Turbo return line filter and cooler?

reclino · reclino's Garage

I am planning on putting a filter on the turbo oil return line. I have also been thinking this would be a great spot for an extra oil cooler. Seems to me this is probably one of the larger heat loads on the system. So how large a cooler should I put. I will be pulling the AC condensor out of the whale tail so that opens up some space for his cooler to go. Would 11x11" 30 row be too large for this?
David

boosted79 · 04-25-2017, 04:31 AM

Why do you want to go to all that trouble? Dump it into the breather cover and let the existing filter and oil coolers do their job.

turbobrat930 · 04-25-2017, 04:41 AM

David, I was thinking about adding this to the oil return line between the scavenge pump and the oil tank.

https://www.summitracing.com/parts/ear-230310erl

Boosted, Isn't that sending the oil throughout the engine before the filter? I guess I need to look at the oil flow diagrams again..LOL
Damn, this CRS is getting old.. LOL

boosted79 · 04-25-2017, 04:47 AM

turbobrat - no, it dumps it into the sump where it's picked up by the scavenge pump and returned to the tank thru the filter.

turbobrat930 · 04-25-2017, 05:40 AM

Quote:

Originally Posted by boosted79

turbobrat - no, it dumps it into the sump where it's picked up by the scavenge pump and returned to the tank thru the filter.

Cool, you are correct. However, if the turbo shells out, or if there is coking of the oil, these foreign objects then get sent thru the scavenge pump gears and through the front oil coolers before being filtered? (at least per the oil flow diagram I looked at)

If one did put an in line oil filter between the scavenge pump and the oil tank (like the one I posted from Summitt), I am wondering what sort of restriction the scavenge pump is willing to handle before not being able to keep up? In other words, just a new filter alone would be too much of a restriction, possibly?

boosted79 · 04-25-2017, 06:03 AM

The screen in the sump will block the big stuff. There are some threads on here about some filters guys have used in that line. That turbo scavenge pump is positive displacement, I don't think a reasonably sized filter will slow it down much. I may stick one of those Summit filters in my line just to be sure. I used gates 3/8 SAE J1019 trans cooler hose rated for 300F, 217 psi. 3/8 npt to hose fitting at the breather, 9 mm cone nipple and 16x1.5 swivel nut at the pump and two oetiker clamps but screw clamps would work fine.

boosted79 · 04-25-2017, 06:23 AM

On second thought, any coking is going to get ground up by the turbo pump before it gets dumped into the sump and goes thru the main scavenge pump. It would be hard to get any metal particles of any appreciable size in the turbo drain line from a journal bearing turbo, not sure what happens on a ball bearing turbo if the bearing fails. I'm looking at this filter

https://www.summitracing.com/parts/wix-58964?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-wix-filters&gclid=CjwKEAjw5_vHBRCBtt2NqqCDjiESJABD5rCJ3Q1q6tBD OmpbeqJtIedC88b3pCp9EDgjH6RsYgG6xBoCptHw_wcB

Ken911 · 04-25-2017, 07:01 AM

The stock turbo drain sump has a strainer in it already. The need for this is really ony with the aftermarket sumps.

turbobrat930 · 04-25-2017, 07:09 AM

Quote:

Originally Posted by Ken911

The stock turbo drain sump has a strainer in it already. The need for this is really only with the aftermarket sumps.

Yep, and I think most of us are running aftermarket turbos. The reason for this (at least for me), is after shelling out my turbo, I cleaned the catch/sump can under the turbo, and found debris. I also found one small piece in the gear of the scavenge pump. Nothing was found in the oil tank or the bottom of the engine. I boroscoped every inch of the engine i could and came up with no other debris found.

Just want to have extra assurance that if this happens again, I will have adequate filtration. I already am running the second oil filter instead of the oil cooler on the engine.

flightlead404 · flightlead404's Garage

Quote:

Originally Posted by boosted79

Why do you want to go to all that trouble? Dump it into the breather cover and let the existing filter and oil coolers do their job.

I like that idea. Did you use an existing hole, e.g. The thermovalve, or drill and tap a new one?

JFairman · 04-25-2017, 08:28 PM

Just use good full synthetic oil then there will be no oil coking. Letting a hot motor idle a minute or two after hard driving is always a good thing.
Don't over complicate the dry sump oil system with stuff the motor does not need.

boosted79 · 03:22 AM

My engine doesn't have a thermovalve so I drilled and tapped a 3/8 NPT into the cover. Yes, any turbo motor should be idled for a couple minutes before shutdown.
If you do this then you have to plug the port in the oil tank that the original line went to. I took a cone nipple that I squeezed shut and then sealed with braze and an M18x1.5 swivel nut .

boosted79 · 04-26-2017, 03:28 AM

As you can see I had to mod the tin and shroud a little to get the hose to clear. Then I made a cover to close it off.

GJF · 04-26-2017, 04:56 AM

A filter in the return would more than likely back up the return oil and push it out the seals in the turbo. Great idea in theory but adds complication...

boosted79 · 05-02-2017, 05:24 AM

I decided to run w/o a filter. The scavenge pump is a positive displacement gear pump, as long as it's turning it will pump the same volume for a given rpm regardless of the discharge pressure so a filter on the discharge should have no effect, it will still pump. The leakage around the gears may increase a little but it isn't like a centrifugal pump where flow decreases as discharge pressure increases. Put a valve on the discharge of a positive displacement pump and close it and one of three things will happen. It will stall whatever is driving it, the input shaft or something else in the pump will break or the discharge line will burst.

copbait73 · copbait73's Garage

There is probably nothing wrong with what you are doing. I suspect the factory would not consider pumping the same oil volume twice, and taking the fractional hp loss doing this, and that is why they pump it once to the tank.

1979-930 · 1979-930's Garage

Quote:

Originally Posted by boosted79

Why do you want to go to all that trouble? Dump it into the breather cover and let the existing filter and oil coolers do their job.

Is there an existing port there or do you need to drill and tap the cover?
Definitely on next Winters list. Thanks for the picture.

boosted79 · 05-02-2017, 06:54 AM

Some years have a hole there for a temp sender, mine didn't so drilled and tapped one for 3/8 NPT. Had to lift up the CIS unit and remove bracket to get the cover off the engine.

Rawknees'Turbo · 05-02-2017, 07:54 AM

^^^

Cole did that same thing (but he added a small filter inline to the breather cover - I didn't see the benefit in that, butt each to their own), and of course, anyone that turbos a n/a 911 engine and dumps the turbo into the sump plate (if one is present) and/or one of the chain box covers is doing the same (not to mention almost every other turbocharged car/truck on the road that drains the turbo into the vicinity of the block oil pan). It sure makes a lot more sense than the ridiculous, original setup - definitely on my "to-do"list.

Ken911 · 05-02-2017, 10:04 AM

I'm thinking that when i fab the new headers i'll make a new turbo drain sump that has a filter similar to the factory one. the inlet line dumps into a round screen with an open top. so the oil flows through filtered. if the screen gets plugged up it just overflows and still feeds the pump suction. to clean it you pull the drain plug and it's attached to the plug.