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Discussion Starter #1
Well i just got my turbo kit finally running after having a few issues that are for the most part resolved....the only thing i have left is im confused on why at idle my blow off valve is wide open; and when i rev the car, i have no boost building up? I understand that the bov operates under vaccuum so it would make sense that since my car has 20 (i have a brain fart for the measurement unit) and then i bump the throttle realy quick it goes up to zero but i dont see boost. My vacuum line from the wastegate goes directly to the turbo and then the other one goes from the bov to the intake also having a t to the wastegate......(my wastegate has two ports) is this setup correct?
 

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if your running off the wastegate pressure then you should have one short line going straight from the turbo compressor housing to the bottom port on the wastegate. the top port should be left open. if you have a manual boost controller, it just goes in the middle of the line. There should be no T fittings at all. If you are running an electronic boost controller then things are different. Your blowoff valve should be connected to the actual intake manifold itself, not the intake tube
 

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Ran into the same problem you have, I solved this by ordering a heavier spring that was rated for the amount of vacumm my motor pulls (21). It doesn't help build boost when you rev the motor, as stated you have to load the motor to make boost or two step it. I just wasn't crazy about the bov being open like tht when the motor was at idle.
 

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Discussion Starter #5
Well i talked to a few tuners in the area and they all said the same thing, that the blow off valve should actually be open..... The bov at idle is seeing vacuum there fore opening the valve, when the car see's boost, the pressure built up in the intake will close the bov. Not unless your building boost at idle then thats when it should be closed. as for the wasgate; i was told to use the bottom port only and to leave the top open..... use a t fitting to tie the bov and wastegate to the manifold. manual boost controller will go from turbo to top of wastegate.
 

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Well i talked to a few tuners in the area and they all said the same thing, that the blow off valve should actually be open..... The bov at idle is seeing vacuum there fore opening the valve, when the car see's boost, the pressure built up in the intake will close the bov. Not unless your building boost at idle then thats when it should be closed. as for the wasgate; i was told to use the bottom port only and to leave the top open..... use a t fitting to tie the bov and wastegate to the manifold. manual boost controller will go from turbo to top of wastegate.
Wow. So one side of the tee is seeing vacuum, one side is seeing boost, and the third side is hooked up to the bov? Yes your valve is going to be open.
The line on the waste gate should only see boost, bottom port on the gate. The vacuum line from the intake should be hooked up to the top port on the blow of valve. No tee.
 

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You need a heavier BOV spring. Having your valve open at idle is no good. You are sucking in unfiltered air and all sorts of other undesireable things. The whole point of the spring is to keep the valve closed at idle/ high vacuum.
 

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Discussion Starter #9
huh???? if you hook anything to the intake manifold, its going to see vacuum so how could you say the wastegate should never see vacuum? And if the bov is also connected to the intake manifold then why not just tee the both into one line going to the manifold?
 

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huh???? if you hook anything to the intake manifold, its going to see vacuum so how could you say the wastegate should never see vacuum? And if the bov is also connected to the intake manifold then why not just tee the both into one line going to the manifold?
You do NOT hook up your wastegate to the manifold. You connect it to the outlet of the turbo which never sees vacuum (if you are running off the spring and not using a controller of any kind). Your blowoff does get hooked up to your intake manifold, it should see vacuum at idle. This is pretty basic stuff, you may want to do some research on how turbo systems work.
 

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Wastegate gets connected to a vacuum source before the throttle body.

Blow Off Valve gets connected to a vacuum source after throttle body.
 

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You want the waste gate line to be connected to the turbo compressor housing so that it reacts quicker and in relation to the turbo. It makes it spool faster and hold boost more steady. You do not want the wastegate connected to the intake pipes at all
 

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Wastegate gets connected to a vacuum source before the throttle body.

Blow Off Valve gets connected to a vacuum source after throttle body.
No wastegate should have a boost reference and should not be hooked up to vacume. Like ls1 and journeyman said turbo outlet is best place to hook it up to
 

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So your telling me at idle there is a positive pressure from the turbo to the throttle body? No, there is vacuum. As far as i'm concerned anything from the turbo outlet to the throttle body is one system. Yes, ideally you want the source as close to the turbo, but if there is pre-existing sources like the breather nipple that is on the throttle body before the blade why not use it?

I will edit my post to represent what accurately happens to the source at idle and under load:

Wastegate gets connected to a vacuum/pressure source before the throttle body.

Blow Off Valve gets connected to a vacuum/pressure source after throttle body.
 

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So your telling me at idle there is a positive pressure from the turbo to the throttle body? No, there is vacuum. As far as i'm concerned anything from the turbo outlet to the throttle body is one system. Yes, ideally you want the source as close to the turbo, but if there is pre-existing sources like the breather nipple that is on the throttle body before the blade why not use it?

I will edit my post to represent what accurately happens to the source at idle and under load:

Wastegate gets connected to a vacuum/pressure source before the throttle body.

Blow Off Valve gets connected to a vacuum/pressure source after throttle body.
There is no vaccum before the throttle body. Go ahead and hook your vaccum gauge to it and see. There is not pressure either. The pipes between the throttle body and the turbo are at normal air pressure until the turbo compresses it to make positive boost pressure. There is no way for those pipes to see vaccum at idle. The throttle body is closed and even if it were open it would not have vaccum. Vaccum is made because the throttle body is closed. When the throttle body opens the engine itself loses vaccum runs at normal air pressure unless its being compressed by a turbo or supercharger
 

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Again do NOT hook the wastegate up to a vaccum source. The wastegate doesn't operate from vaccum at all. If you hook the wrong port up to a vaccum source your wastegate won't open and you'll over boost and blow your engine. I guess I don't know what I'm talking about since it happened to me years ago. The wastegate can't and won't use a vaccum source. It works only under positive pressure. Don't try and Jerry rig it and hook to some port off the throttle body. It simply will not work and you'll bust a ring land. Hook it directly to the turbo compressor housing. The hose shouldn't be more than a few inches long. The wastegate should be located as close to the turbo as possible
 

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So your telling me at idle there is a positive pressure from the turbo to the throttle body? No, there is vacuum. As far as i'm concerned anything from the turbo outlet to the throttle body is one system. Yes, ideally you want the source as close to the turbo, but if there is pre-existing sources like the breather nipple that is on the throttle body before the blade why not use it?

I will edit my post to represent what accurately happens to the source at idle and under load:

Wastegate gets connected to a vacuum/pressure source before the throttle body.

Blow Off Valve gets connected to a vacuum/pressure source after throttle body.
You are about half right you can connect turbo anywhere before TB but it will see boost not vacuum. Although the farther away from turbo the less accurate the signal will be. Think of it this way vacuum means a lack of. So if there was a lack of air between Turbo and TB the car would not run because there is no air. So it is positive pressure that is before Tb even at idle. Even in a NA car there is positive pressure coming in through the air filter block of the air filter and car will stall because it goes into a vacuum, lack of air.
 
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