Hey dudes,
I have an 04 STi w/ TBE, Accesport , Cobb Short Ram and full suspension(not to mention a lot of Carbon Fiber on the outside). Anyway, I have been seriously considering getting an upgraded turbo. I know I'll need the injectors and fuel pump and I'll probably go with an APS top mount. I've been obviously looking at the 20g but it seems like so many people buy that turbo and for good reasons, it's a great turbo! I want to do something a little different though. I was clicking around and came up with some info on the VF22 turbo. Judging by the info it seems like that turbo has a lot of power potential and comes in at a good price at about $799. What you guys think?

Heres the info I was looking at:
The VF22 has the largest potential for peak horsepower. In other words, in the IHI model range, the VF 22 supports the highest boost levels. It is capable of running up to 25 psi. Because it is a roller bearing turbo, turbo lag is minimal...the boost comes on around 3300 rpm. Expect to max out the VF22 somewhere in the 400-450 hp range.
Heres a link:http://www.gruppe-s.com/Subaru/subeng.htm

 

Can someone give me any additional information or experiences with this turbo?

 

well I have a FP green which is about 1/2inch bigger than the stock sti, so makes about 75 to 100whp after a tune, but i am actually selling this one and going with a garret turbo, they make alot of power and spool pretty quick and make full boost around 4500rpm, and you can use low boost and still make alot of power, unlike most turbos you can make power without pushing the turbos boost limits and having the problem of pressure on the stock block. The FP green is pretty good for a daily driver and doesnt take alot of time to install and not alot of changes to the intake. You can probably use the stock injectors with this turbo to, but i have 850cc injectors b.c you can make more power out of aftermarket turbos with bigger injectors...but make sure you have a chip...and i havent really heard much about the 20g's

 

and make sure you can find a good tuner, unless you are going to do it or self

 

I'm not asking about the 20g b/c I am already familiar with the charecteristics of that particular turbo. I want to know more about the VF22.

 

ok yea but the FP green has the same characteristics as the VF22, expect the FP green is alil more expensive, idk about the VF22 but the FPgreen bolts directly on to the car with no extra mods. needed including the intake

 

I actually ran a VF22 on 2 of my 02 WRXs. It was a very fun turbo that I enjoyed a lot. I ran it at about 18 PSI with a front mount and other mods and it spooled quickly and hit pretty hard for an IHI turbo. A lot of people "poo poo" the VF22 but I still rate it as one of my favs.

Also if you are not too worried about price check out the PE1818 and 1820...great bolt on turbos!!

 

Thanks man! I just wanted someone who had experience with that turbo. I'll check out the other turbos you mentioned.

 

NP

Happy hunting..and have fun with it...these cars kill

 

The VF22 is a great turbo, but with an 18g or a 20g you ar egoing to make more top end power. 18g spools super fast, actually quicker that the VF22 when combined with a TD06. It runs out of breath a little early about 5200rpm. The 20g will boost all the way to redline with just a little bit more lag.

 

Cool. So your saying the 18g runs out of breath, right? I know that the 20g is great and all, but I want to do something more unique b/c you don't see really any STi's running bigger VF series turbos than the stock VF39, VF34(JDM STI), and VF43(S204). I like experimenting with different parts and see what kind of gains or loses I get with them and others. I will report back when I install the VF22, PE 850 injectors and the methane injection with dyno numbers after I get the car tuned.

 

I think that a VF22 on a 2.5L would not peform as well as a TD06 18G. You would experience about the same spool rate with less top end by going the VF22 route. There is a reason why you don't see many STis with VF22. There are more versatile turbos that perform better. The 2.5L is a pretty big pumper, you might as well take advantage of it.
Take a look at this,
Stock Turbo 360 CFM at 14.7 PSI
T3 60 trim 400 CFM at 14.7 PSI
IHI VF 23/24 423 CFM at 14.7 PSI
STOCK HYBRID 430 CFM at 14.7 PSI
IHI VF-22 435 CFM at 14.7 PSI
SR 30 435 CFM at 14.7 PSI
T04E 40 trim 460 CFM at 14.7 PSI
Small 16G 505 CFM at 14.7 PSI
Large 16G 550 CFM at 14.7 PSI
SR 40 595 CFM at 14.7 PSI
18G 600 CFM at 14.7 PSI
PE 1820 630 CFM at 14.7 PSI
20G 650 CFM at 14.7 PSI
SR 50 710 CFM at 14.7 PSI
GT-30 725 CFM at 14.7 PSI
60-1 725 CFM at 14.7 PSI
GT-35R 820 CFM at 14.7 PSI
T72 920 CFM at 14.7 PSI

