Crank case vent - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


DIY Turbo Discussion greddy on a 1.8? homebrew kit?

Reply
 
 
 
LinkBack Thread Tools
Old 03-06-2009, 01:11 PM   #1
Junior Member
Thread Starter
iTrader: (6)
 
Join Date: Feb 2009
Location: Salinas, CA
Posts: 446
Total Cats: 1
Default Crank case vent

I am probably over thinking this, but better safe than sorry. In my searches I have found that I should use a geniune Mazda 88 323 turbo pcv valve. My other question though is the left side of the engine breather. Does it matter how close I mount the fitting to the turbo? Or do I want to keep it as close to the MAF as possible? Thoughts?


Name:  turbo12.jpg
Views: 7
Size:  41.6 KB
I suck at MS Paint
Qckslvr is offline   Reply With Quote
Old 03-06-2009, 01:43 PM   #2
Elite Member
iTrader: (5)
 
m2cupcar's Avatar
 
Join Date: Jan 2005
Location: Atlanta
Posts: 7,244
Total Cats: 291
Default

That would work. Seriously consider adding a catch can in line though - just as an extra measure to keep the oil vapor out of the intake, compressor, ic...
m2cupcar is offline   Reply With Quote
Old 03-06-2009, 02:05 PM   #3
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,367
Total Cats: 1,331
Default

Vent it to atmosphere.
Savington is offline   Reply With Quote
Old 03-06-2009, 02:24 PM   #4
Senior Member
iTrader: (4)
 
Join Date: Oct 2006
Location: Tampa
Posts: 780
Total Cats: 0
Default

Quote:
Originally Posted by Savington View Post
Vent it to atmosphere.
+1

I got one of those cheap mini breathers from pep boys and put on the tube.

Whatever you do, don't block it off. Ask me how I know that.
96rdstr is offline   Reply With Quote
Old 03-06-2009, 02:42 PM   #5
Senior Member
iTrader: (2)
 
Join Date: Jun 2007
Location: Shalimar, FL
Posts: 965
Total Cats: 7
Default

Quote:
Originally Posted by 96rdstr View Post
+1

I got one of those cheap mini breathers from pep boys and put on the tube.

Whatever you do, don't block it off. Ask me how I know that.
Going VTA will prevent pressurization issues like shooting the dipstick through the hood, right? But couldn't it also be a major boost leak if the PCV goes bad?

...actually...would there be any disadvantages to going VTA on both sides of the valve cover and block off the PCV port on the intake manifold?
messiahx is offline   Reply With Quote
Old 03-06-2009, 03:25 PM   #6
Elite Member
iTrader: (10)
 
Join Date: Oct 2008
Location: Seattle, Wa
Posts: 1,780
Total Cats: 30
Default

Quote:
Originally Posted by messiahx View Post
Going VTA will prevent pressurization issues like shooting the dipstick through the hood, right? But couldn't it also be a major boost leak if the PCV goes bad?

...actually...would there be any disadvantages to going VTA on both sides of the valve cover and block off the PCV port on the intake manifold?
There is no inherent disadvantage there, except for not being "street legal" due to the PCV system being required by law to meet emissions. If you are going to do that, gut the valve though, or just replace it with a barb fitting.
Jeff_Ciesielski is offline   Reply With Quote
Old 03-06-2009, 05:37 PM   #7
Junior Member
Thread Starter
iTrader: (6)
 
Join Date: Feb 2009
Location: Salinas, CA
Posts: 446
Total Cats: 1
Default

Looks like question answered. I will tap the pipe and plug it. I can then VTA for 2 years, and hook it up for smog.
Qckslvr is offline   Reply With Quote
Old 03-06-2009, 08:10 PM   #8
Junior Member
 
Join Date: Dec 2007
Posts: 159
Total Cats: 0
Default

there is one thing that I think you guys are over looking here. by placing that second breather on the exhuast side in the inlet tract you are effectively creating a vaccum in the crank case. which helps to reduce pumping losses, helps the turbo drain and can help to curb oil burning issues. I've seen many a guy with a turbo having to put a restrictor in the oil line to try to stop oil getting past the seals when simply routing that vent to the intake would stop it and give your turbo more oil. there is a reason race engines often use vaccum pumps to increase H/P. it works.


here this was taken from GZ motorsports website:

"All engines create a certain amount of "blow by" (leakage of compressed fuel and air past the rings into the pan area). The "blow by" airflow created creates pressure in the crankcase, the vacuum pump "sucks" air out of the crankcase with its "negative" airflow. The net difference between the air low being "sucked" out and the airflow being "blown" in by blow by yields vacuum. If the airflow being "sucked" out is less than, or not much more than the air flow being blown in, the vacuum pump is not creating enough "sucked" airflow to eliminate pressure in the crankcase or to create adequate vacuum to not only stop leaks, but to create horsepower.

Typically smaller engines generate less "blow by" and donít require as "big" of a vacuum pump as large displacement engines. However the addition of low tension ring packages, power adders such as Nitrous Oxide, Alcohol, Blowers or Turbochargers (and the ring and piston types, clearances and modifications that go with those power adders) will increase crankcase pressures requiring either a "larger" pump or to spin a "smaller" pump slightly faster. The following guide is based on our experience of testing vacuum pump airflow rates and typical crankcase pressures found in racing motors. "


now in theory your pcv will do this, but when in boost it quits and that is when it is most important .
dynokiller90 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Need help - Stock Balancer and Fastforward overlay pulleys Frank_and_Beans Supercharger Discussion 13 09-12-2016 09:17 PM
My solution for Oiltemp and Oilpressure input into Megasuirt (MS3) Zaphod MEGAsquirt 41 01-24-2016 01:25 PM
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 PM
Missing/knock at idle, can someone point me in the right direction? Mikel MEGAsquirt 4 09-28-2015 05:46 PM
Got bad Crank Angle Sensor and Random Misfire codes, but runs fine. Greasyman General Miata Chat 2 09-28-2015 11:44 AM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 09:15 AM.