Yea, I've seen those but I was a little scared to try that type out. I figured the vacuum pump working off of the filler neck would be better. What about if you have back pressure in your exhaust? Would that not cause the oil pan to pressurize? Guess you'd just need a high temp check valve or something just in case.

Still, I'd probably feel better with a pump.

 

If your smoking sitting still, you do have some blowby issues, and pushing it out the turbine seals. I'd measure case pressure with a water manometer at idle (should be less than 1") to be sure case pressure is your problem. Better yet, idle with the oil cap off.

They did very briefly mention forced induction once at the 1st link, but look at the customer page .... vac pumps are all about big NA drag cars.

http://www.gzmotorsports.com/customers-cars.html

I have a very simple, tiny closed catch tank in the oem return line to the turbo inlet. It gets nothing on the street. It gets nothing at summit point until I start shifting near redline ... finally too much blow by, combined with cornering. Then I get about 1 or 2 oz in 20 minutes. But I'm not putting down more that 300 hp at the wheels.

For high hp, healthy engines, natural venting should do, with the xtra 2nd turbo drain also used as noted. Larger than the tiny stock lines should be used. A big 90 deg on the cap is a good place to start. Check valves should not be needed, unless a vac pump is used.

Yes, the stock system likely worked well stock. I measured over 1 psi worth of vac
at the intake box top (with or w/o filter). This would help purge the case at high revs. But any free flow intake eliminates that.

Any normal blow by, put through a catch can (liquid trap), could be vented back to the turbo inlet with no change in VE. Think about the vent line sizes, and think about 600 cfm flow ...

 

Just depends on how much blow by there is. If the stock setup isnt sufficient that means that there is so much blow by that the stock lines cant flow enough to get rid of it. In the grand picture it might not be much....we'll just have to wait and see I guess

I plan on putting one on my car and testing it out. Might be a while though cause I've got a lot of "odd" projects going on with my car lol

 

The problem, I think, is simply:

1. Boosting produces blow-by.
2. Pressure builds in crankcase.
3. Slosh of oil in long right hand turn blocks escape of pressure through filler neck (via pcv valve or catch can).
4. Pressure continues to build forcing sloshed oil out of filler neck (via pcv valve or catch can).


Once the oil is in the neck, no amount of baffling, basting, vacuuming, etc will stop oil from being forced out if it is blocking the pressure escape. There are only 2 ways I can see to stop it.

1. Prevent the slosh keeping the venting pathway clear.

or

2. Provide alternate path for gas to escape.

Now here is my idea to prevent the slosh. Instead of a baffle plate with a bunch of holes in the top how about one that isolates the filler and forms a channel to the other side of the oil pan with a single very small hole on the left side. That way in a hard right hand turn the oil will be in the left of the pan (with a slight amount of oil coming through the small hole) and the filler neck will have a clear path to the right side of the pan where the gas is. And a hard left will put the oil over to the hole to the right side and the gas can escape though the very small hole in the channel on the left side. Now since this will require alot more work and may not work I am going to try number 2.

If the oil sloshes up the filler neck and there is another path for the gas to escape it will not push the oil out of the neck.

I think the spare oil return is the way to go (though always being single I am not sure where that is yet ). If you have a line on both sides one will always be clear and the pressure will be able to escape not building to eventually expel the oil.

This is of course only the conclusion I have come to after reading this thread and thinking about if for one day....

Shawn

 

first might be worth buying a cheap oil cap, bonding in a copper 1/2" elbo, and putting about a 1/2" vent line into an empty penzoil jug, for short, strait tests. That's a big vent.

 

I think those check valves that are plumbed into the exhaust would only work if you had a open DP. The only time I've seen them used is on "open header" applications with no back pressure in the exhaust after the check valve.

Those big vacuum pumps are used for more than getting fuel/water/vapor out of engines. On a piston engine pulling a vacuum behind the piston can gain some good power by making that piston go back down easier, not possible with a rotary.

 

Ok, I knew there were a lot of people with these issues. There are definately two problems. One is slosh and the other is blow by. The problem is that they both can work together to be a real pain in the ***.

My car does not smoke going in a straight line. It only does it after cornering hard. This seems to agree with kevin2k's theory regarding oil slosh and pressure build up. Once the oil blocks the vent path, your sol.

I am going to do like shawn and vent the otherside of the case using the rear oil return. I will run both lines to my catch can and install a vent on top.

To help with slosh this is what I did already today. I took the filler neck off of the block. When it is removed, you can see the tube that goes down about 2 inches. The diameter necks down slightly creating a lip. What I did was cut a square piece of aluminum with the edges rounded to fit the larger diameter of the tube. I then drilled a hole in the center and pressed the finished baffle down until it bottomed out on the inner lip. This shape gives me a hole in the center and half moons at the 4 edges. I hope this will make things better and not worse. I also added a short tube under the oil cap which connects to the 90 deg fitting I installed.

I have not driven the car so no results yet. I will try and run like this without the second vent just to see if it helps or makes it worse. Then I will add the extra vent.


As for pulling a vacuum, it is a sound idea. I just don't like the idea of pulling it only from the filler neck due to the slosh issues. Once the oil is in the neck the pump will just suck up the oil. This would only happen while cornering though as slosh is a g induced issue. If we connect both vents to the catch can then we can hook up the pump to the can instead of just a filter. I think this would work best.

mike

 

also, for the people who just have to deal with slosh problems from cornering, does your oil overflow come out brown and milky as well? If you do not have a blowby issue, then I would think the oil should just look like what's in the pan. People with blowby would probably get what I have. I think my blowby is easily dealt with while driving straight but is too excessive to manage whilst cornering. If it was less, maybe I wouldn't have all these problems.

