on an un-chipped L?

-Sammy

 

A breather cap has no negative affect on AF ratio....it does have an affect on emissions. A breather helps evacuate crankcase pressure on a forced induction car which is a good thing.

Tom

 

That being said, it will most likely throw a SES light for a lean bank on the pass side.....in fact i know it will...been there, done that

 

Yes, a breather cap will affect A/F ratio, because you are injesting air into the motor that is not being registered through the MAF. The result is more air than the computer is compensating for with fuel, and it gets leaner. It doesn't have a huge affect on WOT, however it will skew the part throttle fuel trims, and usually will cause a lean code after some miles.

The funny thing is I've put breather caps on some trucks that never got a code and on others it will. But when we tune chips, we always compensate for the cap if it's there.

 

So if I install a breather only on the oil filler neck, will it only lean the passenger side? Also, does the leaner mixture result in any power gain?

Thanks...

 

Ok lightning tuner, I stand corrected, hehe. Thanks for the info.

Tom

 

After thinking about this, I needed to give some more info., hehe.

I agree that a breather would add more air to the engine if there is a line going from the filler neck to the TB, as there was on my SC'd mustang (I haven't looked really and I am assuming there is one). Lightning tuner, if you remove that line and plug the holes (as I did on my stang), then add a breather, there may be no lean impact on part throttle A/F ratio, etc. Just thinking here and maybe you can shed some light on this.

Tom

 

The PCV line on the same valve cover goes right to the intake. For those who don't want to have their chips reburned, or for those who don't have a chip yet, you can take a 7/16" ball bearing, pop the PCV out of it's elbow, stuff the bearing in the elbow and put the PCV back in. That will block MOST of the unmetered air.

 

Bottom line, if you block off the drivers side tube that leads to the rubber snorkle, you can run all the breather caps you want and it will have NO affect on A/F ratio whatsoever.It only when unmetered air is introduced into the intake (like Sal was trying to say) that a leaner condition occurs.So you were correct, Lightninfun!

 

Sal, can you tell me how to compensate for that cap then? Ill be throwing a cap on with my pulley and plugs, getting a chip reburned @ the Dyno after its on. Will they see the lean condition in that pass side on the a/f's to compensate for it? Thanks

 

Just go with a filter like many of us have...

Edit: I mean an in-line filter (from a compressed air system) That way it remains a closed system.

Coldie