DIY: Dual Oil Catch Cans 370Z

sixpax · 08-25-2012, 03:26 PM

Quote:

Originally Posted by wstar

Don't recirculate the catch can fluids back to the oil pan, it's a bad idea. It's not just oil trapped in them, it's also blowby gas and other vaporized crankcase gasses, which means it's got a high amount of both raw fuel and combustion byproducts (carbon, etc) blended into it. Just smell it once when you're dumping the cans and you'll smell the fuel in it (and as noted above, it picks up a bit of water vapor too).

(Also: you'd be creating a vacuum leak and/or another PCV flow path if you hooked up open drains back to the oilpan, too).

Indeed ... the whole point of doing them to start with was to keep all that stuff out of the motor. Seems a bit defeative to collect them just to put them back in. It is really not that hard to empty them, and only takes a few minutes.

Vichtz · 08-30-2012, 01:21 PM

So I'm a noob at this sort of thing, but if this can is catching all of this oil, where was it going in the first place? Seems like just wasting alot of oil. It didnt recirculate back into the engine?

wstar · 08-30-2012, 01:35 PM

Without a catch can, it does recirculate back into the engine. But it goes in through your intake and gets burned as part of combustion. Either way you lose the volume in the oil pan (which shouldn't be much, a few oz's every few thousand miles or whatever).

37Z · 09-21-2012, 07:56 PM

Any idea of the pressure level in the PVC lines before/after the dual oil catch can?

sixpax · 09-29-2012, 06:56 PM

Quote:

Originally Posted by 37Z

Any idea of the pressure level in the PVC lines before/after the dual oil catch can?

I'm not a scientist, but I would guess no change. Lines are longer after, but I figure the pressure is all the same.

Vichtz · 08-30-2012, 05:07 PM

Oh ok, that makes sense. But does that mean that combustion will not happen as intended with the cans installed? Sorry, just tryin to get a feel for this

sixpax · 08-30-2012, 05:38 PM

Quote:

Originally Posted by Vichtz

Oh ok, that makes sense. But does that mean that combustion will not happen as intended with the cans installed? Sorry, just tryin to get a feel for this

The blow by is created after (and by) combustion ... so no impact on combustion whatsoever.

wstar · 08-30-2012, 07:55 PM

It means your combustion (and whole upper end, really) will be slightly cleaner, because you're not tossing oily vapors back into the intake to be re-burned. Improves octane by 0.00001% or something probably, too.

In a nutshell:

(1) Why is the crankcase ventilated? If the crankcase wasn't ventilated, you'd get oil leaks at the engine seals due to pressure buildup.

(2) Why didn't Nissan just design it to ventilate to open air instead of recycling it into the intake? Emissions reasons, the EPA doesn't like you ventilating oily vapors.

(3) Why doesn't Nissan install a catch can from the factory, thus meeting EPA *and* not putting dirty oil vapors into the intake? Because you usually have to empty a catch can even more often than you change oil, and if you let it go too long and fill up, the liquid oil will get sucked into your intake via vacuum while the car's running, and that's *really* bad. Most people have a hard time even changing their oil on time, there's no way a consumer car can have catch cans from the factory. They'll just fill up and dump into the engine anyways, possibly catastrophically. Keep in mind cornering/braking/accel G-forces will make the fluid in the can crawl up the walls. You have to keep the level low enough to not walk up to the vacuum line and get sucked in as liquid. Good can design can help with those problems.

Vichtz · 08-31-2012, 08:30 AM

alright that really clears alot up. thanks guys

lastblueprint · 09-01-2012, 08:50 PM

I'm currently looking to do this mod in my car....what are some companies you guys might recommend?

As far as this thread goes, I like this dual can design.....Good job SIXPAX

sixpax · 09-06-2012, 04:31 PM

Quote:

Originally Posted by lastblueprint

I'm currently looking to do this mod in my car....what are some companies you guys might recommend?

As far as this thread goes, I like this dual can design.....Good job SIXPAX

Saikou Michi

... link is at the beginning.

PapaJFresh · 09-18-2012, 10:07 AM

What happened to all the pretty pictures?

All I see are broken links....

sixpax · 09-29-2012, 06:52 PM

Quote:

Originally Posted by PapaJFresh

What happened to all the pretty pictures?

All I see are broken links....

Must have been temporary, I see them all.

spearfish25 · 10-05-2012, 08:57 PM

Can you just run the lines to a point under the car and just let the overflow oil and vapors drip/flow out? I don't give a **** if the EPA doesn't like it. Would be simpler than the cans.

sixpax · 10-06-2012, 07:38 AM

Quote:

Originally Posted by spearfish25

Can you just run the lines to a point under the car and just let the overflow oil and vapors drip/flow out? I don't give a **** if the EPA doesn't like it. Would be simpler than the cans.

You would get a CEL and a crappy idle if you ran it open like that.

