I have a JDM STI 2002, this has a VF35 fitted as standered, I am not happy with this turbo as the the trubo spool up time is to long for me,

I have taken advise and the best cost effective way I have be told to tackle this is to buy a VF34, is this true and what other benifits come with it, or is there another turbo on the market you guys recommend.

I will be doing some mods to get some more bhp, aiming for around 340-370 as I dont want to go fmic yet, is the VF34 ok for this power output?

 

Yours should be a vf 30. A vf35 is type uk bug and is slightly bigger

 

VF35 is the second quickest spooling turbo next to the TD04 mate (it will slightly outspool the 34 due to the smaller exhaust housing). At the 330bhp level you won't find a better performing turbo. If there is a problem with spool threshold/lag, there is a problem with your set up somewhere or you have a duff turbo. The 34 will generally produce a bit more top end than the 35, but realistically, both are 330ish turbos, if you want higher without loss of spool, suggest you look at the SC billet range from Scoobyclinic.

 

VF34 will be better choice,this turbo will make 340-350bhp.
If you are aiming for 370bhp i would suggest 20G.


Jura

 

VF35 on mine made 343 (with supposting mods) and can usually be had considerably cheaper than the 34

There are better turbos than the 20G, which is laggy, for the 370+ level these days, I'd argue, but 20Gs can be had cheap.

 

If the VF35 is typically a 340 bhp turbo then like for like with all supporting mods the VF34 can get to nearly 360 bhp. With all supporting mods. Like for Like.
VF34 usually fetch good money and appear to be in limited supply.
You will not find a significant difference in spool between the smaller VF35 sleeve bearing and roller bearing VF34 and if you are experiencing lag I suggest you look at your overall spec, headers, uppipe, exhaust leaks, induction or possibly mapping.

Some people have it in their heads that the 20G is laggy. There is no doubt that some 20Gs are laggy but a properly built 20G on a well specced and mapped car does not need to be laggy. On a five speed box on a level road from 1700 rpm how about 1 bar in 4th gear consistantly at 3140-3160 rpm? It is not just the turbo ie. 20G but the components used to manufacture the turbo and the overall engine spec.