I was curious as if the stock '05 STi turbo will be a good $500 investment into my '06 WRX??!! I already have the STi TMIC installed along with the OEM STi cat-back exhaust system from my firends '05 STi. Would it be a significant HP gain and is it bolt-on?? (i think it should be) Should've just bought the STi but couldn't afford the insurance payments. Please, any info would help. I am swapping all his STi parts in my WRX as he quickly upgrades (fuel injectors, etc.) HELP??

 

$500.00 for the vf39 is a fair price only if it has less than 3k miles or maybe a little more but ported already and in very good shape, most of them are going from $350. to $400. used.

Can't really say for certain that you'll be able to use the STi injectors on your WRX, IIRC, Wrx's are topfeeds and STi's are sidefeed type.

On your WRX, do you still have a cat in the uppipe? If you do, there's the first thing you'll have to replace.

All the proven power upgrades from the previous WRX models should apply to you but considering you have an 06, it's a bit iffy on how the bigger disp. engine will respond because for awhile now, what works for the WRX doesn't necessarily mean will work for the STi.


Lastly, all these mods would amount to nothing, prolly a disaster waiting to happen if you are not tuned, EM is a very good friend of engine mods, hehehehe, GL to you!

 

So i will get a HP increase? How Much roughly?? newbie cause i used to own a JDM NA 2wd H22A Prelude. I'm new to turbo AWD vehicles, love'em though.

 

Yes you will see hp increase. How much depends on ECU tuning.

 

Now when you say ECU tuning, you mean getting it flashed right?? If so, or if I was to replace it, we're talking a lot of $$$$$ then i would assume. Also, without ECU Tuning, I will still increase my HP with the upgrade and what if I install a boost controller, wouldn't that be the most cost effective approach to getting more boost. I sure it wouldn't cost as much, and, it's adjustable. I put a lot of miles on this baby, 2 months of ownership and over 6k miles so far (I work in sales), so it's important to me that gas consumption is maintained at an minimum state.

 

If you want good gas milege dont modify your car. If you run higher boost you will need more fuel. Stay away from boost controllers. Do some research. The best gains you are going to get is with a turbo back exhaust, catless up pipe and an accessport. If you want to throw in the vf39, then you need the parts listed above and a fuel pump and dyno tune.
If you need anymore help let me know cuz im in Fresno all the time.

 

Your reply is much appreciated and i will keep that in mind. Thanks for all your help, I believe the info has answered my questions. Basically, don't modify my WRX and buy an STI for the weekends!!

 

Hey, a few things: like the man said, research some stuff. No turbo upgrade should be done w/o AT LEAST a knowlegable reflash ($500 or so in Illinois), dyno time preferred ($175/hour)

Maybe the biggest thing: most here would say after what they have experienced, they would START with a reflash (engine management) and experience IMMEDIATE improvement. Sad thing about our cars, the computer WILL NOT allow the engine to improve with bolt-ons, only AFTER the e.c.u. has been altered to accept the mods will the car go faster...

Next, I don't think Sti injectors fit the WRX (ej20 versus ej25), but larger (modified) injectors can be bought pretty reasonably.

Last, i.m.o. with turbo-back exhaust, stock air box & uppipe, a reflash w/o dyno time can, CAN (don't quote me) result in 225whp more or less. This approximates Sti numbers. Others will doubtless know more than me, but it's a start.

TurboXS tbe, APS u.p., Samco inlet, Ecutek reflash.

 

Pick up a Cobb AP and a TBE (turbo back exhaust). Just run Cobb stage 3 and be happy... Your injectors are bigger than the STis so you don't need to upgrade there