This recent thread about Bob Kramer's Accusump letting loose got me
thinking about the pressures the thing actually sees.
My Accusump (3 quart) is plumbed directly into the oil gallery on my TR4. I
run AN12 size hose back to the Accusump, which is mounted on the passenger
side floor. I have a manual ball valve, not the electric solenoid that
Accusump sells. I pre-charged the air side of the bladder with whatever the
instructions said, something like 8 or 12 PSI. I have the one-way valve on
the engine's external oil lines to prevent the Accusump from throwing it's
load out a bad oil cooler or the like. The Accusump gets very hot after a
session indicating it is doing it's job..
With the engine running, my Accusump gauge reads about 5 PSI less than the
oil pressure I have at that moment. I thought that was about right, taking
into account the big bore oil lines I use, gauge inaccuracies, etc. I never
gave it much thought until I was at Watkins Glen and some guy comes up to
me and asks me what I know about Accusumps. His was not getting hot when on
track. I looked at his car, and the gauge on his Accusump read about 80. I
wandered about the paddock and looked at a few others, and saw several
gauges that read about the same.
So how are all these cars I looked at capturing 80 PSI in their Accusumps?
It would seem to me they must closing the valve when the engine is creating
80+PSI of oil pressure.
I never want to see that much oil pressure, even a the end of the longest
straight.
What I do is reach down and close the valve as I am entering pit lane. At
this point the engine is only turning about 3-4K RPM's, and I always seem
to capture only 45 to 50 PSI in the Accusump.
This sounded right to me, never gave it a second thought. Then I see
several people are capturing in the ballpark of 80 PSI in their Accusumps.
So, whaddahya'll think?
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