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Ok I know this is a noob question but I couldnt really find any conclusive information on the net, but is it possible to hook up a blow off valve to our Cobalts (SS S/C) even though they use a supercharger instead of a turbo? Would it have negative effects or would it help out? I love the sound of blow off valves on decent cars (SRT-4s, 95-99 Eclipse/Talon Turbos, Supras, 3000GTs etc) and think it would be cool to have on the Cobalt. I know that with a turbo the blow off valve helps with acceleration but not sure if it would work with our superchargers and if it did if it would still help... any positive feedback would be appreciated, thanks guys.
 

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Not sure about where to get one but they basically do what they are called, they release pressure while shifting or lettin off the throttle so yo udont blow it to smitherines. I would like to have one to replace the stupid diverter valve things.... :rolleyes:
 

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well the bov or dv doens't help with acceleration if it is VTA = vent to the atmosphere the air in the upper ic pipe is released via through the BOV, to prevent it from slamming into the throttle plate.

if its is recirculating the bov releases the air back into the intake track on the turbo to keep it spooled between shifts.

if i remember right it is possiable to put a DV on a superchaged application, but im not sure of how it can be set up on a SS.
 

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only cause i like you guys.... thats all...lol
 

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Novtec1 said:
if its is recirculating the bov releases the air back into the intake track on the turbo to keep it spooled between shifts.
Not always. For instance, VW uses diverter valves on their 1.8 Turbos. They do so because they run MAF sensors. The DV comes after the MAF in the intake piping. So, if the throttle were to close, the pressure would vent to atmosphere but the MAF would still think the air is there. This would result in a super rich condition. You can by blow through mafs for 1.8Ts, but it isn't worthwhile just for the VTA sound.

Also, IIRC, the SS has a factory diverter valve. It'd have to have some means of regulating pressure.
 

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figures.. VW has to do something weird
 

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JDMCivic said:
Also, IIRC, the SS has a factory diverter valve. It'd have to have some means of regulating pressure.
Exactly, and it limits the boost, if someone could do a pcm cal and get rid of that stupid boost limitation it would be fine. But as for now, I dont like em...
 

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You dont need it on an SS and I really dont think you can use one anyways, because the SS has a roots type blower than doesnt use charge piping like a turbo or centrifugal s/c. The boost diverter valve is kinda of the same as a BOV, but theres no reason/need/way to upgrade it.

And the BOV is used to vent pressure after the throttle is closed so whatever boost is left in the charge piping doesnt reverse and slam back into the compressor (NOT the throttle plate) of the turbo or centrifugal s/c and cause compressor surge, which could cause massive bearing damage. Although turbo Buicks have gotten away without them, which is always an interesting point.
 

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MY GTP 8 U said:
The boost diverter valve is kinda of the same as a BOV, but theres no reason/need/way to upgrade it.
Unless you run crazy boost. But, by then, someone will have developed a stronger aftermarket component anyway.
 

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And the BOV is used to vent pressure after the throttle is closed so whatever boost is left in the charge piping doesnt reverse and slam back into the compressor (NOT the throttle plate) of the turbo or centrifugal s/c and cause compressor surge, which could cause massive bearing damage.
i knew i wasn't crazy...

taken from: http://sr20det.nismo.org/basicsofturbos.htm

and i quote:

You're under boost, the turbo is fully spooled, and life is good - then you shift. That means that you foot comes off the gas - and the throttle plate slams shut. Suddenly, instead of flowing in a continous stream through the engine, the intake air smacks into a closed throttle plate. The turbo, which is still spinning and producing boost because if it's rotational inertia keeps producing pressure, and the intake stream, caught between a rock and a hard place, jumps in pressure. In fact, you get a high-pressure shockwave that travels from the throttle plate back to the compressor vanes, that once it gets there, is a little like poking a stick into the spokes of a bicycle wheel.


so the sockwave is the after effect of the throttleplate closing.... man.. i knew i wasn't crazy ..

so the PRIMARY reason is:like i stated above
 

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Reread what you posted. The excess boost hits the throttle plate and bounces back into the compressor. The compressor is what gets damaged, not the throttle plate. DVs and BOVs are used to protect the compressor.
 

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sheesh guys ok...whats the purpose of a bov.. to prevent the air from hitting the throttle body causing a shockwave that will damage the compressor wheel..

better?
 

