MFilippello

iTrader: (2)

I'm putting this here because I am running a single and most of the smart people are here

I have a greddy catch can hooked up to my oil filler neck and the other side to the suction side of my gt40r. after some hard driving(high boost and cornering) my catch can fills up with a coffee colored fluid. It is not just oil. It looks like a chocolate milkshake or like coffee with cream in it. It has a definate fuel smell.

I know a lot of the track guys get a lot of oil in their catch cans. What does it look like? Is it just plain engine oil that is pushed up to the can or is it all contaminated. This stuff definately doesn't belong back in the engine. I emptied about 40% of my greddy catch can after only 4 days of driving. It fills quicker when doing cornering vs just getting on it in straight lines. The stuff that goes in the can however is always the same. I also have a lot of the white milky substance underneath the filler cap.

The other problem is oil smoke after a high boost run and let off. If any oil gets pushed up into the vent lines, then it smokes bad when I let off after a high boost run. I think the oil in the vent lines impedes the venting process which raises crankcase pressure thereby causing the turbo to smoke. As an aside, with the car running at idle, I can blow into the crankcase filler tube with little force and oil smoke will come billowing out the exhaust. It seams that I am pushing oil past the turbine seal. Are BB turbos really that sensitive to crankcase pressure. I am not blowing hard, just a small puff.

I also have oil at the inlet of my turbo. This could be from oil that makes it past the catch can and get sucked into the tubo. I am going to disconnect the catchcan from the turbo and see if I still get oil there. I also wnat to rule out if the smoke coming out the exhaust is from oil blowby past the turbine seal from crankcase pressure or the oil which was sucked through the catch can and int the intake. So much for the catch can doing its job of seperating the oil from the air.

By the way, I have two vents on my filler tube going to the catch can. One at the stock location and one placed into the cap. and yes my oil drain for the turbo is large and straight.

SPOautos

I dont have on however I've reseached some real old threds and have seen people say that had nothing but fuel in them.

I've heard that dynamic seal and bb turbo are both very sensitive to crank case pressure. Its probably why RX7's stock turbo are about the only carbon seal turbos left on the planet haha.

We had a GT40R guy on the dyno at a local meet that was having bad smoking problems. I disconnected the line that goes from the oil filler neck to the uim and just ran that to atmosphere with no check valve. His oil stopped on the next run after that

What kind of porting do you have?

twokrx7

iTrader: (1)

Interesting. My catch can would collect virtually no oil during street driving. there was a small amount of oil in the bottom of the can, perhaps 1/4" level in a 3" diameter can, but the level never changed. I had it setup like yours with a few differences. The vent was at the oil fill cap only (higher is better for less carryover) and it was 1/2" hose to the can. 1/2" also on the vent line from the can to the turbo inlet.

I never tried to blow into the crank while the car was running but just imagine where the vapor would go when you do this test ... no other place but the turbo oil drain lines, right? Probably pushed the foaming oil back into the turbo.

Given your fast oil/muck buildup in your can it soulds like excess blowby internal to your motor, perhaps a coolant leak as well if the can is full of milky stuff. Or maybe the vent lines are too small and you are pushing oil thru the lower vent on the fill neck. If it's really humid in your part of the world maybe enough condensate forms in the motor during cooldown but that doesn't pass my funny look test. Is your can also vented, perhaps thru a filter? This would draw in lots of air and could fill the can with water over time if the air is humid or if you drive in rain.

Best of luck.

ghostrx7

I just have a hose coming out of the oil filler neck venting to atmosphere...havent noticed any smoke whatsoever other then the normal amount coming from the exhaust. btw its a 3/8th line fuel hose I had leftover

Gargamel

I have a hose running from my filler neck into a beer can. Mine spits out lots of oil under boost.

Snook

iTrader: (12)

id like to see a picture of that

Mike listen to SPO he knows his ****

setzep

I think this is what I'm going to do. Think it will work well? I'm sick of the white foamy oil/water/gas in the filler neck and the gas in my oil.
The "kite" at the bottom of the filler neck is a filter.

