986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - Racers. Do you worry about oiling issues, or do you just drive?

Bebbetufs · 10-20-2017, 02:02 PM

Just for kicks. Here's a nice rendering showing tank sloshing and the effect of baffles.

The rendering is of course not directly comparable to an engine as it does not take the insane tornado of windage and the unbelievably rapid flow of oil into account.

Considering the pickup would be in the middle it seems clear that baffle higth is important. The effect of the baffles depend on enough oil being returned to the central space as it is sucked dry by the pickup. At high RPM the oil pump moves about 1 qt (0.9L) pr. second or more. The amount of oil that can be returned at speed into the central space, and how aereated it is, becomes just as important, if not more, than how well the baffles can retain the oil.

Another potential problem could be that it seems like large pockets of air may be introduced as the oil rushes back to fill the empty side of the tank. This may be why some report more spiking in oil pressure with baffles.

Oil flow numbers.
964 - 65L per minute
930 3.3L - 100L per minute (high performance engines from this era uses larger bearing clearances to aid cooling, amongst other things. They need a higher weigth oil and larger flow to maintain the same pressure.
GT3 RS - 83L per minute (clearances are tighter in modern engines so a lower weight oil may be used. This lowers the need for flow and increases efficiency)
3.8 RSR - 57L per minute based on one persons dyno testing.
Source: http://forums.pelicanparts.com/porsche-911-technical-forum/193700-oil-pump-rating.html

10-20-2017, 02:02 PM	#38
Bebbetufs Registered User Join Date: Apr 2016 Location: Norway Posts: 180	Just for kicks. Here's a nice rendering showing tank sloshing and the effect of baffles. The rendering is of course not directly comparable to an engine as it does not take the insane tornado of windage and the unbelievably rapid flow of oil into account. Considering the pickup would be in the middle it seems clear that baffle higth is important. The effect of the baffles depend on enough oil being returned to the central space as it is sucked dry by the pickup. At high RPM the oil pump moves about 1 qt (0.9L) pr. second or more. The amount of oil that can be returned at speed into the central space, and how aereated it is, becomes just as important, if not more, than how well the baffles can retain the oil. Another potential problem could be that it seems like large pockets of air may be introduced as the oil rushes back to fill the empty side of the tank. This may be why some report more spiking in oil pressure with baffles. Oil flow numbers. 964 - 65L per minute 930 3.3L - 100L per minute (high performance engines from this era uses larger bearing clearances to aid cooling, amongst other things. They need a higher weigth oil and larger flow to maintain the same pressure. GT3 RS - 83L per minute (clearances are tighter in modern engines so a lower weight oil may be used. This lowers the need for flow and increases efficiency) 3.8 RSR - 57L per minute based on one persons dyno testing. Source: http://forums.pelicanparts.com/porsche-911-technical-forum/193700-oil-pump-rating.html __________________ 1990 944 Turbo 2007 Renault Clio RS 197 (Sold) 1998 Boxster 2.5L Track Day/ Race Car 2011 Mistubishi i-MiEV Norway Last edited by Bebbetufs; 10-20-2017 at 02:29 PM.