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Old 11-22-2011, 02:01 AM   #1
Bearclawpike
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Default 2006 2.5i turbo help

hey im about to receive a 2006 2.5i from my parents as a gift (so please no replies about how i should trade it for a wrx) because i blew the motor on my 2005 turbo 450rwhp 4.0 mustang .... i have a t3/t4 hybrid turbo that i used on my mustang and was wondering if i could use it for the build on a turbo for the subie ... also i was wondering if anyone knew a good place to find lower compression forged pistons and high strength head studs for it so it doesnt end up like my mustang lol ... im very very new to subaru so im not really sure if i could pull a wrx ecu, exhaust, gauges etc. out of a junkyard car or not and what parts, year models i could use if i could ... thanks for your help guys
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Old 11-22-2011, 03:39 PM   #2
Burks569
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t3/4 will be too big to be any fun on the car...at least with the factory block. if you wanna build your engine give built industries a call, you can find them in the vendors section. Exhaust wise you'll need to do something custom, wrx ecu is unnecessary, IIRC you can do an open source tune on your ecu. There's really way too much that goes into it with every little detail of every different way you can do this (which there are SEVERAL.) The best place to find info on this stuff is over on rs25, a lot more support for N/A to turbo builds. Just go to the turbo and superchargers subsection in the technical section and read the stickies. I've been reading through them all for months now and have done 2 seperate build types on my car. Just about every question you can think of you can find in there.
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Old 01-10-2012, 05:02 PM   #3
pooie713
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read up on rs25 plenty of threads on how to turbo, the t3/t4 turbo is perfectly fine for a na-t build its actually gonna end up being too small with a lower compression ratio. Instead of buying lower compression pistons i would advise you also look into an sti or 2.5wrx shortblock swap since they would drop compression and also be semi-closed deck. If you really want to build the block popular pistons are JE or wiseco, popular rods are Eagle's and arp for head studs. Get your self a cobb accessport for tuning (easily best tuning device for 05+ models) and you can switch maps on the fly. For exhaust you can hit up subydude on rs25 he makes up and downpipes that clear the na crossmember and should fit an 06 and its made to mate up with stock exhausts so you can mix and match from there. yes you can use stock gauges just make sure you got the sensors as well and some bigger injectors and that should about cover you
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Old 01-12-2012, 11:47 AM   #4
dangerousatom
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The 2.5i platform is lacking in all areas for the most part.

-SOHC heads that are not very turbo friendly.....bad high RPM flow
-High compression non forged pistons
-Week rods
-No good place to feed and return oil for the turbo, unless you mod the heads/oil pan/sandwich block the filter
-The injectors are far too small
-The trans is super week and you will strip a gear above 225-250 whp with out question
-The radiator is even too low a capacity for the amount of heat the turbo motor creates
-Either a stock turbo exhaust manifold is needed or a custom one will have to be made....to use the stock UP the NA motor cross member will have to be swapped for a turbo one. Or get a custom UP fabed.

It can be done, but to do it correctly it will cost you a ton

IMO if you turbo the 2.5i, 5-7 psi is the max it will handle on the stock bottom end and that will only net you some where around 215-225 crank hp. That is still shy of a stock WRX and your rpms will be 2k shorter due to the valve train max rpm of somewhere around 6200.
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Old 01-13-2012, 10:21 AM   #5
meifert
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Quote:
Originally Posted by dangerousatom View Post
The 2.5i platform is lacking in all areas for the most part.

-SOHC heads that are not very turbo friendly.....bad high RPM flow
-High compression non forged pistons
-Week rods
-No good place to feed and return oil for the turbo, unless you mod the heads/oil pan/sandwich block the filter
-The injectors are far too small
-The trans is super week and you will strip a gear above 225-250 whp with out question
-The radiator is even too low a capacity for the amount of heat the turbo motor creates
-Either a stock turbo exhaust manifold is needed or a custom one will have to be made....to use the stock UP the NA motor cross member will have to be swapped for a turbo one. Or get a custom UP fabed.

It can be done, but to do it correctly it will cost you a ton

IMO if you turbo the 2.5i, 5-7 psi is the max it will handle on the stock bottom end and that will only net you some where around 215-225 crank hp. That is still shy of a stock WRX and your rpms will be 2k shorter due to the valve train max rpm of somewhere around 6200.

