hey, i was playing in the miata.net forum today (looking into a turbo for the daily driver ) anyway, they were having a discussion about filtering your BOV's. EVERYONE there said filtration is a MUST, as when you are at vacuum you suck air in through the BOV since its open and you are at vacuum, which makes complete sense to me. they also proceded to say that we are stupid people who blow engines on a regular basis because of stuff like this (PS dont shoot hte messenger ). anyone care to comment on this?? just something i thought id bring up, but it probably has been talked about before... anyway, thanks

 

if your turbos are working properly, they should be blowing out a bit at idle. this should not be a problem for most of us

btw: yes vaccum after the throttle body but you should have a bit of boost/airflow before it.

in anycase, i would really not worry about it, i would be more sacred of running too lean and popping my engine that way, 999 out of 1000 fd owners pop their engines becuase of this

the other 1/10 of 1% probally suck up a bolt off the manifold or off the turbo which came free and sucked it in and blew their engine like that

 

mmm....i thought that most BOV's if they had a Vacuum they seal themselves off...hmmm. how would you filter it anyway?? place a filter inside the hose? or wrap a k&n around the BOV??

 

What skunks said... my turbos are good and my blows out a bit at idle( because of the vacuum opening the BOV)

 

Stock BOV is open at idle. It is an inexpensive piece so they traded that performance trait (closed at idle) for being cheap. Plus by dumping the air into the stock air box it makes it quiet. Aftermarket BOV do not have this problem. I used a filter on my stock BOV ... back in the day.

 

hmm so it DOES have some truth? ive been running w/out a filter on my stock BOV for some time....... i will plug it back into the airbox now or get a filter

as far as this not being a problem with an aftermarket BOV can you elaborate? it should function just like a stock one if im not mistaken.......... im thinking about like a greddy type s, but they are all relativly similar in functionality

 

Aftermarket block off valves use springs to hold a valve shut. You adjust the spring or you shim the spring to adjust the BOV. This helps you set the BOV for your car and application. I have no idea what is inside the factory BOV. All I know is that it is open at idle and the factory spec is for it to open at 250mm/Hg which is about halfway between idle vacuum and atmospheric pressure. So by design it is open at idle ....

 

The stock BOV has a rubber diaphram and a spring inside . You can change the spring and have the thing closed at idle . The tip it and low end responce is better . My mechanic has done this and the people with them can tell the difference . extacy7 reported on his modified valve several days ago .

 

The miata guys are obviously being ******** towards FD owners. It just seems that everyone that isnt an enthusiast about RX7's or rotary is out to put us down. Not a problem for me cause I don't care what anyone else says. But its just from a few things they have seen or heard about so it doesn't even really matter. So what if we blow engines all the time, which it isnt true all the time, we can still beat them! I don't even give them the satisfaction of responding to comments like that given by someone in public or even on a forum for that matter anymore, so I wouldn't even worry about it yo!

 

i just though it was funny that we are viewed by the miata folks like that! true we can tear them a new one, but you have to admit their engines do last much longer, and i have seen some crazy things done to those little 1.8L engines......

anyway, i was just posting because i was worried about sucking dirt into my engine (which i am apparantly doing at idle) so back the BOV goes onto the airbox.... i liked the sound but i dont care either way really

and just as a side note: i was on the miata forum trying to find some more info on a DIY turbo instalation for the miata.... i have an extra set of broken twins that i want to put to use so i figured i could just rip the primary off and use it on its own.... apparantly corksport makes a turbo manifold that may work so im happy ....im just going to be using left over parts from the FD (turbo, intercooler, etc) for the setup..... i hope for there to be a little of the FD in every car i drive

 

just some miata stuff for fun.... mods feel free to move this thread where ever

 

look familiar?? well very close at least

 

If the stock blow off value is in the stock location, it can't suck air into the motor at idle...turbines spooling will force air out of the BOV (VERY very little air, but it's still pushing out)

I can see if the BOV is moved after the IC where you do "see" vacuum at idle the BOV could suck air thru

 

Ive seen guys running single turbo setups with no air filter on the turbo... they seem fine.. i wouldent worry about your bov opening a little at idle unless your autocrossing around a gravel lot

 

Gee and people wonder why old forum members don't hang around anymore ... obviously we don' know anything ....