[Land-speed] Dry Sump

[Skip Higginbotham]

Thanks Ed and Elon. If nobody has the numbers, I think that I will 
start by measuring the torque used to drive my BBC HV oil pump with 
the drill for preoiling. If I measure the reaction force I can 
calculate a torque number....... It'll be in the spring 'cause I have 
to redo the engine first.

Thanks,
Skip


At 06:15 PM 1/2/2009, Ed Weldon wrote:
>Elon-- That friction you are measuring is mostly drag from the shaft seal, a
>little bearing friction and some friction from liquid shearing due to
>viscosity at the pumping temperature.  That will not increase a whole lot
>with speed; certainly not by a square function especially with racing motor
>oils at temperatures in the 180-200 degree range. At 80psi output roughly 90
>percent of the hp to pump the oil will be what goes into building the
>pressure.  The formula I gave in the other thread on hydraulic hybrids
>applies here.  Fluid power is psi x gpm /1714 = hp.  Divide that by about
>.85 (which factor allows for the inefficiency in the pump drive belts) and
>you'll get the horsepower use of the dry sump pressure pump stage.  As far
>as the scavenge pump stages are concerned they will be pumping the same
>amount only to a somewhat lower pressure.  If you know that pressure then
>use the same formula and reduce figure that dividing constant of 0.85 will
>be about 1.0 minus 0.08 x the number of scavenge stages (eg 0.76 for 3
>scavenge stages.)  Air entrained in the scavenge pump flow will not have a
>big effect on the total horsepower once the motor is up to speed and the pan
>has been "emptied" of residual oil that was there when the engine fired up.
>My numbers on this come from data I accumulated on the performance of small
>industrial gear pumps in my 1st job with Worthington pump 40 years ago. It's
>a subject I feel I'm fairly well versed in. (& I don't throw away very
>much).  For anyone really that interested in the minutia of the subject I
>will be glad to copy and forward (snail mail or email) what you may be
>interested in. (lots of charts and pump performance curves.)
>Still, if anyone out there has seen actual test stand performance on
>multistage dry sump pumps, especially horsepower readings from calibrated
>electric drives I'd love to look at it and use it to refine the constants in
>my abovementioned formulas.
>Ed
>
>----- Original Message -----
>From: "Elon" <saltfever at comcast.net>
>To: "land-speed submit" <land-speed at autox.team.net>
>Sent: Friday, January 02, 2009 4:55 PM
>Subject: [Land-speed] Dry Sump
>
>
> > Skip, after you raised the question I went out and put a torque wrench my
>4
> > stage, Moroso, gerotor pump. The problem with quantifying ''dry sump'' is
> > there are too many variables. HP will vary with, number of stages, oil
> > viscosity, oil pressure, and gear type (spur vs. gerotor).  Anyway, I put