Ok, here's the deal... 99 2.5RS
12-02-2002, 01:27 PM
#1
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Ok, here's the deal... 99 2.5RS
A good friend of mine has a 1999 2.5RS and she has asked me to do a bit of research for her. I've always loved Scooby's but in all honesty I don't know too much about their specifics like engine / chassis codes and what has been proven to work well on them. Since the forum seems to have been revamped, searches aren't very productive.
In a nutshell this car will remain N/A. Nitrous is not an option either, so basically we're looking at basic bolt on's and possibly cams. We're looking for noticable gains, (but we're not expecting miracles) and frankly a more aggressive intake / exhaust note than the stock pieces.
Since you're the experienced ones I need some insight.
I assume like most other N/A imports, Subaru's work well with cold air intakes. I checked out the intake thread but I was a bit unclear on which CAI would work on her car and which wouldn't. I'm also wondering if it would be better to utilize the hood scoop or if a more traditional "filter behind bumper / in fender" design would be in order. What would you suggest?
I'm not too familliar with the flow characteristics of the stock 2.5's exhaust, but I'd imagine a nice mandrel bent cat back with a good straight through muffler would free up a few pony's. From my experience most high quality aftermarket exhaust's flow roughly the same (unless this does not hold true in the Subaru camp) so it basically comes down to sound. Basically we're looking for a 100% stainless exhaust with a deep bassy exhaust note. Raspy exhausts need not apply. Again I read the exhaust post but I'm looking for a bit more info and some personal experience. What would you suggest?
Excuse my ignorance, but how many headers does a boxer engine have? 1 or 2? I've read a few posts concerning the Borla unit's, but I'm not getting a very good feeling about them. Between CEL's, minimal gains, and undesirable exhaust note chnges I'm a beginning to wonder if borla is the best application for the 2.5. So who makes the best header(s?) for the 2.5? In all reality, bang for buck, are they worth it? 100% stainless is preferred as we're in New England. What would you suggest?
How many Cat's does the 99 2.5 RS have? Where are they located? Just wondering if there is more than one and where Subaru decided to put it (them) Anyone have any experience with high flow cats? Any problems with CEL's, premnature failure, etc? Good experiences? Bad Experiences?
How much of an orderal is it to swap cams in the Boxer engine? I'm not familliar with the engine design so I really don't know how much of a chore swapping cams in one of these bad boys is, but I'm interested to know. We've got an A+ tech on our side so whatever may be involved it's doable, I'm just wondering how much work is really involved. Speaking of cams, have people seen good gains swapping to more aggressive cams? Any suggestions on manufacturer? Remember, this is a daily driver, so nothing too terribly wild. Again, what would you suggest?
The one thing I've learned in all my years of modding cars is to buy the highest quality parts you can find and do it right the first time. If you can't afford the level of quality you desire, keep saving until you can. Please keep this in mind when suggesting parts.
Sincere thanks to all who may be able to assist me.
In a nutshell this car will remain N/A. Nitrous is not an option either, so basically we're looking at basic bolt on's and possibly cams. We're looking for noticable gains, (but we're not expecting miracles) and frankly a more aggressive intake / exhaust note than the stock pieces.
Since you're the experienced ones I need some insight.
I assume like most other N/A imports, Subaru's work well with cold air intakes. I checked out the intake thread but I was a bit unclear on which CAI would work on her car and which wouldn't. I'm also wondering if it would be better to utilize the hood scoop or if a more traditional "filter behind bumper / in fender" design would be in order. What would you suggest?
I'm not too familliar with the flow characteristics of the stock 2.5's exhaust, but I'd imagine a nice mandrel bent cat back with a good straight through muffler would free up a few pony's. From my experience most high quality aftermarket exhaust's flow roughly the same (unless this does not hold true in the Subaru camp) so it basically comes down to sound. Basically we're looking for a 100% stainless exhaust with a deep bassy exhaust note. Raspy exhausts need not apply. Again I read the exhaust post but I'm looking for a bit more info and some personal experience. What would you suggest?