Carl Byck

The brown "stuff" is normal, as for the BB turbos, they are extremely sensitive to set-up of the oiling system. I am not sure I have heard about anyone completely solving the problem. I think this is something Sean, or someone else with a good dialogue with Garrett needs to solve. Perhaps a detailed diagram of our oiling system would help the Garrett folk to figure out why we are having so many problems. What CHRAs does Innovative use? What CHRA does Chris Roth use? I do not remember hearing of problems with ITS DBB set-ups, and I thought they used Garrett CHRAs. I know on Supra Forums, the few guys that tried DBB GT Turbos abandoned them do to smoking, and or Oil related failures. There must be a good fix. My concern is that these are signs of incorrect oiling of the turbo, and that the solutions people are using may in some way compromise the life of the turbos.

Basicly, WE NEED AN ANSWER from Garrett. Didn't somebody(Stephen?) post the actual Garrett reccomended specs on oil pressure for these turbos? Has anyone with a GT DBB measured oil pressure immediately before, and after the turbo? Why does ATP, undeniably a leader in developing Garrett DBB GT turbo set-ups use a flow(NOT PRESSURE) restrictor if Garrett recomends against it as Sean says? Clearly ATP has had more success than anyone else, has anyone called them? Seems like Enzo ought to be able to solve this one as well. I don't own one(too poor, and conservative), but I would if we could get these bugs worked out. Carl

ghostrx7

I would try just venting to atmosphere like I did, simple fix. Attach 3/8 fuel line or what not to the top of the oil filler neck, see if that helps any. I was only running 10 lbs of boost before so that may have been another thing.

Gargamel

I tried that but blowby caused oil to shoot all over my windshield and engine bay. It's nasty.

rotarypower101

iTrader: (1)

Yesterday I was playing around with mine again trying to figure out exactly what I want to do about this situation.
I am running stage 3 oil mods from pineapple, and the loop line, so my pressure will be higher than normal I am assuming. Running –3 from the vertical oil feed galley to the turbo, I took a pressure measurement at the beginning of the turbo 90* inlet with an inline gauge and at idle I was reading a pressure of ~60-65Psi and as I approached 2000RPMs the gauge I was using maxed out at 100Psi so I will have to go get a higher rated gauge to get any real measurement of max pressure.

Right now I am working on a system that can supply a fairly constant 30 Psi feed with a pressure controlled variable dump valve.

I think SPO has got the right idea, decreasing the crank case pressure seems to be the big issue. Decreasing the restriction of the return and depressurizing the pan fixed my smoking problem substantially.

setzep

if you really want to regulate the pressure to the turbo you're going to need a pressure reducing valve to maintain a constant pressure. A small line or a orifice will only get you in a range where the pressure is just right.

Carl Byck

Does a smaller oroficeALA ATP reduce pressure? I would think it just reduces flow. This is my point Re the DBB turbows, is it a flow issue also?

Marcel Burkett

The more you reduce the flow to the turbo , the higher the line pressure will be , infact it would be exactly what you're engines seeing. Maybe you can somehow rig it to measure the pressure AFTER the restrictor.

rotarypower101

iTrader: (1)

exactly why I wont even consider atps solution! it will only be good in certain line pressure ranges.

rotarypower101

iTrader: (1)

It restricts pressure by restricting the volume of flow over a short distance, and then letting it expand and depressurize back into the pre restrictor volume of flow, causing it to decrease pressure, and decrease flow.

zkeller

iTrader: (47)

Don't mess with the GT40r's oil restriction. It is internally set, talk to Shawn at A-spec.

With my GT40r I had a smoke screen when lifting. I installed two 6AN lines off of the filler neck. One in the stock location and the other on the oil fill cap. I ran both of them to a catch can. I put a filter on the catch can too. Oil was spitting out of the filter, so I ran a second catch can and moved the filter to it.

Running 22PSI of boost the first can fills up quick. I can get as much as 16 ounces every few hundred miles out of the can.

I was told this is totally normal running high boost. The crankcase pressurizes and there is not alot you can do about it, but vent it through the filler neck. The smoke you are seeing at high RPMs is related to the abrupt pressure change in the crankcase pushing oil past the turbo oil seal.

If you do not catch it, you will have oil all over your car.

twokrx7

iTrader: (1)

If you are filling a can in a few hundred miles you have issues. I ran many miles on my Innovative dual bb turbo around 19 psi with no tailpipe smoke and never built up over 1/4" of oil in the catch can.

