thezguy Posted November 10, 2014 Share Posted November 10, 2014 If you are pushing hard enough, even two catch cans (one in each line) is not enough to keep oil out of your intake. For 99% of the world probably would be great. Still not enough for me. Need to keep noodling on this some more as I would prefer not to open vent the crankcase. What is your setup? Where are you pulling From? Quote Link to comment Share on other sites More sharing options...
SUNNY Z Posted November 10, 2014 Share Posted November 10, 2014 If you are pushing hard enough, even two catch cans (one in each line) is not enough to keep oil out of your intake. For 99% of the world probably would be great. Still not enough for me. Need to keep noodling on this some more as I would prefer not to open vent the crankcase. Why do you still have it circulating back into the intake? I put a -10 on each valve cover and ran them to a single catch can. Plug/ cap all other spots on valve covers and throttle body / intake. Works like a charm, and doesn't even mist the engine bay. Why make it complicated? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 10, 2014 Share Posted November 10, 2014 Was thinking of doing the same, the idea being that the stock PCV outlets are too small. Did you weld the AN fittings or just tap for 1/2 NPT? Quote Link to comment Share on other sites More sharing options...
NewZed Posted November 10, 2014 Share Posted November 10, 2014 (edited) On the off-topic problem of oily PCV air in the intake system - wouldn't an air-oil separator, in addition to, or replacing, the catch can, do the job? http://www.grimmspeed.com/air-oil-separator-wrx-sti-lgt-fxt/ http://www.dana.com/wps/wcm/connect/897e0128-2bb5-4371-b991-1c6678c06c25/DEXT2-Publ-MTZ__Oil_separation_e.pdf?MOD=AJPERES&CONVERT_TO=url&CACHEID=897e0128-2bb5-4371-b991-1c6678c06c25 For the budget-minded - http://www.amazon.com/JEGS-Performance-Products-52205-Separator/dp/B007WWW6DI Edit 2 - I guess my direct point would be that if you run a catch-can and still get oil in the intake, you might just need a better design of catch-can. Edited November 10, 2014 by NewZed Quote Link to comment Share on other sites More sharing options...
SUNNY Z Posted November 10, 2014 Share Posted November 10, 2014 Was thinking of doing the same, the idea being that the stock PCV outlets are too small. Did you weld the AN fittings or just tap for 1/2 NPT? I had a buddy weld the bungs on, and fill the un-needed holes. Quote Link to comment Share on other sites More sharing options...
260DET Posted November 10, 2014 Share Posted November 10, 2014 What SUNNY Z said/did. Quote Link to comment Share on other sites More sharing options...
thezguy Posted November 10, 2014 Share Posted November 10, 2014 Or save your money and just run the valve cover vents to the exhaust with a one way check valve.. No smell, no dumping catch cans and the harder you push the motor the more vaccum you get to clear the CC. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted November 10, 2014 Author Share Posted November 10, 2014 Ok, cool. Practically, how do you put a vacuum on the puke can, other than pulling the vacuum from the intake side of the engine? Belt driven vacuum pump? Quote Link to comment Share on other sites More sharing options...
thezguy Posted November 10, 2014 Share Posted November 10, 2014 Ok, cool. Practically, how do you put a vacuum on the puke can, other than pulling the vacuum from the intake side of the engine? Belt driven vacuum pump? I would just use the intake port. Quote Link to comment Share on other sites More sharing options...
98blackbell Posted November 10, 2014 Share Posted November 10, 2014 So could you put that to an unused O2 bung on the exhaust? Quote Link to comment Share on other sites More sharing options...
thezguy Posted November 10, 2014 Share Posted November 10, 2014 (edited) So could you put that to an unused O2 bung on the exhaust? Yup, if they are at a 45 degree angle. I've been seeing more and more High HP turbo cars setup this way lately. It provides a good amount of vaccum even under boost which isn't exactly easy to do. I'll be selling my Catch can and going this route soon. Edited November 11, 2014 by thezguy Quote Link to comment Share on other sites More sharing options...
