Due to my recent ***** up i am now looking at buying a 2.5 litre short block for my MY01 STI import. My STI is fitted with an IHI Vf30 turbo. Would or should i be looking at buying a bigger turbo, i.e say a VF34 and what would be the benefit of either???

 

A VF34 is no bigger than a VF30 they are the same size, it just has the benifit of having a Roller Bearing instead of a Thrust Bearing

You don't have to fit a bigger turbo for a 2.5 but it would be a good idea as the power will be very low down in the rev range and there will be nothing towards the top.

I think the smallest turbo reccomended for a 2.5 is a TD05 20G

 

Cheers Dean

Anybody else have the same opinion?

 

I have a ported TD05-16G on my 2.5 converted 97WRX. It made 341bhp and 357lbs/ft torque recently at 1.45 bar. Nearly peak torque at 3000rpm and held till 5000rpm. Peak bhp was made at 5500 rpm. The power does tail off quite quickly after that though.

 

Well done Bruce, thats impressive.

What is the standard type and size turbo for the 2.5 STI?

How much would i be looking at paying for a good secondhand TD05 20G?

 

bttt

 

if it peaks at 5500 then you know you wont have to wring its neck and therefore preserving the engines life.. i never revved my uk wagon like this 555 sti as the power was delivered much earlier ! which i personally like !

 

Been reading a few threads on the turbo options, all abit puzzling to me
Would be happy to have whatever turbo came standard with the 2.5l STI but can't find out which turbo that is??

 

VF39

 

To get a reasonalble hike in bhp/lbft off a 2.5 conversion, the 20g is about as small as you dare go but you will have a sweet road engine with most parts 'unstressed'. Prob about 380 x 380 but you might notice a tail-off above 5500 which suits the stock 2.5 byt if the car is a Jap spec the gears might feel short as you cant rev is to match the Jap engine.

A 20g is a robust turbo, solid as a rock and 2nd hand in good condition will fetch about £550/600 on Snet. A rebuilt one from AndyF will be about £800 but is as good as new.
www.andyforrestperformance.com

I have the later on my stock Sti v3 2 liter, 380 x 370 and has been raced for 3 years with zero problems.

Hope this helps.

Graham

 

Thanks folks