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Old 07-19-2007, 06:43 PM   #1
rhinh25
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Default What is the difference between a 2.5RS and a 2.5i Subaru Impreza?


hey there, I am just wondering what is the differnce between a 2.5RS and a 2.5i Subaru Impreza, besides the fact that the RS is older. And I would also would like to know, why don't they make so many parts for the 2.5i?
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Old 07-19-2007, 06:58 PM   #2
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Well the RS goes up to the 2005 model so it an't that old. But most RS parts are for the older RS Versions that pre date the WRX in north America. Also note the 2.5i means 2006 and 2007, so its still new, so not as much development time for that car as of yet.

The engine in the 2.5i is the iAVLS (http://en.wikipedia.org/wiki/AVLS) which is basiclay a version of honda's vtec. Like vtec all it dose is make the 2.5i engine more gas efficent at lower RPM's while allowing you to keep good power in the higher RPM bands. There are other things as well and it also matters what year you are talking about as between the 2.5i or 2006 and 2007 there are minor differences apparently, tho none I know of.

In the end the 2.5i is the continuation of the RS line, just re badged.
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Old 07-19-2007, 07:33 PM   #3
Spec V to Wagon
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Searching is your friend. Looks different...slightly stronger motor due mainly to the equal length headers as opposed to uel's.
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Old 07-19-2007, 08:44 PM   #4
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okay thanks, for the answer

-Robert Hinh
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Old 07-22-2007, 10:35 PM   #5
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The 2.5i does not have a throttle cable. All electronic Drive-by-Wire.
I personally would prefer the old fashioned cable.
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Old 07-23-2007, 12:00 PM   #6
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Ok, i think GT_Hawk just confused me. I have an 05 RS with DBW, I didnt think i had iAVLS but then again, do I? I know i have DBW so im pretty sure i have the new ECU to match it and im also pretty sure i dont have the stock EL headers that teh 06+ have. So the real question is do i have the iAVLS?
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Old 07-23-2007, 12:36 PM   #7
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You don't have the iAVLS. And you have throttle cable though a DBW? I'm partially confused too.

Last edited by Jerry Xu; 07-23-2007 at 12:51 PM.
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Old 07-23-2007, 12:59 PM   #8
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2005 got DBW but it has a 16bit ECU...

2006-2007 have DBW with a 32bit ECU with iAVLS

2005 has UEL headers and 2006-2007 have EL headers...

i believe the engine code for the pre-2005 cars is EJ251 and now it's EJ253 (according to the service manual)
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Old 07-23-2007, 01:23 PM   #9
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Ok, that clears things up for me. Stupid transitional years.
I always get stuck with cars with transitioning technology. I used to have a '93 S10 blazer with their CPI motor. It had 1 spider shaped fuel injector (which failed often) buried inside the intake plenom. That motor lasted on the market for 2 1/2 years before being replaced.
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Old 07-23-2007, 04:47 PM   #10
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Quote:
Originally Posted by GT_Hawk View Post
Well the RS goes up to the 2005 model so it an't that old. But most RS parts are for the older RS Versions that pre date the WRX in north America. Also note the 2.5i means 2006 and 2007, so its still new, so not as much development time for that car as of yet.

The engine in the 2.5i is the iAVLS (http://en.wikipedia.org/wiki/AVLS) which is basiclay a version of honda's vtec. Like vtec all it dose is make the 2.5i engine more gas efficent at lower RPM's while allowing you to keep good power in the higher RPM bands. There are other things as well and it also matters what year you are talking about as between the 2.5i or 2006 and 2007 there are minor differences apparently, tho none I know of.

In the end the 2.5i is the continuation of the RS line, just re badged.
subaru isnt avls its AVCS. and its nothing like vtec.not even close.vtec the lobes on the cam moves over and LIFTS for the last valve to be opend and a longer stroke..AVCS has no crossover
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Old 07-23-2007, 04:49 PM   #11
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excuse me, it has crossover,no lift
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Old 07-23-2007, 05:06 PM   #12
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Just give it some time on the parts. If you check around you'll actually find that many parts are compatable from previous years. What are you looking for?
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Old 07-23-2007, 06:55 PM   #13
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Quote:
Originally Posted by imprexaRS03 View Post
subaru isnt avls its AVCS. and its nothing like vtec.not even close.vtec the lobes on the cam moves over and LIFTS for the last valve to be opend and a longer stroke..AVCS has no crossover
ummm, for someone who doesn't have any VVT at all, you sure konw your stuff leave it up to the 2.5i owners who know what we have. it more resembles the i-VVTL from Toyota. Aslo, Toyota also has 2 different VVT's [i-VVT-i and i-VVTL] and for us it only changes the intake side. AVCS is like VTEC but don't quote me on that since I don't have it. read the wikipedia that was posted earlier and please read before you post buddy. thanks

