S&B Breather Filter, or PCV Hose to RAI?

[Svashtar]

I got the kit from Jay but haven't installed it yet. I was concerned about running too rich, but think I will install it and then try and get the car dynotuned to see how it's doing.

I had a question for whoever, and it makes more sense to install it in this thread than over at the Garage I think.

I opted for the optional $10 S&B breather filter from Jay, that screws onto the valve cover PCV. Jay says this keeps oil out of the intake, which obviously makes sense now that there is no direct connection. Plus it is a very nice looking little breather filter. He had initially sent me a standard RAI with the 90% elbow for the PCV valve cover hose, but quickly sent me a replacement RAI tube with no fitting when I pointed it out to him.

I mentioned this setup to another forumite, and he informed me that I would be better off with the standard PCV hose setup, as that creates vacuum in the crankcase, which in turn adds horsepower to the car. (?) He said that breather filters used to be used in Nascar apps, until they determined that the standard PCV hose into the intake setup created significant crankcase vacuum which in turn helped performance. (Of course those are what, 600 HP cars?)

He said he uses a Steeda $59 oil seperator instead to make sure no oil gets to the intake, and to monitor the amount of oil running through the PCV hose.

So, I'm polling the experts here. Would I have been better off from a HP standpoint to use the standard valve cover to RAI hose, or will the valve cover breather filter work about the same?

Thanks for any input!

Regards,

Norm

 

[Tucker]

He said that breather filters used to be used in Nascar apps, until they determined that the standard PCV hose into the intake setup created significant crankcase vacuum which in turn helped performance. (Of course those are what, 600 HP cars?)
Norm

These are 2 totally different animals with 2 totally different purpose'.

I would be willing to bet money there is NO HP difference on the dyno or the track.

 

[FordNut]

I got the kit from Jay but haven't installed it yet. I was concerned about running too rich, but think I will install it and then try and get the car dynotuned to see how it's doing.

I had a question for whoever, and it makes more sense to install it in this thread than over at the Garage I think.

I opted for the optional $10 S&B breather filter from Jay, that screws onto the valve cover PCV. Jay says this keeps oil out of the intake, which obviously makes sense now that there is no direct connection. Plus it is a very nice looking little breather filter. He had initially sent me a standard RAI with the 90% elbow for the PCV valve cover hose, but quickly sent me a replacement RAI tube with no fitting when I pointed it out to him.

I mentioned this setup to another forumite, and he informed me that I would be better off with the standard PCV hose setup, as that creates vacuum in the crankcase, which in turn adds horsepower to the car. (?) He said that breather filters used to be used in Nascar apps, until they determined that the standard PCV hose into the intake setup created significant crankcase vacuum which in turn helped performance. (Of course those are what, 600 HP cars?)

He said he uses a Steeda $59 oil seperator instead to make sure no oil gets to the intake, and to monitor the amount of oil running through the PCV hose.

So, I'm polling the experts here. Would I have been better off from a HP standpoint to use the standard valve cover to RAI hose, or will the valve cover breather filter work about the same?

Thanks for any input!

Regards,

Norm

If you use a breather instead of connecting to the intake tube, you are connecting an unmetered intake air source to your intake manifold, affecting the MAFs ability to accurately measure air going into the engine. I would not use a breather, not for power reasons but for tuning reasons.

 

[Svashtar]

FordNut, thanks very much for your input, but I am missing something. I'm not disconnecting the MAF, all I am doing is removing the crankcase ventilation hose from the system and replacing it with a standalone breather. The engine will still get the same or more air, and it will still go through the MAF, correct?

As far as I know there is no meter or sensor in the PCV valve cover to intake hose that provides feedback to the system. The only thing that could possibly change is that there might be less of a vacuum pull in the crankcase now, which I am willing to concede, the question being will that have a negative factor on horsepower? Or will the crankcase have a problem venting just as well as it used to?

I like the idea of eliminating any source of airborne oil from the intake, as that theoretically anyway means that I will have to clean the TB less down the road, but wanted to double check as I am no mechanic.

Thanks,

Norm

 

[Brutus]

If you use a breather instead of connecting to the intake tube, you are connecting an unmetered intake air source to your intake manifold, affecting the MAFs ability to accurately measure air going into the engine. I would not use a breather, not for power reasons but for tuning reasons.

Even if you plug the hole on the intake tube?
I thought only positive crankcase pressure was vented into the intake as configured on a stock setup. The positive pressure comes from blow-by gasses from combustion, which comes from metered air. It was my understanding anyhow.

 

[FordNut]

Both valve covers have connections. The drivers side is the inlet and there is no PCV valve on that side. The passengers side is the outlet and it is connected thru the PCV valve to the intake manifold after the throttle body, thereby going directly into the heads, cylinders, etc. If you are connected to unmetered air on the drivers side, the PCM can not accurately balance the air-fuel ratio since it is not able to measure the air going into the engine.

I have not studied this enough to know what is done with supercharged cars, since there is a positive pressure in the intake during boost situations. I do know some people (on other forums) add a check valve in line with the PCV valve.

 

[Marauderjack]

Disabling the PCV system is asking for premature engine wear!! :help:

The PCV system was developed many years ago by the military and was not designed to reduce emissions.....The military doesn't care about emissions!!

The system was designed to extend engine life by "sweeping" unburned fuel and moisture out of the crank case....By doing this the oil lasts much longer and is not diluted by "Blowby" fuel and moisture!! :bows:

In race cars it makes no difference since the engines are basically run at WOT and don't have the vacuum required to make a PCV system operate (most use vacuum pumps to seal rings and "sweep" crank case gases)....Also race engines are only designed to last a few hours....thus oil changes...bearing life...etc. are not a factor. Our "Street/Drag" cars are designed to run a looooong time at less than WOT constantly.....So be careful when you mess with the PCV system!!

My $.02???

Marauderjack :bandit: