hey I got a question
does your car run (idle) with the BOV vented to the atmosphere
and if so how ???
whats your vacuum at reading?

 

It shouldn't idle, because the stock BOV opens at ~12inHg of vacuum, and your engine should idle at at least 15inHg.

Don't listen to anyone who suggests a check valve to get around this problem. Restricting its flow is hardly a good idea. If you're determined to open-vent the stock BOV, do this instead.

 

thank you for the reply nzconvertible
but when I disconected my BOV just for a try
the car behaves the same as if stock (connected)
just the that air/fuel mixtures gets little richer

 

It still idles at 750rpm? If it does, you must have low compression (causes weak idle vac) or a faulty BOV. Like I said, it should be open (and causing a huge vac leak) if the manifold vac is 12inHg or greater. What does your boost gauge read at idle?

 

get a stock fd bov then you can open air have it vented to the atmosphere. Think FC stock bov uses it as part of the vacuum but fd doesnt.

 

The FC and FD BOV's work exactly the same and are used in exactly the same manner. The FD's BOV opens at even less vacuum (~9inHg) so it'll cause exactly the same problem.

 

nzconvertible my vacuum at idle is strange

when I start up the car it idles at at 16 inHg
but when driving for a good half hour or longer
it drops to like 13- 14 inHg

 

NZ...I have my BOV vented to the atmosphere via a 1" check valve. It idles perfectly, but I want to know if there are some down sides to this besides running rich during shifts.

-Joe

 

That sounds perfectly normal. Cold idle should be a little higher than normal, hence the higher vacuum.

If you know what a BOV does, then you should know that restricting its flow is not a good idea. Check valves designed for use in plumbing are very restrictive when used in an air system.

 

Not this check valve...when open, the opening is the size of the stock BOV outlet (about 3/4"). It just depends if you get a shitty valve or a good one.

-Joe

 

Sorry to hijack the thread, but I only see about 12HG of vacuum with my 650rpm idle i have set now. I have a new reman motor with about 750km on it, starts everytime, revs smoothly, but i have the check valve on the bov. do you think that this is the source of a vacuum leak?

ryan

 

hey guys, if i replace the stock bov with an aftermarket one that vents to the air, and put a plug where the stock bov returns back to the intake, this vac leak is obviously eliminated with a properly adjusted bov?

 

Yes. You adjust it so it's just kept closed at idle.