Catch can question
Thread Starter
Instructor
Joined: Jan 2007
Posts: 135
Likes: 0
From: Houston TX
Catch can question
Just installed a catch can I got from Cajun. He took great care of me on the sale. Can anyone tell me how often I should expect to empty it? I don't race or drive really hard, not sure if that matters. Thanks for the info.
Team Owner
Joined: Sep 2005
Posts: 20,352
Likes: 568
From: Ventura County, Calif
No personal experience but here's a discussion to get you started.
http://forums.corvetteforum.com/c6-t...neth-over.html
http://forums.corvetteforum.com/c6-t...neth-over.html
Melting Slicks
Joined: Dec 2006
Posts: 2,694
Likes: 106
What increases oil collection is high vacuum, not necessarily high rpm. Therefore if you do a lot of coasting, it's going to collect more than just high rpm. Bottom line is it's going to depend on your driving habits. I'd pretty much do what you said: check it at 1K rpm, and adjust your interval accordingly.
Team Owner
Joined: Oct 2004
Posts: 27,420
Likes: 64
From: San Clemente CA
We hear different amounts of oil from different owners. Some find lot's oil in a short time and others like me see almost none. I will be removing mine in a few months for my smog test and will take a good look at it then. I will reinstall it after the test. 
Melting Slicks
Joined: Jun 2012
Posts: 2,226
Likes: 1,029
From: Thomas Texas
Why do you say that? My understanding is at high rpm there is more oil mist in the crank case thus more oil in the air going into the catch can.
I drain mine every oil change. I get about a shot glass of oil from just street driving cruising with a few WOT runs.
I drain mine every oil change. I get about a shot glass of oil from just street driving cruising with a few WOT runs.
Safety Car
Joined: Nov 2007
Posts: 4,435
Likes: 874
From: Bay Area CA
There is more oil vapor that gets pulled into the intake at high rpm on deceleration. Vacuum is at the highest on deceleration. At WOT vacuum is at 0. Therefore, oil vapor gets pulled into the intake on deceleration. You are correct at higher rpm more oil vapor is produced, but it needs to be pulled into the intake with vacuum.
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Melting Slicks
Joined: Jun 2012
Posts: 2,226
Likes: 1,029
From: Thomas Texas
There is more oil vapor that gets pulled into the intake at high rpm on deceleration. Vacuum is at the highest on deceleration. At WOT vacuum is at 0. Therefore, oil vapor gets pulled into the intake on deceleration. You are correct at higher rpm more oil vapor is produced, but it needs to be pulled into the intake with vacuum.
Add to that the blow-by at high rpm WOT that pressurizes the crank case and pushes that oil mist out thru the PCV into the catch can.
You are correct that on deceleration vacuum is high and pulls air and oil mist into the catch can.
Safety Car
Joined: Nov 2007
Posts: 4,435
Likes: 874
From: Bay Area CA
Manifold vacuum at WOT is low but not zero. I scan my tune and the MAP at WOT ranges from 94kpa to 99 kpa with 100 kpa equal atmospheric pressure
Add to that the blow-by at high rpm WOT that pressurizes the crank case and pushes that oil mist out thru the PCV into the catch can.
You are correct that on deceleration vacuum is high and pulls air and oil mist into the catch can.
Add to that the blow-by at high rpm WOT that pressurizes the crank case and pushes that oil mist out thru the PCV into the catch can.
You are correct that on deceleration vacuum is high and pulls air and oil mist into the catch can.