borat52

I've just retired an abused V5 sti impreza wagon, I'll be breaking it for spares for the next project, and want some advice on what the best engine for would be for me.

I've had 3 classic imprezas (ver 1 WRX, then 2 x V 5 Sti wagons) and a Forester Sti.

I wasn't a massive fan of the engine in the Forester, while it had lots more torque it didn't rev anywhere near as nicely as the sti 5's did. I also found the 6 speed box a bit more cumbersome in its engagement compared to the 5 speed in the classic (not sure if it's just the short shifter or something else but the shift in the last sti's feels incredible)

So I know what I'm looking for, its a sti5/6 and I want to build my ultimate spec so I'll be forging the engine and aiming for around the 400bhp mark (MD321H possibly as I have one on the shelf).

Which brings me to my question, what's considered the best revving engine. I can't stress enough how much I prefer the character of the 2l over the 2.5.

I know 2.1, 2.2 and 2.35 are all options. Am I better sticking to the 2l or is one of those potentially better?

domino46

if you like it to rev then just stick with the 2.0 ,, iv found the extra cost to go 2.1 wasn't really worth it unless chasing numbers

stockcar

2.1 is basically the same cost as 2.0 if your starting from scratch..........

borat52

Cost isn’t the primary concern, I want the best 400bhp engine that likes to rev so 8k+ redline.

2.2 CDB worth considering as the start point?

Linksfahrer

If you want 400bhp and 8k rpm a 2.0 - 2.1 over bored 93mm EJ207 block is a good start point , Forged Pistons probably Mahle or Wiseco / uprated head studs / oil pump kits available from Roger Clark Motorsport or built units from Lateral would be my advice ( advise go read the sticky in General technical on recomended upgrade path first ) the rpm requested is fairly high , so Im guesing sprint/track applixation the Turbo you suggest is a very good alrounder that is good for 400bhp but once you have a block capable of 500bhp you might go bigger. At 8k rpm Id be making very sure the rods and pistons have identical weights, To make an engine rev , typically a lighter moving mass is requied, a short stroke 2.0 is the choice On mini engines I used to be shaving material off the rods and cranks and rocker gear to get the moving mass down, then to run very high lift cams, with 10000 revs . The Subie crank Id leave alone and a good set of H rods and forged pistons are already well optimised , so getting the Cam profile you prefer will have the largest impact on the hig rev running character, but even with AVCS heads getting the top end will cost some tractability and low rev . If you want a road users engine though , the old adage is there is no substitution to cubic capacity to making power.