08-30-2012, 01:21 PM	#2 (permalink)
Vichtz Track Member Join Date: May 2012 Location: Unknown Posts: 538 Drives: PG 09 Nissan 370z Rep Power: 16	So I'm a noob at this sort of thing, but if this can is catching all of this oil, where was it going in the first place? Seems like just wasting alot of oil. It didnt recirculate back into the engine? __________________ очень быстро ... Stillen Gen 3 CAI// Stillen CBE// B&M SS with PWJDM Shift Knob// Custom OCC// Drilled/Slotted Rotors//Halo/painted Headlights// Under-hood dress up

08-30-2012, 01:35 PM	#3 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3596	Without a catch can, it does recirculate back into the engine. But it goes in through your intake and gets burned as part of combustion. Either way you lose the volume in the oil pan (which shouldn't be much, a few oz's every few thousand miles or whatever). __________________ 7AT Track Car! Journal thread / Car setup details

09-21-2012, 07:56 PM	#4 (permalink)
37Z Enthusiast Member Join Date: Jun 2009 Location: Florida Posts: 476 Drives: 370Z MB 6M -sold Rep Power: 265	oil catch cans Any idea of the pressure level in the PVC lines before/after the dual oil catch can?

08-30-2012, 05:07 PM	#6 (permalink)
Vichtz Track Member Join Date: May 2012 Location: Unknown Posts: 538 Drives: PG 09 Nissan 370z Rep Power: 16	Oh ok, that makes sense. But does that mean that combustion will not happen as intended with the cans installed? Sorry, just tryin to get a feel for this __________________ очень быстро ... Stillen Gen 3 CAI// Stillen CBE// B&M SS with PWJDM Shift Knob// Custom OCC// Drilled/Slotted Rotors//Halo/painted Headlights// Under-hood dress up Last edited by Vichtz; 08-30-2012 at 05:09 PM.

08-30-2012, 07:55 PM	#8 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3596	It means your combustion (and whole upper end, really) will be slightly cleaner, because you're not tossing oily vapors back into the intake to be re-burned. Improves octane by 0.00001% or something probably, too. In a nutshell: (1) Why is the crankcase ventilated? If the crankcase wasn't ventilated, you'd get oil leaks at the engine seals due to pressure buildup. (2) Why didn't Nissan just design it to ventilate to open air instead of recycling it into the intake? Emissions reasons, the EPA doesn't like you ventilating oily vapors. (3) Why doesn't Nissan install a catch can from the factory, thus meeting EPA and not putting dirty oil vapors into the intake? Because you usually have to empty a catch can even more often than you change oil, and if you let it go too long and fill up, the liquid oil will get sucked into your intake via vacuum while the car's running, and that's really bad. Most people have a hard time even changing their oil on time, there's no way a consumer car can have catch cans from the factory. They'll just fill up and dump into the engine anyways, possibly catastrophically. Keep in mind cornering/braking/accel G-forces will make the fluid in the can crawl up the walls. You have to keep the level low enough to not walk up to the vacuum line and get sucked in as liquid. Good can design can help with those problems. DEpointfive0 and SyndicateZ like this. __________________ 7AT Track Car! Journal thread / Car setup details Last edited by wstar; 08-31-2012 at 09:35 AM.

08-31-2012, 08:30 AM	#9 (permalink)
Vichtz Track Member Join Date: May 2012 Location: Unknown Posts: 538 Drives: PG 09 Nissan 370z Rep Power: 16	alright that really clears alot up. thanks guys __________________ очень быстро ... Stillen Gen 3 CAI// Stillen CBE// B&M SS with PWJDM Shift Knob// Custom OCC// Drilled/Slotted Rotors//Halo/painted Headlights// Under-hood dress up

09-01-2012, 08:50 PM	#10 (permalink)
lastblueprint Enthusiast Member Join Date: Apr 2010 Location: Moreno valley Posts: 273 Drives: 370z 40th ann. Rep Power: 17	I'm currently looking to do this mod in my car....what are some companies you guys might recommend? As far as this thread goes, I like this dual can design.....Good job SIXPAX __________________ 2010 370z 40th Anniversary

09-18-2012, 10:07 AM	#12 (permalink)
PapaJFresh Base Member Join Date: Jul 2011 Location: Tampa Bay, FL Posts: 35 Drives: '11 370Z Tour/Sport Rep Power: 15	What happened to all the pretty pictures? All I see are broken links.... __________________ 2011 370Z 7AT Touring + Sport + Navi \| Stillen G3 CAI \| Berk HFC \| F.I. CBE CF 18" res \| 13.295 @ 102.88 mph

10-05-2012, 08:57 PM	#14 (permalink)
spearfish25 A True Z Fanatic Join Date: Mar 2009 Location: Naples, FL Posts: 4,117 Drives: to work Rep Power: 1858	Can you just run the lines to a point under the car and just let the overflow oil and vapors drip/flow out? I don't give a **** if the EPA doesn't like it. Would be simpler than the cans. __________________ 2013 Cadillac V-Wagon, RIP Z

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