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BoxxerSix BoxxerSix is offline
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Join Date: Jun 2006
Location: Ballston Spa, NY
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Originally Posted by NathanUK View Post
It's better to pull the fuel relays as you do not want fuel diluting the oil in the cylinders.

Build boost up to .5bar a few times after the miles.

I understood that 50miles with no boost was enough?

Good note on the fuel relays to avoid cylinder wash...

And this is just to simply break in the thrust bearing. The cartridge bearings are fully floating(bearing floats on oil in CHRA, turbine shaft floats on oil in bearings) so there's very very little contact to actually break in aside from the thrust. the piston ring does break in in a sense, but again it happens very quickly as it floats and is rotating in a bore rather than sliding up and down like in a motor. If any "breaking in" is happening it does when you shut the motor down and the pressure drops inside the CHRA while the turbine is still spinning(more metal to metal contact). The turbo will literally break itself in at idle in a few minutes. It doesn't take much as the contact surface on the thrust and thrust washer are minimal in comparison to an engine. Full BB CHRA's need no break in time, just oil and spin them up.

One rule Garrett always advises us is that on any new turbocharger is you should let it come up to full operating temperature before hammering on it, on it's first run at the very least, allowing the parts to expand to their designed clearances. This is to avoid galling on the thrust surface.

I see alot of weird stuff rebuilding turbos over the years. One of the best was a spanking new GT409(non porsche) that the installer forgot to remove the feed hole plug from the factory before attaching the line. Turbine was friction welded into the CHRA! $1500 right out the window
Adam Hennessy
Old 10-03-2007, 07:45 AM
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