I was just wondering how loud the blow-off valve on the Cobalt SS supercharger is. Is it really loud or kind of on the quite side? Because a friend of mine has a some SE Jetta that comes stocked turbo and the blow-off valve isn't that loud, it sounds kind of wimpy.

it doesnt have a blow off valve
most superchargers dont, *most*
and at a low psi that they run at. its not really needed

I talked to someone about putting one on before I really had much information on superchargers, and I guess it's actually just more work that necessary, and it doesn't really do much for it. They're mainly needed on turbos.

Well, on most factory boosted vehicles they dont use blow off valves. those are mainly aftermarket equipment. they use bypass valves that are used with vacuum lines and such, a lot cheaper than installing a bov on every car.

THe Supercharger on the SS has a bypass valve that is controlled from the coputer by a solenoid to open ans limit boost to 12 or 12.5 psi.......

it doesnt have a blow off valve
most superchargers dont, *most*
and at a low psi that they run at. its not really needed

Well your partly right.

Rootes based superchargers don't need a BOV because the throttle plate is before the blower. So when you let off the gas the throttle plate closes and no air gets to the compressor to create any boost. So there is no excess boost to that needs to be vented.

Most of the time cruising on the hiway at lower throttle the boost guage is at negative 10-20. Open the throttle and it hits 7-12.5 almost instantly.

http://auto.howstuffworks.com/question122.htm

Good stuff on there. Theres also a good article on differentials (Open, LSD, etc)

Well, on most factory boosted vehicles they dont use blow off valves. those are mainly aftermarket equipment. they use bypass valves that are used with vacuum lines and such, a lot cheaper than installing a bov on every car.

The Blow Off Valve & Compressor Bypass Valve (CBV's) terminologies are often used interchangeably. Ie. My talon came with a CBV stock but is most commonly referred to as a BOV.

Aftermarket BOV's also use vaccum lines to actuate the diaphragm - for turbos anyway.

recirc>bov

yes it is all the same concept is to vent air when letting off the throttle when under boost to releave the pressure in the intake system...

i get so use to calling bypass valves the same as BOV and it is a bad habbit but it is all the same and yes on roots they use a plate system...

on turbo and centrifigul blower they are bypass valve (when stock) and BOV when modded and higher boost. also when driving around the motor is in vaccumm and keeps the bov/bypass venting air and when WOT the vaccuum is lost closing the BOV/bypass and creating boost...

Most cars will run 22-15 Hg in vaccuum when driving around in part throttle. now on a NA motor you motor will say at 0 hg/boost in the WOT runs

that is because the throttle butterfly is open...ie no vaccum, all air

The By-pass valve on your M62's are to reduce parasitic drag. When you are not giving the car throttle the bypass opens up so the charger only requires about 1/3 hp to spin. Making the motor more efficent out of boost. On the Cobalts they electornically controlled it in order to keep you from raising the boost levels. Keep it at what they feel to be a safe level.

:lol: :lol: :lol: :lol: :lol: :lol: :nono:

"slaps head" :)

The Blow Off Valve & Compressor Bypass Valve (CBV's) terminologies are often used interchangeably. Ie. My talon came with a CBV stock but is most commonly referred to as a BOV.

Aftermarket BOV's also use vaccum lines to actuate the diaphragm - for turbos anyway.


They are basically the same but because of where they vent to it's a good practice to keep the names seperate

By-Pass will vent back into the intake after the Air Filtrer

Blow-Off will "Blow Off" out of the intake system.

only ricers care about how loud a BOV is :)

only ricers care about how loud a BOV is :)


Or people such as myself who just love driving a car that has no sound killing so every little noise in the car is heard. It's like music to me...

http://www.msprotege.com/members/Brian%20MP5T/New%20Stuff%20For%20UL%20-%20(27).jpg.jpg

Nice looking setup man.

dude, the blowoff on the ss is crazy...

its like... vroooooomm SPOOOOOOOOSH!!!! vrooooooooom SPOOOOOOOOSH!!!!

it's crazy!!!!!!

Nice looking setup man.


Thanks, It's easy to keep clean if you never drive in the winter. It took a couple of years to get it to this point...

Or people such as myself who just love driving a car that has no sound killing so every little noise in the car is heard. It's like music to me...

you ricer! wheres your Twin SSQ RFL BOV? :lol:

my original comment was directed at people with boosted cars who go out and buy the loudest BOV they can find as their first mod just so they can have the cool sound. :thumbsdow

its like... vroooooomm SPOOOOOOOOSH!!!! vrooooooooom SPOOOOOOOOSH!!!!

it's crazy!!!!!!


:lol::lol::lol:

you ricer! wheres your Twin SSQ RFL BOV? :lol:

my original comment was directed at people with boosted cars who go out and buy the loudest BOV they can find as their first mod just so they can have the cool sound. :thumbsdow


Kewl... :twothumbs

roots type chargers dont use a blow off valve...they dont build boost that way... they have a bypass valve to...which is good, it means your car will run like it was NA...and then it closes when you floor it...and BOOOOSSSSSTTTTTTT

roots type chargers dont use a blow off valve...they dont build boost that way... they have a bypass valve to...which is good, it means your car will run like it was NA...and then it closes when you floor it...and BOOOOSSSSSTTTTTTT


That valve could be allowed to vent rather than Re-Circ but that would sound cool but be really dumb.

Basically...

You want TURBO sounds... Go Get a Turbo...

That valve could be allowed to vent rather than Re-Circ but that would sound cool but be really dumb.

Basically...

You want TURBO sounds... Go Get a Turbo...


Or get a centrifugal SC :cool:

or get this :lol:
http://www.sunamiturbo.com :lol:

what is the purpose of blow off valve anyways? is it just a wastegate that make a sound?

or get this :lol:
http://www.sunamiturbo.com :lol:

:lol: :lol: :lol: :lol: that has to be one of the funniest things ive seen in a while!!

it doesnt have a blow off valve
most superchargers dont, *most*
and at a low psi that they run at. its not really needed
most is right..... only centrifugal superchargers, or a boost source before the throttle body needs them.... since on the ss, the throttle body is first, they are pointless. The main purpose of a blow off valve is to bleed off boost after the throttle is in the closed position, this allows the boost to escape, rather than back up into the turbo, they basically prolong the life of the turbo, by releasing the pressure, rather than the pressure comming back to the turbo.....

what is the purpose of blow off valve anyways? is it just a wastegate that make a sound?
vent excess boost to protect the engine either recirc or open

does not have a BV it has a nice whine to it tho:twothumbs

what is the purpose of blow off valve anyways? is it just a wastegate that make a sound?


Vent Charge Pressure in a TURBO setup to maintain the Spool and Kill Lag between Shifts.

A Wastegate is a completely diferent part.

does not have a BV it has a nice whine to it tho:twothumbs

The SS SC DOES have a BPV.