going to get really good flow out of Ej18 heads. Even heavily ported, the valves are just too small. Not to mention, the combustion chamber is so damned small you will never make serious power with them. You would want something like the EJ25 heads, doesn't matter if they are SOHC or DOHC, as they both flow great. All that you really would need is a custom domed piston with valve cut outs to get the CR up without valve to piston contact issues. Then you could rev the piss out of it.

This really is not unlike the R spec EJ20 NA that they have in Japan. I don't remember the numbers on it, but it is something like 210hp with AVCS and an 8000rpm redline.

Last edited by Matt Monson; 06-21-2005 at 04:02 PM.
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Old 06-21-2005, 04:21 PM   #5
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Quote:
Originally Posted by Matt Monson
This really is not unlike the R spec EJ20 NA that they have in Japan. I don't remember the numbers on it, but it is something like 210hp with AVCS and an 8000rpm redline.
I think that it is time to import an engine or two for a build up. j/k
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Old 06-21-2005, 04:23 PM   #6
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Yeah. Also, they use turbos to get more power. Why make an NA car with dangerously high HP, when you can make a cheaper more cost effective motor that makes more HP with the same or even less engine wear.
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Old 06-21-2005, 05:00 PM   #7
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Originally Posted by STiTkacik
Yeah. Also, they use turbos to get more power. Why make an NA car with dangerously high HP, when you can make a cheaper more cost effective motor that makes more HP with the same or even less engine wear.
aaahh, the seemingly mandatory: "why not just add boost" post.

Some people like things that are a bit different or more a challenge. Not because it makes more power or is cheaper, but because they made it work and THEY are happy with it.

Jared
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Old 06-21-2005, 05:07 PM   #8
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Quote:
Originally Posted by gtwagon941
aaahh, the seemingly mandatory: "why not just add boost" post.

Some people like things that are a bit different or more a challenge. Not because it makes more power or is cheaper, but because they made it work and THEY are happy with it.

Jared
True. I was just talking about why Subaru hasn't mass produced a high hp NA car.

I for one think it's awesome seeing 200 + hp low displacement motors... But it's just not Subaru's "bag."
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Old 06-21-2005, 05:15 PM   #9
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i don't think theres a big market for na subarus (performance wise). i think subaru just sees the na motor for those customers who just want a subaru for awd and all these other nice stuff without the extra cost for having extra power that they will never use. i think theres a bigger market in the performance department, for turbo motors cuz (especially us americans) the word "turbo" makes us want to buy a car more then if it didnt say "turbo" kinda like a marketing scheme typish thing. thats just my 2cents
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Old 06-21-2005, 05:43 PM   #10
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yeah we don't have enough of an aftermartket to take a N/A subaru engine over the 270+ hp mark reliably. I for one would like to have a super N/A engine but when I reach that limit of 270 hp I'll have to stop, which I really don't want to do. But I do believe that people will try to get more out of these engine without having to go the forced induction way. What I meant with the turbocharge being faster than the N/A is that they can have more tq and hp not saying that with the same hp the turbo car will be faster.
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Old 06-21-2005, 07:32 PM   #11
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Horse power is horse power, turbo or NA. Hp at the crank or flywheel is a calculated figure (550 ft.lbs. per second) that car companies feed us. Horse Power that is measured at the wheel is a dyno machine measuring torque and converting it into horse power.

If a turbo car has a dyno graph EXACTLY the same as a NA car that weighs the same with the same gearing and so on, they will accelerate the same.

NA cars are probably faster than turbo cars of the same HP because of, maybe turbo lag, or maybe better low end torque due to bigger displacement, and other outside factors.

A ton of bricks weighs the same as a ton of feathers. One just hurts a lot more to get hit with.
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Old 06-21-2005, 07:53 PM   #12
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feathers hurt too. especially if it weighs a ton
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Old 06-21-2005, 09:11 PM   #13
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Quote:
Originally Posted by Matt Monson
Well,
This really is not unlike the R spec EJ20 NA that they have in Japan. I don't remember the numbers on it, but it is something like 210hp with AVCS and an 8000rpm redline.
Quote:
Originally Posted by impr25rs
I think that it is time to import an engine or two for a build up. j/k
Heres the actual subaru info about that motor:

http://www.subaru.co.jp/legacy/b4/me.../07/index.html

190ps, 7200rpms AVCS, etc.


