Hello, just bought another impreza. 03 blob wrx this time, fairly standard except PPP, sti intercooler, coilovers all round and 18" wheels.
Looking at tuning it after its mot, gathering bits just now, will be going for a bigger turbo and looking for 330-350 bhp.
The question is I have aquired a turbo back system, comprising of 3" DP, 2 1/2" after that, keeping the 2 1/2" prodrive back box, will this system flow ample for my target BHP? thanks in advance

 

Yes, you will only start to see restrictions when pushing high 300's/400

 

Good stuff, I will just use it then. next on the list, turbo, injectors, fuel pump....

 

I just built a similar engine with rods and valve train upgrade. I have been advised our Crank doesn't like Hight revs or much above 400hp! Don't know how true this is though!

 

Not true at all, I was using a standard 79mm crank at 666bhp

 

Ok Great! Was getting worried! Your is thrust bearing at #3 position?

I have set my limiter at only 7000rpm cause of this! Wanting more!!

 

thats why im aiming for circa 330-350 bhp as per first post

 

EJ22 block rear thrust conversion, mine was set to 8200

 

I've been trying to blow my 03 Blob engine for years constantly hitting the limiter at 7,400rpm, car runs fine still.

I even sold the back up engine as I got fed up of it not going bang. I even ran it very low on oil several times. I'd love to know what the Blob engine, Clutch and box can actually take with good oil.

 

Hi there

2.5" exhaust can be restrictive,some run their 2.5" at high 400bhp without the issue,but I would suspect Prodrive backbox will be quite restrictive at low/middle 300bhp,due this I would go with 3"

Rev limit depends on valvetrain,but on 2.1L we run 7800/8000RPM rev limit,with 2.35L we run 8250RPM rev limit

Jura

 

I ran a newage engine with sti 3 heads at 522bhp for 10k miles

 

Im on a h&s 2 1/2'' from a 3'' downpipe and happily seeing 440/440.