Auxilliary oil separator: Reduce oil consumption, prevent runaway.

[Dr. Diesel]

So I'm closing in on finally being ready to race my old TD Wabbit. It's been off the road for pretty well 2 years. My last stint on the track was a blast. Check it out:

vw rabbit turbo diesel autocross race

Anyway, early last summer the clutch disassembled itself while doing 100km/h in 5th on the highway, which lead to a 10km jog home at 5am after a tought 12 hr nightshift. At that time, the marriage preparation dial was set to "insane" and long story short, I only got as far as pulling the trans off before abandoning it for 8 months. Fast forward (before this becomes a novel) to this summer and after a host of improvements, this little Rabbit is REALLY dialed in!

Some gratuitous Wabbit porn:







On the rack, getting a REAL alignment. (this guy is both an oval track and road course race driver, and has been pit crew chief for teams in both areas)





To the point. So during an early test drive, I was halfway through fourth gear in a circular highway on-ramp and still accelerating, and just as I straightened out,



the car went into full oil runaway, billowing clouds of smoke, clattering, the real deal. I had to hold the brakes to prevent over-revving 4th, and didn't want to risk shifting into 5th. By the next off ramp, it had mostly cleared out, but a tap of the accelerator pedal would send it into runaway again, no doubt sucking up the pooled oil in the intercooler.
Clearly, the extremely high lateral G-force this car is now capable of producing allows oil in a hard right hand turn to blow out the breather. Something had to be done, I wasn't about to start taking it easy in corners after all this work!
I parked at a friend's house and we went shopping.
TSC (a farm-hardware store) had a beautiful solution for improving oil separation.
It's called a "Line Strainer", and features a uni-flow 40 mesh screen inside the bowl. I installed a 90º fitting in the bottom, and routed the OE oil separator's output into the strainer. I then routed the strainer's output to the fitting on the turbo inlet pipe. The small drain fitting on the bottom of the strainer is routed down to the block-off plate (mechanical fuel pump mounting pad, in ancient times) next to the vacuum pump.
It works beautifully! After a very hard, 100km drive at speeds I won't admit to, here are the results:

The strainer:


You can see oil in the pipe between the OE separator's outlet and the aux. separator's inlet:


However, the aux. separator's outlet pipe is BONE DRY!


And the little drain tube is full of liquid oil. (there's a short section that has to travel slightly uphill before curving down into the block)


I'm very pleased with these results. Hard cornering hasn't resulted in the smokey spectacular whatsoever. I'm now firm in my opinion that there must be a certain amount of oil vapour that finds it's way into the engine intake, even in regular driving. This auxilliary oil separator system appears to collect ALL of it. If you route it back into the sump, or collect it for pouring back into the engine at whatever interval, it would appear that you can actually significantly reduce oil consumption.

[rs899]

I don't race my Caddy, but I was getting concerned about blowby and oil consumption, so I installed a Mercedes 240D oil separator on it a few weeks ago.  I made the mistake of not putting a good clamp on the return line to the sump and it popped off and showed me what a great job it had been doing.....

[8v-of-fury]

dayumm, running like a raped ape! lol LOVE IT!


and cool oil separator too

[Dr. Diesel]

bump for GTIKRUNK to look at this post.

[DJPyro]

Could we get some better pictures of how you routed everything? I have an aftermarket catch can from my old Nissan I was going to put in my system because of all the excessive oil in my intake, but I still haven't. I ended up picking up a $5 PCV off the shelf at Canadian tire, and installing it between the vent in my valve cover, and the stock flying saucer, then routed that to my intake. I still get some oil from the lower crankcase vent that finds its way into the intake, but it's not nearly as bad as it was. I find I get hanging throttle when I'm flogging mine through the trees, so I understand the concern you've got, and mine isn't pulling Gs like yours just yet.

I'm working on figuring out a way to impliment a remotely activated CO2 fire extinguisher in my intake tube. (CO2 extinguisher is the friendliest way to shut off your run-away diesel) Just for in case, I have a legitmate kill switch in the car. 

[Dr. Diesel]

Interesting idea with the CO2. I wonder if the 'snow' would erode turbo impeller blades?
I can't take any pics, as i'm on the other side of the planet now. If you ask again in october, I may be able to comply.

