[Diy_efi] Turbine inlet & outlet pressures, housing A/Rs

[Grant Beaty]

Any idea where to get a banjo discharge?

Thanks,
Grant Beaty

----- Original Message -----
From: "Greg Hermann" <bearbvd at mindspring.com>
To: <diy_efi at diy-efi.org>
Sent: Tuesday, January 07, 2003 9:47 AM
Subject: Re: [Diy_efi] Turbine inlet & outlet pressures, housing A/Rs


> At 3:49 PM 1/6/03, Grant Beaty wrote:
> >Oh Greg,
> >
> >Just saw some old posts of yours in the archives,
> >http://www.diy-efi.org/diy_efi/archive/1999-January/msg00237.html
> >
> >> >I think the REAL unexplored gain is in (more efficient) pressure
recovery
> >> >from the Mach .75 velocity in the gas spiral at the turbine outlet,
> >though.
> >> >The circumferential component of the flow in that gas is distinctly
> >greater
> >> >than the axial component.
> >
> >Hugh McInnes states that increasing pipe diameter right after the turbine
> >outlet will convert axial flow into turbulent flow. But in your post you
> >don't seem to consider that as an option, instead opting for a banjo
> >discharge. Is there any reason for that? Have you tried larger pipes
without
> >success? Any idea how much larger the pipe needs to be than the turbine
> >inducer?
>
> A banjo would do an even better job of converting the spiral flow to
> straight turbulent (less static pressure loss) than a step in the down
> pipe, that's all. I think a step up from the exducer to the down pipe of
> 3/4" to 1" is generally sufficient to shock the flow out of the spiral.
>
> The more of that static pressure you can recover (less shock loss), the
> lower the effective outlet pressure is going to be at the turbine outlet,
> and the less inlet pressure you will need.
>
> Greg
> >
> >Forgive my lack of understanding of your post, but are you suggesting
that
> >exhaust gas velocity post-turbine could be more than doubled by
> >straightening the flow? Wouldn't that imply pressures < ambient? Or would
> >total velocity out the turbine decrease, and more would go out the
> >wastegate? Either is good, I guess.
> >
> >Thanks for any help,
> >Grant Beaty
> >
> >----- Original Message -----
> >From: "Greg Hermann" <bearbvd at mindspring.com>
> >To: <diy_efi at diy-efi.org>
> >Sent: Monday, January 06, 2003 10:56 PM
> >Subject: Re: [Diy_efi] Turbine inlet & outlet pressures, housing A/Rs
> >
> >
> >> At 7:21 AM 1/6/03, Grant Beaty wrote:
> >> >Does anyone know how turbine outlet pressure effect the inlet
pressures
> >(TIP
> >> >& TOP)? Does it work off of a pressure ratio like the compressor, or
is
> >it
> >> >linear, and increasing TOP by 1 psi results in a 1 psi increase in
TIP?
> >>
> >> Absolute pressure ratio, all the way.
> >> >
> >> >How about exhaust housing a/rs. Will a larger a/r always produce a
lower
> >> >TIP,
> >>
> >> Sure should.
> >>
> >> Higher EGT at the turbine inlet should require a bit lower pressure
ratio
> >> across the turbine to get the same shaft power (boost level at a given
> >> engine rpm) out of the compressor.
> >>
> >> Greg
> >> >
> >> >Thanks for any help,
> >> >Grant Beaty
> >>
> >>
> >>
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> >
> >
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