Airspeed question

[Jake Lindeke]

> 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

I think part of your problem with this is that you are incorrect abotu the air 
speed required for a whistle effect. have you ever blown on a whistle it takes 
lots less then 300 miles per hour of air speed to creat that sound accually if 
you put in in your mouth and bairley blow on it it will still make the noise. i 
think there is a similar effect going on inside the carb or manafold and the test 
took place at much lower speeds then 300mph.
thats my guess from what you said.  


--Jake Lindeke
--SOGI South-East Chapter Coordinator
--http://sesogi.bsfh.org