CAI and Exhaust

5SpdImpreza2010 · 08-08-2010, 12:49 AM

Hey everyone,

I have a 2010 Impreza 2.5i Premium 5-door, and I was thinking about doing a few performance upgrades. My two main ideas are to get a CAI and a new exhaust system. I've done some research, and from what I've found, it seems that a CAI can cause some problems (most namely in the rain/driving through puddles). Some posts suggest going with a "hybrid" intake, which I'm not exactly sure of. As for the exhaust system, I've found one made by Subaru that seems to be just what I'm looking for. My only concern is if it is just four looks/sound, or does it actually boost my power, throttle response, etc. Here is its link - https://www.subaruonlineparts.com/pr...oducts_id=1136. In addition to these two mods, I also took a look into headers. It seems to me, though, that they are a modification mainly reserved for the wrx/sti models (or any turbo'd model), as they help increase upper end power in the rev range.

So, in short - Is it a good idea to invest in a CAI? Is the exhaust I found worthwhile in terms of power? Are headers meaningful for N/A Imprezas?

Thanks in advance!

-Michael

* Registered users of the site do not see these ads.

Imp-RS · 08-08-2010, 02:42 AM

http://forums.nasioc.com/forums/showthread.php?t=345720

http://forums.nasioc.com/forums/show....php?t=1471819

http://forums.nasioc.com/forums/show....php?t=1420502

flightwatch · 08-08-2010, 06:53 AM

There are literally thousands of threads that will answer your questions......but, I will try and answer them here.
The exhaust that you chose is probably made for the WRX and not the 2.5i. My suggestion is that you save yourself around $400-500 and get an exhaust shop to build you a custom exhaust. Either way, you will not see much (if any) gains from a cat-back alone. You will have to do headers-back to see any real gains.

You are correct that headers will shift your powerband to the right. The type of headers you get would also determine what type of power increase you will see. EL headers will give you the most gains, but you will not have the boxer rumble. UEL headers will not give you as much of a gain as EL's will, but you will have that unmistakable boxer rumble...99% of people will choose UEL's over EL's for the sound alone. Either route you go, it will require some customizing to make it work since there is currently no company that makes direct bolt-on headers for the '06 and newer N/A's.

The intake is up to you...do your own thing. Don't listen to everybody on here. Personally, I am running the hybrid. Not because somebody said that it was the safest alternative, but because I saw the best gains overall with that setup. I also tried a cai and a sri. I have run cai's on several cars that I owned, and I never had an issue. Remember, even on a lowered car, the filter on a cai is going to be sitting a foot or more off the ground and will be protected by the stock splash guards. On top of that, the filter would have to be completely submerged to start sucking water...that means you would have to be driving through a 2+ foot puddle to have issues. IMHO, you have to be acting like an asshat to start sucking water up the filter.

Hope that helps

cmiovino · 08-08-2010, 09:53 AM

I agree with most of the things in flightwatch's post. Mainly the exhaust is meant for sound, unless you do the entire thing AND swap to EL headers. That will net you a bit of power, but not much. Expensive too. Personally, I'd just roll with an axleback/muffler. No use doing a catback if you see near zero gains. It might sound slightly louder or a little different with the different midpipe. Not enough to justify the cost IMO.

And intake... oh boy... lol. Heated topic. I say no to the SRI and especially CAI due to the sucking up water thing. I understand it doesn't happen as much as people claim it does, but if there is any reasonable chance it could happen, it's not for me. Plus, I've done a lot of research and even just slapping a cone filter on the end of the MAF can make turbulent airflow, throwing the MAF off. This will usually cause your engine to run lean which is bad.

And finally, even if the intake doesn't suck up water or cause any AFR issues, it will shift the power band higher in the rev range. One of the benefits of the boxer engine and Subarus is their low end grunt. I'd like to keep that power.

So I dunno... the hybrid seems to be the way to go. You can try the others though.

