TBI on blown small-block?

[Walter Sherwin]

Jess,  the small displacement Whipple screws (with moderate ICR's, and as
the public can generally purchase them) are marginally better than the
Eaton/Magnuson equivalents in terms of adiabatic and volumetric efficiency,
but, are far more efficient than most of the straight lobe roots offerings
for sure.  Like most other things in life, you have to examine comparable
units at comparable flows and pressures.  If comparing screw's VS root's,
you'll generally find screws are slightly more efficient overall across the
majority of the engine/crank speed range versus modern root's units.  If
comparing screws to centrifugals, then you'll find the two equivalanet at
ideal RPM's and operating conditions, with the screws superior at lower
RPM's.  Can an available screw have 80-85% effiiciency on an IC engine?
Adiabatic (important) NO.  Volumetric YES.  Just my own personal
impressions.  You might want to bounce these off Whipple if so
inclined...........


Walt.



----- Original Message -----
From: "Jess Gypin" <jessmx5 at earthlink.net>
To: <gmecm at diy-efi.org>
Sent: Tuesday, September 25, 2001 3:58 PM
Subject: Re: TBI on blown small-block?


> The efficiency of the Eaton type blower is crap compared the the Whipple
> type charger. The best that an Eaton can do is 70% efficiency where the
> Whipple (Autorotor) can make about 80-85% due to the screw design.
>
> Jess
> ----- Original Message -----
> From: "Bruce" <nacelp at bright.net>
> To: <gmecm at diy-efi.org>
> Sent: Monday, September 25, 2000 13:34 PM
> Subject: Re: TBI on blown small-block?
>
>
> >
> > If Whipple listened to his engineers, he may have gotten to have a
decent
> > product.   It seems that they never did get the cals right or they would
> > have sold alot of the kits.   In other words they didn't get the fuel
> > management right.
> > Bruce
> >
> > From: "Eric Bryant" <BRYANTE at ghsp.com>
> > Subject: TBI on blown small-block?
> > > Is anyone out there running a TBI on a Roots-style blower on a GM V8?
> I'm
> > > kinda-sorta thinking that one of those small B&M/Holley blowers would
be
> > > neat on one of my B-bodies, which runs the 16136965 C3 PCM.
> > > I'm just wondering if a one-bar MAP system can be used, with the MAP
> > sensor
> > > measuring the absolute pressure between the throttle plate and the
> blower.
> > > I'm not sure if this is a workable setup, as I'm pretty green when it
> > comes
> > > to blowers.  I remember seeing Whipplecharger kits for the TBI pickups
> > that
> > > mounted the throttle body on top of the blower, but I have absolutely
no
> > > knowledge of how they handled fuel management.
> > > Eric Bryant
> >
>
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