Excuse my ignorance, but how many headers does a boxer engine have? 1 or 2? I've read a few posts concerning the Borla unit's, but I'm not getting a very good feeling about them. Between CEL's, minimal gains, and undesirable exhaust note chnges I'm a beginning to wonder if borla is the best application for the 2.5. So who makes the best header(s?) for the 2.5? In all reality, bang for buck, are they worth it? 100% stainless is preferred as we're in New England. What would you suggest?
How many Cat's does the 99 2.5 RS have? Where are they located? Just wondering if there is more than one and where Subaru decided to put it (them) Anyone have any experience with high flow cats? Any problems with CEL's, premnature failure, etc? Good experiences? Bad Experiences?
How much of an orderal is it to swap cams in the Boxer engine? I'm not familliar with the engine design so I really don't know how much of a chore swapping cams in one of these bad boys is, but I'm interested to know. We've got an A+ tech on our side so whatever may be involved it's doable, I'm just wondering how much work is really involved. Speaking of cams, have people seen good gains swapping to more aggressive cams? Any suggestions on manufacturer? Remember, this is a daily driver, so nothing too terribly wild. Again, what would you suggest?
The one thing I've learned in all my years of modding cars is to buy the highest quality parts you can find and do it right the first time. If you can't afford the level of quality you desire, keep saving until you can. Please keep this in mind when suggesting parts.
Sincere thanks to all who may be able to assist me.
12-02-2002, 05:54 PM
#2
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Wow, there are a ton of questions in that long essay. I will do my best to knock some of them off.
I am not sure if there is a good CAI for the MY99 still because of their finnicky MAF sensor, but I am not sure of this because I have a MY00. I know that before every CAI that was made would blow out the sensor, and was costly to replace. There is also a fuel drop off with CAI and the MY99, so a S-AFC is recommended to deal with this.
Exhausts don't really have good increases, they only are good for a few HP. Stromung makes a very popular exhaust which is supposed to yield one gains among exhausts. I personally don't like exhausts that are too loud, so I can't really guide you as far as sound. I am going with an STi backbox and a custom midpipe, because I just want a little louder, deeper tone, and am not too concerned about max gains.
The RS has one header, it has is a flat engine so their is a cylinder bank on each side, and the header merges in the center. You are going to get similar gains from all headers I think, you will lose some low end power in exchange for more in mid to upper ranges. Even those gains are minimal.
The RS has two cats, one behind the header, and another one a little further back, like many other exhaust items by itself, you will get minimal gains with high flow units, and I am not sure, but I don't know that the o2 sensors will like the high flow units, so you might get a cat inefficiency code or something.
How hard it is to swap cams depends on how good you are with engines, if you don't know much more then how to install basic bolt ons, I would recommend getting it done. The cobb tuning street cams are nice, and I think are dyno'd for 19hp max. There is a write up somewhere on how to do this, but I don't know if this user is on the board anymore. You will need a special T25 tool to do the swap, but I think Cobb might supply this, also you have to reset the valve lash after 3000 miles.
I hope that I have answered your questions. Feel free to ask any others that you may have.
-Wes
I am not sure if there is a good CAI for the MY99 still because of their finnicky MAF sensor, but I am not sure of this because I have a MY00. I know that before every CAI that was made would blow out the sensor, and was costly to replace. There is also a fuel drop off with CAI and the MY99, so a S-AFC is recommended to deal with this.
Exhausts don't really have good increases, they only are good for a few HP. Stromung makes a very popular exhaust which is supposed to yield one gains among exhausts. I personally don't like exhausts that are too loud, so I can't really guide you as far as sound. I am going with an STi backbox and a custom midpipe, because I just want a little louder, deeper tone, and am not too concerned about max gains.
The RS has one header, it has is a flat engine so their is a cylinder bank on each side, and the header merges in the center. You are going to get similar gains from all headers I think, you will lose some low end power in exchange for more in mid to upper ranges. Even those gains are minimal.
