N/A EJ25 power limits
11-27-2002, 08:46 AM
#46
Guest
Posts: n/a
two things,
1. The improvement in torque should be about equvalent to the improvement in BMEP which is the ratio of new CR divided by old CR - result taken to the 0.4 power
Example - if you had 10:1 and now have 10.1:1 (10.1/10.0) to 0.4 power is 1.00398
OR 100 ft lb -> to 100.398.
2. The 2000 RS has almost 11:1 compression...
I can't verify either of these items but they are interesting to note.
1. The improvement in torque should be about equvalent to the improvement in BMEP which is the ratio of new CR divided by old CR - result taken to the 0.4 power
Example - if you had 10:1 and now have 10.1:1 (10.1/10.0) to 0.4 power is 1.00398
OR 100 ft lb -> to 100.398.
2. The 2000 RS has almost 11:1 compression...
I can't verify either of these items but they are interesting to note.
11-27-2002, 12:45 PM
#47
Guest
Posts: n/a
I thought the highest was a 10 to 1 compression? 11 to 1 sounds damn high already. Maybe then Tony Rigoli builds a 2.7L conversion kit for a non-turbo application. 2.7L's and 12 to 1 compression. Hell might as well do the H6 3.0L idea I mentioned earlier.
11-27-2002, 03:50 PM
#49
Guest
Posts: n/a
It would be hell of alot more reliable than a turbo. These are some of the things I have done/will do to my car.
Cobb Intake
Cobb Heads/Mild Cams
Custom Intake Manifold/TB
MRT Exhaust
N1 Pulleys
Apexi S-AFC
Proecm Chip
Phenolic Spacers
Walbro Fuel Pump
Some type of Upgraded Spark
Exedy Clutch and Flywheel
How unreliable does that sound? IMHO it sounds as reliable as stock..
Cobb Intake
Cobb Heads/Mild Cams
Custom Intake Manifold/TB
MRT Exhaust
N1 Pulleys
Apexi S-AFC
Proecm Chip
Phenolic Spacers
Walbro Fuel Pump
Some type of Upgraded Spark
Exedy Clutch and Flywheel
How unreliable does that sound? IMHO it sounds as reliable as stock..
11-29-2002, 03:14 PM
#50
Registered User
iTrader: (1)
Join Date: Nov 2002
Location: Mid-Atlantic somewhere
Posts: 820
Car Info: '97 Legacy 2.5GT sedan
I have Cobb Stage 1 heads, Street cams, an Injen intake, MRT full exhaust, and an S-AFC. All together the car has put down about 37.5hp over stock at the wheels on an AWD dyno. So, I figure I'm in the 205hp ballpark at the crank.
The car feels like it's lost some low end as a result of all of the modifications, but on the dyno the graphs show that it's up on torque even at 2500rpm. I think it feels slower because the top end is so much better, if that makes any sense.
I think there's quite a bit more power to be had with an aftermarket ECM of some sort. As it is now it seems like the stock ECU is pretty confused - throttle tip-in at lower RPMs is sometimes less than smooth, the idle can be a bit jumpy, AFR is not ideal (even with the S-AFC), I'm sure timing isn't optimum, etc.
Oh, with the Stage 1 Cobb stuff the redline does not need to be raised to get the full benefit. The Stage 2/Club Racer combo is what works best with a higher redline.
Pat Olsen
'97 Legacy 2.5GT sedan
The car feels like it's lost some low end as a result of all of the modifications, but on the dyno the graphs show that it's up on torque even at 2500rpm. I think it feels slower because the top end is so much better, if that makes any sense.
I think there's quite a bit more power to be had with an aftermarket ECM of some sort. As it is now it seems like the stock ECU is pretty confused - throttle tip-in at lower RPMs is sometimes less than smooth, the idle can be a bit jumpy, AFR is not ideal (even with the S-AFC), I'm sure timing isn't optimum, etc.
Oh, with the Stage 1 Cobb stuff the redline does not need to be raised to get the full benefit. The Stage 2/Club Racer combo is what works best with a higher redline.
Pat Olsen
'97 Legacy 2.5GT sedan
11-30-2002, 12:16 AM
#51
Big Baller
iTrader: (1)
Join Date: Nov 2002
Location: Washington
Posts: 1,821
Car Info: 93 BG5, 00&01 GM6, 06LGT, 07STi
Cams are easy. Time consuming, but easy. In fact I just installed them today. I need to double check my valve lash (I may have forgot to do #4) because it's clackin' pretty bad. Even with the clacking, it sounds stronger and OH SO GOOD!
It's parked until I can fix it.
I'm pretty confident I'll be pushing over 200hp now.
It's parked until I can fix it.
I'm pretty confident I'll be pushing over 200hp now.
11-30-2002, 06:44 PM
#52
Big Baller
iTrader: (1)
Join Date: Nov 2002
Location: Washington
Posts: 1,821
Car Info: 93 BG5, 00&01 GM6, 06LGT, 07STi
adjusted the valves.
The cars power is sooo smooth. The ECU is still learning (I reset it). It has only run for about 40 min on the new cams, but it runs great. I think my O2 sensor might be going out because the car is running a little rich, but that could be the ECU learning as well.