IHI VF 23/24 388 CFM at 18 PSI
T3 60 trim 410 CFM at 20 PSI
IHI VF-22 460 CFM at 18.0 PSI
AVO 320HP 465 CFM at 17.5 PSI
T04E 40 trim 465 CFM at 22 PSI
SR 30 490 CFM at 22 PSI
Small 16G 490 CFM at 22 PSI
Large 16G 520 CFM at 22 PSI
AVO 400HP 580 CFM at 17.5 PSI
PE 1820 600 CFM at 22 PSI
AVO 450HP 650 CFM at 20.0 PSI
SR 40 650 CFM at 22 PSI
20G 695 CFM at 20.0 PSI
AVO 500HP 725 CFM at 23.0 PSI
SR 50 770 CFM at 22 PSI
GT-30 790 CFM at 22 PSI
60-1 800 CFM at 22 PSI
GT-35R 880 CFM at 22 PSI
T72 1000 CFM at 22 PSI

HKS GT2835 Turbo about 400 hp approx 580 CFM, pressure not specified
HKS GT3037 Turbo about 460 hp approx 670 CFM, pressure not specified
HKS GT3040 Turbo about 490 hp approx 710 CFM, pressure not specified
HKS GT3240 Turbo about 570 hp approx 830 CFM, pressure not specified

So basically what your looking at is the CFM for any given turbo at a rated psi. VF22 at 14.7, forget about it, at 18psi still not up to snuff.

I won't go into the calculation as it is a real pain.
Anyway
A 2.5L running at 18psi/5000rpm flows about 500cfm
at 7000 rpm/18psi about 620cfm
now the calculation is very ballpark figures but as you can see the VF22 is considerably undersized for the application.

 

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Wow! Thanks for the info, now I really understand the differences of all these turbos at different points of the power band. What I was hoping to gain with the VF22 was more top end b/c the VF39 seems like it falls on it's face hard at about 6k. So it still seems that the VF22 generates considerably more power at 5k and 7k over the VF39. But your still saying my 2.5 at 18 psi at 5k rpm should be at 500 cfm when in reality the VF22 will only be making 435, and at 7k rpm, I should be at 620cfm and obviously the VF22 falls well short of that....hmmmm.
In the VF22's defense though, I've read various things and you should be able to run the VF22 more than 18 psi though, supposedly up to 25 psi. I'm not saying that I will be running it at that psi, more like 21 psi judging by what other people are telling me. But I think I get it though, I should still be seeing 620 cfm at 7k at 18 psi and I will still only be seeing 460 cfm at 7k rpm at 18 psi. But wouldn't an increase in psi pick up the slack of what cfm the car is making at 18 psi? Wouldn't running a higher psi increase the amount of cfm's, especially at a higher rpm? Thanks again for the info, I think I'll save it to my computer.

 

You need to learn how to read compressor curves. You will see that you are so far out of efficiancy range the turbo is useless. As you increase pressure you increase heat. While not considerably increasing CFM. Now if you increase CFM(bigger wheel) at a lower pressure, you will have a more dense air charge, cooler temperature, more power.
For example compare the 20G CFM @ 14.7 compared to the vf22 CFM @ 18psi. Which do you think will make more power?

 

I see, the VF22 doesn't even come close. Looks like I have some thinking to do. Would you say though the VF22 is signifigantly more powerful than the stock VF39? Is it worth the $400(Got the VF22 for super cheap) I'm going to spend on it and install myself along with injectors and pupmp?