AVO turbos are making 200 AWHP at like 6 psi. the SOHC cams are not turbo friendly, just change the cams. AVOs kit costs $3200, minus injectors. install and a tune will depend on the shop but if you keep the boost down you won't have any issues if the tune is good.
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Old 01-13-2012, 11:17 AM   #6
dangerousatom
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Quote:
Originally Posted by meifert View Post
AVO turbos are making 200 AWHP at like 6 psi. the SOHC cams are not turbo friendly, just change the cams. AVOs kit costs $3200, minus injectors. install and a tune will depend on the shop but if you keep the boost down you won't have any issues if the tune is good.
$3200+ is my basic point. that is basically the cost of a turbo motor with all things needed, and turbo-ing a NA motor without forged anything = 1/2 or less the life of the motor.
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Old 01-13-2012, 11:26 AM   #7
meifert
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Quote:
Originally Posted by dangerousatom View Post
$3200+ is my basic point. that is basically the cost of a turbo motor with all things needed, and turbo-ing a NA motor without forged anything = 1/2 or less the life of the motor.

i pushed 17 PSI through a non-forged Ford 3.8l v6 and made over 500 rwhp. it it still going strong today. it's 90% tune, bad tune means blown motor it doesn't matter if it's forged or not.
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Old 01-13-2012, 12:15 PM   #8
revin-it02
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Quote:
Originally Posted by dangerousatom View Post
$3200+ is my basic point. that is basically the cost of a turbo motor with all things needed, and turbo-ing a NA motor without forged anything = 1/2 or less the life of the motor.
you do realize the WRX and STI motors dont have forged internals right?
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Old 01-13-2012, 12:23 PM   #9
revin-it02
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Quote:
Originally Posted by dangerousatom View Post
The 2.5i platform is lacking in all areas for the most part.

-SOHC heads that are not very turbo friendly.....bad high RPM flow
Up to 5.5k, the SOHC heads actually flow better than the DOHC
-High compression non forged pistons
As stated above the WRX does not have forged internals in the US. The compression ratio is lower to prevent detonation.
-Week rods
Week should mean weak... and they arent that bad, about 300HP is when they get dicey.
-No good place to feed and return oil for the turbo, unless you mod the heads/oil pan/sandwich block the filter
Only thing I Agree with.
-The injectors are far too small
Its pretty easy to upgrade injectors, WRX guys do it all the time because even theirs max out with little mods.
-The trans is super week and you will strip a gear above 225-250 whp with out question
Same as a WRX....
-The radiator is even too low a capacity for the amount of heat the turbo motor creates
Same as a WRX...
-Either a stock turbo exhaust manifold is needed or a custom one will have to be made....to use the stock UP the NA motor cross member will have to be swapped for a turbo one. Or get a custom UP fabed.
No, AVO addressed this issue and you can use your stock manifold.

It can be done, but to do it correctly it will cost you a ton

IMO if you turbo the 2.5i, 5-7 psi is the max it will handle on the stock bottom end and that will only net you some where around 215-225 crank hp. That is still shy of a stock WRX and your rpms will be 2k shorter due to the valve train max rpm of somewhere around 6200.
You get about 200WHP, thats not bad. The valve train max can easially go up with some upgraded springs and retainers (about 6.8k).
See above.

Last edited by revin-it02; 01-14-2012 at 12:43 PM.
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Old 08-24-2012, 10:55 PM   #10
Suby2.5i
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I have a 2007 2.5i. I did a turbo kit on it I made myself. Wrx parts mostly. Oem header. Grimmspeed uppipe w/ 38mm Ewg. Td04. Hks downpipe. Fmic. Open source tune. Car has been running 9.8 psi for over a year now. And I go very hard on the car. And it's automatic
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Old 08-24-2012, 11:51 PM   #11
olsen726
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yep, i ran stock block at 7psi for a long ass time before i decided to build my motor
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Old 08-25-2012, 12:42 PM   #12
revin-it02
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Im about to be running an avo kit here in the next few weeks. I hate how people bash the 2.5i when they don't even know the facts.
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Old 08-25-2012, 04:25 PM   #13
olsen726
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a bunch of people don't realize that our cars can be opensource tuned... which takes a big chunk of work out of turboing them
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Old 09-26-2012, 08:58 PM   #14
Myshel
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I have a 2007 impreza 2.5 rs (non turbo). im wanting to put a turbo on it with the top mount intercooler. Will i have to change anything to do that?
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Old 09-30-2012, 08:10 PM   #15
ej25turbo
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t3/t4 is completely fine on a 2.5l. ive been running one since 1999, but its on a DOHC.

