[s-cars] [NurSC] Optimized garret chip... should I be scared

[tedebearp at yahoo.com]

K03s do make more boost with a chip, and there's a big seat of the pants difference with the chip.  The issue is durability.  They're small for quick spool, with V8-like throttle response, and already close to their design limits with factory tuning.  Spinning them faster, especially at altitude, seems to kill the K03s.

That wouldn't be such a big deal on the UrS4, but replacing the turbos on a B5 S4 requires removal of the engine or dropping the front crossmember.  It's about $3k labor.  Mine had an APR (sorry, I think I might have said AWE before) chip installed with the 91 octane program, and the turbos needed replacing 10k miles later, at 50k miles.

Now my car has K04s.  There's now some detectable lag, where there wasn't any with the K03s, but it's minimal and still much less than the UrS4 (either K24 or GT2871).  Still running the same chip.  The upper end is stronger, as the stock turbos used to fall off noticeably at 5000 rpm, whereas the K04s make it to about 6000 rpm.  The boost drop off with the K04s is likely due to the chip programming, but I haven't gotten around to upgrading anything due to concerns about the Tiptronic.

-Teddy

-Teddy

Taka Mizutani wrote:
> Vincent-
> On anything tuned, make sure you get a proper compression and leakdown test
> on the engine.
> I'd also be concerned about the turbos- what level of boost is that thing
> running? K03s don't really do much with a ton of boost except make heat.
> Were the turbos upgraded?
> How about the bypass valves?
> Taka
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