Breather cap question

[RFMustangGT]

You can get twist in caps like the cap I posed earlier in the FRPP catalog to fit your 60's era valve covers. Contrary to what others may say (I've run open breathers and closed and stopped after learning how exactly the PCV system is set up and works) you cannot use a PCV valve and the open filtered breather cap. The reason is the PCV draws air from the crankcase, and with a closed cap the air from after the MAF is diverted to the crankcase to prevent a vacuum and to put fresh air into the crankcase in place of the corrosive vapro laden air drawn out by the PCV. This is a 1 for 1 swap so the air fuel ratio is not thrown off. If you run an open filtered breather cap the air is drawn out of the crankcase, and unmetered air is drawn into the crankcase along with 100% of the intake charge. This extra air leans the air fuel ratio. The computer can only compensate so much with the adaptive fuel strategy (adaptive fuel limits) , if the A\F ratio goes too far out of tolerance you're pinging.
Tim

Thanks! now I know what to do!

 

[juiced_94gt]

I used another FRPP number for my breather, same deal tho...Just run a 3/8" line from the cap to your CAI...just like the stock oil fill line used to run to your factory rubber inlet...

part#m-6766-g302 is like mine, push in type for a "closed" crankcase...depends on your style of VCs..

Another shot...just run a line to your CAI...I only run one breather...the drivers side is blocked...

2 things, first off your car is AWSOME and number 2: what kinda camera do you use and at what resolution? your pictures are amazing also.

 

[RIO5.0]

Thanks...
The camera is a Canon A10 Powershot, 1.3 mp.. I got it with a Dell PC I ordered....I paid a tad over 100.00 for it with the PC...Nothing fancy but it works well..
I take the pics at 1280/960 or large resolution, to get good clarity, then re-size to fit em on here to 715/536 or so..

 

[rio95]

You can get twist in caps like the cap I posed earlier in the FRPP catalog to fit your 60's era valve covers. Contrary to what others may say (I've run open breathers and closed and stopped after learning how exactly the PCV system is set up and works) you cannot use a PCV valve and the open filtered breather cap. The reason is the PCV draws air from the crankcase, and with a closed cap the air from after the MAF is diverted to the crankcase to prevent a vacuum and to put fresh air into the crankcase in place of the corrosive vapro laden air drawn out by the PCV. This is a 1 for 1 swap so the air fuel ratio is not thrown off. If you run an open filtered breather cap the air is drawn out of the crankcase, and unmetered air is drawn into the crankcase along with 100% of the intake charge. This extra air leans the air fuel ratio. The computer can only compensate so much with the adaptive fuel strategy (adaptive fuel limits) , if the A\F ratio goes too far out of tolerance you're pinging.
Tim

I do agree with you, but if you plan on tuning it, I think it is just fine. I am still undecided on what set-up to run with my turbo. Could I run a line from the stock valvecover to my fox TB or can you not do this with boost?? This would boost the crankcase wouldn't it?? Now what if you put a check valve in a line from the stock cover to TB??

Right now (without turbo) I just ran a line from the stock position to my BBK CAI and have my fox TB plugged, with a PCV.

 

[18mustangs]

I do agree with you, but if you plan on tuning it, I think it is just fine. I am still undecided on what set-up to run with my turbo. Could I run a line from the stock valvecover to my fox TB or can you not do this with boost?? This would boost the crankcase wouldn't it?? Now what if you put a check valve in a line from the stock cover to TB??

Right now (without turbo) I just ran a line from the stock position to my BBK CAI and have my fox TB plugged, with a PCV.

When we get into boost my expertise begins to wane! However, keeping the PCV system with the check valve seems like a great and logical choice to me. Is this check valve similar to a blow out valve where if the pressure exceeds a given amount it vents to the outside?
Tim

 

[rio95]

When we get into boost my expertise begins to wane! However, keeping the PCV system with the check valve seems like a great and logical choice to me. Is this check valve similar to a blow out valve where if the pressure exceeds a given amount it vents to the outside?
Tim

No, a check valve simply allows something (fluid, air..) to flow only in one direction in a line. Most use a diaphram that opens when there is pressure on one side and then closes when there is pressure on the other side.