09suby · 08-08-2010, 12:02 PM

Intake, headers, and exhaust is not worthwhile to put on your car without a tune. And since you have a 2010 model, there is no definitions as yet for you to tune. I would suggest doing some suspension mods until you can be tuned. I would suggest a new set of tires, as the stock ones aren't that great. You can also do front sway bar upgrade,and add a rear sway bar. You can also do front and rear strut bars. You would be able to go fast in turns instead of fast in a straight line.lol

Wrencher86 · 08-08-2010, 04:23 PM

I have the same car as the OP and have the same questions. I"m glad that he asked and it's nice to see he's not getting flamed like I figured somebody would if they asked that. I know the stock response to these questions is "Do a search", but I've spent hours reading through these threads and haven't really come up with anything.

Does anybody know what kit to start with for the hybrid intake? I'd rather not have to hack up one of the $15 ebay kits into thirty pieces. How about a good DRY drop in filter?

cmiovino · 08-08-2010, 05:22 PM

Quote:

Originally Posted by Wrencher86

I have the same car as the OP and have the same questions. I"m glad that he asked and it's nice to see he's not getting flamed like I figured somebody would if they asked that. I know the stock response to these questions is "Do a search", but I've spent hours reading through these threads and haven't really come up with anything.

Does anybody know what kit to start with for the hybrid intake? I'd rather not have to hack up one of the $15 ebay kits into thirty pieces. How about a good DRY drop in filter?

The kits you start with are the ebay ones you hack up. It's very easy to modify. There are no hybrid kits that come pre-cut and ready to install.

Good dry drop in filter is the AEM dryflow or Apexi. Though, regular paper ones work just fine. You'll see no difference.

Wrencher86 · 08-08-2010, 06:29 PM

Is the ebay kit the only one out there, though? I'm not concerned about the work, it's just that judging by the pictures around here it doesn't look very good when you get done. Also heard about some fitment issues.

AEM doesn't seem to offer any direct fit drop ins. Not that I could find, anyway. The filter is more about convenience and saving money. I had an AEM filter on my Honda and loved it. Just rinse it every six months or so and slap it back on the car.

flightwatch · 08-08-2010, 11:07 PM

09Suby is 99% right. The best performance mod you can do to our car is to get a tune. It doesn't net significant gains, but the drive-abilty is amazing. The stock tune is fine for the bolt-ons...when you start doing more serious upgrades (cams, pnp) is when you would need to be tuned. Irregardless, a tune is a great thing to get done since the stock Subaru maps are absolute dog poo.

An ebay intake might be your only way to go...unless you really want to ruin a $300 intake. Either way, you will have to hack the pipe up to make it fit...you guys have a lot more junk in the way than the older cars do.

tylere · 08-09-2010, 02:03 AM

i have a cat back from lachute performance for my 2008 2.5i. (http://www.lachutesubaru.com/cgi-bin...categoryid=532) it ran me about a grand with shipping (its from canada) and i got it around 2 years ago when the car first came off. it sounds really good for NA. I also had a CAI from cosmo racing. i would not buy that intake again. they gave me the wrong mounting bracket and it wound up rubbing a hole in my air conditioning and caused about $500 worth of damage.

flightwatch · 08-09-2010, 04:34 AM

Holy crap...They are ridiculously expensive. They want $755.00 for just a downpipe w/cat. I didn't spend that much on my entire exhaust (headers-back.)

resident1155 · 08-09-2010, 12:21 PM

I personally feel that ANY CAI does wonders for manual subies, but makes the 4EAT automatic transmission turn to rubbish. I had the cobb intake on for 3 years, it made the car sound like a space ship and it just ran like crap. The choice is yours, I wouldn't worry about the car gulping up water though. The only intake that goes that far into the fender well is the Injen. I would go for something of a hybrid intake and run some flexible tubing (available at autozone or pepboys) from the stock intake (remove snorkus/silencer crap) to the fender well. Worked like a charm for me and retained stock appearance.