But seriously, im still waiting for someone to fiddle with that motor...

I mean, to start of our usual bolt on mods will definatly benifit that motor. Full N/A exhaust, +15hp, Cobb like intake, +5-10hp, lightweight flywheel, underdrive pulleys, etc. should get it up to 220hp easy considering how we get our 2.5's up from 165hp to ~190hp.

Then use a 2.5 short block instead of the 2.0 (might require different pistons for valve clearance or even compression ratio, but who knows until someone tries) which should net at least 20 more hp, if not more. Add that too some ECU reflash tuning, or something like rallitek's unit to get the motor running more properly and using that AVCS for a couple more hp.

Then throw in even more drastic stuff like upping the Compression ratio, Porting the heads ala Spec-C style, and even extrude honing the intake manifold. Then throw in a 4.444 5-speed with RA gearing and it should be a nice and quick car without being another WRX swap.
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Old 06-22-2005, 06:23 AM   #14
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Quote:
Originally Posted by Kostamojen
Heres the actual subaru info about that motor:

http://www.subaru.co.jp/legacy/b4/me.../07/index.html

190ps, 7200rpms AVCS, etc.


But seriously, im still waiting for someone to fiddle with that motor...

I mean, to start of our usual bolt on mods will definatly benifit that motor. Full N/A exhaust, +15hp, Cobb like intake, +5-10hp, lightweight flywheel, underdrive pulleys, etc. should get it up to 220hp easy considering how we get our 2.5's up from 165hp to ~190hp.

Then use a 2.5 short block instead of the 2.0 (might require different pistons for valve clearance or even compression ratio, but who knows until someone tries) which should net at least 20 more hp, if not more. Add that too some ECU reflash tuning, or something like rallitek's unit to get the motor running more properly and using that AVCS for a couple more hp.

Then throw in even more drastic stuff like upping the Compression ratio, Porting the heads ala Spec-C style, and even extrude honing the intake manifold. Then throw in a 4.444 5-speed with RA gearing and it should be a nice and quick car without being another WRX swap.
Werd!

Now all we have to do is find a place where we could buy this motor. If I could find a place to buy from I would save up for it. However I think I would keep it in 2.0L form for a while and see what is possible then maybe switch over to the 2.5 block, but who knows.
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Old 06-22-2005, 09:52 AM   #15
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there IS a DOHC AVCS version of EJ25 for last gen legacy. although it only makes 170 hp.
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Old 06-22-2005, 01:09 PM   #16
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yeah that sounds like a good idea. but wouldn't it be cheaper if you just bought the head, ecu, and harness if you're going to swap the block?
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Old 06-22-2005, 01:12 PM   #17
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why wouldn't you just throw some higher comp pistons and stronger rods into an ej22 or ej25?
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Old 06-22-2005, 01:18 PM   #18
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the point is that turbos are very efficent if you think about it, they use energy that would normally be wasted by your exhaust (turning the energy into random heat to make the exhaust charge quiter) to force air into your engine. but everyone that has a serious performance subaru has a turbo. I got a subaru in the first place I wanted to be different, here in iowa the only people that have imprezas are the few rich kids, a couple of guys in midlife crisis, and a few college kids with beaters like mine.
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Old 06-22-2005, 09:33 PM   #19
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Quote:
Originally Posted by CitySubie
A ton of bricks weighs the same as a ton of feathers. One just hurts a lot more to get hit with.
Awe man! This was a cool saying until you said a ton of bricks would hurt more than a ton of feathers. They both will do a ton of damage.
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Old 06-22-2005, 09:40 PM   #20
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Originally Posted by josh...just josh
You dont many really powerfull N/A subarus out there though....and almost never any that spin 8500-10000rpm like the hondas do, and why not?