The RS has two cats, one behind the header, and another one a little further back, like many other exhaust items by itself, you will get minimal gains with high flow units, and I am not sure, but I don't know that the o2 sensors will like the high flow units, so you might get a cat inefficiency code or something.
How hard it is to swap cams depends on how good you are with engines, if you don't know much more then how to install basic bolt ons, I would recommend getting it done. The cobb tuning street cams are nice, and I think are dyno'd for 19hp max. There is a write up somewhere on how to do this, but I don't know if this user is on the board anymore. You will need a special T25 tool to do the swap, but I think Cobb might supply this, also you have to reset the valve lash after 3000 miles.
I hope that I have answered your questions. Feel free to ask any others that you may have.
-Wes
12-02-2002, 07:26 PM
#3
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I appreciate the time you took to respond to my questions, thank you.
If there is truly an issue with CAI's damaging MAF sensors, and causing lean conditions which the ECU cannot compensate for by itself, I'm afraid we'll be staying away from the cold air's. I seriously doubt this girl is interested in installing an AFC and having the car dyno tuned either. Is there a conversion which will allow for the utilization of the factory hood scoop, or are these plagued with problems as well? (Or is the MAF in the way?) Otherwise, what would you folks suggest as far as intakes go? I've never been a fan of short ram (hot air) intakes, but I guess I like stock even less, so whatever we have to do, we'll do it as long as it will be reliable and generally hassle free. If anyone can give me a bit more info as to why the CAI's seem to damage the MAF's it would be appreciated too... I'm curious about this.
I keep hearing about Stromung Exhausts. It seems to be the exhaust of choice for quite a few people and it fit's the 100% stainless bill so it looks like we might go in that direction.
I guess as far as the header goes I'll have to find out for certain where she prefer's her power. If I remember correctly the car has pretty good low end stock, but tends to run out of breath in the higher rev's. She may be willing to trade a bit of low end for a gain in the high end.
I'll look into those cobb street cams. Just out of curiosity, it there any headwork necessary to take advantage of these? From what I understand the 2.5's head isn't the best flowing thing out there, so I don't want to end up with the head holding back the gains from the cams too much.
Finally, I assume the 99 RS is OBDII, correct? If so, where are the o2 sensors located? Downpipe / secondary cat, Primary cat / secondary cat, etc? I'm not worried about CEL's from a Test Pipe or high flow cat, as I've had great luck with O2 sensor simulators on a variety of vehicles.
If there is truly an issue with CAI's damaging MAF sensors, and causing lean conditions which the ECU cannot compensate for by itself, I'm afraid we'll be staying away from the cold air's. I seriously doubt this girl is interested in installing an AFC and having the car dyno tuned either. Is there a conversion which will allow for the utilization of the factory hood scoop, or are these plagued with problems as well? (Or is the MAF in the way?) Otherwise, what would you folks suggest as far as intakes go? I've never been a fan of short ram (hot air) intakes, but I guess I like stock even less, so whatever we have to do, we'll do it as long as it will be reliable and generally hassle free. If anyone can give me a bit more info as to why the CAI's seem to damage the MAF's it would be appreciated too... I'm curious about this.
I keep hearing about Stromung Exhausts. It seems to be the exhaust of choice for quite a few people and it fit's the 100% stainless bill so it looks like we might go in that direction.
I guess as far as the header goes I'll have to find out for certain where she prefer's her power. If I remember correctly the car has pretty good low end stock, but tends to run out of breath in the higher rev's. She may be willing to trade a bit of low end for a gain in the high end.
I'll look into those cobb street cams. Just out of curiosity, it there any headwork necessary to take advantage of these? From what I understand the 2.5's head isn't the best flowing thing out there, so I don't want to end up with the head holding back the gains from the cams too much.
Finally, I assume the 99 RS is OBDII, correct? If so, where are the o2 sensors located? Downpipe / secondary cat, Primary cat / secondary cat, etc? I'm not worried about CEL's from a Test Pipe or high flow cat, as I've had great luck with O2 sensor simulators on a variety of vehicles.
12-02-2002, 08:03 PM
#4
Big Baller
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For N/A Subys like ours COBB Tuning has a lot of cool stuff.
