Al,
Good data, but for clarification, aren't you running a 13B pump on your 20B?  Are you running stock main pulley or an undersized pulley?  The 20B pump should flow more gpm due to a slightly larger impeller.  Also, comparing a 20B eccentric pulley with a 13B from an 89 n/a engine, the 20B pulley is larger, which should also increase flow, up to the point of cavitation.

Mark S.

I don t disagree with your flow assessment for the car; but consider this.  My engineering analysis (all the same stuff that our friend Bill Shertz has now plotted out for everyone) for designing a somewhat optimum cooling system for my 20B told me I needed 40 to 50 gpm flow rate at 6000 rpm and 260 hp; that range depending on variable factors. For a 13B that something like 22 to 33 gpm.  When I measured the flow rate during the dyno tests I was pleased to find that the pump produced 48 gpm, with no thermostat, and 37 gpm with a thermostat.  This was pumping thru the engine and through the dyno loop which I know has less back pressure than my plane s cooling loop, so my actual flow will be less.

 

So I don t see any excess flow over what I need at high rpm/power, even running the engine without a thermostat.  Yes, there are regimes where it will be pumping more than I need in the same regimes where I don t care whether I m wasting 1 hp driving a bit more flow than needed.  And, I could also put in bigger (heavier) radiators and run a larger delta T and a bit less flow.

 

(OK, I lied, get on with the beheading it s only because I m not feeling well and sitting around at my computer instead of working on the airplane; honest)

 

Al