rickyw

lol and im in nc whats that got to do with anything we can sit there and pm or if you have aim we can do that. three heads are better then non and since sheek has had it done and noremorse has some idea i thinki it would be great for this help

Cman06sssc

this thread is like a turd that wont flush.

NoRemorse

got yea, I htought literally help you, which I would if you were within an hour or 2

Witt

That makes sense when the throttle plate is opened to the point that the the manifold is neither in vacuum or boost, basically atmospheric pressure. The blower will only flow 71 cubic feet per minute if the throttle plate allows that much air in the first place. When the throttle plate is closed or nearly closed, such as in deceleration, vacuum exists and those numbers are inaccurate. The less air available for the blower to intake, the less it will exhaust, regardless of speed. Remember volume of air changes under pressure or vacuum. If the supercharger would be feeding the engine more air than it can handle, boost would exist in the manifold and your boost gauge would reflect that. As a matter of fact, the engine would not decelerate at all, it would begin to increase in speed. With the bypass valve open, it allows air to flow from the point of highest pressure (the nearly closed throttle plate) to the point of highest vacuum (a decelerating engine intake). The engine in deceleration creates the higher vacuum by wanting to ingest more air than the throttle plate allows and lower vacuum exists near the throttle plate from the small amount of incoming air passing through it.

Its a good discussion actually, and thanks for keeping it civil.

Edit: Some interesting numbers to find are; What volume of air does the engine flow at 6000RPM and what volume of air does the supercharger flow when the incoming air to the blower is at 20 inches mercury vacuum.

NoRemorse

The diffeance that the of the CFM the SC pushes with the throttle open or closed is negligable, I would say within 5%.

the bolded part is wher you are wrong. Let's pretend that the bypass is closed. The SC is sucking air from a closed throttle plate making an INSANE vacuum. And pushing it into the manifold where the engine is not requiring all that air because it is trying to sit at 900rpm or so. So you open the bypass so taht pressure can fill taht void and recirculate, creating ZERO pressure differantial (other than that caused by the restriction of the bypass, which is somehwta begligible in this argument)

sheek360

noremorse, just tell witt what u do 4 a living and leave it at that dude.

NoRemorse

lol, but I shouldn't need to! I rather explain why!

sheek360

sorry bout that man. i have such a bad head ache and i almost got arrested when i was getting my car serviced. Im in a terrible mood. Sorry for being a jerk Witt, you will eventually read my last post and think im an ass.

Witt

I know what he does for a living, how do you know what I do for a living?

sheek360

see post 108, sorry. bad day bro. if i had a button that would destroy the world id push it.

NoRemorse

lol sheek you ar a jerk

and witt, your profile says what you do for a living

Witt

Actually its not negligable, or a bypass valve would not be needed.

The bolded part is where you are not making sense to me. Pushing air into an intake manifold, the engine will ingest it. The ONLY time it doesn't require it is when you stomp on the throttle and the blower pushes more air than the engine can intake, and obviously boost is made. If the manifold is in vacuum, it quite simply means the engine is not getting enough air to ingest. If the engine is trying to sit at 900 rpm, its doing so only because of a restricted throttle plate. The engine will react directly to how much pressure is in the manifold. The supercharger sucking air from a closed throttle plate is still less vacuum than the engine drawing air from the intake manifold itself.

Witt

Nah, I don't take offense to anything I read on the internet.

NoRemorse

Good call, there is way too much **** to get offended about if you do!

NoRemorse

1st bolded part... EXACTLY!! in order to maintain idle, it must recirculate taht air!! because id wouldnt idle at all if it ingested the air!! and that is my point!

2nd bolded part... this is not true!! the SC flows more air at idle than the engine... see numerb I posted. If you don't believe the numbers, I can post the math behind them.

I HAVE made the bypass stay shut, and let me tell you, the engine does nto stettle down!! It get's into a positive feedback loop, where more boost makes more rpm,. and more rpm makes more boost!

Witt

The only problem is, every source I find (yeah, I know, this is the internet) is stating quite the opposite.

http://my.is/forums/showthread.php?t=138184 Post number 5 and 23

That video shown earlier, obviously.

http://www.superchargersonline.com/content.asp?ID=76 The part on a twin screw where it states that a bypass valve is needed to recirculate compressed air, which is a disadvantage of a twin screw over a roots.

http://forums.nasioc.com/forums/showthread.php?t=605625 Post number 25

I have more, but you get the idea.

NoRemorse

quoted from one of those links:

To keep it from boosting at lower RPMS (which is caused by the blower flowing MORE than the engine) it lets that air recircualte BACK through the bypass!

Also taken from something you posted:

Those links you posted just agree with me if you read into them!

Witt

I'm not sure what parts of those links you got those, but in those links, they also talk about centrifugal and twin screw as well. The second quote you included in your last post was definelty about a centrifugal or twin screw, because our blowers don't compress air in the first place.

NoRemorse

Yes they do. They say that :

Citrifigul needs a BOV

Twin screw needs to be clutched because they compress the air anyways and use up power, but a bypass helps a bit

and roots needs a bypass to keep the manifold from building pressure

DJMKAFKA

Is This Really Worth 6 Pages?

NoRemorse

Yes

Tomtwtwtw

I'll be the first to admit I don't know that much about what you guys are talking about, but I'm trying to learn. Hell, that's the main reason I'm here. To teach when I can and learn when I can't.

Anyway, I found this site, which had this to say about the Eatons.

Witt

Is it worth you complaining about us discussing a topic?

Witt

I found that as well, but also found a page by Magnusson (who Eaton owns) that says the opposite. I'll see if I can dig it up.

NoRemorse

lol, good point, he is jsut amking the thread longer!