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

b5quattro at shaw.ca b5quattro at shaw.ca
Wed Feb 4 14:29:28 EST 2004 

One tuner has done exactly that, replacing the 2 smaller turbos with a huge one.  Try search the AW B5-S4 forum for details and pics, it's a black S4.  

The main reason for 2 turbos on a V6 is due to relative ease of plumbing, 1 turbo on each bank of cylinders, and smaller lag.  A single turbo conversion is just too complicated, you need to join the exhaust from 1 bank to the another, that's a huge PITA especially in the already tight engine bay.  You may gain a lot more top end hp (like the Supra guys do) but you will increase the lag and seriously affect drivibility.

Quincy

----- Original Message -----
From: robert weinberg <centaurus3200 at yahoo.com>
Date: Tuesday, February 3, 2004 3:27 pm
Subject: Re: [Biturbos4] Replacement turbos - buyin A6 2.7T with blown turbos

> of course i'm just talking out my ass here (i'm a
> total benchracer), but what about a single turbo
> conversion?
> 
> does the engine really need two turbos? what about a
> really efficient single turbo and i'm not talking
> single turbo supra size.
> 
> Robby
> 
> --- David Pramanik <dap128 at hotmail.com> wrote:
> > 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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