Does anyone know of a good not hugely noisey blow off valve, im pushing just a bit over 420 horse at the flywheel and it was recommended to me to go with an aftermarket BOV for sound and safty. Does anyone have them and how do they like them. Thanks for the replies.

 

If price doesn't matter, get a name brand BOV... Like GREDDY or HKS.

 

In my opinion i have heard the Apex Twin Chaimber BOV's and they sound really good and you can adjust the sound to how much boost ya pushin, also if not those the get the HKS SSq bov ya can get universals for 3 something or get the kit for the car for bout 5 im getting the apex in a couple of months after i get my car outa the shop.

 

whoever made the recommendation...they're wrong....the stock recirc's are great. Why vent the excess boost when you can recirculate it back to the intake?

 

recirculate <--- stock BOV are great for stock 300zx twin turbo but when u have upgraded its best to upgrade to a same type but newrer model ... if i were u i would try ( HKS ) BLOV but trys these if price is a issue http://cgi.ebay.com/ebaymotors/90-96...37906777QQrdZ1

HKS ? http://cgi.ebay.com/ebaymotors/HKS-S...38304776QQrdZ1

WOW !!! u get free HKS stickers WOW !! :-)

 

aftermarket BOVs DO actually put the recirc into the intake again... the advantage to them is you can set them for higher pressure than stock so you don't waste your boost pressure . ( i am already using a Boost regulator and larger turbos) i am mainly into preserving turbo life and as it was explained to me without the proper BOVs you get a nasty backpressure spike that can over time weaken and deform the blades on the turbo. I just don't know which ones are annoyingly loud and which ones are tried and tested, since they seem to be rather expensive id like to hear some opinions before going back on a Ramen noodle diet.

if you don't beleive me about the BOVs recirc take a look at importsextreme.com and look at pictures of his car under the hood, they are set up right on each of the intake pipes.

thanks for the post on the Greedy BOVs, i also saw the apexi ones for sale for 164$ each...now all i have to do is find someone who has one of each and listen to them i guess.
The Quest continues!

 

well wat ya wanna do on the Apex i know a site to where ya could hear the apex, ya just gota look fo it its streetfire.net, man they sound sick.

 

HKS Super Sequential... it's the ONLY blow off valve that never needs adjustment and cannot (by design) leak.

For what it's worth, you're going to be doing it pretty much purely as a cosmetic-type mod. There are plenty of higher-horsepower Z32's (like mine) that run stock recirculation valves with no trouble.

However, I only run stock recirculation valves because my SSQV's were stolen.

One of the advantages of the SSQV is that it has an adapter (sold seperately) that you can fit onto the opening to turn it into a recirculation valve.

Three different fins available for different sounds too, and none of them are that loud (I loved mine... I admit it).

Yes, the high price is worth it, if you really want a blow off valve. But it also really isn't necessary.

 

From this pic of his... the BOV's ARE NOT recirc:
http://www.importsextreme.com/

 

here's another angle:

 

As stated, stock recirc's are great for modded Z's, stock Z's, etc. BOVs are often just a consmetic mod.

 

BOVs do NOT recirculate the pressure back into the intake. they blow the pressure off to the atmosphere, hence the PSSSSSHT you hear. the recirc valves prevent the backpressure spike exactly like the BOVs. because the Z has stock recirc valves, BOVs are unnecessary, and purely for look at me value. on a car that has no stock recirc valves BOVs would serve a purpose, but are completely unnecessary on the Z.

 

Aftermarket BOV's do not recirc.. I have the Blitz BOVs, they came with the car. But, many BOVs do have adapters that will recirculate into the intake. I would say that it's all in what you like. My Z has the recirc's still in, with the Blitz BOV. Since i'm running the Dual POP charger, JWT makes it necessary to have them for the low speed drivability. Now why Stillen had the BOVs installed, beats me

 

The recirculation serves a performance purpose (among other things)and it is to keep the turbo spinning. When the valve sends that air back rushing into the intake plumbing ahead of the turbo its going to rush through the compressor and keep that wheels spinning between shifts which keeps the car on boost. When you vent to atmosphere you stall the compressor wheel every time and drop back down to 0 boost between shifts. On a drag car this isn't a big deal caue you spend so much time at high RPMS that the you can sustain a decent amount of boost without the aid of a recirc. But on a street car where you're shifting at reasonable RPS's that recirc. really helps. So if you do decide to go with a BOV it would be a good idea to get an adapter to hook up a recir. pipe/hose.

 

Not entirely correct... When you let off the THROTTLE it will go to 0+ boost (actually vacuum) no matter what. And the BOV keeps the compressor from stalling even if it vents to the atmosphere... THAT'S IT'S ENTIRE JOB. True, if recirc, it will keep it spinning faster, but only a small amount.

 

good stuff to know, upon futher reading on the subject the recirc valves do just about the same job as the Blow off valves, releive excess pressure during shifts and decelleration. the BOV vents it to atmo and the recirc dumps it in the intake. Im pretty sure the BOV opens and closes at certian pressures and from what i read about them you can set that threshold making them slightly more tunable than standard recirc valves. Plus they do make a pretty neat sound. i heard the HKS ones if anyone has seen the short movie "Gettaway in Stockholm 2" they can get a good idea of what they sound like. Its a 20min long flick of a exhibition race between a modded late model supra turbo and a Cosworth. pretty interesting.

 

You can also hear them pretty good in the new Maxima commercial but I'm not sure why they used the sound of a turbo car in a Maxima commercial. Anyone else catch that?

Rod.

 

Actually the main purpose of the blow off valve to save the turbo from destroying itself. It's meant to stop blow back from demolishing the compressor wheel and/or thrust bearing. But to get totally technical the original intended purpose of the BOV was actually to prevent boost levels from rising high enough to blow out I.C. end tanks and intake hoses. It was a safe guard. Of course it had many other benefits that we now use it for. I do admit I was wrong in saying it stalls the compressor wheel. I honestly dont know why I put that.