Anyway, I don't know what kind of power difference there is right now. I've been driving easy to give the cams some more break in time and the ECU time to learn. BUt I can tell you that it is so SMOOTH and fluid. The hesitations around 4kRPM isn't there.
The cars power is sooo smooth. The ECU is still learning (I reset it). It has only run for about 40 min on the new cams, but it runs great. I think my O2 sensor might be going out because the car is running a little rich, but that could be the ECU learning as well.
Anyway, I don't know what kind of power difference there is right now. I've been driving easy to give the cams some more break in time and the ECU time to learn. BUt I can tell you that it is so SMOOTH and fluid. The hesitations around 4kRPM isn't there.
11-30-2002, 06:54 PM
#53
Guest
Posts: n/a
Since we are on the topic, does anyone have anyclue as to how many HP (roughly of course) a full header back sys. and cams would yield ? and would there be any emissions issues ? I have heard of people failing. Right now my future plans look like this :
TWE Exhaust sys. & Cams , Hyper(whatever the hell) ground wires, intake and ECU tuning. After this a nitrous setup with progressive controller.
While am it, What kind of maintenance is required with cams ?
Thanks for hearing all my crap LOL. P.S. am not looking to break speed records just hold my own
TWE Exhaust sys. & Cams , Hyper(whatever the hell) ground wires, intake and ECU tuning. After this a nitrous setup with progressive controller.
While am it, What kind of maintenance is required with cams ?
Thanks for hearing all my crap LOL. P.S. am not looking to break speed records just hold my own
11-30-2002, 09:30 PM
#54
Big Baller
iTrader: (1)
Join Date: Nov 2002
Location: Washington
Posts: 1,821
Car Info: 93 BG5, 00&01 GM6, 06LGT, 07STi
from COBB: Dyno testing, comparing a stock 2.5L with and without camshafts, has shown a +14 PEAK HP GAIN to the wheels and +13 ft-lbs PEAK TORQUE GAIN, with maximum gains of +19 HP at redline!! These gains were seen when comparing otherwise unmodified, stock cars. More gains are possible if your vehicle is modified with upgraded intake and exhaust systems
I do, however, have COBB cams and Borla headers. I'll let you know what kind of improvements I have after the break in time. I'll go run the 1/4 next week.
11-30-2002, 09:33 PM
#55
Big Baller
iTrader: (1)
Join Date: Nov 2002
Location: Washington
Posts: 1,821
Car Info: 93 BG5, 00&01 GM6, 06LGT, 07STi
also from cobb regarding their stage three kit:
Many customers have enjoyed this reliable system for several years. Those that have taken their RS to the drag strip have typically run low 14's in the 1/4 mile
Many customers have enjoyed this reliable system for several years. Those that have taken their RS to the drag strip have typically run low 14's in the 1/4 mile
11-30-2002, 11:11 PM
#56
Guest
Posts: n/a
Well, my theory is that in order to produce more power with the EJ25, we have to have enough airflow to increase spark, increase fuel pressure, and produce power.. The stock intake manifold and throttle body suck. If we could have a setup like this; COBB CAI-> ITB->Custom Manifold->Cobb Heads->Cobb Cams->Built Block->MRT Headerback, we would have serious gains with a S-AFC or something equivalent.
12-01-2002, 12:21 AM
#57
NASIOC Slut
iTrader: (2)
Join Date: Nov 2002
Location: Roseville, CA
Posts: 4,723
Car Info: 1995 Subaru Impreza 1.8 L
Originally posted by N/ABeast
Well, my theory is that in order to produce more power with the EJ25, we have to have enough airflow to increase spark, increase fuel pressure, and produce power.. The stock intake manifold and throttle body suck. If we could have a setup like this; COBB CAI-> ITB->Custom Manifold->Cobb Heads->Cobb Cams->Built Block->MRT Headerback, we would have serious gains with a S-AFC or something equivalent.
Well, my theory is that in order to produce more power with the EJ25, we have to have enough airflow to increase spark, increase fuel pressure, and produce power.. The stock intake manifold and throttle body suck. If we could have a setup like this; COBB CAI-> ITB->Custom Manifold->Cobb Heads->Cobb Cams->Built Block->MRT Headerback, we would have serious gains with a S-AFC or something equivalent.
12-03-2002, 04:39 PM
#58
Registered User
Join Date: Nov 2002
Location: Delta, BC, Canada
Posts: 99
Car Info: 2000 Impreza 2.5RS BRP
Sometimes I wonder if it would have been more fun driving an N/A beast (230-250hp to the crank) vs a turbo'd sleeper (300hp or so to the crank). I mean, the money spent on N/A is probably at least the same, if not more compared to the higher output turbo setup. Sure, the car would last longer compared to the turbo, but you really aren't getting all that much gain for the money, and lots of labour both ways. Somehow to me, a Subaru is meant to be turbo'd even though the EJ25 might not be. Who knows - maybe I will go N/A after thinking turbo for a few years, just to save the wear and tear, even though I might spend even more with N/A setup.
12-03-2002, 09:41 PM
#60
NASIOC Slut
iTrader: (2)
Join Date: Nov 2002
Location: Roseville, CA
Posts: 4,723
Car Info: 1995 Subaru Impreza 1.8 L
Not to mention a high powered N/A configuration would maintain a better weight ballance and with the 2.5, a sheep load of torque without turbo lag to worry about...