Gargamel

Mine spits out lots of oil too.

nyt

iTrader: (1)

most blowby issues ive seen have been from poorly clearanced side seals.

i might not be environmentally friendly, but i dont have that much blowby. i just run a hose from the top of my oil filler neck under the car. doesnt leave any drips..

Carl Byck

Sorry, but this seems all wrong. Zkeller, Even running ~30psi, I don't get more than an ounce or so of oil. I use a large JAZ can, and it has a breather about twice the size of the ones on the greddy can for example. Anyway, like I said previously, why is ATP using a restrictor, and Sean not??? IT DOES NOT MAKE SENSE. Also, there is no way that much oil should be blowing by the seals. You guys are band-aiding a problem IMHO, good luck.

MFilippello

iTrader: (2)

this is where I am at with things. It does not seem right that I should be getting this much blowby. If the brown stuff is normal, then what is it? is it mostly fuel and by products from combustion mixed with a small bit of oil? Carl, did you also corner hard? did you notice any more fluid in the can from hard conering? was your fluid like mine or just pure oil?

In regards to the turbo smoking, it only does it after getting on it after a hard corner. I can boost on and off all day long while driving straight and it wont smoke. Make a hard corner(right handers mostly but it has done it on a hard left as well) accelerate hard out and as soon as I let off I get a smoke screen. It could be the brown stuff filling the vent lines and clogging up the vent untill it gets all the way to the can. This temporary blockage is enough to spike the crankcase pressure and make my poor sensitive turbo cough up.

I think the reason I filled up my container so qickly was three fold. I think excess crankcase pressure combined with good suction from the turbo and hard connering all added up to fill the can with a lot of this brown stuff. I am going to run just vented to atmosphere and see if it fills less quickly. This will eliminate the suction part of the equation. I want to drop one variable at a time. If it works better while still cornering hard, then I'll just leave it vented to atmosphere.

The thing that puzzles me is that my catch can is full of this brown stuff but the oil in the pan is perfectly clean. How is the contaminated fluid that comes from the crankcase only in the catchcan but not in the crankcase?

also I run evans so there is no water in my coolant.

MFilippello

iTrader: (2)

This fators in also. My compression after rebuild was 6.5/7.5/7.5 on the front rotor. This would indicate a bad side seal or improper clearanced corner seal. The end result would be excess problems like I am seeing. I just don't know how much of this is normal and how much is problamatic. I did not have this issue before rebuild but had a different turbo then also (rx6b). I also did not have a catchcan. My vent was only from the filler neck to the suction side of the turbo. I could have had the brown stuff and would have never known. I think though I would have still smoke from injesting the oil and burning it in the combustion chamber as opposed to having it burn at the turbine.

nyt

iTrader: (1)

the oil in your catch can isnt from oil blowing by the seals, thats what happens when your motor smokes.


whats happenning is under boost, the air/fuel mixture is pressurizing the crank case due to poor sealing. most often from poorly clearanced sideseals. what youre seeing in your catch can is air/fuel/oil mixed.

when this pressure builds too high, it pushes the oil past the oil seals also, creating smoke from your exhaust since its being burnt.

I'm not a fan of using a turbo inlet for suction for positive crankcase vents, i find venting to atmosphere the best solution.

having restrictors in your crank case vents is something i never heard of and dont know why someone would do that.

Also, if you have so much blowby its generally an engine related issue.

All these fancy catch cans are exsessive. a simple hose from your crank case (i run mine from top of the oil filler neck) to a soda bottle or something will suffice.. i just let mine hang under the car. then again, my sideseal clearancing is tight and i generally dont have that much blowby

Carl Byck

The brown stuff is fuel, and oil emulsified, like oil, and vinager dressing after you use a blender(motor) to combine the two. I road race, so plenty of hard cornering. Check with Mazda Comp, but I know Many racers that run 1/2 quart, or more low on oil to reduce this problem. I don't do that, since I dont get much oil, but I know a bunch of third gen AX guys that do. You may be right about cornering putting oil into a line it would not ordinarily be in, but I have not seen this personally. Still, way too many people are having this general issue(rotary, and piston), I think we need a statement from Garrett about it. The only community that is not talking about this(from what I have read) is the Audi/VW community(ATP customers primarily), Thus all my questions relating to them. Carl