HP

[jmantle]

I did machine / hydraulic design before I retired, GPM x PSI divided by 1714 gives you the HP required. Flow is going to vary with rpm but 10 GPM at 80 PSI is only about .5 HP. Even if the pump is only 50% efficient it's only 1 HP. I've never measured the pump flow but regardless I don't see the HP being significant.

Jim Mantle V/SA 6632

[GTX5877]

There may be other factors that add to the results of lowering oil pressure or volume in a race engine that the engine dyno does not see. Most sportsman engine builders use 300 RPMs per second as the "rate of acceleration" as a standard. You may not see much if any difference, from standard tension rings vs low or light tension rings for instance on a dyno at 300 RPMs/sec. As a typical SBC stocker engine leaving the line will see 500-600 RPMs/sec or more. Oil pressure and/or volume may see some of the same results on the dyno, but may be quite different on the race track, because the dyno may not replicate the "rate of acceleration" as in the real word. Decreasing oil pressure to a point may be the point where there is less oil flooding the cylinder walls so those light tension rings can show their benefit, there may be less oil dropping on top of the crankshaft and camshaft adding to the windage issues and robbing horsepower, let alone unnecessarily flooding the valve covers. If oil pressure was not an issue in a race engine, companies such as Melling's shark tooth pump and Schumann's modified pumps would not show their benefits and therefore racers and engine builders would not buy them if there was no Gain. A good way to tell the benefits of your max effort engine on the dyno is run it as usual at 300 RPMs/sec and at the end of the session run it at 600 rpms/sec and see the difference. You will normally 'loose HP', but the less you loose, the more benefit you will see at the racetrack.
On the other side of these statements, I have tested oil pressure on the dyno on a purpose built dyno competition engine with external adjustable oil pressure with horsepower in the 700 range with 10w-30 oil. The results from those test showed that reducing oil pressure 5 lbs was 5 hp gained, 10 lbs lower was a 10 hp gain...your results may vary!

Tom Hestness