NewZed Posted November 11, 2014 Share Posted November 11, 2014 The topic seems to have changed to PCV. On that, and its effect on performance, it doesn't get mentioned often that the gases carrying the oil in to the intake system are combustion gases. Depleted of oxygen, so reducing power output. Somebody out there has probably done the math or measurements on how much. An HP or two from an externally vented crankcase might be worth the effort. On the original topic of monitoring vitals, since low oil pressure has immediate effects, an audible warning based on pressure at the pump outlet would seem worthwhile. Kill the engine or let off the gas when the alarm goes off to save cash. Who can monitor all of their gauges second-by-second? Quote Link to comment Share on other sites More sharing options...
heavy85 Posted November 11, 2014 Share Posted November 11, 2014 So could you put that to an unused O2 bung on the exhaust? Thats not legal in most road racing - not sure why but rules. Here's my set-up. I am trying to keep a PCV system but minimize oil in the intake. Only partially successful but get about a cup out of them per track day. Interestingly drain the same from each can. The top port is actually a long diffuser tube that steps down and has small radial holes around it to help condense the vapor. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted November 11, 2014 Author Share Posted November 11, 2014 How do you know you are getting a cup of oil into the intake? Do you pull it after each race and pour it out? I've just been driving the hell out my car for two years...that's why I don't understand this problem. I'm checking my oil level and its doing fine. Quote Link to comment Share on other sites More sharing options...
alainburon Posted November 11, 2014 Share Posted November 11, 2014 Ok, cool. Practically, how do you put a vacuum on the puke can, other than pulling the vacuum from the intake side of the engine? Belt driven vacuum pump? Here is a diagram of how it is supposed to be hooked up. Quote Link to comment Share on other sites More sharing options...
mistafosta Posted November 11, 2014 Share Posted November 11, 2014 I run an open breather setup, (2 -10 lines from the vcs to a breather) but my engine makes 870hp on the low boost setting and should do well into 1k for the higher boost. Most guys run an ls6 breather setup with a oil separator or catch can in line to the intake, which works great for low or non boosted setups. I've never seen issues with oil retention in the heads on an ls engine so I never looked into a return setup for that. Has anyone had that issue with an actual ls engine or is it just spilling over from past experiences of other engines? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 11, 2014 Share Posted November 11, 2014 I've never seen issues with oil retention in the heads on an ls engine so I never looked into a return setup for that. Has anyone had that issue with an actual ls engine or is it just spilling over from past experiences of other engines? Guessing you didn't read the whole thread. Heavy85 has. It's a pretty common problem with autocross and road race LS engines. Drag racers don't put lateral loads on the oil and slosh it up into the PCV tubes. It consumes a lot of oil through the PCV. With stock PCV system one catch can helps, two is better, the LS5 valley Cover integrated PCV doesnt help at all. I'll drain about a cup of oil from the catch cans throughout a track day. If you are on a track where gear ratio keeps you way up in the revs and are on real stickytires, then when you restart it will get a big white/blue oils smoke plume. Freaks you out at first but then realize it just burning off oil condensed in the intake manifold. Quote Link to comment Share on other sites More sharing options...
260DET Posted November 12, 2014 Share Posted November 12, 2014 As a general observation, oil mist with combustion gasses that have blown into the crankcase is not a good mixture to have coming back into the intake, from a performance point of view. heavy85's setup partially minimumises that problem by removing part of the oil mist and condensing it in containers. The amount of condensed oil mist he collects shows just how much is involved, it seems pretty significant to me. But as far as I can tell the setup does not change the amount of combustion gasses removed from the crankcase so it has no influence on lubrication matters compared with stock. Which still leaves me thinking that, other than using a vacuum pump, the only way to improve head oil drain down is to vent the crankcase directly to the atmosphere, and, remove oil from the heads either by external drains or scavenge pumps. Ideally, a vacuum pump if used should draw from the crankcase. Does all that make sense? Quote Link to comment Share on other sites More sharing options...
heavy85 Posted November 12, 2014 Share Posted November 12, 2014 How do you know you are getting a cup of oil into the intake? ......... I've just been driving the hell out my car for two years...that's why I don't understand this As you can see in the pic, there is a drain valve on each can. You need to push harder Quote Link to comment Share on other sites More sharing options...
heavy85 Posted November 12, 2014 Share Posted November 12, 2014 I have to wonder if crankshaft windage is a big contributor instead of head drains. Quote Link to comment Share on other sites More sharing options...
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