SV: Airspeed question

[Roland Johansson]

Having a Scirocco GTI converted to turbo I've managed to get
whistle sounds in my tubing when boost passes 0 boost and
between 3000 - 4000 rpms. This started as I changed my old
plumbing in iron and rearranged the plumbing and made new in
aluminium.
And personally I think flow is less important on a turbo motor
since you have breathing help.
But if you building a race motor ok.



Roland Johansson
Scirocco 1,6l TIC -82
Http://hem.passagen.se/toker


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> Från: Gary Derian <gderian at cyberdrive.net>
> Till: diy_efi at efi332.eng.ohio-state.edu
> Ämne: Re: Airspeed question
> Datum:  den 5 juni 1998 14:30
> 
> I have never heard that air whistles only at over 300 mph. 
Even if this
> were true, the ports could have some local eddies that cause
whistling even
> though the velocity in the middle of the port is much less.
> Gary Derian <gderian at cybergate.net>
> 
> -----Original Message-----
> From: Robert Humphris <r.humphris at indigo-avs.com>
> 
> >Fellow EFi'ers
> >
> >As the techincal advisor of the Renault 5 GT Turbo owners
club, I have
> >often heard some strange tales, many of which turn out to be
utter
> >rubish.  But last night I heard something that I cannot
decide upon, and
> >I would like to ask the amassed knowledge in this list their
opinion.
> >
> >Now we all know that flow is important in NA engines, with
Turbo engines
> >airspeed is just as important if not more so.   So with this
in mind one
> >of the members was asking a porting shop about their mods to
carb and
> >manifold.  They said that they were 70% up on standard
flow... which
> >they claim to be able to prove, so we will leave it at
that...  The bit
> >that I am not sure about is on the subject of airflow, when
questioned
> >they said that "When you put the carb and manifold on the
flowbench it
> >whistles.  Air only starts to whistle at 300mph, so we know
that the
> >airspeed is greater than 300mph..."
> >
> >Now this seems to be quite a claim... And I have never heard
such a
> >thing before.  Is this true?  or not true, if so why?
> >
> >Obviously I have a mission to trash any bogus claims from
tuning
> >companies as the members of the club shouldn't be tricked
into parting
> >with their cash, so you advice will be received greatfully.
> >
> >Cheers
> >
> >Rob Humphris