I've just bought a 2005 facelift Forester Sti, currently standard except for decat exhaust, RCM induction kit and RCM map giving 325bhp/375lbft.

It's quick but I want a bit more out of it.
I've got a MD321H sat in the garage on the shelf which was destined for a classic impreza, I'm guessing on the 2.5 400/400 should be possible with this turbo.

What other upgrades do I need to get there, is it just a case of injectors and away we go?

Also I've seen the MD321H is advertised as VVT and non VVT, whats the difference as mine is likely non VVT (purchased used on here for a classic)?

 

rods and pistons,,,,,

i wouldn't push a stock 2.5 much about 350

 

Agreed. Unless you go fully forged I'd leave that turbo on the shelf in your garage. You'll grenade the engine in no time.


The standard VF41 turbo can and has achieved 350-360bhp on quite a few FSTI's now. Mine is at that level now and it's great.

 

The standard Foggy STi intercooler is the same size as the Impreza WRX. If you get the Newage STi version you will need to mod the trunking.

 

Thanks for the replies, haven't kept up to speed with new age impreza engines and thought the wisdom was 400/400 was OK, I guess we have more data now on where they fail.

Appreciate the thoughts and will make some enquiries as to if the stock turbo can go a bit futher in that case.

 

I clearly need to get mine mapped again then, from my build post

I will post the graphs later but essentially 321 bhp and 350 Ftlbs of torque.

Slightly disappointed with the bhp figure at 1.4 bar of boost when considering the mods in place.

Syms sports cat
Fujitsubo Legalis R cat back exhaust
Cosworth panel filter
SWRD colossus 340 lph pump
NKG heat 7 plugs
SWRD 3-port boost solendoid