supercharger Q

I'm no expert but doesn't the supercharger bypass valve kind of act like a blow off valve? Releasing pressure off the supercharger, where a blow off valve releases exhaust pressure from the turbo. I could be absolutely wrong here.
 
do they make an aftermarket blow offvalve for the thunderbirds


or can i buy one and make one
 
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And what exactly do you feel the purpose of such a device on your car would be? I'm curious what motivates such a question.

In the stock configuration, all of the air that enters the supercharger is metered air. Thus if you "blow off" any air that's under pressure you are leaking metered air which will have quite a negative impact on the EEC-IV's ability to handle control of the fuel/air mixture.

you would have to dramatically change how either air is metered, or how the EEC-IV calculates proper fuel/air mixture.
 
Mike8675309 said:
And what exactly do you feel the purpose of such a device on your car would be? I'm curious what motivates such a question.

In the stock configuration, all of the air that enters the supercharger is metered air. Thus if you "blow off" any air that's under pressure you are leaking metered air which will have quite a negative impact on the EEC-IV's ability to handle control of the fuel/air mixture.

you would have to dramatically change how either air is metered, or how the EEC-IV calculates proper fuel/air mixture.
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what do you think, he wants the pshhh sound like the little civic boys
 
no i was just wondering if u could get one.... or they make one .. im just trying to see what they make for the t bird.. because i dont want to mess anything up so im trying to cover all my bases.. this is my first SC im buliding

my first one i just drove it like i stole it

i just want to make an SC monster thats it
 
umm you kind of jumped around the question of why you would want that on your car and it seems you liek the sound of spray on deoderant.

would take too much work and would be pointless. and an "sc monster" takes alot of money and these cars are tempermental.
 
To get back to the actual question:

Yes, you could put on a blow-off valve. Nothing is made specifically for the T-Bird SC, but you could fab something up with a generic BOV.

But:

No, it will not do anything good. Even if you plumb the blowoff back into the intake after the MAF to keep the mixture right.

Why not:

Because, as somebody already said, the bypass valve is sort of like a blowoff already.

And:

Because the SC is tied directly to engine speed and will not overboost like a turbo. Unless you had some crazy overdrive ratio, which is unlikely and almost pointless.
 
ironworker said:
no i was just wondering if u could get one.... or they make one .. im just trying to see what they make for the t bird.. because i dont want to mess anything up so im trying to cover all my bases.. this is my first SC im buliding

my first one i just drove it like i stole it

i just want to make an SC monster thats it
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The SC uses a draw thru MAF to meter the intake air and uses a bypass valve to unload/bypass the supercharger inlet when the throttle is lifted or when the motor is not under enough load to reduce vacuum to the point where boost is required to acclerate.

Even with the bypass valve open the supercharger is still moving the same amount of air (rpm based). Which means it's circulating that air thru the IC and IC tubes and a portion of the air goes back to the inlet side of the supercharger which provides some cooling to the IC and tubes when not operating under boost. Defeating the bypass and using a BOV would also defeat this benifit and cause the intake system to retain more heat. The supercharger will also tend to whine almost constantly and will sound like a powersteering pump that's very low on fluid.

I doubt the BOV would even open unless the bypass valve was forced to stay in the closed position by removing the vacuum hose from the acuator. The BOV is also operated by vacuum ans a spring that has enough tension to keep the valve closed under the amount of vacuum your motor produces at idle. When the vacuum signal (after throttle body) is high enough to overcome the spring pressure, the valve opens and exhaust any positive manifold pressure. Instead of rerouting the metered air back into the inlet side of the supercharger like the bypass valve does, it dumps the air to atmosphere causing the hissing noise that all the kids think is so cool. On a SC, when it dumps the metered air the motor will go temporarily rich.

The BOV is intended for use with a turbo or centrifical supercharger to prevent the excessive air pressure (between blower outlet and throttle body)created by quickly closing the throttle plate, from damaging the blades of the compressor wheel and to keep from blowing the IC tubes off. The reason there is excessive pressure, is because the compressor wheel is still spinning and creating boost and quickly closing the throttle blocks the air path.

David
 
i was just wondering if u could put one on.. im new at this and i just wanted to ask that question.. i just want the best for my motor and i dont want to mess anything up ..

thanks for the info...
 
ironworker said:
i was just wondering if u could put one on.. im new at this and i just wanted to ask that question.. i just want the best for my motor and i dont want to mess anything up ..

thanks for the info...
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No problem with asking questions, that's how we all learn stuff about these cars.

David

PS: You might also want to reduce the size of the picture in your signature.
 
David Neibert said:
Instead of rerouting the metered air back into the inlet side of the supercharger like the bypass valve does, it dumps the air to atmosphere causing the hissing noise that all the kids think is so cool. On a SC, when it dumps the metered air the motor will go temporarily rich.
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I think you could avoid the mixture problems by plumbing the BOV back to the inlet side, just like you said. That's what a lot of turbo users with MAFs do. I hear that you can still get some exciting "whoosh" noises by plumbing it in close to the air filter. But, anyway, the bypass valve is already doing the same thing, so I don't think it's a good use of time and money. Also, like you said, the BOV would probably never even do its thing unless you also blocked off the bypass, which would create extra heat and SC wear and reduce your mileage.
 
ironworker said:
can u put a blow off valve on a supercharger... i know its a stuped Q
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Hi,

Okay in all seriousness, that's a neat idea, but these cars were made more for the 'suprise factor'. It was engineered as a quiet vehicle that is intended for all-day high speed.
Most folks who advertize their modifications won't know what's coming when they give us the look at a lite and rev their engine at us. Then, when they get a car length ahead, and we dump the clutch in second gear, they go: "holy s++t!".

If you want more noise, you will get a little more by simply removing the Intake Silencer located inside the passenger wheelwell... My car makes a noticeable "hisssss" at/above 2000 RPM now after taking that out....
Do a search, and you will be pleased with the result of removing that I aam sure!

paul:)
 
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