Ok, getting some sensible answers! And so far nobody has called me DS...
A number of the responders have indicated that the round tank with
tangential return helps to de-air the oil as it returns. That brings up
a whole set of other questions: one is just how much oil actually flows
at full boogie? Another is how much oil is bypassed in the pump because
the pump exceeds the pressure setting as rpm increases? Excess pressure
has to be circulated inside the pump when pressure exceeds set point on
the regulator, no other place for the excess oil to go. And that heats
the oil.. And that excess pumping around and around takes hp. I think
that's the reason that the NASCAR oil pressure regulator I have was
used. The excess oil is simply dumped back into the pan and eliminates
excess pumping and heating. Has anyone actually see how much oil is
returned during a full rpm run? I know it has to be the same amount that
the pump takes in but how much is that? Anyone have dry sump pump data
showing the flow vs rpm vs pressure? Pressure is needed because the
amount of oil pumped through the motor has restrictions so the flow is
way less than free flow... One fo the reasons I ask about flow is with
that info I can determine the actual flow velocity of the return oil. I
suspect it is way lower that anyone suspects.
comments?
larry
______________________________
drmayf
Worlds Fastest Sunbeam, period.
204.913 mph flying mile
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On 10/19/2013 9:25 AM, Larry Mayfield wrote:
> I am considering the use of a dry sump system. Why? Well, the aspect
> of fire caught my attention. Ventilating the pan with a lot of oil at
> full boogie makes a big mess and even bigger fire if it gets ablaze.
> So, a smaller blaze with a small oil pan for oil collection only.
>
> If there is a link to something that can provide me with an education
> on the kinds of questions below, I sure would appreciate it! I suspect
> others would like it also!
>
> Just put your comments after the questions for me?
>
> I see there are at least two different types of tanks: round and
> square. Seems to me that a square or rectangular tank provides for
> more oil than a round one of the same basic dimension, however, there
> appears that there are more round ones than rectangular. Any idea as
> to why? Seems like a flat sided one would be easier to locate and mount.
>
>
> I have seen some in catalogs with removable tops or panels, both round
> and square and I guess that would be for removable of debris; but
> seems to me that if debris is present in the tank then the pump is
> probably toast. So, why would a LSR team need a cleanable tank like
> that? Looks like another place to leak.
>
>
> Now, does the shape of the tank have anything to do with deareating
> the oil returned from the engine sump? Is round better for getting
> rid of air in the oil? Why would that be? Does the tank need a vent?
> Other than the cap? I would guess so since air can be trapped in the
> oil as it goes though the engine and it needs a place to escape.
> However, if a crankcase vacuum system is used though, would the vent
> be required? Maybe a vent connected to the engine internally with a
> hose so that air pressure is balanced everywhere?
>
>
> Should the tank be located below the pump to prevent siphoning or
> draining back into the engine pan when the engine is off?
>
>
> For LSR type activities, are multi stage scavenge systems needed? I
> have see some with pick ups in the lifter valley, the valve covers,
> and the pan in two or more places. Are pumps driven at engine speed?
> Or under/over driven?
>
>
> Finally, pressure regulators. Since oil is incompressible, then the
> pressure regulator is also a flow regulator as well. I have an
> external NASCAR regulator on my parts shelf, but where to actually put
> it in the system? Seems to me that putting it just after the pump is
> draining flow from the engine. The "extra" oil being dumped could be
> put directly into the pan where the scavenge system would return it to
> the tank or actually plumbed to the tank directly: that seems better,
> but, is it? What if the OP regulator is at the last place to get oil?
> Wouldn't that be an ideal place because that way oil is delivered at
> full flow and pressure to those places that absolutely must have both
> flow and pressure: main bearings and rod bearings.
>
> Standing by for any and all replies, no matter what they might be! I
> get a lot of "you dumb f**k" so even those are ok.
>
> larry
>
> aka dipstick, dumb shit, idiot, no brains etc...
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