I put on headers, took out the cats and run a stromung exhaust SS Dual tip. The sound is great and combined with a K&N filter I dropped over 1/2 second in the quarter. So those who say that the gains are small.... half a second is pretty good.
I also recently installed the COBB cams. The install calls for a Torx Plus. I used a T40 from Snap on and it worked fine. My engine had only 34k miles. Older engines may have more problems. Also the 99 is dual overhead cams not SOHC like the 00 and up.
The SOHC engines have a stronger bottom end. Subaru used a different piston and wrist pin design that is weaker on the 98-99 RS's. So if you're looking for more power capability the 00 and up is the way to go.
When concerned about the MAF sensor and aftermarket upgrades the answer is simple, but expensive. A link system or other aftermarket engine management system can be used to eliminate the MAF and all the problems associated with it. Link is great because it fits in the stock ECU harness and assembly and uses all stock components (sensors). However it runs about 1400.
I recommend an aftermarket engine management system, COBB Cams, Headers (any style you want) and full exhaust. GET RID OF THE STOCK CATS. They are the biggest problem. My 1/4mi time dropped 3/10's after I changed the cats to a higher flow 2 1/2" pipe.
Cobb cams are great! If you have the money, their heads are supposed to really help out the power of the motor.
Headers are awesome. What type depends on what you want to do. The Brullen and MRT's yield the highest power gains. I'm running the Borlas and love them.
I put on headers, took out the cats and run a stromung exhaust SS Dual tip. The sound is great and combined with a K&N filter I dropped over 1/2 second in the quarter. So those who say that the gains are small.... half a second is pretty good.
I also recently installed the COBB cams. The install calls for a Torx Plus. I used a T40 from Snap on and it worked fine. My engine had only 34k miles. Older engines may have more problems. Also the 99 is dual overhead cams not SOHC like the 00 and up.
The SOHC engines have a stronger bottom end. Subaru used a different piston and wrist pin design that is weaker on the 98-99 RS's. So if you're looking for more power capability the 00 and up is the way to go.
When concerned about the MAF sensor and aftermarket upgrades the answer is simple, but expensive. A link system or other aftermarket engine management system can be used to eliminate the MAF and all the problems associated with it. Link is great because it fits in the stock ECU harness and assembly and uses all stock components (sensors). However it runs about 1400.
I recommend an aftermarket engine management system, COBB Cams, Headers (any style you want) and full exhaust. GET RID OF THE STOCK CATS. They are the biggest problem. My 1/4mi time dropped 3/10's after I changed the cats to a higher flow 2 1/2" pipe.
Cobb cams are great! If you have the money, their heads are supposed to really help out the power of the motor.
Headers are awesome. What type depends on what you want to do. The Brullen and MRT's yield the highest power gains. I'm running the Borlas and love them.
12-02-2002, 08:51 PM
#5
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Sounds like a nice setup you have there. Right up my alley!
Unfortunatly I doubt this girl is goung to go for the stand alone. I have a feeling it would be much more money than she'd want to spend right now, and more involved than she wants.
She's just getting into modding, so the bug hasn't quite bitten her as hard as it did us... Give it some time though and I have a feeling she'll become a victim like the rest of us!
After hearing some sound clips I'm loving the sound of the Blitz Rear Section / Stromung midsection / Borla Header, so I think that's what I'll be suggesting. Between that and the Random Tech cat's I think the exhaust should be exactly what she'll be looking for.
I was looking at the cobb site and noticed they said that the 99 was a sohc, not dohc, so I'm not sure who's right. If the 99 does in fact have the sohc with stronger bottom end, then absolutely great! Anyhow, if the cams work with the stock ecu as well as cobb's site claims I think they would be great for her. I'm a bit skeptical though because if the stock Ecu has trouble compensating for a CAI by allowing a lean condition, then how is it managing to run aggressive cams without at least a piggyback for the ecu?
In all honesty I think I'll get her started with the Header, cat's, midesction and rearsection. In the meantime I'll try to do some more research on the intake side of things and try to figure out what's going to be right for her. Then we'll see if she's down to swap those cams out!
