Aerochargers are better than a twin screw!! hahaha ;-)

[Stephen Andersen]

Greg,

I understand what you are saying about efficiencies.  I will
however reiterate that my initial point was that the boost
curve for the PD supercharger on aerocharger's site is 
a crock!!!

That doesn't neccessarily mean that a lysholm compressor
is better, just that aerocharger is misrepresenting the 
facts.  Don't forget that there is theory, and practice
and quite often the two don't match.  I am basing some
of my comments not on compressor maps and calculations, 
but real-world evidence that the lysholms, when sized and 
driven properly, often make within 10-20% of peak boost
at very low rpm on many applications.  Take that for 
whatever it is worth.

Suffice it to say that I did not intend to talk
down to the list, nor did I intend to flaunt my
credentials.  This list is one of the last places
on the planet that I would think myself capable
of talking down to anyone, regardless of the 
signal to noise ratio (which IMHO is very poor).

I have my sig there because I use this computer mostly
for work and it appends my sig for me.  I usually don't bother
to delete it when composing a message, as I didn't think it 
was either flaunting, or offending anyone.

Steve

> -----Original Message-----
> From: owner-diy_efi at diy-efi.org [mailto:owner-diy_efi at diy-efi.org]On
> Behalf Of Greg Hermann
> Sent: Monday, October 15, 2001 2:48 AM
> To: diy_efi at diy-efi.org
> Subject: RE: Aerochargers are better than a twin screw!! hahaha ;-)
> 
> 
> OK--see my post to the list. For want of a better word, I 
> think it is fair
> to say that the Lysholms have a wider "dynamic range" than even a well
> selected conventional turbo, and that a VATN turbo, in turn, 
> has a wider
> "dynamic range" than a Lysholm.
> 
> There is NO doubt that any type of a turbo allows getting a 
> much higher
> expansion ratio out of an engine, whereas a mechanically driven
> supercharger has no effect at all on the engine's expansion ratio.
> Certainly, there are very significant efficiency/bsfc 
> implications to this
> fact.
> 
> I think I gave a decent synopsis of my thoughts on the 
> reliability problems
> which have been experienced with VATN's in my post to the 
> list, as well as
> my thoughts on curing said problems.
> 
> As far as ethical boundaries go, no, I don't think you "crossed" any,
> either. The other side of it is that there are a _LOT_ of 
> guys here (on the
> list) with a _LOT_ of heavy duty credentials. Most of them 
> don't feel the
> need to flaunt them. It tends to keep the discussions a bit more
> egalitarian when it's done that way, and that approach _does_ 
> seem to add
> to the availability of knowlege on the list.
> 
> What I mean by "egalitarian" is--present facts, back 'em up, 
> and let them
> stand or fail on their own. No one should presume that anyone 
> elses facts
> (or writing) are rendered more credible (on the list) because 
> of anyone's
> credentials. I have found that taking this approach on the 
> list to be good
> exercise in logical thinking as well as humility !
> 
> What makes the list worthwhile to most is presentation of 
> facts, nothing
> else. I wanted --and apparently got-- your attention because 
> I figured you
> were either talking down to the list or had not really done 
> your homework.
> I'm sort of glad it was the former, because, at least you are 
> _capable_ of
> contributing more to the list --all that is needed would be for you to
> decide to go ahead and DO it. Of course, if the latter were 
> the case, that
> wouldn't be possible.
> 
> There are many on the list who _don't_ know that the Lysholms 
> are NOT quite
> as efficient as a well selected centrifugal.  Lot's of folks 
> seem to think
> that because the Lysholms have been described as "much more efficient"
> (than Roots blowers) that they must also be much more 
> efficient than good
> centrifugals! The numbers you quoted below would have been 
> useful toward
> the education of a lot of folks.
> 
> Later--
> 
> Greg
> 
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