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Subaru WRX/STi 20G-XT Turbocharger

10K views 22 replies 5 participants last post by  rwatkinsii 
#1 ·
Ok so i have decided that this is the turbo i want! I will not be installing this until all supporting parts are in and i will trailer the car to my tuner. With this turbo im running the following.

Subaru WRX/STi 20G-XT Turbocharger


Fast motorsports FMIC
DW 1300CC Injectors
DW 300 Pump
3 port
ETC


Im going to order this turbo tomorrow and im unsure what turbine housing to get. I plan on drag racing and spending a lot of time at 3500-5500rpm but i also drive the car. Or should i get the 3" inlet. I have already decided this the turbo i want. i dont plan to run it at max power planing on about 350WHP But once i get the cash saved to do the bottom end and tranny i will have plenty of turbo for what i want todo.
 
#5 ·
I have decided on the 10CM because i like to go to the track once and a while and dont realy fly around on the road there for the 10CM will put my peak power in upper rpm range. As for injectors 1300 might be overkill for gas but i want to plan for future. I also just got 3" turbo inlet tube, Grimmspeed uppipe with external wastegate, aem Cold air intake, perrin by pass valve. A friend of mine has an 11 sti and after doing all this work decided to build a shortblock and do a rotated setup.
 
#6 ·
10 cm is going to destroy your bottom end. A friend has a 10cm Blouch Dom 3XT and now has to downshift to pass on the highway, where with his old 8cm he didn't have to.

And that intake is going to be a restriction. And like I said, there are more parts you're gonna need beyond what you listed. At this power level, stuff starts to break. You're at shortblock territory yourself.
 
#7 ·
why does the cm matter with a EWG and 4" open bell mouth DP? by 4" i mean just the head of the DP then it drops to 3" a few inches later.

FYI the blouch now has a 20gxt-R.
 
#8 ·
Not exactly sure i was just told by the dude i deal with that larger CM will make your peak power in higher rpm. as far as killing bottom end i dont mind having less bottomend boost. This will save me gas as i putt around town. im not going into busting stuff territory as i dont beat the shit out of my car. i my friend has a 05 sti on a stock block with 425 at the wheels and has been driving for 2 years without issue. i dont beat the crap out of it every drive. i made a mistake on the intake im not sure exacly what one he has but it is a big maf cai.

I have an entire list of things im getting. these are just a few parts. I just wanted opinion on the turbine size. Thanks for the help.
 
#9 ·
Hate to promote my own turbo. :D But, the 2.5XTR is probably a lot easier to get 350whp from and I still had to do a lot of work to get it on pump. E85 it'd get there a lot easier. Who is your tuner btw?
 
#11 ·
True. I mean these cars could be flashed with a gt35 map making 500hp and be totally fine, if you never hit wot. I'll try to find an article that interviewed Crawford, Yimi and cosworth I think or AMS. They all said what they think about the 2.5 motor, what it can handle, what it's downsides are etc. Good read.

Here's a like of a link, pics are sweet!

http://www.subyclub.com/topic/2882-...ies-engines-are-they-as-weak-as-tuners-claim/
 
#13 ·
Crawford worries me a bit saying 400whp is ok stock and AMR saying double factory HP is ok. Hell that's 424whp for the 09+ WRX. At least they change there mind later when saying what 400hp requires.
 
#15 ·
Yea I was shocked about the 400whp and wasn't sure if I was reading it correctly that they changed to needing internals later. I'm only gonna run this up to about 350whp until I get bottom end done. I just want to have the turbo todo the job later in the build. My goal is 400 any more is bonus. But for now gonna tone it down a little.
 
#16 ·
Did you read it?

Crawford: 400 whp. There are no internal engine modifications needed at this power level. The car would need a larger turbo, intercooler, fuel injectors, fuel pump, AOS, and retune of the ECU.

AMR: 400 whp. We suggest a set of forged AMR pistons and billet rods to safely boost up the engine.

Yimi Sports: 400 whp. For an EJ205, you should be doing a basic build on the block that would include forged pistons, rods, good bearings, and head studs. Obviously, quality machine work and tight tolerances/quality control are crucial. For an EJ255 and EJ257, all the block needs is a set of forged pistons. 400 whp (particularly on 91 octane pump gas) is when cylinder pressures are high enough that a random knock event can take out the stock pistons. The rest of the internals are more than up to the task.

My tuner says 350ish is where you need at least pistons. Because like stated some bad knock can kill a piston pretty easy above that range.
 
#17 ·
Well there's lots of people out there at 400whp. It "could" be a matter of time but a good tune and a place that sells perfect gas could make it last a long time! Hell I could make it last forever since I'm hardly ever in boost and not drive a lot. When I do it's a highway road trip which is why I have a lot of miles. O well, even factory motors blow for a number of reasons. Luck of the drawl.
 
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