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Old 12-30-2012, 02:36 PM   #16
Suby2.5i
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My 2007 impreza 2.5i that was turboed running 9.8 psi. now has a built bottom end. (cp pistons, manley h beams, sti nitride treated crank, supertech valvesprings) its now going on the dyno to be tuned (opensource) on 19 PSI on a TD06 20G. with deastchwerk 1,000 cc injectors and a DW301 fuel pump. this 2.5i will be way in the 3XX whp territory and probally close to 400 wtq
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Old 01-04-2013, 11:48 AM   #17
gdoggmoney
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Quote:
Originally Posted by Suby2.5i View Post
My 2007 impreza 2.5i that was turboed running 9.8 psi. now has a built bottom end. (cp pistons, manley h beams, sti nitride treated crank, supertech valvesprings) its now going on the dyno to be tuned (opensource) on 19 PSI on a TD06 20G. with deastchwerk 1,000 cc injectors and a DW301 fuel pump. this 2.5i will be way in the 3XX whp territory and probally close to 400 wtq
Very nice!

I'm planning on possibly moving the 3076R off my bent MKIV Jetta to my 07 2.5i
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Old 01-08-2013, 08:44 PM   #18
chimaira4deth
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@suby2.5i
Quote:
Originally Posted by Suby2.5i View Post
My 2007 impreza 2.5i that was turboed running 9.8 psi. now has a built bottom end. (cp pistons, manley h beams, sti nitride treated crank, supertech valvesprings) its now going on the dyno to be tuned (opensource) on 19 PSI on a TD06 20G. with deastchwerk 1,000 cc injectors and a DW301 fuel pump. this 2.5i will be way in the 3XX whp territory and probally close to 400 wtq

Interesting..
throw up some results when you do that, thats pure information for n/a to turbo crowd.. and the answer to op's question.
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Old 01-09-2013, 12:58 PM   #19
XSV Klutch
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+1^ very interested in results.

Last edited by XSV Klutch; 01-13-2013 at 04:29 PM.
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Old 05-24-2013, 12:46 PM   #20
olsen726
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Hey subi2.5i what map sensor are you running?
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Old 05-24-2013, 01:48 PM   #21
revin-it02
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olsen,

I had to run the wrx MAP
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Old 12-23-2013, 12:21 PM   #22
VIsubi
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Quote:
Originally Posted by dangerousatom View Post
The 2.5i platform is lacking in all areas for the most part.

-SOHC heads that are not very turbo friendly.....bad high RPM flow
-High compression non forged pistons
-Week rods
-No good place to feed and return oil for the turbo, unless you mod the heads/oil pan/sandwich block the filter
-The injectors are far too small
-The trans is super week and you will strip a gear above 225-250 whp with out question
-The radiator is even too low a capacity for the amount of heat the turbo motor creates
-Either a stock turbo exhaust manifold is needed or a custom one will have to be made....to use the stock UP the NA motor cross member will have to be swapped for a turbo one. Or get a custom UP fabed.

It can be done, but to do it correctly it will cost you a ton

IMO if you turbo the 2.5i, 5-7 psi is the max it will handle on the stock bottom end and that will only net you some where around 215-225 crank hp. That is still shy of a stock WRX and your rpms will be 2k shorter due to the valve train max rpm of somewhere around 6200.
You are an idiot..lol the heads flow more than LS1 heads and any DOHC that Subaru makes also why do you think the STI guys use our intake manifold instead of a cosworth expensive one it flows more thats why haha loser
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Old 12-24-2013, 02:55 PM   #23
ProfessWRX
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Quote:
Originally Posted by VIsubi View Post

You are an idiot..lol the heads flow more than LS1 heads
Technically, they don't. If they did you'd have much higher whp figures in real life applications.
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Old 12-26-2013, 04:51 PM   #24
VIsubi
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I'm talking flow bench readings buddy and yes they do lol..matted with our intake manifolds and I don't have to explain about those theres tons of threads started of manifold bench mark flows.
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Old 01-02-2014, 07:36 AM   #25
wreckitralph88
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How its tuned makes a lot of difference.
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