Dry Sump System

[toyo rob]

just chatting to a mate of mine, doing an apprenticeship at a F*** Garage:eek:, he told me about a dry sump system, apparently used in WRC for ages. On hearing the benefits, like limits oil leak if i damage my sump, my response was if im driving over humps that fast i dont deserve my car!!, but he said something about it increasing or at least helping with the compression. he then tried explaining it but i totally lost him about 2 words in.

 

So in short, 1 has anyone done this?

2 is it any good?

3 what am i looking at in time and effort if i do go down that road?

 

Cheers

 

Rob S

[Ian C]

I think, and I'm ready to be corrected, that there are two good reasons for a dry sump. One is to avoid oil starvation under high G loads, and two is to lower the profile of the engine and therefore mount it lower and therefore get a lower centre of gravity.

 

Cons are - bespoke build, costing a shedload, and if anything goes wrong with it your engine gets lunched.

 

-Ian

[SimonB]

I think the other reason for having a dry sump is that the crank doesn't thrash around in oil so there is less friction in theory. I think you'd have to have an engine designed that way to start with really though.

[Digsy]

You should be able to do a bolt-on dry sump kit but as Ian says it won't be cheap.

 

Main benefits are (as mentioned above). No oil starvation / aeration under accel / decel / cornering due to uncovering the pickup pipe, and no oil aeration due to crankshaft windage (although the crank shouldn't really be splashing around in the oil anyway). The lowering of the centre of gravity is a god benfit on a race car, ut of course to take advantage of that in a Supra you would have to lower the driveline after doing the dry sump conversion.

 

You may be surprised to learn that a lot of "normal" road cars can pull almost 1g lateral acceleration, so testing for sump surge / oil aeration / starvation at min oil fill at up to 0.9g isn't uncommon, so the stock oil pan should be well up for anything we throw at it (especially since the Supra uses solid tappets).

[Chris Wilson]

A big efficient scavenge stage(s) on a modern race dry sump pump can pull a vacuum in the sump, heping piston ring seal at *serious* RPM's, the sort of RPM's no one here will ever see on their Supra engine. F1, F3000, Indy car stuff. It allows use of 1 or 2 ring pistons with VERY narrow rings indeed to reduce drag.