bypass valve- NEED HELP

supercharged3.0

Registered User
Hello guys.
Is here any one, who can explain to me what does that bypass valve on the supercharger line?
Here is why i am asking.
I have a different car, it is a Ford Probe, but i installed a M90 supercharger in it and mounted a custom throttle body behind the supercharger. I am running front intercooler and i have 2.5" pipes. Basically, i can not adjust the idle, because when it is low (800-900) the engine shuts down. I use to keep 1100 rpms. Also, i have one more problem. When i rev the engine and let the gas pedal, the engine shuts down again. I think, when i rev the engine, the supercharger pumps the air in to the engine and when i close the throttle plate, the engine can not get more air and it shuts down. That's why i want to know what DOES THAT BYPASS VALVE.
PICT0008-3.jpg

PICT0007-1.jpg
 
On an sc, the bypass allows air to bypass the supercharger and enter the engine. When in boost, the bypass snaps shut and all incoming air is routed through the supercharger.
 
I don't see any bypass in that picture. :confused:

I did not use any bypass vlave, because i took off the OEM throttle plate from the intake manifold and made a custom one which is mounted on the back of the supercharger.
One question. Does M90 pumps more air than engine can use under 800-900 rpms?
Probably, because, i did not put that little bypass valve and blower pumps more air in to my engine and that's why i can not adjust the rpms
 
Blower bypass systems simply are a valve that sits in a tube that connects the outlet of the blower with the inlet of the bower. On the SC, the bypass sits on the plenum to the intake manifold, and has a hose that runs over to the intake plenum.

The valve has a vacuum diaphragm actuator which is hooked to the blower outlet. When the outlet sees vac, the vac pulls on the diaphragm which opens the bypass valve. This eliminates any surging and allows the blower to basically idle, drawing no more than 1-3 hp. As soon as the vac drops (as you open the throttle) the valve starts to close, causing the blower to start bulding positive pressure.
 
Blower bypass systems simply are a valve that sits in a tube that connects the outlet of the blower with the inlet of the bower. On the SC, the bypass sits on the plenum to the intake manifold, and has a hose that runs over to the intake plenum.

The valve has a vacuum diaphragm actuator which is hooked to the blower outlet. When the outlet sees vac, the vac pulls on the diaphragm which opens the bypass valve. This eliminates any surging and allows the blower to basically idle, drawing no more than 1-3 hp. As soon as the vac drops (as you open the throttle) the valve starts to close, causing the blower to start bulding positive pressure.

Thank you, Sir!!!! That is the answer i was looking. I have a compressor SIRGE. That's why i can not adjust the rpms.
How you guys adjust the idle?
How can i mount one bypass like that? Is that possible get one?
 
Thank you, Sir!!!! That is the answer i was looking. I have a compressor SIRGE. That's why i can not adjust the rpms.
How you guys adjust the idle?
How can i mount one bypass like that? Is that possible get one?

The bypass valve needs to go between the throttle body and supercharger so you'll need to space that throttle body off the SC a little bit.

- Dan
 
You do not need a bypass for the engine to run perfectly. The only problem will be that the supercharger will get extremely hot. Sounds to me like you have other issues like vacuum leaks or something like that. Is this system running speed density or MAF?
 
Did anyone notice there are two IAC's and also two throttle plates????? I'm guessing one ought to be done away with.........Dan
 
No, but that is kind of kooky looking. I'm assuming that the other TB has the plate removed...

I did notice that it would appear he has the BP sensor hooked up to engine vacuum though. That can't be good.
 
You do not need a bypass for the engine to run perfectly. The only problem will be that the supercharger will get extremely hot. Sounds to me like you have other issues like vacuum leaks or something like that. Is this system running speed density or MAF?
I do not have a MAF. I have a speed density system.
 
No, but that is kind of kooky looking. I'm assuming that the other TB has the plate removed...

I did notice that it would appear he has the BP sensor hooked up to engine vacuum though. That can't be good.

Yes, i removed the OEM throttle plate. I have a only one throttle plate which is mounted in the back of the supercharger and which does not have a bypass valve
 
From the picture it looks like you have rewired the IAC valve to the throttle body at the supercharger inlet and transfered the TPS from the stock location to the new throttle. What I can't tell from the picture is if the throttle plate moves in the same direction on both throttles..I'm asking because that also determines which way the TPS sensor moves. Have you checked to see what you are getting for TPS voltage at idle and wide open ?

David
 
You do not need a bypass for the engine to run perfectly. The only problem will be that the supercharger will get extremely hot. Sounds to me like you have other issues like vacuum leaks or something like that. Is this system running speed density or MAF?
Yes, I noticed that, when supercharger did not have a throttle plate in the back, it was producing EXTREMELY hot air. My front intercooler was getting too hot. Also, it was driving me crazy by the loud NOISE it was making. Plus, i had a BOV just before my OEM throttle body and it was doing PSHHHH>>>PSHHHH every time when i was touching the pedal. After driving like that, i removed my INTAKE throttle plate and made a custom one and put it in the back of the supercharger. Took off the BOV and let to control the idle from supercharger's throttle. After these modefications, the supercharger was not producing hit like before. If i am going to put that BYPASS valve, will it start producing hit again??
 
From the picture it looks like you have rewired the IAC valve to the throttle body at the supercharger inlet and transfered the TPS from the stock location to the new throttle. What I can't tell from the picture is if the throttle plate moves in the same direction on both throttles..I'm asking because that also determines which way the TPS sensor moves. Have you checked to see what you are getting for TPS voltage at idle and wide open ?

David

Actually, it is a my OLD setup from 2006. Right now, i have a twincharged setup, which has a turbocharged feeded a supercharger. I post these pics to know where is that BYPASS valve will go.
Here is my setup now. I still have that throttle plate in the back of the supercharger and it still with out a bypass valve
http://i275.photobucket.com/albums/jj290/supercharged_2008/vulcan/PICT0560.jpg
 
The bypass needs to go after the TB but before the supercharger, over to the intake manifold plenum. Is it a Ford speed density system or aftermarket?
 
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