[kismetcapitan]

with a lot of investigation of my turbos, it looks like they are in stock sized housings, very new looking, and so far as I can tell, the turbines are steel. The bearings are for sure journal-type.

I'll get the numbers off the Garrett housing, that might help explain what exactly I've got to you turbo experts (which I am clearly not!!), but in theory, if you have a stock turbo (inlet, vane angle, and whatever all those other measurements are) but it's steel instead of ceramic, to what bar of boost can you push them? 1.4bar (the point where ball-bearing N1s run out of steam)?

Ball-bearings are better than journal-type, as the conventional wisdom goes, but they're more sensitive to oil supply? Is there anything on the upside regarding journal bearnings?

 

[kismetcapitan]

anyone? anyone?

 

[ahapartridge]

I would guess 1.3/1.4 would be towards the top of the efficiency range of the stadard units with a steel rear wheel.

The ball bearing turbos give better spool and response but are more expensive to rebuild than a plain bearing turbo and I would have thought the plain bearing turbo would take more abuse than a ball bearing unit.

 

[kismetcapitan]

The ball bearing turbos give better spool and response but are more expensive to rebuild than a plain bearing turbo and I would have thought the plain bearing turbo would take more abuse than a ball bearing unit.

that's kinda what I thought - after my 700cc injectors go in, I'm raising the boost to 1.4bar, see how it goes.