ðð> what is the difference between dry sump and a plain old pressurized
ðð> system. Just the fact that there isn't an oil pan on a dry sump system,
I assume by "plain old pressurized system" you mean the stock oiling system.
Now, a true dry sump system consists of a large oil tank (usually about 14
quarts - 3.5 gallons for a 4 cylinder application) which is mounted in the
rear of the car (hatch or trunk), feed and return lines to the engine
compartment, a belt driven high pressure pump, a sort of convex plate that
replaces the oil pan that has a fitting at it's lowest point for the oil
return to the tank, and various high pressure feed lines from the pump to
the engine. There may be a low pressure transfer pump in/near the tank, and
there may or may not be an oil cooler somewhere along the line - probably
not necessary with that large of volume of oil and length of supply/return
The advantages are multi fold. Putting the holding tank in the rear
(usually) helps weight distribution, the fact that the tanks are usually
fairly tall and narrow, and that the feed line is located at the bottom of
the tank, means that no amount of cornering/acceleration/braking force can
cause the oil to "slosh" away from the supply line, therefore allowing for
constant positive oil pressure. The large volume of oil affords very stable
oil temps, as well as a much higher dilution factor in regards to
contaminants in the oil. The fact that there is virtually no oil sitting
below that crankshaft means that there is less HP loss from the crank having
to "slice" through the oil in the oil pan.
The down side is cost (a whole dry sump system is MAJOR $$), and loss of
trunk/hatch space, which isn't an issue in a race car. The more cost
effective way to deal with this is to get/fabricate a well baffled oil pan,
and, possibly, get a device called an "Accusump", which is a small (1 or 2
quart) cylinder, similar in appearance to a fire extinguisher, that mounts
vertically in the engine compartment, and is plumbed into the oiling system
so that the supply to the pump comes from the bottom of the cylinder, and
the return is attached to the top. This setup retains the oil pan and stock
pump, but works like a dry sump system in regards to having a constant oil
supply which is not affected by cornering/acceleration/braking, without the
large tank and belt driven pump.
The Accusump system can also be used as a pre-oiler to provide positive oil
pressure prior to starting the engine.
I think that about covers it, but feel free to ask any questions...
Ok dry sump questions Mr animal. does the fore mentioned kits include a new sump? is this sump shallower as there is no need for oil storage? does this enable me to mount the engine lower in the car?
yeah, it allows you to drop the car as the replacement sump is much lower profile. However, you'll need a smaller flywheel. as that's the practical problem. which is a bummer, as you need a special flywheel etc... and it all starts getting expensive (sorry, EVEN more expensive)
Thanks for your help , i didnt realise it was that involved . i knew i wolud need a tank , feeds , new pumps etc , but didnt expected teh flywheel and starter motor . Did everything come with yours ?
Im pretty good with knocking things up and planned to make my own cover for where the sump was .
Im getting a bespoke steel flywheel made as no one sells one , how would i work out how much smaller it needs to be ? from experiance , would you say its worth it ?
no no no... the flywheel etc is only if you want to lower the engine
you've got the right idea about the sump, pump, hoses etc. It's a good idea to use aeroquip stuff for the oil hoses, as it can easily take the pressure. pace make pumps etc, and SBD get a custom casting made. try the adds in motorsports news for some second hand stuff.