Better MPG with lines to intake tube unplugged?

[89Saleen215]

I went on a 800 mile trip with the one pcv line and other line that connects to the intake tube unplugged. My mpg's went up by 2-3 mpg's. Can anyone explain why this happened? Just for fun I did it again today when I went for a 30 mile trip and I was able to repeat the results.

 

[Catmonkey]

You're allowing unmeter air into the engine. In effect, you're leaning out the air fuel ratio.

 

[1320 Junkie]

Whiskey Tango Foxtrot

 

[Black Sex]

How did it not run like crap or throw a code?

 

[19COBRA93]

I'm sure your pistons just loved it. Nothing like an 800 mile burn.

 

[KRS]

It might be a good idea to pull a spark plug or two and see how they look.

 

[Red-GT500]

Mmmm fried pistons in the morning.... I hope you where not doing any boosted runs during that time.

 

[1320 Junkie]

Its almost comical caring about MPG with a big V8 thats supercharged...if thats a concern get a damn Prius dont unplug vaccum lines to lean out the engine...lol.

Sorry had to be said..lmao

 

[celticfdguy]

Nice prius, does it come with a dental dam?

 

[89Saleen215]

No driveability issues, no codes. I failed to hook them back up when I put the CAI back in place after doing some work. I just happened to notice the mpg increase and it just made me curious as to how this was possible without the car running like crap. I mean I pulled some mountains, did some passing, and I might have even run 2 or 4 track sessions that way too. I don't remember when I caught it, but the car ran without any problems.

 

[07 Black Beauty]

To get a little extra boost I sometimes remove my intake and TB completely, it really let's the engine breathe.