Unfortunatly I doubt this girl is goung to go for the stand alone. I have a feeling it would be much more money than she'd want to spend right now, and more involved than she wants.
She's just getting into modding, so the bug hasn't quite bitten her as hard as it did us... Give it some time though and I have a feeling she'll become a victim like the rest of us!
After hearing some sound clips I'm loving the sound of the Blitz Rear Section / Stromung midsection / Borla Header, so I think that's what I'll be suggesting. Between that and the Random Tech cat's I think the exhaust should be exactly what she'll be looking for.
I was looking at the cobb site and noticed they said that the 99 was a sohc, not dohc, so I'm not sure who's right. If the 99 does in fact have the sohc with stronger bottom end, then absolutely great! Anyhow, if the cams work with the stock ecu as well as cobb's site claims I think they would be great for her. I'm a bit skeptical though because if the stock Ecu has trouble compensating for a CAI by allowing a lean condition, then how is it managing to run aggressive cams without at least a piggyback for the ecu?
In all honesty I think I'll get her started with the Header, cat's, midesction and rearsection. In the meantime I'll try to do some more research on the intake side of things and try to figure out what's going to be right for her. Then we'll see if she's down to swap those cams out!
12-03-2002, 07:25 AM
#6
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>I was looking at the cobb site and noticed they said that the 99 was a sohc, not dohc, so I'm not sure who's right.
99 is SOHC, 98 was DOHC
99 is SOHC, 98 was DOHC
12-03-2002, 11:24 AM
#7
Big Baller
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Yeah Peaty is right. 99 is SOHC, but MAF. Sorry.
I don't know if my O2 sensor is about to go out or something, but right now my car is indicating rich after the cam install.
I don't know if my O2 sensor is about to go out or something, but right now my car is indicating rich after the cam install.
12-04-2002, 01:23 AM
#8
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No worries about the SOHC / DOHC thing, as long as we're all on the same page now... I haven't ordered any parts yet. 
Concerning the rich condition after the cam install, on the bright side at least it isn't leaning out like I would have expected. Especially when cramming more air in the cylinders than the ecu was ever expecting... Then again stoich would be nice huh?
I guess in all reality, if I get her to do the cams I might as well try to get her to get some kind of engine management system, be it a stand alone ECU or an AFC. Even if the cams do give the +20HP or so gains they claim on Cobb's site, (me = skeptical) I'd imagine things could only get better with some good tuning on a dyno wih a wideband 02, right? I doubt she'll go for it at the moment, but perhaps after she starts feeling the hunger for performance increases things will fall into place.
For the moment I think I'm going to get her setup with the exhaust mods and see where it takes us.
Concerning the rich condition after the cam install, on the bright side at least it isn't leaning out like I would have expected. Especially when cramming more air in the cylinders than the ecu was ever expecting... Then again stoich would be nice huh?
I guess in all reality, if I get her to do the cams I might as well try to get her to get some kind of engine management system, be it a stand alone ECU or an AFC. Even if the cams do give the +20HP or so gains they claim on Cobb's site, (me = skeptical) I'd imagine things could only get better with some good tuning on a dyno wih a wideband 02, right? I doubt she'll go for it at the moment, but perhaps after she starts feeling the hunger for performance increases things will fall into place.
For the moment I think I'm going to get her setup with the exhaust mods and see where it takes us.
Last edited by Haadkoe; 12-04-2002 at 01:27 AM.
12-04-2002, 06:07 AM
#9
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Originally posted by ImprezaRSX
I don't know if my O2 sensor is about to go out or something, but right now my car is indicating rich after the cam install.
I don't know if my O2 sensor is about to go out or something, but right now my car is indicating rich after the cam install.
