[urq] AAN or 3B swap

[Martin Pajak]

For what its worth my old '85 with 3B and a huge 944 turbo intercooler had
no issues building instant boost (with stock K24).
Throttle responce was excellent as well.

HTH
Martin Pajak

http://www.quattro.ca 

1981 VW Scirocco, all original
1982 Audi Ur-quattro, SQ project
1983 Audi 80 quattro, Euro 2-Tür
1993 Audi 90 CS quattro, 2.5 TDI with 6-speed
1993 Audi 80 quattro Avant, 2.5 TDI with 6-speed
1994 Audi S2 Avant, stock


-----Original Message-----
From: urq-bounces at audifans.com [mailto:urq-bounces at audifans.com] On Behalf
Of David Glubrecht
Sent: 3-Feb-14 00:36
To: s.b.mills at gmail.com
Cc: urq at audifans.com
Subject: Re: [urq] AAN or 3B swap

That is what I thought the concern was, but being as how a turbo is not a
positive displacement devise, I don't see how it could have much of an
effect.  I suppose it could affect where the turbo is in the compressor map
while spooling up, but in practice (in an extreme case) Huge volume and old
school turbo motor (MC) that is known to have significant lag, I do not see
any effect.   I mean this vehicle really does have about the same post
compressor intake volume as a remote mount turbo.
 Perhaps it might have a noticeable effect on a newer motor with minimal
lag.

This is somewhat academic, as I can't/won't change this vehicle and will try
to minimize the 3B UrQ anyway.  
But I do want to understand the significance of this.


  David Glubrecht
  



Intake tract length is a major factor in turbo lag. The turbo has to work to
compress and maintain pressure on the intake volume, and the larger it is
the longer it takes. It's not the end of the world, but it's desirable to
minimize it. 
On Feb 2, 2014, at 4:13 PM, David Glubrecht <daveglu at hotmail.com> wrote:




Another 3B swap here.  Will definitely be doing the 3B as I have two of
those and no AAN's.
I also plan on going stand alone with the adaptronics 1280 and this will run
COP.
While I feel free and able to modify mostly anything I want, intake track
length is only a concern due to room constraints.
I was concerned a little on my last project about intake track length
(volume) as it is very long/large.
This is a MC running CIS with 3' cis to turbo, 2' turbo to intercooler,
large intercooler, 3.5' intercooler to intake. All plumbing is ~2.75id.
 I have not seen anything with this much post airflow meter volume and was
concerned, but I have not noticed any adverse effects.
What is the concern with intake volume?  


  David Glubrecht


> I do believe the AAN is a better engine, but the AAN can require a lot of
fabrication to install. I personally would go with an ABY (late S3) or ADU
(RS2) sourced from Europe, or installing an SQ style intake on the AAN that
moves the throttle body to the front of the engine. This should minimize the
required modifications and also minimize the length of the intake path. 

 		 	   		  
 		 	   		  
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