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

[Greg Hermann]

At 7:07 PM 1/8/03, Grant Beaty wrote:
>Thanks for all your help Greg. Sorry for the stupid questions, I know zilch
>about air flow.
>
>Do you think oval tubing might have the same effect? Burn Stainless just
>added some to their catalog.
>
I kinda doubt it--

Greg

>Grant Beaty
>
>----- Original Message -----
From: "Greg Hermann" <bearbvd at mindspring.com>
>To: <diy_efi at diy-efi.org>
>Sent: Wednesday, January 08, 2003 10:10 AM
>Subject: Re: [Diy_efi] Turbine inlet & outlet pressures, housing A/Rs
>
>
>> At 6:45 PM 1/7/03, Grant Beaty wrote:
>> >Any idea where to get a banjo discharge?
>> >
>> >Thanks,
>> >Grant Beaty
>>
>> I think you''d have to make one. There sure is a picture of a nice one in
>> McInnes' book, no clue where it came from.
>>
>> Might try asking Turbonetics--
>>
>> Greg
>> >
>> >----- 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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>> >>
>> >>
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