Peaty
12-08-2002, 02:23 PM
#10
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These threads are taking the long route to telling you that without cams, you won't get real big gains from any combo of bolt-ons. Caveat, however, I have an '01 and am not totally familiar with the SOHC, MAF of the '99. I have only heard that they cause a lot of headaches when you mess with airflow. Basically, replace all the exhaust including cats and get the cams, and you should be good for at least 185-190 hp, or more. Don't mess with the intake unless you are ok with blowing a MAF every 4 months or so, and I don't think many people are. Also, the AFC might not be a bad idea, since you can somewhat effectively butt-dyno them. Just use it to slowly lean everything out until you hear that first ping (don't do it without someone with good ears who knows what to listen for) and also make sure that if you tune on 91 octane, DON'T GO BACK to 87, ever.
12-08-2002, 02:26 PM
#11
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Originally posted by Haadkoe
No worries about the SOHC / DOHC thing, as long as we're all on the same page now... I haven't ordered any parts yet.
Concerning the rich condition after the cam install, on the bright side at least it isn't leaning out like I would have expected. Especially when cramming more air in the cylinders than the ecu was ever expecting... Then again stoich would be nice huh?
I guess in all reality, if I get her to do the cams I might as well try to get her to get some kind of engine management system, be it a stand alone ECU or an AFC. Even if the cams do give the +20HP or so gains they claim on Cobb's site, (me = skeptical) I'd imagine things could only get better with some good tuning on a dyno wih a wideband 02, right? I doubt she'll go for it at the moment, but perhaps after she starts feeling the hunger for performance increases things will fall into place.
For the moment I think I'm going to get her setup with the exhaust mods and see where it takes us.
No worries about the SOHC / DOHC thing, as long as we're all on the same page now... I haven't ordered any parts yet.
Concerning the rich condition after the cam install, on the bright side at least it isn't leaning out like I would have expected. Especially when cramming more air in the cylinders than the ecu was ever expecting... Then again stoich would be nice huh?
I guess in all reality, if I get her to do the cams I might as well try to get her to get some kind of engine management system, be it a stand alone ECU or an AFC. Even if the cams do give the +20HP or so gains they claim on Cobb's site, (me = skeptical) I'd imagine things could only get better with some good tuning on a dyno wih a wideband 02, right? I doubt she'll go for it at the moment, but perhaps after she starts feeling the hunger for performance increases things will fall into place.
For the moment I think I'm going to get her setup with the exhaust mods and see where it takes us.
12-08-2002, 08:21 PM
#12
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this could have been summed up by... www.cobbtuning.com
call and ask. they have all the answers and they know more about the 2.5 motor than just about anyone on the forum. THey also have a ton of experience.
call and ask. they have all the answers and they know more about the 2.5 motor than just about anyone on the forum. THey also have a ton of experience.
12-11-2002, 10:00 PM
#13
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Originally posted by Peaty
While my front O2 sensor was going bad (and finally went and threw a CEL) I saw increased fuel consumption and had a fair amount of carbon on my exhaust tips. After I replaced it all is well. Mine went at ~56K. I have some info on the scoobymods site regarding replacement and such. FWIW the rear sensor will not effect the AF ratio, it's just an indicator of cat efficency. (I'm talking the NA RS I have)
Peaty
While my front O2 sensor was going bad (and finally went and threw a CEL) I saw increased fuel consumption and had a fair amount of carbon on my exhaust tips. After I replaced it all is well. Mine went at ~56K. I have some info on the scoobymods site regarding replacement and such. FWIW the rear sensor will not effect the AF ratio, it's just an indicator of cat efficency. (I'm talking the NA RS I have)
Peaty
so that's what's happening!
what type of sensor did you get Peaty? I'm at 88k!!!
-Gagan
12-12-2002, 08:25 AM
#14
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the ej25 has two headers, borla is the most economical, look at www.borla.com By all means open the scoops in the summer time, beign in new england I would leave them close in the winter, to prevent dirt and snow from sitting in your engine bay. AFC highly recomended with or with out CAI, Cam is the biggest increase in HP, exhaust very little HP increase, I suggest you buy a GTECH pro competition meter, so you can monitor the HP increases, and find out if the money your spending is making a difference. Between the GTECH and AFC you should be able to tune the car in and make the most of your mods.