First off, this is not an arguement or debate about the virtues of a pcv valve. With that said, I am curious of the consequences to the computer when the pcv is removed or capped. If the PCV valve were to be removed and replaced with a breather and the TBI unit, or throttle body, hole capped, would the car run fine? Since the engine takes in air, although not clean air, from the pcv valve under vaccum, would the tune be off on our cars? Would a new chip need to be burned to compensate?

 

I can't imagine it would cause any computer issues. I would not recomend doing this. But to answer your question, it should run fine.

 

Anyone else? I will be doing a dyno test to compare the stock pcv setup to a breather to see if a breather will make any more power. My thought is that under WOT the engine makes no vaccum, therefor the pcv valve will be closed and the engine can not vent the crankcase gasses, so a breather might make slightly more power under wot. I'm just not sure if it will run right under vaccum with no air coming from the pcv valve.

 

Whereas I see what your saying, and more than likely would not have an effect on your computer, I cannot imagine you would get any gains in power from doing that, let alone actually see any. And on top of that, the car doesn't take vaccume at WOT, which means that the no-vaccume statement would only be good 20% (or maybe a lil' more, depending on the lead-foot) or the time. I'm guessing its a street car, which would mean you would most likely want it working properly. With a breather on it, there would be no vaccume relife(sp?) for the crankcase either, just more of a vent. Now more than likely that last sentance isn't even remotely right, but it makes a lil' bit of sense to me. The way I look at it it was put there for a reason, so I'd leave it to be safe. Be interesting to see actually numbers though. You got an open element? Do one with that on/off and tell us what you see there, too!

Bruce (90RS305)

 

Right, under WOT there should be no vaccum, which means the PCV valve will be closed and there would be no way for the crankcase pressure to escape. There would be no vaccum pulling the crankcase pressure out with a breather, but atleast it would have a way of excaping during WOT. Just my theory, again the real question was about the effect at idle and part throttle, since the engine would be taking in less air and may throw off the tune.

 

https://www.thirdgen.org/techbb2/sho...hreadid=249530

 

Thanks for the link, so I guess no problems with the tune when it is removed?

 

Personally couldn't tell a difference.

I would think it would be better with the intake charge being contaminated with crankcase vapors.

 

25th,

The crank case will still vent at WOT if there is possitive pressure. that positive pressure will open the valve, so you get neutral pressure. Also, rings seal better with some crankcase vacume (read: all that part throttle driving.), I didn't get into it the first time, because you asked specificly not to talk about the pluses and minuses.