what are the safe limits of the crank in terms of rpm (once balanced) on the st170

also what are the power limits for the standard pistons and rods?

 

Si @ Sitech buzzed his engine a while ago and the datalog showed nearly 10,000 rpm without the crank letting go!

I'm planning to rev mine to between 8500rpm and 9000rpm - that's on a lightened, knife edged and balanced ST170 crank.

In all honesty, i'm not sure the ST170 crank is any different to a normal 2.0 Zetec one - i think the differences are in the rods and pistons.

You can run around 300/300 on the standard ST170 internals - first thing that'll let go is the ring lands!

 

well a normal blacktop crank is good for just over 500bhp

 

thanx guys i'll be taking mine up to 7500 in normal conditions and might bump it up to 8 on rolling roads etc.

i'm not going to be anywhere near the 500bhp mark coz i'm keeping it n/a just going for a 2.1 bore and proper rods and pistons and a cr of about 12.5:1 and throttle bodies