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Novtec1 said:
if its is recirculating the bov releases the air back into the intake track on the turbo to keep it spooled between shifts.

yeah the porsche cars blow back into the intake.. it's pretty effecient. most of the subaru/imports just blow back into the atmosphere which is useless unless you just want to hear a sound
 

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selfinfliction said:
yeah the porsche cars blow back into the intake.. it's pretty effecient. most of the subaru/imports just blow back into the atmosphere which is useless unless you just want to hear a sound
All cars with MAF sensors blow back into the intake. It isn't needed with a MAP sensor.

As someone mentioned, you can purchase blow by MAFs that allow the MAF sensor to be moved back to incorporate a BOV that vents to atmosphere.
 

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Novtec1 said:
i knew i wasn't crazy...

taken from: http://sr20det.nismo.org/basicsofturbos.htm

and i quote:

You're under boost, the turbo is fully spooled, and life is good - then you shift. That means that you foot comes off the gas - and the throttle plate slams shut. Suddenly, instead of flowing in a continous stream through the engine, the intake air smacks into a closed throttle plate. The turbo, which is still spinning and producing boost because if it's rotational inertia keeps producing pressure, and the intake stream, caught between a rock and a hard place, jumps in pressure. In fact, you get a high-pressure shockwave that travels from the throttle plate back to the compressor vanes, that once it gets there, is a little like poking a stick into the spokes of a bicycle wheel.


so the sockwave is the after effect of the throttleplate closing.... man.. i knew i wasn't crazy ..

so the PRIMARY reason is:like i stated above
This doesn't happen on roots type supercharged applications because once you release the throttle the supercharger stops making boost that instant not like turbos or centrifugals that keep spinning and making boost. Roots type superchargers are positive displacement units.
 

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could be done but you would need to create some type of "tank" to hold the air and than relase it all at once to make the noise

a roots type SC does not make boost it moves air, the air is than compressed in the intake manafold. so as soon as you let off the throttle the SC stop pushing air, unlike a turbo which does not stop making boost in no throttle conditions as long as it was already spolled up i will keep making it, and that amount of air need to be vented to not cause damage to the engine.


And the moral of the story

Roots Type SC DOES NOT NEED A BOV, could prob make one up that would make the noise but than i would have to call you a ricer. because it would make NO power gains at all
 

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navymitch12 said:
Roots Type SC DOES NOT NEED A BOV, could prob make one up that would make the noise but than i would have to call you a ricer. because it would make NO power gains at all
:confused: This is coming from someone with "Silverstar exterior lighting","Boost and A/F Gauge pillar 'like totally mounted 'instead of say sitting in your lap'" :confused: ,"APC Grill front and rear" and worse of all "Carbon Fiber Corner Lights" as part of their listed mods.

hyp·o·crit·i·cal ( P ) Pronunciation Key (hp-krt-kl)
adj.
1. Characterized by hypocrisy: hypocritical praise.
2. Being a hypocrite: a hypocritical rogue.
3. Being named Mitch and threatening to call other people ricers.





PS your car looks sharp :D
 

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navymitch12 said:
could be done but you would need to create some type of "tank" to hold the air and than relase it all at once to make the noise

a roots type SC does not make boost it moves air, the air is than compressed in the intake manafold. so as soon as you let off the throttle the SC stop pushing air, unlike a turbo which does not stop making boost in no throttle conditions as long as it was already spolled up i will keep making it, and that amount of air need to be vented to not cause damage to the engine.


And the moral of the story

Roots Type SC DOES NOT NEED A BOV, could prob make one up that would make the noise but than i would have to call you a ricer. because it would make NO power gains at all
Roots blowers do make boost. Boost is the amount of pressure above atmospheric in the intake manifold. It's all boost, whether it's turbo, centrifugal or roots type. Your entire engine moves air.
 

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My car- 2001 Black Camaro Z28- Mods- SSF 3500, SSRA, Transgo shift kit, Direct Flo Lid, Ported TB, MTDR, Lakewood LCAs, and some other stuff.
its about time sum1 gets a little since and stops spendin 10 grand on civics and integras and all them imports to get em into the 12's when u can spend 2 grand on Z28 ,like darrik , or a mustang GT to get them into the 11's i meen come on people love the cobalt SS and Srt-4 neons but come on get some since.
 
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