It is because of VTEC
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Old 06-22-2005, 09:46 PM   #21
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Quote:
Originally Posted by josh...just josh
why wouldn't you just throw some higher comp pistons and stronger rods into an ej22 or ej25?
Cause the heads will still be garbage.
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Old 06-22-2005, 11:52 PM   #22
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hmm... another high hp N/A thread

An RS for example with 230hp N/A vs a WRX with 230hp turbocharged, the RS might win due to its being 100 pounds lighter and having no turbo lag, but it also might lose as to not having as much high rpm pull as the turbo, although with a 230hp built n/a motor i think cams and heads of such might give you that high rpm pull. This example is really unrealistic, a turbocharged vehicle can pull out way higher hp figures than an N/A motor for a lot less money, its just as simple as that. If you want a crap load of hp n tq go with a turbo kit, if you want somethin that'll be faster than most things on the street go with the N/A buildup.

Its rather simple. You can pull off aroudn 300 hp tops off a RS n/a buildup which would go faster than an STi since the STi is 300 pounds heavier. All in all a built 2.5rs will rev up to 8k (depending on parts used) pull off around 300hp tops and is 100 pounds lighter than a WRX and 300 pounds lighter than a STi. Yet the amount you spend on that will leave you wondering why didn't i just go with a turbo buildup.
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Old 06-23-2005, 03:08 AM   #23
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If anyone wants 300hp N/A in a scoob, then screw the H4 and go for an H6.
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Old 06-23-2005, 08:59 AM   #24
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The bore/stroke ratio has little to do with the top end hp. One of the latest car mags just did an articule on this using an engine set up two different ways ie big/short and small/long. They saw little difference from either setup and posted the numbers. Porsche/ Farrarie(sp) and most top end engines utalize a square to large bore to stroke ratio. Subaru has chosen a larger bore to stroke ratio and cam their engines for mid rpm torque which is what we need for daily driver. An additional benifit of a shorter stroke engine is that piston speeds are lower which results in less piston and cylender wear and less friction/heat. The smaller the engine capacity the easer it is to get high rpm but the bottom line is you get less torque for a given rpm which is the important thing.
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Old 06-23-2005, 10:29 AM   #25
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Quote:
Originally Posted by Caplin 2.5
hmm... another high hp N/A thread

An RS for example with 230hp N/A vs a WRX with 230hp turbocharged, the RS might win due to its being 100 pounds lighter and having no turbo lag, but it also might lose as to not having as much high rpm pull as the turbo, although with a 230hp built n/a motor i think cams and heads of such might give you that high rpm pull. This example is really unrealistic, a turbocharged vehicle can pull out way higher hp figures than an N/A motor for a lot less money, its just as simple as that. If you want a crap load of hp n tq go with a turbo kit, if you want somethin that'll be faster than most things on the street go with the N/A buildup.

Its rather simple. You can pull off aroudn 300 hp tops off a RS n/a buildup which would go faster than an STi since the STi is 300 pounds heavier. All in all a built 2.5rs will rev up to 8k (depending on parts used) pull off around 300hp tops and is 100 pounds lighter than a WRX and 300 pounds lighter than a STi. Yet the amount you spend on that will leave you wondering why didn't i just go with a turbo buildup.
I think you guys kind of missed the point on my example, especially given that whole ton of bricks vs ton of feathers metaphor that other guy used. If you look at the dyno sheets, my 225hp Ej25 has more power under the curve than a 227hp WRX. I make and hold 200+ft/lb of torque from +/-3000rpm, all the way to redline at 6400rpm. Even with a few hundred more rpm on the EJ20, it isn't going to make much difference. As has been stated, HP is just a measurement of torque@rpm. While the peak HP number comes out the same, my engine produces more torque across the board, and therefore more "average" horsepower. And as such, even if my engine were in a WRX chassis, with the same gearbox, and no significant difference in weight between the two cars, the NA EJ25 powered car is going to be fasterer.
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