CutMasterT

iTrader: (2)

Hi all after some advice


I am soon going to be getting a forged 2.1 built, but I really wanted to know if its absolutely necessary to have a CDB?


Power wise I will be only running my current SC42 so nothing crazy, 420 maybe a bit more?


The car will be used only on the road, zero track days, and driven with mechanical sympathy, few blasts here and there nothing mental tho. The car spends most its life in a garage so doesn't get used a lot either.


So is it really necessary for me to have a CDB?


Brgds
Alex

FMJ

iTrader: (2)

I am prepared to be shot down in flames by a respected engine builder but from what I have read over the years a SCDB should manage that. Yes the CDB will be less likely to flex and therefore stronger but a SCDB is fairly strong and should be fine at that level. Getting a bigger head stud conversion will help keep it all bolted down firmly but again you will probably get away without it. You can also get SCDB converted (basically inserts fill the gaps) if you like. In theory the more you spend on stronger parts the more reliability you will get but in reality that doesn't always translate.

I would speak to somebody who builds Impreza engines for a living and see what they think.

Steve Whitehorn

iTrader: (13)

Who is building it? who is doing the machine work?
CDB helps future proof it.... However perhaps stick with a 2.0 forged approach given that it will not be used in anger that often.

My best mate in Kent is an ex group N rally mechanic. Once you get it up and running he is the guy to get to keep an eye on things.

CutMasterT

iTrader: (2)

Hi thanks for the replies, I haven't decided yet who to use, but most likely will run the car down to engine tuner for the work and then initial mapping.

By the sounds of it I may as well go CDB for extra strength

Steve - Would you be able to forward me contact details of your mate? I'm in Thanet so would be good to get someone in Kent to look after it

Brgds
Alex

ditchmyster

iTrader: (7)

CDB is not really necessary in the scenario you describe, if your going to be kicking the **** out of it and possibly go above 500bhp then yes, but a SCDB is more than enough as they are proven at 500bhp and even a little more, you'd get away with an ODB at early 400's so SCDB is actually future proofing.

Subaru 2.0L Blocks aren't really a problem area, much better to spend the extra on a cross drilled Nitride crank which will be of more benefit to engine longevity than a CDB for your power requirements.