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If you put that turbo on your car, you still want to get some type of fuel management. Be it uteck, accessport, or ecutek. Get something. You can't just change the turbo and run the stock ecu. And also, you will be waisting your money getting that turbo, you might as well get a vf 34, 30 or 22. Also I doubt that he had a vf 39 on a stock wrx and made that kind of power. That's the STi turbo, and it doesn't even do that type of power with that turbo, and it's properly tuned.
 

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you don't want to compare a wrx with a vf39 vs a stock one, you want to compare it to a stage 2 car with a TBE and EM. The vf39 will not net you too much for all the expense of an intercooler, injectors, fuel pump, and the turbo itself where going to a vf34 or bigger will see a more substantial gain.
 

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Vicious LSD said:
Just curious to know if anyone has any ideas on how much horsepower will be achieved by installing a vf39 on a stock wrx. I'm getting one for a killer deal!

IMO the VF39 is crap but if you are getting a super deal it is better than the stock wrx turbo. I wouldn't expect very big gains HP or Torque wish without other supporting mods.
If you are ready for a bigger turbo I recommend the EJ5-40T it out proforms the VF-34 hands down and it is very streetable. I have seen package deals for around $850...just do some research. Otherwise I have a used VF34 for $650 if you want it...
 

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VF39 is a 350 crank h.p. turbo. From my personal experience, its a good turbo. About the equal of the Mitsubishi small 16g's and Garrett T28's I've run on DSMs, with a little later spoolup. It does have a pretty wicked midrange with a really strong kick in the backside starting right around 3700 rpm (Sti). Top end is pretty good, I'm not complaining.

On a stock car with stock boost, I see very little power gain from just slapping it on, might even lose some bottom end power (i.e. slower spool). You need fuel management, increased boost, and an exhaust to make it work.
 

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Discussion Starter · #12 ·
well i did my mods yesterday.... VF39, invidia downpipe, fujitsubo catback RM01A exhaust, GTSpec Headers, GTSpec uppipe, Forge Intercooler Hoses, Pony express MIL fix, and a resister fix for the EGT. Everyone kept telling me I couldnt do these mods without engine management. My boss and co-workers said it will be fine. After I finished all the work I hooked up the Subaru Select Monitor and checked most of the data. Car runs great without engine management. Im gonna wait till winter to do some other mods and EM but boy there is no comparison. My car hauls some major ass now.... defintily happy with the outcome.
 

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Vicious LSD said:
well i did my mods yesterday.... VF39, invidia downpipe, fujitsubo catback RM01A exhaust, GTSpec Headers, GTSpec uppipe, Forge Intercooler Hoses, Pony express MIL fix, and a resister fix for the EGT. Everyone kept telling me I couldnt do these mods without engine management. My boss and co-workers said it will be fine. After I finished all the work I hooked up the Subaru Select Monitor and checked most of the data. Car runs great without engine management. Im gonna wait till winter to do some other mods and EM but boy there is no comparison. My car hauls some major ass now.... defintily happy with the outcome.
Your boss and co-workers are wrong. You are running a serious risk of damaging your engine. The reason your car runs "better" is because it's leaning out. Probably knocking too. You have no way of adjusting your fuel and timing to compensate for the extra boost. Yes, it's faster, but it's very dangerous to your engine.

Running a bigger turbo on stock engine management is a bad idea. Period.

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Discussion Starter · #16 ·
so the select monitor is giving off wrong readings? Select Monitor is Subaru's scanner. He has his own performance shop and tuning as well as owning a dealership. None of his clients ever had any problems. We made a few runs logging the data and it doesnt show any lean conditions as well as any knocking.
 
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