Yes. With supporting mods a 34 is a good DD turbo. I just put a VF39 on my wrx(2.5ltr) and I feel that the TD04 was just the wrong turbo to come stock on the 2.5 imho(but most cost effective), reason why the 06-07 wrx did not come with a VF39 on them, plus they would have been close to STi power, so I could see them worrying about sales as well.

My car just seems to like the VF39 better than the TD04

 

According to your profile, I see you have an '06 WRX. Yes, with proper exhaust, I/C, and tune upgrades, it will be a direct bolt-in turbo.

However, I feel that the VF34/39 are a poorly-matched turbo to the 2.5L engine (the TD04 even more so).

The smallest turbo I would go with would be a Blouch TD05H-18G with the upgraded 8cm^2 exhaust housing. I recommend the Blouch because they use the TD06H compressor housing.

If you're going to do a turbo swap, you may as well do it properly:

750cc injectors (tuners preference on brand) and Walbro GSS342.

Quality TMIC (TurboXS, APS, Perrin, Spearco)

Aftermarket UP (EWG preferably) - yes, your OEM one is catless, but an aftermarket one will flow better (read: quicker spool and more power). EWG sounds awesome, and gives you even more benefit.

PnP exhaust manifold / aftermarket headers.

Aftermarket intake - I like the APS 65mm CAI, as the filter is in the fender, and the OEM black plastic scoop directs air right on it. You'll be far enough from stock that your OEM intake will be a restriction. A post-MAF hose (Samco, Perrin, Cobb) is relatively inexpensive. Installing a turbo inlet hose (Perrin, Samco) might be good since you're swapping turbos; "while you're there" type thing.

Aftermarket boost control - solenoid or MBC, tuner preference.

Good custom tune - if you're going to spend the $$ for a turbo swap, get a proper map for it. If you can't get to a tuner due to location (none in a 4-hour radius), an Internet/e-mail tune would suffice.

 

I will agree with EJ257 though. If your going to be in there upgrade big. I just got a really good deal on the VF39, so I took it.

Down the road however I will be looking into a 20G, so he does have a point.

 

I will agree with EJ257 though. If your going to be in there upgrade big. I just got a really good deal on the VF39, so I took it.

Down the road however I will be looking into a 20G, so he does have a point.

The ONLY reason to buy a VF39 is because they're cheap, since everyone in their sun with an STi is selling their OEM turbo.

An 18G vs VF39 will be make more power everywhere in the powerband.

 

Oh I trust you on that lol.

 

pardon my ignorance on the subject,but the stock turbo is an 18g right?
im not looking to make huge gains,just a small uphrade for the turbo i found a good deal on one so ill pick it up for later.

 

pardon my ignorance on the subject,but the stock turbo is an 18g right?
im not looking to make huge gains,just a small uphrade for the turbo i found a good deal on one so ill pick it up for later.

No, the stock turbo on your car is a TD04.

An 18G would be a good size turbo upgrade. It will give you a good bump in power all around, most notably in the top-end.

If you want to go for the VF34, then by all means, go for it. I just think that if I was going to spend the time/$ for a turbo swap, I would do it differently.

 

gotcha,well i was outbid on it so i didnt get it anyways,i guess ill look for something else,would an 18g be my best bet then?
or jsut wait till i build and do something bigger?

 

gotcha,well i was outbid on it so i didnt get it anyways,i guess ill look for something else,would an 18g be my best bet then?
or jsut wait till i build and do something bigger?

Get the turbo and supporting mods I mentioned in my previous post. It will probably be enough of a bump in power to suit your needs.

 

I would have to agree as well. I have a VF34 and it spools fairly quickly but I feel like it does lack some top end. Decent turbo, but an 18G would have much more of a kick in the pants. A buddy of mine has an 02 with a TD06-18G and I believe he is running either a VF map or his stock TD map because he hasn't got a 18G map yet, either way we were neck and neck in a straight line. The 18G outflows the VF's by about 170cfm. Once he gets a 18G map on his car, that and he has a FMIC, he will be blowing my doors off.

 

I completely agree with EJ257. I have a Blouch TD05H-18G 8cm^2 on my EJ257 hybrid build. IMHO it is the perfect turbo for a 2.5L that is a daily driver, as it has an awesome powerband.

 

Would this be a good choice from slowboy?
WRX/STi Bolt on 18G
8CM Turbine Housing
Internally Wastegated
Includes Water Lines

 

Would this be a good choice from slowboy?

Seriously, the Blouch is the turbo you want. You're looking at saving a little with the SBR turbo, but the Blouch comes ported, so that makes up for the difference.