[Diy_efi] Seen one, want LOTS more !!

[Greg Hermann]

At 3:29 AM 1/10/03, Grant Beaty wrote:
>Sorry for double post, saw the book here:
>
>http://www.amazon.com/exec/obidos/tg/stores/offering/list/-/0879386576/all/r
>ef=dp_bb_a/103-3670362-3807068
>
>Grant
>
>----- Original Message -----
From: "Grant Beaty" <gbeaty at ufl.edu>
>To: "List for general do-it-yourself EFI talk" <diy_efi at diy-efi.org>
>Sent: Friday, January 10, 2003 3:11 AM
>Subject: Re: [Diy_efi] Seen one, want LOTS more !!
>
>
>> Crap, I thought you had all the answers ;) I've always wondered about
>> turbine maps, you can find some charts in Garrett's new catalog,
>> http://www.turbobygarrett.com/turbobygarrett/jsp/index.jsp I'm not sure
>how
>> to read them, but I'm guessing Oolan's links will help.

I'm beginning to find some links, and am going to have to go hog some time
on one of the machines at our local library in the next couple of days
(they have a T-1 link !!), and sort the info out.

There is another, more detailed turbine map earlier in the Humphries book.
The curves have got to be run at a standardized outlet static pressure and
inlet EGT, and there is a formula (not stated by Humphries) for adjusting
the curves to compensate for non-standard inlet temp/outlet pressure.
Humphries does state that the curves generally are based on pressure ratios
using inlet "total" pressure and outlet "static" pressure, and that the
efficency curves INCLUDE the mechanical (bearing) losses.

One can arrive at  the TEMPERATURE ratio (inlet vs. outlet) via the usual
formula from the pressure ratio, and total heat (temperature drop times
specific heat times mass flow) times efficiency would give net power to the
compressor. Since mass flow through the compressor (plus fuel mass flow) is
equal to mass flow through the turbine, one has enough "knowns" to solve
all the equations and find the actual operating line of a turbo charger.

Yes, it's a choice of an iterative or graphical solution--or converting the
graphical turbine and compressor info (as well as the VE info for the
engine in question) to look up tables and building a rather complex spread
sheet, but it _CAN_  be done once one has the turbine maps.

Greg
>>
>> I've also heard "Turbocharging the Internal Combustion Engine", also out
>of
>> print, has great info.
>>
>> Grant
>>
>> ----- Original Message -----
>> From: "Greg Hermann" <bearbvd at mindspring.com>
>> To: <diy_efi at diy-efi.org>
>> Sent: Thursday, January 09, 2003 7:17 PM
>> Subject: [Diy_efi] Seen one, want LOTS more !!
>>
>>
>> > Santa wife, who is a librarian the rest of the year, managed to get me a
>> > copy of the (out of print) Humphries book "Automotive Supercharging and
>> > Turbocharging Systems" (Motorbooks)
>> >
>> > GREAT book, best one I've ever come across on the subject, including
>> > McInnes and Bell.
>> >
>> > Long story short, on page 112 (bottom left) is a TURBINE MAP, credited
>to
>> > Garrett and said to be for a TO-25 turbine. Essentially, it consists of
>> two
>> > graphs -- one is Turbine Pressure Ratio vs. Turbine Efficiency, the
>other
>> > is Turbine Pressure Ratio vs. Corrected Turbine Mass Flow (in
>lbs./min.).
>> > In this particular case, because the TO-25 has an integral waste gate,
>> > there are five lines on each of the two graphs--each line for different
>> > waste gate positions between 0.0" (closed) and 0.4" (wide open).
>> >
>> > The main point is that THIS DATA EXISTS--- SOMEWHERE-- and quite likely
>> > exists for every possible pairing of turbine wheel trim and exhaust
>> housing
>> > (each A/R housing and configuration--on center, tangential, or split--
>> > should have a different curve, for each and every Garrett turbo !! In
>the
>> > case of turbos without integral wastegates, there would only be one line
>> on
>> > each graph, BUT THAT'S ALL THAT WOULD BE NEEDED !
>> >
>> > My POINT is that THESE turbine curves are ALL of the rest (besides the
>> > compressor maps) of the info needed (only other number needed is pre
>> > turbine EGT !!) to do a full quantitative turbo match to an engine,
>rather
>> > than doing it "by guess and by golly" !!
>> >
>> > SO--does _ANYBODY_ know where to find copies of the rest of these
>turbine
>> > maps for Garrett (or any other mfgrs.) ???
>> >
>> > Thanks,
>> >
>> > Greg
>> >
>> >
>> >
>> >
>> > _______________________________________________
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>>
>>
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