Turbo Gravity Drain question???

WydRyd · 09-24-2006, 06:09 PM

Guys,

I'm looking at tapping my left chain cover at this point shown below (note: it's a RHD vehicle, so mine is the passenger side chain cover).

I'm using the Schnell 930 Headers with extra flanges to raise the GT35R up 0.5" - 1".

Is the point pictured below a good spot to tap the return line, with respect to where the 930 headers positions the turbo and oil drain port?

The picture shows 5/8", but I'm making it 7/8" for extra flow

Input appreciated

WydRyd · 09-25-2006, 05:25 PM

Anyone know? Raceman, are you out there?

911pcars · 09-25-2006, 10:53 PM

Merv,
If no one else answers, here's my observation. That area of the cam box cover is the lowest drain point of the engine and is often used to gravity drain turbo oil. The turbo housing drain and this location are often close to the same level. A raised turbo housing position would be better.

Sherwood

beepbeep · 09-26-2006, 12:48 AM

Hello!

Yes, you can dump oil into lower portion of chain-cover but it isn't cover itself that is the problem here. It's positioning of the turbocharger.

As you are planning to use Garrett turbocharger which looks different than OEM unit, knowing position of KKK paperweight means nothing.

930's have special oil sump/suction pump for turbocharger only which alow them to sit low. If you plan to use gravity-drain on your engine, you must make sure that:

1. Drain pipe has sufficient diameter to allow effective draining from non-pressurized oil from turbo CHRA.

2. Drain pipe doesn't tilt more than 15 degrees from vertical axle, at least not for inch or so.

Mounting turbo too low or having problems with drain pipe will cause oil pooling in CHRA and in worst case, being pushed out trought the seals.

hobieboy · 09-26-2006, 04:17 AM

I agree with Goran. When I first bought the car, the PO gravity drain it to the bottom of the case (where you drain oil typically).

After much discussion/research, I thought it would be safer to simply get a factory scavenge pump and do it the factory way.

I also heard that Garrett turbo, in particular, does not like too much oil (i.e. scavenge them fast). Not sure how true that is.

WydRyd · 09-26-2006, 03:43 PM

Thanks all. This is the drain fitting I'm going to use under the turbo:

It has a 90 degree angle from the flange, so I guess if the turbo is "clocked" properly, it should work fine as long as the oil drains on a downward slope and the line does not become horizontal.

If need be, I have a 1/2" thick flange to raise the turbo up slightly for a bit more angle on the drain path. 7/8" ID is plenty big enough I'd think.

patkeefe · 09-26-2006, 04:07 PM

It will work on the street. If you run the car on boost for a bit, like on the track, you will not be able to drain the turbo...ask me how I know.
My solution is an electric oil pump, but haven't fitted it yet.
Pat

mb911 · mb911's Garage

Quote:

Originally posted by patkeefe
It will work on the street. If you run the car on boost for a bit, like on the track, you will not be able to drain the turbo...ask me how I know.
My solution is an electric oil pump, but haven't fitted it yet.
Pat

so that was the issue????? Wow very cool

I think the 930 unit or electric are the way to go if you are doing it. thats probably what I will do when I get mine back together

patkeefe · 09-26-2006, 04:38 PM

I think what happens is exactly what Goran says, with my case being the oil pushed back out the through the turbine section (Ben, that's only one problem!) As I have to get my engine back out anyway, I will advise on the feasibility of electric vs 930 mechanical pump. I think the electric will be a good solution.

Merv, please note that in my location, I have basically no pitch to the left chain cover. You may get 1" if you really mount the turbo high, but the engine mount bar obstructs the mount.
Pat

mb911 · mb911's Garage

Quote:

Originally posted by patkeefe
I think what happens is exactly what Goran says, with my case being the oil pushed back out the through the turbine section (Ben, that's only one problem!) As I have to get my engine back out anyway, I will advise on the feasibility of electric vs 930 mechanical pump. I think the electric will be a good solution.

Merv, please note that in my location, I have basically no pitch to the left chain cover. You may get 1" if you really mount the turbo high, but the engine mount bar obstructs the mount.
Pat

very true note your turbo (wydryd)will have to be very small to clear the engine mount . My T4/TO4E is very tight no room to bring it higher without going side mount.

WydRyd · 09-26-2006, 05:51 PM

Thanks for the feedback guys.

My understanding is, as long as the oil "exit port" on the CHRA is higher than the point entering the chain cover, it should be fine.

Car is purely street and sees occassional full boost sprints, so I think it would be a viable solution. I'll known pretty quick if oil seeps past the seals and starts smoking. In which case, I'll either fit a 1/2" flange between header collector and turbo inlet, or go to an electric scavenge pump solution and be done with it.

I'm just looking for the cheapest and most robust solution here