 

We NEED to VERIFY if we should be running and external restrictor on the GT40r dbb turbos.

Let's get that issue cleared up first.

Can someone answer that question? Remember, the GT40r is water cooled too.

 

Oh yea. By the way, a well known rotorhead recommended that I only run the inner oil control ring, so I am.

I have absolutely no smoking issues. I had smoking when letting off but the catch can fixed that. But, with the two 6AN lines, (one at the stock location and the other tapped in the oil fill cap, I get a full catch can fairly quickly. Compression is good.

 

Yes. Brown, milky, nasty. Alot of us have seen the overflow tank overfill in a single track session, so there was talk of either restricting the flow to it, or plumbing the dump tube to return the "oil" to the crank case. Not sure i'd really be into either by the looks of the stuff.

I let it sit in the can for a while once, and when I tried to empty it, it had clogged the drain...

 

What about just welding a tray at almost the very top of the oil pan that goes about 3/4 the way across toward the passengers side. That way blow by could still get out but the oil wouldnt climb up into the filler neck.

Seems like that in conjunction with a vacuum pump to keep the oil pan under vacuum instead of pressurized or atmosphere to aid in keeping the oil cleaner and turbo drain would be an ideal setup. Well you can also just enlarge the vent nipples and run some bigger line to a catch can then to the intake but personally, I dont want all of those heated vapors going back into my intake. Thats why I'm going to install a pump at some point.

 

Can someone give me a diagram of how a catch can is usually hooked up?

 

I dont have a diagram but basically there are 2 nipples on the oil filler neck. Most people run a line from one of those nipples to a nipple on the catch can. Then on the other side of the can you could either keep the nipple open to atmosphere or run it back to the intake. Running it to the intake works better cause it keeps your oil pan under vacuum, the downside is your sucking nasty hot vapors into your intake

 

SPO:

I thought about a 2/3 -3/4 width solid tray too, with a stand pipe to go up to the dip stick hole. Sounds reasonable ... crisprx made a sandwiched tray, but still had too many/big holes as I recall.

Made me wonder why turbos oil drains didn't back up on long lefts, and blow oil out the turbine seals ... esp if lifting off and dropping exh back pressure.

There is no significant vacuum at the turbo inlet pipe/hose if you have an open intake. With reasonable line sizes, and healthy rotor seals, no vacuum would be needed. If you don't want to recycle vapors, you don't need a pump, just get rid of them out down a draft tube, or jazz tank filter. The pump would keep the oil cleaner, and help with excessive blowby, as you stated.

 

Thanks SPO

 

I think that the plate idea would help some but the unused turbo return won't really work.I say this because we have to remember that the oil isn't sloshing its way up the filler neck,it's being pulled by the old Gforce in those fast sweeping bends.
So whether you have one air passage open all the time you still have the G to deal with, this will inevitabily pull the oil out of either vent whether or not the other is open or not.
One sure way to fix the blowby,pressurising,oil starvation is to dry sump it.Only drawback is cost.

 

Disagree on extra turbo port. See my 1st post. At 1 g, oil will set as if engine tilted 45 deg. I don't think that puts it at the stock vents. Pressure does that.

I proposed this mod 6 mos ago, and 1 track guy pm'd me that it worked very well.

 

Oil in the filler neck is not the problem.. G-forces are not going to force all of oil out into a catch can. It is when the sloshed oil blocks the blowby gas that the problem occurs. If the blow by gas had another path it would not matter if the oil was in the neck.

Shawn

 

I'm not saying the oil isn't being forced into the catch can by Gforce alone what i'm saying is it takes a fair ammount of oil to fill the filler neck pathway before it's completely full.Up until this point there is still somewhere for the pressure to vent,so what causes the oil to get this far in the first place? it isn't pressure.
After it's full is when the pressure forces on the oil and starts to really throw it out.
If we look at when it's happening it's in high G long sweeping bends, i don't believe there is alot of sloshing going on there like there is G force acting on the oil.
Kevink2, i think the turbo return vent will help, but there will be times when it will be overcome just like the filler neck.Just my opinon anyway.

 

"... So whether you have one air passage open all the time you still have the G to deal with, this will inevitabily pull the oil out of either vent whether or not the other is open or not."

This I disagreed with. Under constant lateral G, oil level in case will tilt at exactly 45 deg, likely putting it partially up into filler neck, but not beyond the kink (FD) and to the vent ports. The new xtra turbo port vent will prevent the case pressurization the pushes the oil up higher, and main level lower until vapor enters and percolates up through the oil.

That's my theory. I have one solid data point of proof at the track.

 

They do! At least mine did with the stock twins on a local track here (long 180 degree left hander). I always thought it was from the prior turn- a 180 degree right hander until I removed/relocated the oil vent line.

Gene

 

So in your case Gene, having one vent open (filler neck) still didn't stop the oil from backing up threw turbo return,this is what i was getting at.

 

Correct.

Also get a full full catch can from the long right handers even after plumbing the catch can line the top of the damn oil filler cap as per Crispy et al. So, I believe that it is a combination of blow-by and slosh.

Gene

 

Has anyone else running the GT40r used a restrictor? I looked on ATP's site and they have one, but the GT40 series are not listed to be used with the restrictor shown. It is a .035.