Upgrading from VF28
 

Hi guys,

I have a '99 STI and was after some more power. I bought a GD intercooler (not yet installed) and wanted to upgrade my stock turbo. I have the usual mods of TBE, Walbro fuel pump, and intake which makes about 244 hp.

I know going from a VF28 to a VF34 isn't much of an upgrade in some peoples minds but would like to hear from someone who has done this and their thoughts as to if it's worth it. If not, I would like some other turbo options. My main goal is more low to midrange grunt.

Thanks.

If you want more low to midrange grunt, VF24. I believe the VF34 is slightly bigger then the VF28 so that would not achieve what you want.

A VF34 has a lot more midrange punch than a VF28/Vf29 - mainly due to the 34 having a far more modern Compressor wheel compared to the 28/29.

The VF34 is effectively a ball bearing version of the VF24 - Both have the same P18 hotside. The 34 has a slightly larger compressor and holds high rpm power better due to this.

You should see somewhere around 260-270hp ath with the VF34, GD sti cooler & re-tune - the spool is nearly identical to the vf28/29 too.

The best I got out of my Vf34 was 320hp at the hubs @ 1.7bar (on my built motor with cams).

Vf34

[url=http://www.carmodsaustralia.com.au/vf34-turbocharger.html]VF34 Turbocharger[/url]

$1195 delivered. Not a bad price at all.

Ordered!!!

From the reading I have done on the vf34, it seems as though if I get a P20 housing (rather than P18) I will gain more top end power and lose a bit on the low end. If anyone has gone from a P18 to a P20 housing on their vf34 can you share your experience with us?

Vf34 gc8
 

Brand new everything just done 10,000k on motor
Bottom end Brand new sti 2.5L
set of cosworth cams heavy duty valve spring full recon heads ARP head stud kit
Timing belt full kit inc tensioner Face fly wheel Excedy racing clutch kit
6spd R180 4,1 Vipec ecu VF34 IHI housing empire unequal header Twin system four tip
Dyno 355hp 245kw 7000rpm 12psi Whoop ass 11.741 No limits blew rear diff,too many launch but love it do it again
This is a first tune safe tune/ Wheels rota drift 18x10 offset 38
Will take the limits off on the next dyno and open her up more to red line
I have another one just come back from dyno 411 awhp 537 torque safe tune Track tune capable of 750+
2.7L stroker extreme built with all the fruit

[QUOTE=patifred;814268]Brand new everything just done 10,000k on motor
Bottom end Brand new sti 2.5L
set of cosworth cams heavy duty valve spring full recon heads ARP head stud kit
Timing belt full kit inc tensioner Face fly wheel Excedy racing clutch kit
6spd R180 4,1 Vipec ecu VF34 IHI housing empire unequal header Twin system four tip
Dyno 355hp 245kw 7000rpm 12psi Whoop ass 11.741 No limits blew rear diff,too many launch but love it do it again
This is a first tune safe tune/ Wheels rota drift 18x10 offset 38
Will take the limits off on the next dyno and open her up more to red line
I have another one just come back from dyno 411 awhp 537 torque safe tune Track tune capable of 750+
2.7L stroker extreme built with all the fruit[/QUOTE]


Got a dyno sheet of the 411 hp run?

Was it this one from 18 months ago?

[QUOTE=patifred;762148]I started by replacing suspension tein coil, wheel bearing,brakes,and anything that was not right under the car.Then I bought a vf34 installed,vipec jnstalled 850ccinjector jnstalled,empire extractors,varex exh for those late night,engine was replace at 167000k now at 180000k dyno at allstar 355hp 210 torq Shes fast enough tested at RAC track tar/dirt wanted to see if it really does what they say about wrx.I now install a m8 wide bodykit and bonnet,[B] I have another wrx in building mode right now with 2.7ltr cp piston,cosworth cams,etc Will let ya know when shes complete,hopefully this weekend.[/B] Cheers ps thank you all.[/QUOTE]

355hp but who is torque?

Yeah Rossco ASG did all the dyno for both cars I have all the paper work for everything that is done to it Forgive my rudeness for not posting and update as you can see the time I log on or get to look on the net.Shaun should have dyno records of these two cars cause Vipec ecu programe {not all vipec are direct plug in with gc8}Not all dyno are the same too as Ive already tested this theory out with other awd dyno I did really wanted a 22b but after much effort of finding one and at the time there was only one going and already sold to a fellar in USA I decided to built something with the same year as the 22b I do have 3 wrx all gc8 {97/98 Sti with the open hatch on the roof that I have not added in the RA section Vin check but already check as a version3/4} Also 98 evo club spec/ and a 98 wrx with the fibreglass widebody I kept all the boxes that parts came with so I know which works good and last and which not to buy As you know performance parts do not carry warranty You break it but another one

Just an update...had the new intercooler and VF34 installed and tuned, dyno of before and after attached...seems as though VF28 had more power earlier in the rev range. Overall not a great deal difference between the turbos...

[IMG]http://i822.photobucket.com/albums/zz142/soroush999/e6254891058cd2d35975e7a3674b2bee.jpg[/IMG]

[IMG]http://i822.photobucket.com/albums/zz142/soroush999/f13f506b95112d9f8ba3177686927350.jpg[/IMG]

It needs more than 1.4bar of boost............ That plus it's 30 odd degrees outside which will give you a lower figure........Still 14HP & 13nm more power.

Ps you have 2psi drop in boost from peak to redline. What boost controller do you have?

What did Sean say?

Hey Rossco,

I don't have a boost controller, it was not recommended when I first took it to ASG. Sean didn't say much- just said it's not a huge improvement but VF34 is similar to a VF28...what do you think I should do?

[QUOTE=Sammy82;816046]Hey Rossco,

I don't have a boost controller, it was not recommended when I first took it to ASG. Sean didn't say much- just said it's not a huge improvement but VF34 is similar to a VF28...what do you think I should do?[/QUOTE]

P20, more boost and rev that fucker!

[QUOTE=BXT;816048]P20, more boost and rev that fucker![/QUOTE]

Good advice!

I think I will try somewhere else for a tune...anyone know anywhere else besides Mao that can tune power fc ECU? I've heard good and bad things about maximum Motorsport...any recomendations?

All Star Garage can do them

Your best to keep with ASG and get Sean to fit a electronic boost controller to your car.

[QUOTE=seagull;816467]Your best to keep with ASG and get Sean to fit a electronic boost controller to your car.[/QUOTE]

No need for a boost controller with the Power FC - it uses the factory solenoid & Map sensor.

It needs more boost wound in however. Sean conservatively tunes all GC's at 1.4 bar.

Turns out there aren't many tuners that deal with powerfc and my options are limited. I might wait a little bit and go back to ASG and talk to Sean. I will say that the car definately felt faster and more responsive with the VF28...

The fact of the matter there is limited company's in Perth that have staff that can tune from scratch let alone tune a power FC.

ASG are all rounders, Sean has a lot of knowledge on this front.