i know with a gravity drain setup the drain needs to be quite large but im wondering if the same rules apply when the oil is going into a pump. i plan to run a small feed line with a restrictor, probably 1/16" into the turbo. ill have a large hose from the drain of the turbo to the oil pump. the question is, how big should the line be going from the oil pump back to the motor? i would think it doesnt have to be huge but with such a small restrictor feeding the turbo and the fact there is an oil pump to return the oil, can i run something as small as -4?

the oil pump moves ~1.8gpm and will be wired to run off a switched 12v source if it matters

 

with the style of oil pump I've seen being used on these, what you've proposed sounds fine. The biggest thing is if you're using the pump to just return the oil to the oil pan, a larger line will be less restrictive and will make the pump struggle less to move the oil. I plan on having my twins on their own separate system, so the outlet of this pump will go directly to the turbos and the pump I'm looking at should have no problem doing this and supply something like 50psi oil pressure.

 

i plan to pump the oil back up to the valve covers. dont want to do any hole punching into the pan. do you still think that the -4 will be enough? the rise will be under 3 feet and less then 10ft in legnth

 

These pumps are usually positive displacement pumps, which means they will move x volume of fluid for y rpm of the pump. If the pump you're looking at has a really tiny motor on it and you put a tiny line on it, it may not have the power to continue to turn at normal rpm and thus move less oil. I think -4 or 1/4" line at those rise and lengths should be well away from any trouble area. You could always put just a short -4 line on it and have it pump say a gallon of oil from one container to another just to verify its performance is at least close to the rating before committing to the entire setup.

 

really appreciate the advice, will definitely be doing a flow test as suggested.

cant wait to do a built thread, i now how everyone likes odd stuff

 

I used a -4 nitrous feed line all summer with no issue, turbo was upgraded and the builder said it looked brand new inside.

 

the good pumps have a -6 fitting, so one would think -6 line. Good idea to run a vented drain, vent before the pump, stops the pump from pulling too much vac.

 

What kind of pump are you useing, I'm going to be in the market for one soon.Don't mean to hi-jack this thread.Randy

 

I'm sorry, i didn't read your original post very carefully. My feed is a -4, but my drain goes as follows:

-10 90* fitting out of the turbo, 3 feet of -10 from the turbo to the oil return pump (up hill), -8 from the pump to the oil pan.

You could probably get away with -6 from the pump up to the oil pan, but that would probably depend on what pump your using. If you look at the photos on STS turbo's website it looks like they are using either -8 or -6 for the return right out of the turbo.

 

Thanks!

 

wouldnt a 1psi hobbs switch do the same thing? ive know sts uses one on the feed side of the pump. ive seen people using them and ive seen people who dont

 

What is the hobbs switch used for?I was thinking is was a oil pressure switch that I have seen on some.

 

I'm not sure what the hobbs switch is for, but it just sounds like some extra junk to go bad to me. Perhaps they are only trying to run the pump when the oil backs up to prolong the pump's life. I wouldn't do a vented return before the pump either because guess where the oil goes if your pump fails and it is vented? Thats right, out the vent, i saw it happen on a low mounted STI and the mess was horrible. It pumped out 2 quarts in a matter of moments. If this would have happened at the rear of the car near the tires at the track it would get ugly real quick. Now if you have a sealed off return before the pump, and pump goes bad it will smoke, and i don't think it would damage the turbo since you often see people on here with returns that are too small and the issue is resolved after the restriction is removed with out harming the turbo.

As far as everyone worrying about the vacuum in a non vented oil return pump setup sucking the bearings dry, i have serious doubts on this theory.

 

I am just running the drain out of turbo to a small tank than to the pump hope that works,been reading up on them.

 

The setup I did has a 4an feed to the turbo.

The drain is about 16 in. 1/2 id hose to the pump. Then 3/8 id line back to the valve cover.
Works just fine.

 

im assuming thats what sts uses it for. basically cycling the pump on and off as needed. ive talked to denmah on this forum who has a remote mount chevy truck and he runs no vent and no hobbs. 3000 miles under his belt with no issues so far. i dont like the hobbs switch because if it fails, the pump wont come on unless the hobbs is designed to fail in the on possition. and i dont like the vent for many reasons, one you mentioned. i guess unless i find a hobbs switch that fails in the on position ill be just running a closed oil system (no vent).

 

i do like the hobbs switch that defaults to the off position. I was pondering on my lunch break how to run the pump only when needed and i had an idea.

Since Rdakota340 is going to be running a small tank, why not put a "Low oil sensor" from a GM (northstar, LQ truckmotors etc) in the small oil drain tank, that way when the tank started to fill up the pump would run until the level dropped again. Then again if the level is just right the pump will toggle on and off quite abit. I guess i like my full time pump/no vent too.

 

No hobb switch for me,On our older CH Mack's that have S400's on them with a -6 feed,The oil return from the turbo drains into the oil fill tube I can see the oil flowing and it is flowing fast so the pump should not run out oil while runnig, the only thing that that worry's me is the oil temps that the pump is going to see.If yall our running strait from the turbo with no issues then I will try that first with out a tank.

 

What pump were you going to run?

 

I was planning to run a differcia pump like the roundy round guys there was a couple on here that has run this type of pump