so i juz bought an rnr 50 trim used from a guy on here and everything checks out but one of my freinds called a shop and they said to machine the turbo manifold flat were it bolts up to the block. has any one ever had to do this? he told me that if its a little bit warped it will start to pull the botls from the block and ruin the threads. ne takers

 

I would for the piece of mind take it to a machine shop and have it miced to see if its off. If it is off a little they can mill it. Having a warped manifold sucks and will give you a nasty exhaust leak. most metal surfaces will have minor variences on the surface and a specification for those variences. But then thats one of the purpouses of gaskets, to fill in the minor inprefections between mating surfaces.

 

Non Ball bearing = slow spool up

 

Stock turbos are not BB, they spool up pretty good. Maybe not so with a larger turbo?

 

Really, I just learned something new today. I was under the impression that the size of the turbine in conjuction w/ the size of the hotside dictated spool up. A ball bearing housing may save a few hundred RPM and have better transient response but it's nothing amazing. A lot of non ball bearing turbos spool up quickly and provide good power. Like the stocker or the FP Green for example.

 

i thought 50 trimms were ball bearing, those twin screw 35rs and crazy spool up

 

no, not all