i'm in a debate with a buddy of mine. he is saying that a turbo will be no fun without a BOV. i'm saying that it's probably nice to be a total sleeper without it. he is saying yes that's true but, after a while you'll want to hear that psshhhh sound of the BOV.

one kit that i was looking into offers a recirculating valve (i believe that's what it is) it was said that it doesn't make the sound of a BOV but, more of a fludder.

one tuner was saying that with a BOV you constantly loose boost psi when shifting where as with a recirculating valve you don't loose that psi and the turbo doesn't have to build it back up.

so my question to those of you with and without the BOV is, does having the BOV make it more fun when driving a turbo or s/c'd car and hearing that pssshhh sound? and if you have a recirculating set up is it sweet that you can be a sleeper without the BOV sound?

 

The purpose of the BOV is to discharge air being pushed back towards the turbo during shifts to prevent compressor surge which can damage a turbo after time. So it is more of a reliability thing than it is a "cool thing to have".

But, IMHO I like the sound of a blowoff valve alot (why most people choose one BOV over another). A recirculated valve shouldn't flutter more than an open blowoff valve. It just depends on the type of bov used, the tightness of the spring, and amount of boost/load on the motor that creates the flutter.

You really don't loose psi through a shift from an open atmosphere bov, and if you do it is not noticable. The reason alot of cars need a recirculated bov is so it doesn't mess with the MAF and cause the engine to stumble (3000GT VR-4's have had trouble with this). Most stock cars come recirculated because of the noise. It is alot quieter than open.

 

As 002-M-P stated, a blow-off valve is necessary to prevent compressor surge when the throttle butterfly closes.

A recirculating blow-off valve simply vents the air back into the intake piping after the MAF, which usually muffles the sound.

The sound issue is a personal one. I don't particularly love the sound and I hate the ******** who hammer the throttle in front of my home just to sound cool. I would much prefer a recirculating blow-off valve myself, because everybody thinks the Z is slow, and I prefer to leave it that way. I don't need anymore attention from the police anyway.

 

Doesnt' the APS have a combo setup; Recirc at lower psi, and blow-off at higher boost? That sounds like the best of both worlds. The stealth when your just crusing, but the fun sounds when you hammer it.

 

Also bov in my opinion is much like aftermarket exhaust and body kits. If you compare 3 or 4 kits with comparable price, quality and performance gains, it comes down to how that person thinks it sounds or looks to decide to buy it.

I guess in short: To each there own.

 

A recirculating valve (no longer BOV) will not be as loud as a BOV but it will make darn near the same ammount of noise. In the subie world most of us keep the stock recirc-valve and take out the intake silencer or throw on a short ram. The sound between shifts is still there and it is still loud. The only real difference between a recirc and BOV is the ammount of fuel that will be added to the motor between shifts. Depending on the tune your car will do different things between the two. As far as subies go, when a BOV is put on the car runs rich between shifts and if catless likes to afterfire. This actually slows the car down (very little). If your buddy has the APS kit tell him to keep the APS dual vent BOV. It is one of the quietest valves on the market and is puts air back into the intake at low boost, and at high boost it vents to both intake and atmosphere. A good BOV/recirc-valve will not loose pressure under boost.
It is also possible to not have a BOV/recirc. But it is loud as h3ll and not the best for your turbo. My Grand National didn't come from the factory with one and I havn't installed one. When I let off the throttle it is one of the loudest/scaryiest sounds most people will ever hear.

Nick

 

You do not need a BOV to Vent to the atmosphere to gain that "turbo" sound that everyone wants. It also depends on the BOV that you use. Greddy type S is loud, and will be heard recerculating or not. With an HKS, probably the same, but these i've never really seen with a recirculation kit, although HKS does make such a kit. I had an evo8 before my Z, and all i did was put an open element K and N filter setup on it, and you could hear the stock BOV even. Then again, the proximity of the BOV to to the filter is very close on and evo, in comparison to a FI Z. But to make a long story short, you'll noticethe BOV regardless....

 

If you want a loud BOV get teh turbo XS RFL (really fu*kin loud).

Nick

 

Get a recirculating valve. Its the healthiest thing for a FI engine, and your can still be fast with out being noticably furious.

 

that's what i was thinking and i think i'm going to go with that set up instead.

 

Which kit were you thinking about getting that has a bypass valve? I know the JWT kit is coming with two of them they claim.

 

What do you basis this statement on? Unless the BOV is leaking or improperly mounted in the wrong location, it should make no difference in terms of engine longevity or health. The only reason that many factory cars run recirulating BOV's is so that they can pass smog. The EPA doesn't like it when any gases escape from an engine, even though there little chance of pollution being expelled from the BOV. The reason the APS kit run recirc....is so they too can have a shot at passing CARB.

As long as the BOV is placed prior to the MAF, the car should run, idle, and cruise exactly like normal.

 

Do anyone have a pic of the proper placement for a Greddy type S prior to the MAF?