hi all, just a quick one to hear your thoughts on this. looking into just the fuel pump, full decat, panel filter and remap on my stock wrx uk hawk. i know from reading up that this will get me in the region of 280hp 340lbft give or take. i know people wanting more tend to go for the hawk sti turbo and this will go to about 360hp 400lbft... but in my eyes thats more then what i want and id always be waiting for something to die like the gearbox, pistons etc.
so would something like a vf28 get me somewhere in between. i.e around the 320hp 370lbft mark give and take, so its a nice gain but still well within the limits of the stock components for peice of mind.
if this is doable, what do you need to do to fit it as ive read up about porting wastegates for use on a 2.5. and the stock pistons in the 2.5 are said to be safe under 1.35 bar... are the figures ive said about right for a vf28 on a hawk 2.5 with the other above said mods at say 1.3 bar to be safe. thoughts and experiences welcome and appreciated please. thankyou

 

The vf28 is better suited to the 2.0L engine. You are better off going for a VF43 or VF48 really for the 2.5L engine. I'm running a VF48 on my hawk WRX at 334bhp & 381lb/ft and have done so for 5+ years with absolutely no issues at all. Really great car to drive now. Don't worry about the gearbox as the Hawk 5 speed is the strongest 5 speed built to date (with exception of the prodrive PPP box) and can handle a power increase ok.

You may need a new clutch at those levels though. That said I'm now at 73K on my original standard clutch!

 

Im running a vf24 (same as a 28) on my bug wrx and its been grand for a few years now, I think the torque figures you are wanting are a little high for it though.
The turbo is a little upgrade on the likes of a td04 but there is definately a trade off with a little lag.

 

Hi thanks alot for the reply. that sounds great, so what cars are the vf 43 and 48 fitted to as standard then? and are they a straight swap for the 2.5 and no additional machining or fiddling needed?
They are great figures, I bet it does drive well! So what other supporting mods did you fit to achieve this, what max boost is it set to and in terms of response with them turbos what kinda rpm are you seeing full torque/boost. thanks again mate i appreciate it! Aaron.

 

VF43 was fitted to hawkeye 06-07 STI and VF48 was fitted to hatch 08 STI onwards. They are both a straight swap for your current TD04, but you would benefit from an STI intercooler, silicone pipes & scoop undertray at this point as the pipes under the WRX intercooler and not good enough for these power levels and the WRX intercooler is not as good as the STI cooler. The std pipes tend to start to collapse or restrict under boost.

My car has:
VF48
STI spec C intercooler
STI under tray
Samco silicone boost hoses
3" sports cat downpipe to 2.5" end
2.5" resonated centre section
2.5" back box
Walbro 255 fuel pump in the tank
K&N panel air filter
prodrive 3 port boost solenoid

However, each car will vary in the power it produces and I've seen cars with less fitted make much more. Mine is mapped to 1.35bar MAX boost to try and save the engine a little. Still 100% standard internals and still going great.

I would say the minimum would be:

Turbo, downpipe, STI intercooler, boost hoses, STI newage undertray, fuel pump, new air filter & remap.

Good luck!

 

Couple of graph pics of mine for you.

 

mate thats awesome thanks alot for your help!

 

Any time!