08-08-2010, 12:49 AM	#1
5SpdImpreza2010 Scooby Newbie Member#: 231561 Join Date: Dec 2009 Vehicle: 2010 Impreza 2.5i Dark Gray	CAI and Exhaust Hey everyone, I have a 2010 Impreza 2.5i Premium 5-door, and I was thinking about doing a few performance upgrades. My two main ideas are to get a CAI and a new exhaust system. I've done some research, and from what I've found, it seems that a CAI can cause some problems (most namely in the rain/driving through puddles). Some posts suggest going with a "hybrid" intake, which I'm not exactly sure of. As for the exhaust system, I've found one made by Subaru that seems to be just what I'm looking for. My only concern is if it is just four looks/sound, or does it actually boost my power, throttle response, etc. Here is its link - https://www.subaruonlineparts.com/pr...oducts_id=1136. In addition to these two mods, I also took a look into headers. It seems to me, though, that they are a modification mainly reserved for the wrx/sti models (or any turbo'd model), as they help increase upper end power in the rev range. So, in short - Is it a good idea to invest in a CAI? Is the exhaust I found worthwhile in terms of power? Are headers meaningful for N/A Imprezas? Thanks in advance! -Michael * Registered users of the site do not see these ads.

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08-08-2010, 02:42 AM	#2
Imp-RS Scooby Newbie Member#: 212003 Join Date: May 2009	http://forums.nasioc.com/forums/showthread.php?t=345720 http://forums.nasioc.com/forums/show....php?t=1471819 http://forums.nasioc.com/forums/show....php?t=1420502

08-08-2010, 06:53 AM	#3
flightwatch Scooby Specialist Member#: 231058 Join Date: Nov 2009 Chapter/Region: South East Location: St Petersburg, FL Vehicle: 2012 Hyundai Sonata terbo	There are literally thousands of threads that will answer your questions......but, I will try and answer them here. The exhaust that you chose is probably made for the WRX and not the 2.5i. My suggestion is that you save yourself around $400-500 and get an exhaust shop to build you a custom exhaust. Either way, you will not see much (if any) gains from a cat-back alone. You will have to do headers-back to see any real gains. You are correct that headers will shift your powerband to the right. The type of headers you get would also determine what type of power increase you will see. EL headers will give you the most gains, but you will not have the boxer rumble. UEL headers will not give you as much of a gain as EL's will, but you will have that unmistakable boxer rumble...99% of people will choose UEL's over EL's for the sound alone. Either route you go, it will require some customizing to make it work since there is currently no company that makes direct bolt-on headers for the '06 and newer N/A's. The intake is up to you...do your own thing. Don't listen to everybody on here. Personally, I am running the hybrid. Not because somebody said that it was the safest alternative, but because I saw the best gains overall with that setup. I also tried a cai and a sri. I have run cai's on several cars that I owned, and I never had an issue. Remember, even on a lowered car, the filter on a cai is going to be sitting a foot or more off the ground and will be protected by the stock splash guards. On top of that, the filter would have to be completely submerged to start sucking water...that means you would have to be driving through a 2+ foot puddle to have issues. IMHO, you have to be acting like an asshat to start sucking water up the filter. Hope that helps

08-08-2010, 09:53 AM	#4
cmiovino Scooby Specialist Member#: 134005 Join Date: Dec 2006 Chapter/Region: MAIC Location: Pittsburgh, PA Vehicle: 2004 WRX Premium PSM	I agree with most of the things in flightwatch's post. Mainly the exhaust is meant for sound, unless you do the entire thing AND swap to EL headers. That will net you a bit of power, but not much. Expensive too. Personally, I'd just roll with an axleback/muffler. No use doing a catback if you see near zero gains. It might sound slightly louder or a little different with the different midpipe. Not enough to justify the cost IMO. And intake... oh boy... lol. Heated topic. I say no to the SRI and especially CAI due to the sucking up water thing. I understand it doesn't happen as much as people claim it does, but if there is any reasonable chance it could happen, it's not for me. Plus, I've done a lot of research and even just slapping a cone filter on the end of the MAF can make turbulent airflow, throwing the MAF off. This will usually cause your engine to run lean which is bad. And finally, even if the intake doesn't suck up water or cause any AFR issues, it will shift the power band higher in the rev range. One of the benefits of the boxer engine and Subarus is their low end grunt. I'd like to keep that power. So I dunno... the hybrid seems to be the way to go. You can try the others though.