[DJPyro]

That's why you use a  CO2 one, no snow, nothing, it just releases Carbon Dioxide, which the motor can't run on. My buddy's a licenced truck and coach mechanic, and it's what they were taught in school. I've seen it work first hand. Goes from terrifying RPMs to cough, dead. Can't burn anything if there's no oxygen, runaway or not.

That's also why I'm going to rig something up with a solenoid/punch, and one of those little CO2 cartridges from a BB gun. The cartridge will be replaceable and only used in the event of a runaway. I hope to never use it, but I also don't want to sit helplessly in the middle of the bush and watch my motor eat itself alive.

[Dr. Diesel]

My impression was when firing off a CO2 extinguisher, it freezes the water vapour in the air, making the (snow) white cloud you can see. In any case, I suppose whatever minimal erosion it might cause would be minimal and a helluva lot more acceptable then a grenaded engine.
Incidentally, in the three vehicles I've had that were prone to runaway, (deliberately incurring it was the only way to pass at highway speeds in an old 1.5L wabbit!) it was very easy to stall the engine in gear with the brakes. Perhaps not as gentle as the CO2 idea, but significantly less complex! 

[RabbitJockey]

i had one that was prone to running away but it was an automatic and on the automatics when u let off the gas pedal they go in to neutral, pretty crazy.  that engine survived too, only real damage was a blown head gasket, but i reringed it while i was in there.  i added a breather to the block and it ran like a top after that

[keaton]

Could we get some better pictures of how you routed everything? I have an aftermarket catch can from my old Nissan I was going to put in my system because of all the excessive oil in my intake, but I still haven't. I ended up picking up a $5 PCV off the shelf at Canadian tire, and installing it between the vent in my valve cover, and the stock flying saucer, then routed that to my intake. I still get some oil from the lower crankcase vent that finds its way into the intake, but it's not nearly as bad as it was. I find I get hanging throttle when I'm flogging mine through the trees, so I understand the concern you've got, and mine isn't pulling Gs like yours just yet.

I'm working on figuring out a way to impliment a remotely activated CO2 fire extinguisher in my intake tube. (CO2 extinguisher is the friendliest way to shut off your run-away diesel) Just for in case, I have a legitmate kill switch in the car. 

the idea i had was to use a old BMW (or any) throttle body and put it pre turbo on a hard turbo inlet pipe. the throttle body always wants to close so rig it so its always open with a pin. then in the even of a run away you pull the cable which removes the pin and the TB slams shut killing the air flow to the motor. and as you stated no oxygen = no running motor

[DJPyro]

See that doesn't work. I've seen a 2-stroke detroit sucking oil past the valve seals as it runs away, and smothering the intake doesn't work. It just finds other places to draw air. A small shot of CO2 in the intake eliminates all oxygen in the engine long enough to stop combustion and stop the motor. I'm sure these little motors aren't as difficult to smother as a truck motor, but it's still a painless way to stop the motor.

And Dr. Diesel, I don't think the small amount of frost that would be created would pose an issue on the motor, it's not there long enough to significantly change the temperature of anything I don't think.



At the very least I'll be keeping a CO2 fire extinguisher in the car.

[keaton]

or a CO2 paint ball tank... they are cheap small. then keep the fire extinguisher for just in case fires

[blackdogvan]

Is the oil return on your fart separator above or below the oil level?

[Dr. Diesel]

above the oil level in the pan.

I second that about the detroits! At my last job there was a big aircraft tug w/ a detroit 453. I was pulling the airplane and suddenly the tug got all smokey and was down on power. I just kept on going and towed the plane into it's spot. Then opened the hood for a look. Turns out the emergency shutdown valve on the blower had somehow closed. Didn't kill the engine.

[DJPyro]

or a CO2 paint ball tank... they are cheap small. then keep the fire extinguisher for just in case fires

You may notice I mentioned that earlier... ^



Yeah, scary stuff when you snuff the air intake and you hear it just start drawing air in through the valvecovers and everywhere else it can suck air in... And it just keeps running... There's some fresh brick work in Fanshaw College because of a runaway diesel.