[DeTomaso] Fwd: Re: High Ported Iron Closed Chamber 4V head flow results

michael at michaelshortt.com michael at michaelshortt.com
Sun Feb 9 22:13:04 EST 2014


> Well I guess that answered that.
>
> ;-)
>
> Thanks.
>
> Michael
>
> On Feb 9, 2014 10:03 PM, "Daniel C Jones" <daniel.c.jones2 at gmail.com>
wrote:
>>
>> > Not sure why the Jet engine was used as an example, those S shaped
port directors in those engines are designed to slow the air down by
several hundred miles per hour before it enters the jet engine.  SST and
SR71 did too
>>
>> The 727 is subsonic so no need to reduce the flow by several hundred
>> MPH.  There are vortex generators, turning vanes and stators, none of
>> which are used to slow air down. The pupose of vortex generators is to
>> energize the boundary layer (intentionally trip the laminar boundary
>> layer to turbulent) because turbulent boundary layers are less likely
>> to separate. Turning vanes are used to direct flow and stators are
>> designed to cancel the swirling effect of rotating elements like
>> compressors.  On supersonic aircraft, inlets are designed to reduce
>> flow to subsonic speeds before it flows through the compressor.  This
>> can be done with active geometry (opening up throat area) or by using
>> a shock wave.  The SR-71 used variable inlet geometry and also
>> directed most of the flow at high speeds around the compressors to the
>> outside of the engine into ramjet like sections of the engine.
>>
>> > Why would you want to slow down your fuel air mix? Performance items
like Blowers and Superchargers are used to increase the speed and pressure
to attain greater performance.
>>
>> For a normally aspirated engine, there are flow losses that occur as
>> you get transonic speeds.  As speed is increased to 0.6 Mach or so,
>> the energy required to increase the flow speed is more than the power
>> increase associated with the increased velocity.  The limiting case is
>> the choked flow that occurs as throat velocity is increased to Mach 1.
>>  In cases like that, increasing the minimum cross-sectional area to
>> slow the flow will result in increased power.  With a supercharger,
>> you can get an increase in mass flow rate due by compression.
>>
>> Dan Jones
>>
>> On Sun, Feb 9, 2014 at 5:57 PM, michael at michaelshortt.com
>> <michael at michaelshortt.com> wrote:
>> > Not sure why the Jet engine was used as an example, those S shaped port
>> > directors in those engines are designed to slow the air down by several
>> > hundred miles per hour before it enters the jet engine.
>> > SST and SR71 did too.
>> > Why would you want to slow down your fuel air mix? Performance items
like
>> > Blowers and Superchargers are used to increase the speed and pressure
to
>> > attain greater performance.
>> >
>> > I don't get why that was an example.
>> >
>> > Michael
>> >
>> > On Feb 9, 2014 6:47 PM, "Sean Korb" <spkorb at gmail.com> wrote:
>> >>
>> >> I'm not sure if this is germane but I am utterly fascinated.
>> >>
>> >> http://speedtalk.com/forum/viewtopic.php?t=4785
>> >>
>> >>
>> >> On Sun, Feb 9, 2014 at 5:55 PM, Charles Engles <cengles at cox.net>
wrote:
>> >> > Dear Dan,
>> >> >
>> >> >
>> >> >               You wrote:  "....and shear vanes screwed into the
intake
>> >> > port
>> >> > floors."
>> >> >
>> >> >               For the amateur engine builder, what are shear vanes?
>> >> >
>> >> >                              Very curious,  Chuck Engles
>> >> >
>> >> > -----Original Message-----
>> >> > From: DeTomaso [mailto:detomaso-bounces at poca.com] On Behalf Of
Daniel C
>> >> > Jones
>> >> > Sent: Sunday, February 09, 2014 4:24 PM
>> >> > To: POCA list
>> >> > Subject: [DeTomaso] High Ported Iron Closed Chamber 4V head flow
results
>> >> >
>> >> > A while back, Dave McLain flowed a set of old iron closed chamber 4V
>> >> > heads
>> >> > with the 1970's Pro Stock style high port exhaust plate and shear
vanes
>> >> > screwed into the intake port floors.  I thought I'd share the
results.
>> >> > Flowed on a Super Flow bench.  Tested at 10" and converted to 28".
>> >> > 2.19"
>> >> > intake valve and 1.71" exhaust. Completely stock combustion
chambers.
>> >> >
>> >> >  Lift   Intake Exhaust
>> >> >
>> >> >  Inch   CFM    CFM
>> >> >
>> >> >  0.025   15.9   10.2
>> >> >
>> >> >  0.050   33.2   28.5
>> >> >
>> >> >  0.100   65.6   60.0
>> >> >
>> >> >  0.150  100.6   89.0
>> >> >
>> >> >  0.200  137.8  109.8
>> >> >
>> >> >  0.250  167.6  124.1
>> >> >
>> >> >  0.300  195.8  141.4
>> >> >
>> >> >  0.350  224.0  155.4
>> >> >
>> >> >  0.400  245.6  166.8
>> >> >
>> >> >  0.450  261.4  176.7
>> >> >
>> >> >  0.500  278.8  185.3
>> >> >
>> >> >  0.550  289.7  194.7
>> >> >
>> >> >  0.600  300.9  204.2
>> >> >
>> >> >  0.650  312.1  215.2
>> >> >
>> >> >  0.700  322.0  225.8
>> >> >
>> >> >  0.750  325.7  234.4
>> >> >
>> >> >  0.800  307.8  239.7
>> >> >
>> >> > Not too bad for 1970's small block cylinder heads.
>> >> >
>> >> > Dan Jones
>> >> >
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>> >>
>> >>
>> >>
>> >> --
>> >> Sean Korb spkorb at spkorb.org http://www.spkorb.org
>> >> '65,'68 Mustangs,'68 Cougar,'78 R100/7,'60 Metro,'59 A35,'71 Pantera
#1382
>> >> "The more you drive, the less intelligent you get" --Miller
>> >> "Computers are useless.  They can only give you answers." -P. Picasso
>> >>
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