VerrÜckt

No problem. :-)

S4mig@PEB tuning

No, the blades do NOT grind the housings. Unless the turbo has failed that is.

Imolavirus@BuehnEngineering

on a stock turbo, the wheel DOES NOT touch the housing. we add coating to reduce clearances

Josh@StatusRacing

Just remember that this technology is from KKK! We'll be posting data and dyno numbers as soon as they are available.

malcho

to this type of techology since '99. It seems to have worked well for them.
N

Stealth4

and if i have time over the break ill work it out for you.

other usefull info would be max operating temp and max rpm.

thanks

QCRAZY

Heat expansion is going to pull a little bit more coating off once installed. Once you get the turbo at high RPMs for an extended time the blade will "except" more heat (have time to move closer to equilibrium) and expand further into the coating.

Is this huge deal?? No.
BUT this will lower the effeciecny lower than what is published. Again, not a huge deal but something that I consider.

The second part:
As the bearings wear, and they always do, you'll pull more of the coating away. The more coating that is removed the more you move toward the initial effeciency of the turbo. This will be a slow decline but a decline non the less. The bearings will wear and the effeciency will be in a constant decline ("should" happen over a long time).

I don't think you can really answer the "life" question because it's really the bearings life. There's just too many factors in that for ANYONE to know. But I would still be interested to see if your IAT's have changed in 7k miles!

Bearing an Coating Status:
This effeciency decline will take place as the bearings age. In a UrS4 (where you can easily pull the turbo) this isn't a problem because you can inspect the coating and see how your bearings are doing (nice touch actually). But in the S4tt, you can't do that very easily. With the S4tt you really have to watch you IAT's to get an idea on the coating and bearing condition.

This is a great product but I'd like to see the life of it. Luckily, it's not expensive to do, but I would chose to spend the money on something else......at this point.

If I had no choice I would get a turbo with the coating, but I would also expect a slow progressive decine in performance! Hopefully, a VERY slow decline!

Thanks for the discussion and for keeping it civil :-) Is this really the S4 forum??

QCRAZY

...I think I illustrates my concerns better than I've done so far.<ul><li><a href="https://forums.audiworld.com/s4/msgs/1495605.phtml">Click!</a></li></ul>

TRM

and see if they last and if they continue to produce the bump in power as stated.

kudos to Achtuning however. it's good to see some "real" tuning with OE parts for a change.

TRM

metal in a turbo isn't some pliable plastic behaving strangely over temperature ranges. expansion and contraction is predictable. and remember it's hottest state might not actually be the state creating most wear. [did your high school science professor ever do the steel ball in the metal ring trick?]

take it up from cold to max operating temp in one drive and i'll bet all the wear of the coating is complete...less long term shaft and bearing wear and out of round effects.