Ok folks, I have a MY00 OBS, rated stock at 142.

I put in an Amsoil filter, removed the intake silencer, added platinum 4 plugs, Stromung Muffler and a Under drive pully.

So whats the concensus on the HP gains?

I know it feels faster, just curious.

Next step, Cobb Tunings new intake! http://www.i-club.com/ubb-files/smile.gif

About 146-148!!!

Max

Woah, I say too low.. That combo has got to make at least 10% Thats what it feels like.

What do you base your estimate on?

Individually Stromung gives 4-6% Pully is 6-8hp, intake say 3hp. I got these figures from various sites.

...but the effects are not neccessarily cumulative. The intake and exhaust work together for example, and the plugs really don't do anything for you. Some people will say, I've got +5 for intake, +10 exhaust, +5 pulley, +5 bored throttle body, +12 flywheel, so +37 hp right? Highly doubt it. I'd say 150ish.

Brian
http://members.nbci.com/_XMCM/northursalia/impreza/index.htm
I think I bent my Wookie.....

I know you can't just add them up.. http://www.i-club.com/ubb-files/smile.gif And my figures don't.

If I did that I would be pushing around 160, instead I say 10% - around 156.

Sold!!! http://www.i-club.com/ubb-files/smile.gif

Brian
http://members.nbci.com/_XMCM/northursalia/impreza/index.htm
You and the Captain make it happen....

no way jose,

you can't magically add hp to an engine. With a better filter and muffler and pulley, your just making it easy on the engine to extract energy from the fuel more effectivley. For example, better throttle response, lower operating temperature, effective sparking (better fuel consumption). But to magically add hp is a misconception. I don't care if a filter adds 3% and muffler adds another 5% (fact). That is not true horepower, your engine is not producing more power. If you want to add hp get cams, computer, turbo, add displacment or a FULL exaust setup (even then). yes it's not cheap, but when was it ever.

Not sure I agree with you there. The mods you recomend are simply an extension of making th engine breath better. Which is the purpose of the Intake and Muffler. The pully is only freeing up parasitic loss, I will give you that...

What does forced induction do? Gives a bigger volume of air, bigger bang, etc, etc.. So if after market filters are supposed (and I say that tongue in cheek) to give around 50% better flow than stock, and a tweeked exhaust system reduces back pressure. Then your natuarally going to get more throughput. No huge gains like a turbo, but your still making more power.

Thats all cams do too. http://www.i-club.com/ubb-files/smile.gif I know simply adding a muffler is not going to give huge increases, but it's still a step in the right direction.

After all Cobb Tuning states:

Stage 1 improves power by approximately 10% over stock and significantly improves throttle response, torque, and even gas mileage. Power package consists of Stromung Single Tip Performance Muffler System**, Stromung 57mm Intermediate pipe, K&N Replacement Air Filter, and the Power Pulley Kit. All these combine to improve performance without taking away from the drivability of your car.

Hehe, I like this game of pulling numbers out of no where.

http://www.i-club.com/ubb-files/biggrin.gif

Ash, you oversimplified everything. Cars are not lawnmowers and there is much more things that "big" exhausts do besides reducing the backpressure, which is actually not always too good.

I think that your mods are difenetely steps in the right direction. If you really want to "fell" some power, get a better clutch and lightened flywheel. I consider these 2 alone to be the best power mods you can do to a NA car besides a good intake and exhaust.

WRXWanabe,
True that you're not adding HP to the engine with the basic mods and that you are just eliminating the "parasitic losses" etc. Once those restrictions are removed though, the power that was once being used to "fight" the engine before now can be used to move the car down the street move effectively though (i.e. quicker http://www.i-club.com/ubb-files/smile.gif )

-Shawn

I don't think I am being too basic. I mean The whole point of the tuning game is to make the engine more efficient. Just adding a performance muffler is reducing some backpressure and you have to put some faith in the designers that they did it right. I know there are lots of other things, heat of the gasses, velocity etc. etc. (educate me if I missed something) but the name of the game is getting the air in and out of the engine as effectively a possible. And yes, I do know you have to have some backpressure! http://www.i-club.com/ubb-files/smile.gif

Also, I suppose I used the wrong terms... I do know that you 'release HP' not add it. http://www.i-club.com/ubb-files/smile.gif

Let's make an auction !!!

I say 178 FLYWHEEL HP. and 182 FLYWHEL Lb.

More anyone?

Going 1, going 2 ....

Eugene

well, the stromung dual tip cat back on a RS was 6hp peak... probably somewhat less on your smaller engine. Plugs, nada... unless you had bad plugs, but that just replaces the lost power. Pulley. Claimed at 5hp. Probably true. This is probably fairly static between the ej22 and ej25. Removing the air intake and replacing panel filter. Who knows. FWIW the panel filter is only worth 1-2hp Simply removing the intake is a mixed bag. Sure it flows better, but now you're taking in hotter air. (get a CAI) Intakes on the ej25 are looing at 13-15hp peak on a ej25. You migth be getting half of that? (and that includes the filter) so maybe 4+5+7 is 16hp... probably not all at the same peak, so maybe 12 hp peak Im guessing, and alot of noise that makes it seem quicker than it really is.
edit: if you're not using the midpipe, you're probalby making even less power than that.

