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Discussion Starter · #1 ·
We are running some GT55r's on our new pro mod car and we seem to be having some issues with oil drainage.

We have -4 lines feeding the turbos pilled down with size 28 nitrous jets. -12 returns t'd together going to 1 scavenge section.

I am starting to think the seals are shot in these turbos. I believe that we may have not had enough of a breather on the car and these pressure may have damaged them.

After the intial start when we shut it down we heard like air pissing out of the downpipe. After a comp and leak down we comfirmed it is not a valve seat or seal issue.

I just don;t know if the sections sucks so hard it pulled the seals in or if it isn't doing shit and the turbo built pressure in the bearing section and spit them out.

I know there are a lot of you guys out there with low mounted turbos and no issues not sure what our issue is but i'm losing my mind trying to figure it out.

Oh yeah we are spinning the pump at 50% I had a K&N oil filter split and lost some oil pressure caught that problem and thought that was our issue causeing it to back up. Changes to a frame and the bitch makes 75 lbs at an idle.

I am going to try to back the spring out tomorrow leave the speed high for scavenge purposes but lower the pressure.

Lets here your thoughts.

Thanks
Carl
 

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i had a single vdo oil scavage pump for two low mount turbos it was making smoke on cruise and light thottle the pump could not keep up put a second pump on and fixed it i also had the gt garretts ,they do have a restricter in the center body which you will only need -4 feed line
 

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Could you post some pics of the oil drain lines coming out of the turbos and how they go to the pump? How many thousandth's is a 28 nitrous jet?

When the oil goes through the center sections with the turbos spinning that fast, it aerates the oil and makes it foamy like, which is usually difficult for a pump to suck.
 

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i had problems like this till i put a vacuum pump on.one though though-what is your oil pressure past the restrictor,i always put a gauge after the restrictor to figure out the correct size restrictor.
 

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I bought a turbowerks pump to suck the oil out, fixed my problem's, with oil running out the exhust, even when shut off it would run out. I also put oneway pressure valves on the feed so when motor was off, oil couldn't run into the turbo.
 

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i sell oil return pumps to pump the oil back to the pan, and suggest a one way check valve as well

chad
 

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I have a set of twin 88mm turbos that are mounted low. I had some smoking problems when the car had no vacume pump. With the vacume pump no smoking problems.The slightest amount of crankcase pressure will cause them to smoke in an application where there is no gravity feed to the drain. It is not the turbos. the seal rings in the turbos are not designed to keep an oil tight seal. the are like a piston rings on an engine they are only designed to keep the hot gas in the turbine housing.
 

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I have a set of twin 88mm turbos that are mounted low. I had some smoking problems when the car had no vacume pump. With the vacume pump no smoking problems.The slightest amount of crankcase pressure will cause them to smoke in an application where there is no gravity feed to the drain. It is not the turbos. the seal rings in the turbos are not designed to keep an oil tight seal. the are like a piston rings on an engine they are only designed to keep the hot gas in the turbine housing.
The seals have some similarities to piston rings, but there are oil slingers in there. The oil rides the turbo shaft out towards each wheel and the slinger slings the oil back towards the center section. If the drain line set-up isn't sufficient, it'll be like turning on your windshield wipers in a hurricane. There is so much oil it overcomes the slingers abilities. This is in reference to a traditional journal bearing center section, as some do differ.

- Brian
 

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I have my turbo mounted low also and have a tilton pump on mine, but it never gets the oil back because its on a up hill climb, at first when i started the car (new engine turbo etc.) it didnt smoke no wit does while its running??? will a vacum pump cure the problem and let the pump work corretly,, i am feeding the turbo with a -4
 

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We have no issues with our GT47-88's. Simple -4 feeds with no restrictors and -10 returns on each side of the pan. We run a external wet sump with a Moroso vacuum pump.

I dont know how low yours are mounted but these are in the grill area.
 

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Discussion Starter · #12 ·
Sorry i haven't gotten back on here to let you guys know we got it fixed.

Still using the nitrous jet. We turned the pump 3% faster and took the 120 fitting and used a 90. Turned the oil psi down at idle speed to 35 psi no more issues took it off the dyno today and we are looking good.

Thanks, still no vac pump but -12 breathers
 
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