Evening all,

Essentially I've got a 2007 2.5 Impreza Prodrive which is 100% standard.

I've already ordered a Tein Coilover kit, AP Racing brake kit (all round) etc etc, but I'm after more power.

What are these blocks good for before I need to started thinking about pistons, rods etc?

I'm looking for around 400bhp for now, nice and reliable and not too crippling on the pocket.

Any info is much appreciated, and I apologise in advance for my newbie-ness!

Cheers all,

Ryan

 

Wrx or sti?

 

STi

 

Needs to be rebuilt to stay reliable for 400

 

To be save I would go with a rebuild. I am sure there will be a few running that on std setup but it not "safe"

 

These blocks are so unpredictable its impossible to say what the safe limit is. Some people have had failures on standard blocks where as others have been lucky and run higher figures. Mine has been running around 390bhp for about 4 years now but thats on low boost (1.2 bar) and with arp 11mm headstuds. Im currently having a 2.1 built for mine but if i were in your position i'd look at going with a good set of forged pistons, some cosworth head gaskets and some decent headstuds. Then get a decent panel filter, and a remap. I'd expect to see around 360bhp with peace of mind

 

Cheers guys. I guess future proofing the car isn't a bad thing either.
What rod/piston combos do you guys normally go for? I don't mind maxing out the standard turbo and then upgrading to a bigger snail later down the line.

What about uprated valve sets, fuel pumps, injectors etc? Doesn't my PPP already come with a few upgrades in that respect?

Thanks

 

I agree with these guys, mines is getting forged as we speak and shat itself after 350hp, speak to an engine builder they point you in right direction

 

Ppp will already have uprated fuel pump, injectors are dependent on power. 650's are good to 450-480 I believe. Also if your going for high power it may be wise to look at fmic. Don't quote me on this but I'm led to believe the sti tmic is close to its limits at 400+

 

Also as for rods and pistons, that all depends on budget. With a 2.5 if budget allowed I'd be looking at cosworth. A cheaper option may be Mahle or wiseco pistons and k1 rods