[Biturbos4] Replacement turbos - buyin A6 2.7T with blown turbos

Tue Feb 3 17:00:44 EST 2004

The K04s are large enough to handle increased boost without much worries of
turbo failure.  Very few problems are reported with the K04s, which are
right in their efficiency range at chipped boost levels and even slightly
beyond.  The K03s are pushed to their limits by chips (and are even known to
fail on stock boost).

There are a number of reasons for not using turbos larger than K04s on the
2.7T.  The most obvious is space limitations.  You simply can't fit anything
bigger than a K04 (K04/K16 hybrids are being used in some cases, but the
housing from the K04 is used so it fits).  Also, the larger the turbo gets
the more the lag will be.  S4s are so much fun due to the low end torque
(from quick spoolup).  Give up too much of that and the car won't be as fun
to drive.  Lastly, You are using exhaust from 1.35 L of the engine (1/2 of
2.7L) to drive each turbo.  If you use too large of a turbo, there won't be
enough exhaust gas to spin the turbo as fast as necessary to make the
desired boost.

-Dave Pramanik

----- Original Message ----- 
From: "robert weinberg" <centaurus3200 at yahoo.com>
To: "David Pramanik" <dap128 at hotmail.com>
Cc: <Biturbos4 at audifans.com>
Sent: Tuesday, February 03, 2004 4:26 PM
Subject: Re: [Biturbos4] Replacement turbos - buyin A6 2.7T with blown
turbos

> so, what is the benefit of the K04? i understand they
> are slightly larger. but it seems wierd KKK would have
> too very similarly sized turbos. do you think, more
> likely, that the K04 is a revised and tougher version
> of the K03? maybe admitting the problems with the K03?
>
> will the K04s infact last longer and end this whole
> blown turbo problem?
>
> hey, why don't i throw some K24s on the 2.7T motor?
> ;-) kidding, aren't those the twin turbo porsche
> turbos?
>
> Robby
>
> --- David Pramanik <dap128 at hotmail.com> wrote:
> > K04s are (slightly) larger than the stock K03s.
> > They don't spool up faster,
> > but the size difference is pretty small so the
> > increase in lag is probably
> > less than 500 rpm.  Peak torque will be higher with
> > a K04 due to higher
> > boost/more airflow, but it will be delayed slightly
> > due to the small
> > increase in lag.
> >
> > -Dave Pramanik
> >
> >
> > ----- Original Message ----- 
> > From: "Michael Benno" <mbenno at yahoo.com>
> > To: "David Lau" <toomanycars at mac.com>; "robert
> > weinberg"
> > <centaurus3200 at yahoo.com>
> > Cc: <Biturbos4 at audifans.com>
> > Sent: Tuesday, February 03, 2004 12:43 PM
> > Subject: Re: [Biturbos4] Replacement turbos - buyin
> > A6 2.7T with blown
> > turbos
> >
> >
> > > Your points are very good. The list is not a
> > proper maket representation.
> > >
> > > However, regarding your comments on the spool up
> > time of the K04 vs.
> > K04...Most people (on Audiworld) who have done the
> > conversion to K04 claim
> > much faster spool up times. I can't say much about
> > the torque but mathmatics
> > would lead me to believe that torque is directly
> > related to boost, so that
> > must be higher too. To be honest I really don't know
> > the mechanical
> > differences between the two.
> > >
> > > Anyone care to enlighten me?
> > >
> > > Mike Benno
> > > a6 2.7t MTM1
> > >
> > >
> > > David Lau <toomanycars at mac.com> wrote:
> > > Sounds like a plan to me, Robby, you may never go
> > back to the SHO!
> > >
> > > But I do think the K03 problems are out of
> > proportion on this list. What
> > > percentage of biturbo owners worldwide are on this
> > list, maybe 5%? and
> > what,
> > > 10% of us have had failures? Total guesses, you
> > understand. And we're
> > harder
> > > on them than most, chipping and all, yet probably
> > maintain them better
> > too,
> > > so that may wash. (How many average owners even
> > THINK about that cold,
> > thick
> > > oil squeezing through those tiny passages at
> > startup?)
> > >
> > > I've heard the K03s were designed for torque, not
> > feindish horsepower
> > > anyway. Being small, they spool quickly, and give
> > full rated (stock)
> > torque
> > > at only 1800rpm. High rpm, sure, they run out of
> > cfm to maintain high
> > > boost...
> > >
> > > David
> > > -- 
> > >
> > > some of you know i am lurking on this board
> > > researching A6 2.7T as my potential next car
> > (along
> > > with the 540i 6 speed). well, what about buying an
> > A6
> > > 2.7T with blown turbos wholesale. either private
> > party
> > > or from a dealer that just wants to get rid of it.
> > > then put a K04 upgrade on it and be happy?
> > >
> > > am i dreaming? what do you guys think?
> > >
> > >
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