xicema17x

iTrader: (22)

I was doing some research on buying my mods for my STI, and i kinda thought of instead of paying all that money to buy a full turboback w/o cats and header, why dont i buy a new turbo instead. I just wanted an idea if i did change the turbo.

Krinkov

iTrader: (21)

I ran a VF34 off the stock injectors and ECU just fine for 20K miles, I picked up 13whp with it by itself, though I was also running a TBE and headers, so you wont make quite as much as I did with just the turbo swap. I think the best reason to run the 34 if your going to put on a TBE you can have it ported and readey to go when you put everything back together instead of having the downtime of having to pull your turbo out to get it ported. and for what 34s are going for nowadays, you can sell the stock 39 and its almost an even swap.

Kevin M

iTrader: (12)

It depends on what you already actually have. VF39s come with one of two exhaust housings- the P17 or P18. The P18 is what is used on the VF30/34, and the compressor side of the VF39 is the same size as the VF30/34 as well,just a different wheel design. So, if you have a P17 housing from an earlier car, switching to a VF34 will shift your powerband slightly higher up the rev range. You'll hit boost slightly later, but you'll also be able to taper boost later which makes more peak power, as horsepower is a function of torque and RPM. You won't see much gain in torque, but by making it at slightly higher revs you get more hp. I'm pretty certain this accounts for most of the 13 whp Krinkov found with his VF34. You had a fairly early STi with the P17 housing right Krinkov?

Now, if you have the P18 housing, you essentially already have a VF34, just with a slightly more efficient compressor wheel. It's really not worth putting a VF34 on your car unless you're getting boost creep. If it were me, I'd put a VF22 on the car at the very least if you're interested in making more power. Your stock fuel system can keep up with it.

apssti

iTrader: (1)

i say save the money and dont be in a hurry, i think that once u pu that vf34 on you prob gonna replace it in the future, the stock turbo has potental, i was puting down 310@ the wheels wit the stock turbo@ only 18lbs

mw1029h

I agree and if you port the vf34 and are using EM ECKUTEK you are going to be in for trouble believe it. keep the 39 on do the EM upgrade and at least the CB exhaust you will be happy for a while. You will them want to do a turbo and injector upgrade 20g or green etc.

Kevin M

iTrader: (12)

What's wrong with the VF34 and Ecutek combo?

UK n00b

iTrader: (3)

If you think the stock 480cc ish injectors on the USDM STI are capable of keeping up with a correctly tuned VF22 you are gravely mistaken. The stock fuel system see's IDC's above 90% on a ported VF39 running at no more than 17-18psi using a Walbro drop in as well. Admittedly these cars also have full catless systems (headers to) and put down about 270whp and 290ftlbs.

Mike

UK n00b

iTrader: (3)

I would buy a turboback (catted or catless), fuel pump and get some engine management instead of slapping a bigger turbo on the stock setup. You'll yield far more appreciatable gains that way.

Mike

mw1029h

Its a difficult tune one that most don't know how to do. Trust me you will not be able to make any boost if you P&P a vf34 with Ecutek it has something to do with the pill size and if that doesn't work you will have to run a boost controller. Only Ecutek has this problem. It cost me alot of money coming up with nothing so I put back on my VF39. I'm running the following: Ecutek, walbro , Injen FMIC, CAI and C/B exhaust. The car runs great. If I were to upgrade it would be a 20g and injectors re tune Ecutek.

UK n00b

iTrader: (3)

I would speak to whoever did the tune for you then as your statement above could not be further from the truth, there is no difference tuning a ported and polished VF34 with EcuTek than tuning a VF39 ported or otherwise with EcuTek, sure some of the maps need changing but they do with any tune such it's sometimes called mapping

I would suspect either the port job was a little over zealous causing you to not make/maintain boost or the tune/tuner was off.

Mike

mw1029h

All I have to say to you is have you done it, I would say by your statement that you haven't. I have and the tunner was Ben Dagenais of Ecutek he did the tuning and the Vf34 was P&P by deadbolt please don't be like other people and talk about something you heard and not what you did. If you do a search on the Nasioc technical section you will know what I already know.

Kevin M

iTrader: (12)

Umm, dealing with this is common knowledge. I used to work for vishnu Performance Systems, and part of shipping a VF34 OR reflash package is ensuring that the customer gets the proper restrictor pill and/or bleeder. Whoever installed your turbo didn't know what he was doing since he obviously didn't get the vacuum lines correct.

Krinkov

iTrader: (21)

hoo boy,
Your new here so I guess you dont know who your trying to flame, but Mike is the in house dyno tuner for Gruppe-s and has more experience making power out of Subys with every combination of turbos and mods than 99.9% of the other talking heads on this forum. So um, yes he does know a bit more about what hes talking about than you or I and does not pass on any info that he has heard and not experienced.

And as for searching NASIOC, you might just run across my post in the 2.5 forum where I put down 276whp/307wtq on a tuned P+Pd VF34, and Matt (Still Will) put down 279whp/323wtq on a tuned P+Pd VF34. So yes, you can make a bit of power with a properly tuned P+Pd VF34

cheers

Kevin M

iTrader: (12)

And yes, UK n00b has done this before. I'll let him explain the details.

mw1029h

Will Matt is not running a Ecutek is he. And flaming is not my goal and if you think you know all and you are telling me that it didn't happen or you are telling me that Ben or Deadbolt screwed up that is another thing. But from what I have heard Jerry and Ben are one of the best in their respective business. It doesn't really matter to me what is said maybe you should ask Shiv if he knows Ben btw he did the tunning of the STi in tunner transformation. I don't have to be new here or anywhere to know what I know. I will say this, I was one of the first ones to do it so it was something new then, btw every pill was tried then. I didn't want a helper spring or boost controller. I never said it couldn't be done I said that it is difficult and you would need someone who really knows the craft or it will be a pain. lastly the little gain that you get is not worth the cost. might as will save you money and get a 20g,inj fuel pump and tunning. my setup puts down those numbers even if not greater then the above.