08-08-2010, 12:02 PM	#5
09suby Scooby Newbie Member#: 222590 Join Date: Sep 2009 Chapter/Region: South East Location: Clermont,Fl Vehicle: 2009 Impreza 2.5i Spark Silver Metallic	Intake, headers, and exhaust is not worthwhile to put on your car without a tune. And since you have a 2010 model, there is no definitions as yet for you to tune. I would suggest doing some suspension mods until you can be tuned. I would suggest a new set of tires, as the stock ones aren't that great. You can also do front sway bar upgrade,and add a rear sway bar. You can also do front and rear strut bars. You would be able to go fast in turns instead of fast in a straight line.lol

08-08-2010, 04:23 PM	#6
Wrencher86 Scooby Newbie Member#: 250463 Join Date: Jun 2010 Location: Evanston, Il Vehicle: 2010 Impreza 2.5i Silver	I have the same car as the OP and have the same questions. I"m glad that he asked and it's nice to see he's not getting flamed like I figured somebody would if they asked that. I know the stock response to these questions is "Do a search", but I've spent hours reading through these threads and haven't really come up with anything. Does anybody know what kit to start with for the hybrid intake? I'd rather not have to hack up one of the $15 ebay kits into thirty pieces. How about a good DRY drop in filter?

08-08-2010, 06:29 PM	#8
Wrencher86 Scooby Newbie Member#: 250463 Join Date: Jun 2010 Location: Evanston, Il Vehicle: 2010 Impreza 2.5i Silver	Is the ebay kit the only one out there, though? I'm not concerned about the work, it's just that judging by the pictures around here it doesn't look very good when you get done. Also heard about some fitment issues. AEM doesn't seem to offer any direct fit drop ins. Not that I could find, anyway. The filter is more about convenience and saving money. I had an AEM filter on my Honda and loved it. Just rinse it every six months or so and slap it back on the car.

08-08-2010, 11:07 PM	#9
flightwatch Scooby Specialist Member#: 231058 Join Date: Nov 2009 Chapter/Region: South East Location: St Petersburg, FL Vehicle: 2012 Hyundai Sonata terbo	09Suby is 99% right. The best performance mod you can do to our car is to get a tune. It doesn't net significant gains, but the drive-abilty is amazing. The stock tune is fine for the bolt-ons...when you start doing more serious upgrades (cams, pnp) is when you would need to be tuned. Irregardless, a tune is a great thing to get done since the stock Subaru maps are absolute dog poo. An ebay intake might be your only way to go...unless you really want to ruin a $300 intake. Either way, you will have to hack the pipe up to make it fit...you guys have a lot more junk in the way than the older cars do.

08-09-2010, 02:03 AM	#10
tylere Scooby Newbie Member#: 175548 Join Date: Mar 2008 Chapter/Region: Tri-State Location: king of Prussia,PA Vehicle: 2008 Impreza 2.5i metalic grey	i have a cat back from lachute performance for my 2008 2.5i. (http://www.lachutesubaru.com/cgi-bin...categoryid=532) it ran me about a grand with shipping (its from canada) and i got it around 2 years ago when the car first came off. it sounds really good for NA. I also had a CAI from cosmo racing. i would not buy that intake again. they gave me the wrong mounting bracket and it wound up rubbing a hole in my air conditioning and caused about $500 worth of damage.

08-09-2010, 04:34 AM	#11
flightwatch Scooby Specialist Member#: 231058 Join Date: Nov 2009 Chapter/Region: South East Location: St Petersburg, FL Vehicle: 2012 Hyundai Sonata terbo	Holy crap...They are ridiculously expensive. They want $755.00 for just a downpipe w/cat. I didn't spend that much on my entire exhaust (headers-back.)

08-09-2010, 12:21 PM	#12
resident1155 Scooby Newbie Member#: 92659 Join Date: Aug 2005 Location: Chicago Vehicle: 2002 Impreza RS	I personally feel that ANY CAI does wonders for manual subies, but makes the 4EAT automatic transmission turn to rubbish. I had the cobb intake on for 3 years, it made the car sound like a space ship and it just ran like crap. The choice is yours, I wouldn't worry about the car gulping up water though. The only intake that goes that far into the fender well is the Injen. I would go for something of a hybrid intake and run some flexible tubing (available at autozone or pepboys) from the stock intake (remove snorkus/silencer crap) to the fender well. Worked like a charm for me and retained stock appearance.