would a standard crankshaft handle big bhp?

plan on forging a cdb but will the existing crank cope?

 

AFAIK, yes. Depends how much power you're talking about, but there are plenty of souped up Imprezas around with standard cranks. I'm doing a forged CDB myself right now, and it never even crossed my mind to use a stronger crank.

 

just wondered as i see you can get crossed drilled cranks on ebay that give better oil flow to the bearings or so it says, dont wanna buy a crank if its not gonna make much difference.

if your building ur own cdb look at my other post and maybe u can answer those questions too lol

 

v7/8/9 sti cranks have improved oil cross drillings and v9 sti is Tuftrided also.
All above are rear thrust.

 

Sti v9 crank is nitrided and the mains are cross-drilled. You can get it from rcm or possibly other specialist maybe even cheaper.
You will just need to have the CDB machined to take the v9 crank.

Otherwise you can stick with the standard new crank.

 

RCM told me recently that there is NO advantage/disadvantage to wether you have rear or centre thrust crank, Faliers that are atributed to centre thrust cranks in their oppinion are realy due to them being older engines with knackerd oil pumps, they are happy to use a stock centre thrust crank up to and above 500 hp and claim to have never had a crank related failier,
so thats good enough for me untill proved otherwise

 

i'll stick with the crank i have

sounds easier and will do the job

 

The early crank itself is strong so stick with it unless you want to machine your block to take rear thrust and desperately need a later crank for some reason.

 

The standard cranks are very strong, and you're unlikely to break one, with even people like Andy F using one in his race car. However, the oil way design is improved on the later phase two cranks, and ultimately, it may give better reliability.

The cost of the phase one/phase two cranks are very similar, so it would only be the cost of machining a CDB.

I appreciate what RCMS have told you, but the bottom line, is that they don't run the standard crank in their own race engines, but a billet crank which is low pressure cross drilled.


Mark.

 

Point taken they dont use them in their own engines, neither would anyone given the budget they have, Bearing in mind their engine is well over 800 hp also,
would a fair assesment be that stock cranks are strong enough for all but the most extreme street engines??
And after that you pay your money and make your choice

 

I'm planning on running 500bhp max in my engine I'm building at the moment so by reading this so long as I use a decent oil pump I'll be ok just getting a new center thrust bearing crank, sound good to me

 

Actually this isnt quite true, only the JDM twin scroll cranks are like this not the UK cars.

Tony