Where does the oil pressure go? I mean it comes into the turbo at 60psi at wot and then you say it just trickles out at the oil return line? where does all the pressure go to. Is it lost by going from a small 3an line to a 8an or 10an line?

 

nobody know's the answer? How come everyone quotes that it has no pressure but yet no one know's why? Hmmm.....

 

i dont think trickles is the word , usualy people use -10 line for return line , its more like pours back in the pan

 

sweet question, i've thought about that before but didnt dwell on it long enough to make a post about it. my best guess is what u said.. the difference in size between the feed and return.

if u think about it.. if u were to blow into a straw out into a peice of pvc pipe.. that pvc wouldnt have much pressure.

 

I dont know many who say it trikles most people say that it gravity feeds back to the pan. Which is true after the oil enters the turbo it spreads out through small passages which allow the oil to just run over the shaft and bushings. If oil were to be pressurized through the shaft and bushings you would blow out the seals andruin the turbo. Here is a pic you can somewhat see what I am talking about.

 

I think it would be cool if turbos came with some sort of pressure limiting valve built in.

 

Pressure depends on volume..you have a small feed line going into the turbo cartridge...the volume of the cartridge is greater...and your return line has a larger diameter as well..therefore your return line pressure is less..I think I right about this..someone can fill in if Im wrong

 

Any of the oil or fitting suppliers here on h-t mind responding? I'd really like to hear from one of you guys....so far it looks like it's just the fact that it goes from a small line to a big line.

 

There is oil pressure at the rod and main bearings correct? (yes) Where does that pressure go? (it deminishes as it leaves the bearing joints) You are asking about the turbo supply oil pressure...but they are basically the same theory.

Decrease in resistance = Decrease in fluid pressure
Oil entering the turbo and moving through the bearing cartridge = there is resistance, so there is a measurable presssure. Once it leaves the bearing cartridge the resistance drops greatly = loss of pressure, just a flow of oil back to the oil pan.

 

Just because there is 60 psi at the turbo does not mean a lot of oil flows through it. Turbos dont use that much oil, it only uses a requires a thin amount amount of oil that seeps through the clearances in the bearings and the clearances act as a restriction. Its like when you just barely turn on a faucet and a little water trickles out, theres more than enough pressure and water in the pipes behind the faucet to let it spray out but you are only letting a little trickle get by. If there was no restriction at the turbo it would just dump straight through into the pan and you would loose your 60psi of pressure the pump has built up and you would be in trouble(like when a motor spins a bearing and the engine looses oil pressure due to the loose cleanance of the worn bearing). The drain has nothing to do with it, the big drain is just so it can get into the oil pan as fast as possible to properly cool the hot oil instead of letting it cook.