This is a stupid question im sure... but can u gain or lose any performance depending on the type of bov u use? and why are some louder then others?

 

the BOV relieves pressure. i'm pretty sure you don't lose performance. And you can amke you BOV sound like anything you want. People hook up tricycle horns to them sometimes.

Of course you already know the SC's don't use BOVs, but yeah, tehre are different 'types' but they all do the same thing.

 

mmm plz tell me this isnt for your ss/sc... unless your turboed.
the bov is just meant to release the pressure built up in your intake. some are louder because they're designed to amplify the sound. as far as i know they dont gain/ lose any performance

 

well the reason im asking is... my cousin has a 1.8 turbo gti... he said the guy at the car shop he went too told him, the louder it is, the less performance his car would get...

no its not for my friggin car.

 

ahaha thank god, i didnt mean to sound rude by how i said it, you just never knwo nowadays! the tone is given by how the opening is shaped/ some are designed for a stealth sound while some are designed to make your presence known. shouldnt hurt his performance

 

in a sense, the guys shop is correct.

the louder it is = the less performance.

let me explain why.

The louder it is, is relative to the smaller the opening...the air is trying to go through a small opening which causes the sound. (unless hooked up to a turkey call, or anything else people do).


the best performance BOV is a large opening. you really shouldnt hear anything at all unless you got your ear by it...

but, in short.

Small opening = less amount of air to escape at any amount of time = back pressure on the turbine wheel = boost lag.

Large Opening = more amount of air to escape at any amount of time = free spinning turbine wheel = less boost lag.


However, the change is so minimal, its nothing to worry about. However, the change is measurable (if you were a all time drag pro champion with thousands of hp/tq..and even so its measured in the .00X range).


So tell your cousin to get whatever he/she wants, because it literaly wont make a difference on such a small scale turbo settup found on the GTI.

Besides, the shop owner is an idiot. Best performance is from a Recirculating Bypass Valve.

BOV = Releases air into the atmosphere...
RBV = Releases air back into the intake system (up stream of the MAF)...

BOV = Releases already computed air (from the MAF)...so the engine will bog down a bit when the air...because its trying to accomodate the more air with more fuel...but the BOV made the air go bye bye...so its just dumping fuel in...

RBV = releases the air into the intake stream, which is better for the car's computer, because the pressure doesnt change...so the MAF can accurately calculate the amount of air being inserted.


RBV's generate no sound, however, there are some dual's which are a Recirculating bypass valve, with a blow off valve...you will only hear the BOV if the pressure is too great for the RBV.



I hope that helped.

 

awesome write up man

 

holy shizzle. Im going to copy and paste that in an email to him. thanks

 

TCarter FTW! haha

 

x2! TCarter rocks!

 

yeah, a recirculating bov would be beneficial on a maf controlled car. but if the vehicle only has a map, then it doesnt matter. but sound is produced by how the air escapes the valve opening. take the hks ssqv, you can change out the inserts at the nose for changing the sound (i personally like the stock set up that it comes with, which ill be running on my saturn). gfb has different horns you can put on a few of their bov's to completely change the sound it makes. oh yeah, know too that a bov should be placed near the throttle body.

now valve sizes on external wastegates can be performance robbing.

 

/bow

 

I have also herd that the pressure in some high HP applications can surge back hard enough that it will actually reverse the turbine and will reduce your turbo's life greatly. It is like throwing your car in reverse while going 20mph over and over. BOV's and RBV's are necessary IMO.

 

The 1.8t should not be used with a blowoff valve. The boost MUST be recirulated through the use of a diverter valve.