Open crankcase breather or closed: effect on gas mileage

[aldive]

The validity of using a open ( to the atmosphere ) crankcase breather or the stock closed one came up in a previous thread (http://www.explorerforum.com/forums/showthread.php?t=197445&highlight=breather ).

I have been using the open breather for quite some time with no problems whatsoever.

Since I had to make a quick trip down I75 to Naples and back ( 100 miles each way ), I decided to conduct a little test.

The first leg of the trip was with the open breather and the return leg was with the stock system.

Each leg was driven as close to 70 MPH as possible. The fuel used was BP 89. The computer tune was one I developed for maximum mileage.

Results

The first leg yielded 30.4 MPG whereas the second leg netted 30.2 MPG.

This brief experiment show that neither breather system yielded better mileage; both were virtually identical.

The only difference that I determine is a much cleaner TB when using the open breather. I shall continue its use.

 

[frickea86]

nice, there have been very many disputes and discussions about this, awesome results

 

[muzzymaniac]

You do a lot of great testing Al! Thanks

And check your PMs!

 

[gijoecam]

Ditto. Thanks, Al!

Just another thing to note: In some states, the PCV system is considered a part of the emissions system, and tampering with or modifying the emissions system may cause the vehicle to not pass your state's inspection. Modders Beware... Don't say we didn't warn you.