~Clinton
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Old 07-23-2007, 07:13 PM   #14
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Quote:
Originally Posted by Spec V to Wagon View Post
Searching is your friend. Looks different...slightly stronger motor due mainly to the equal length headers as opposed to uel's.
The RS's came with equal length headers also. You are the one who needs to do some searching.
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Old 07-23-2007, 07:32 PM   #15
Jerry Xu
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Wow, these posts are nice n spicy
Still confused does the 05 have a throttle cable or not???
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Old 07-23-2007, 07:35 PM   #16
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Quote:
Originally Posted by Jerry Xu View Post
Wow, these posts are nice n spicy
Still confused does the 05 have a throttle cable or not???
the '05+ has Drive By Wire. The '04 STI's had DBW but I don't know about the WRX/RS's.
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Old 07-23-2007, 08:27 PM   #17
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wow... once again another thread with a whole ****load of misinformation

the 04 RS has a cable throttle, UNequal headers and NO fancy valve timing

the 05 RS has throttle-by-wire, UNequal headers and NO fancy valve timing

the 06+ i has throttle-by-wire, EQUAL headers and fancy valve timing
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Old 07-23-2007, 10:50 PM   #18
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2006+ 2.5 turbo (WRX/STI) has AVCS. 2.5i has AVLS, which IS kinda like VTEC.

AVLS is on intake only, and only affects one of the two valves. One valve is always at full lift, the other is normally on low lift until you hit high load/high RPM.

There's a link to this somewhere, I'll post when I find it.
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Old 07-23-2007, 10:52 PM   #19
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found it:
AVLS: http://www.drivesubaru.com/Spring07_whatmakes.htm

AVCS: http://www.subarudrive.com/Win05_WhatsInside.htm

Currently no Subarus come with both AVCS and AVLS that I'm aware of....but the 06+ 2.5i/se models definetly have AVLS. WRX and STi has AVCS.
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Old 07-23-2007, 11:19 PM   #20
Jerry Xu
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Quote:
Originally Posted by Naito View Post
found it:
AVLS: http://www.drivesubaru.com/Spring07_whatmakes.htm

AVCS: http://www.subarudrive.com/Win05_WhatsInside.htm

Currently no Subarus come with both AVCS and AVLS that I'm aware of....but the 06+ 2.5i/se models definetly have AVLS. WRX and STi has AVCS.
Good write up!
Jerry
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Old 07-23-2007, 11:26 PM   #21
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Quote:
Originally Posted by sc00ter View Post
The RS's came with equal length headers also. You are the one who needs to do some searching.
haha silly sc00ter, equal length headers are for 06's+!!

and to DZnuts, agreed the info here hurts my brain cells....
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Old 07-23-2007, 11:46 PM   #22
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Quote:
Originally Posted by imprexaRS03 View Post
subaru isnt avls its AVCS. and its nothing like vtec.not even close.vtec the lobes on the cam moves over and LIFTS for the last valve to be opend and a longer stroke..AVCS has no crossover
LMAO man read the wiki I posted. LMAO I even provided proof and you still said no, LMAO sorry man but I am relay having a good laugh at this one

I made a post a while ago containing all links to info on the iAVLS system and I just wen and found it so anyone who would like to look. Lots of useful info and will get people the understanding of the system. But like I said its vtec like, Honda people just like to think that vtec is this great system when in the end its relay just letting the engine burn less gas at lower rps's so you can keep a little bigger engine.

http://forums.nasioc.com/forums/show...ighlight=iavls

Also DZnutz is 100$ correct in his post, believe him

The intake is also different for the 06+, IE 3 hoses on the intake vs 2 on the 05. Meanes that a CAI for a 05 needs to be modded to fit the 06+ but its a simple fix using a 2fitting to put 2 hoses into 1 connection on a CAI. Suspension wise I have head one yar had aluminum lower control arm and another did not, but this could be the WRX, I would love someone with more details here. Also I have seen a great thread that tells what size and type breaks that the WRX/STI/RS lines had over the years, but I think that there are differences between some of the RS and 2.5i but can't find that link.

Last edited by GT_Hawk; 07-24-2007 at 12:02 AM.
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Old 07-24-2007, 12:25 AM   #23
Naito
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2.5i has steel control arms
06 WRX has aluminum control arms, 07 WRX has steel ones
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Old 07-24-2007, 01:31 AM   #24
thebetguy
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what i want to know is where can i get a service manual. My dealer will not sell me one and my clutch is gone in my 06
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Old 07-24-2007, 06:56 AM   #25
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it's on their site i believe...well i know they have the owners manual on there...not sure about the service and maintenance

https://my.subaru.com/vehicle/Manual...ers_manual.pdf
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