[This message has been edited by Midwayman (edited December 22, 2000).]

I'll give it a cumultive 4% for each modification except the plugs - no gain there. 159.73hp. I think that 17.73hp is reasonable over all for the combined effect.

[delete]

[This message has been edited by donjuan (edited December 22, 2000).]

Thanks guy's thats my thoughts too.

I think the plugs do contribute too though, not that much, but the car definately picked up 1 mpg after the change (done seperately from the other mods) to the 4+ must add something.

Yes it did pick up a lot of noise, but I do know what real power is as my last car was a 98 C5 convertible. http://www.i-club.com/ubb-files/smile.gif My biggest worry about putting the Stromung on was making the car simply buzz with no go. But happily that does not seem to be the case. I got onto the freeway neck and neck with a V6 Mustang last week, that was from the filter light, so both of us hit the gas on the green light.

And to all those early posters... yep, to some these mods may not seem worth while. But if I were you, don't ever discount the small stuff, cause it can all add up! A friend back in the UK had the same car as I, he went for the intake and the muffler, whilst I just replaced plugs, points, ht leads etc.. (yes this was a while ago and the cars were already 10 years old) and added a K&N filter. I was still as fast as him and he couldn't figure it out. Then he took care of the small stuff and then had me always playing catch up! http://www.i-club.com/ubb-files/smile.gif

Greborb has convinced me that the next step is the headers anyway... gotta wait till Jan, maybe Feb for that though. <sigh>

And another thing.... ok, so some see this as presents for the car... age old argument from both sides.

Who cares, we like it... So to all you that run these mods down :P

Hey after all, spending hours cleaning waxing, polishing and vacuming the car every so often always picks up a few stray lost HP. Doesn't a clean car always feel faster, but only when you wash it yourself! lol

Hey Ashley...my $0.025:

1. with amsoil filter= +7 hp
2. with 1. + stromung= 12 hp
3. with 2. + pulley = 14 hp plus much quicker revving
4. with 3. + CAI into fender = 24 hp= stock RS+1
5. with 4. + borla h.+ ce light = 31 hp

CAI fender also has immeasurable ram air effect not included....so round it up to 175 hp.

$40+/hp...that ain't bad

So your car may be quicker and faster with 1-5 than a new 2002 stock wagon 2.5, which is rumored to be porky at around 3100lbs. And you saved yourself 6+ grand (new-trade). So your return on investment is around 450%.

Stay the course! http://www.i-club.com/ubb-files/biggrin.gif

Bob

P.S. 1-5 plus iridium plugs=215 hp http://www.i-club.com/ubb-files/biggrin.gif http://www.i-club.com/ubb-files/tongue.gif http://www.i-club.com/ubb-files/biggrin.gif
'Tis the season for the Butt Dyno to be Jolly...and remember that this board has --naysayers and optimists --at the bell curve extremities.


[This message has been edited by Greborb (edited December 22, 2000).]

actually if you go by your quote...camming is just making better use of your stock motors ability as well..not adding HP..just retuning it...

alas..adding cams, pistons, valves, injectors, pumps, pulleys, exhuast, headers, FI of sort, NOS, tb's, or anything is adding HP, just depends on where in the rpm range. may take AWAY 3 down low, but add 9 up top...only way to be really sure is get your self and engine dyno (not $$$ effective, unless you have a speed shop or such) and then tune and make pulls...BUT an easier way is to do some baselines with a clicker box (timing setup...like auto-x) or go to track (1/4mile) and do runs and base you HP gains on that...

anyhow...good start, now juice that motor to 22B specs http://www.i-club.com/ubb-files/wink.gif

I agree with imprezer, if you change the fly wheel and clutch (if you have 5MT) you'll see a world of difference.

Just don't expect to have the same or equal horsepower rating as an RS. There is no replacement for displacment. You might see the difference in the "butt dyno" but I highly doubt it.

I only say this becuase I also have a EJ22. But you got to remember, that this engine is worth about 500 bucks, and so you can beat the livining crap out of it and get another one for cheap, thats why if you put 600 bucks into the engine you might be defeating the purpose.

Executive Summary:
Butt-Dyno says you will have 24% gain with CAI fender and header additions.

[This message has been edited by Greborb (edited December 24, 2000).]

just add some clear tail lights, racing strips, put on a Type-R badge, and put racing stickers all over and im going to guess around 90 HP.... http://www.i-club.com/ubb-files/rolleyes.gif
that would be the best way to go....

space

Sounds a 'lil too spacey and splashy for an english gentleman! http://www.i-club.com/ubb-files/rolleyes.gif