Twin turbine TBI pump (was Suction through a unpowered Tank Pump.)

[Greg Hermann]

>I'd suspect that only in a really large engine setup. and it would probably
>be diesel.
>Bruce
>>>I'm trying to figure out if this is a multi-motored/shafted, execusion, of
>>>have a twin turbine pump, I've never seen such an animal.  On one of the gm
>>>they used to little turbines blowing against each other but it didn't look
>>>like anything trick
>>>Bruce

Two turbine pump stages in series would be about right to make the 13--18
psi required for a TBI system, with a fairly small impeller diameter. If
they wanted to avoid using a positive displacement type pump, this might
well be what they did.

Greg
>>
>>My thought--not having seen one, let alone apart, is that it has two
>>stages, so as to get higher pressure. both first and second stage turbines
>>would be mounted on the same shaft, one motor to drive. A
>>"turbine"--otherwise know as a "side chamber" --type pump or blower will
>>give a lot more pressure rise per stage than a regular centrifugal pump or
>>fan.
>>
>>Greg
>>>
>>>>
>>>>
>>>>>I'm not sure of what your looking for but the twin turbine pumps were
>>>>common
>>>>>shaft and fixed, so I really dond't see the big deal.  Please clear up this
>>>>>please.  The only ones I've had apart were gm tbi+ multi.
>>>>>Bruce
>>>>
>>>>
>>>>Clear up what??  Glad to see you back on line and in good spirits Bruce!
>>>>
>>>>Walt.
>>>>
>>>>
>>>>
>>>>
>>>>>
>>>>>
>>>>>>>>
>>>>>>>>(I'm looking for about 80 gallons per hour at maybe 3 or 5 psi from an
>>>>>>>>in-tank pump.) (750 HP)
>>>>>>>>
>>>>>>>>Point is that 3 or 5 psi should be plenty to keep a vapor separator (and
>>>>>>>>fuel accumulator) full and also to keep the HP pump well enough primed
>>>>for
>>>>>>>>it to stay free of any cavitation..
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>Greg, there are a number of aftermarket in-tank fuel pumps that will
>>>>handle
>>>>>>>such flow requirements.   One suitable candidate is the Holley 12-903
>>>>(aka
>>>>>>>the Walbro GSS346M).  This particular pump is of a gerotor design, so it
>>>>is
>>>>>>>relatively quiet.
>>>>>>>
>>>>>>>Any more progress on your project?
>>>>>>
>>>>>>Once I get the printing press to making those portraits of dead presidents
>>>>>>in better quality, the project should pick up speed! :-)---but I think I
>>>>>>may finally have found a pair of the twin plug heads for it!!
>>>>>>
>>>>>>Something tells me that shortening up the flame travel with that 4.685"
>>>>>>bore might turn out to be a wonderful concept!
>>>>>>
>>>>>>I have a Walbro catalogue around, didn't realize they would flow that
>>>>much.
>>>>>>I shall check it again!
>>>>>>
>>>>>>Thanks--Greg
>>>>>>>
>>>>>>>Walt.
>>>>>>
>>>>>>
>>>>
>>
>>