I want to hear how much louder the stock BOV sounds when it vents while it's disconnected to the corresponding hose.

QUESTION: Is it safe to disconnect both BOV's ? If not, which one should I disconnect? The one closest to the front of the engine or the one in the back nearest the manifold? Thanks for your advise and comments.

 

if you use a filter, then yes

the rear "bov" is for venting secondary turbo pressure when you are < 4.5k rpms, it's called a charge relief valve

the front is the BOV, you can vent it, but keep in mind, it sucks air in under vaccum, so i would put a filter on the end

 

Placing a filter (small autozonish type?) on the end will mute the loud venting sound I'm trying to achieve, right?

 

not really

 

93BlackFD: Did you incorporate this system on your FD?

 

I have had both my BOV and CRV vented with small K&N filters on then for over a year now. I didn't notice a difference in the noise level with a without a filter.

 

I ran my BOV for about a month open before getting an aftermarket anyways, I had no problems and no oil dirtying up my engine bay either. Stock BOV sounds good though, the CRV won't make any noise though, at least not that I noticed.

 

Can you post the part number of this filter and where you bought it?
Know a good website that sells these filters?

 

for about 3 days until i realized how pathetic it was, then i ordered a FMIC with a HKS SS BOV welded onto the piping

if you want your car to make cool noises, step up your budget and run with the big boys

 

I'll try the PO Mans' version first and then decide if I want to splurge on an aftermarket bov. Thanks.

 

My Apex'i BOV took a **** on me and now I'm running two stockers. I like to think of myself as one of the big boys.....wanna run ?

 

How does that saying go...?; If it ain't broke.......

 

that's your fault for buying an Apex'i cheap bastard

 

The only blowoff valve I would ever buy would be an HKS SSQV. Also, and I have always wonderd this, how are you suppose to hook it up with the twins. It would only make since, having an efficient set-up, to have 2 bov's. Would you just 'T' the lines with a single bov?

 

The BOV is not SUPPOSED TO SUCK air under vacuum - IF it Sticks open It MAY suck air , but it is designed as a One Way flow valve.

 

The stock sustem only has ONE BOV the other bov looking valve is the CRV and functions quit differently from the BOV. When running NON-SEQUENTIAL (like Rich is) the CRV can be plumbed to operate as a second BOV.

 

Excuse my ignorance please , but what does the CRV do differently from the BOV? I had mine routed to "atmosphere" and it was pretty loud. I think I'm going to get a turbo xs unit. What Aftermarket bov's are you guys running?

Matt

 

93blackrx : I don't think it does anything different.... It just does it at different stages of boost. From what I've read here in the Forum, the CRV functions only after the second Turbo has kicked in which should occur on or about 4500 rpm. And the CRV only "protects" the second Turbo from back pressure. So I think it also acts as a pressure relief valve just like the BOV hooked to the first turbo. I may be wrong!!

 

the bottom bov is good enough, but it sucks when your driving around on vaccum around 5-1. whats wrong with venting it in the air box? i think its more sleeper.

 

scratchjunkie : There's obvoiusly nothing wrong with the stock/original BOV hook-up to the air box, but it muting effect on the BOV when it releases back pressure. Therefore, venting the BOV (disconnecting it from the hose to air box set up) creates a louder sound when the BOV does its job. Makes for a cool sound!!, .. And it's very cost effective when you compare the price of aftermarket BOVees that function in the the manner. The only plus is that some aftermarket BOV's can be adjusted for specific pressure relief.

 

The CRV vents the excess boost from the 2nd turbo PRIOR to Transition, when the CCV (charge control valve) is closed blocking the 2nd turbo outlet, The BOV opens when the throttle is closed suddenly under boost at any engine speed and any turbo operating condition, primary transition or secondary, preventing Compressor SURGE. They (either the CRV or BOV) DO NOT function to control boost in any way. The BOV is controled by a Vacuum hose connected directly to the LIM without any intervention from the ECU, The CRV is controlled by the ECU via the CRV soleniod.

 

maxpesce: Thanks. Great explanation!!

 

What would be considered excess boost? It sounds like it acts as a pre-spool wastegate?

 

For the best explaination I will answer the ?'s In reverse order.

No, not quite - remember the CRV is only open when CCV is closed so the CRV provides the ONLY outlet for the Second Turbo's Compressor prior to transition The CRV actually closes a split second PRIOR to the CCV opening to deliberatly SURGE the 2nd turbo up to 120,000 rpm (aprox 10-20% over speed) to prevent excessive boost drop when the CCV opens. In essence prior to transition it is acting as a 0psi Pop Off Valve for the second turbo. The major Functional Diff between the CRV and the BOV is that the CRV is controlled by the ECU and only vents the Second Turbo Prior to Transition and the BOV is not ECU controlled and vents either THe PriTurbo (pre Transition) or BOTH turbos (post Transition)
The Turbo PRE-CONTROL Valve (TPC) acts as a WASTE GATE for the PRIMARY turbo - It vents some EXHAUST to the second turbo prior to transition (as long as the primary is producing at least 8psi boost) reducing the spool up time @ transiton b/k the turbo is already spinning at 50-60% of it operating speed.


In this case excess boost is really ANY Boost, the CRV opens a soon as the TPC opens and starts the 2nd turbo spinning

 

So much confusion about something so simple...