BBK 52mm throttle body question
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BBK 52mm throttle body question
Hi,
I have a 52mm BBK throttle body (link with picture below) in my 1991 L-98.
http://www.bbkperformance.com/produc...?car_motor_key[]=1502&car_motor_key[]=1513
Does any one know for what is the gold hose conection that appears hidden in the upper left of the picture? My car had connected one of the breathers from the valve covers, but i guess that doesnt make sense since there is preassure being sent in opposite directions through that hose..
Thanks!!
I have a 52mm BBK throttle body (link with picture below) in my 1991 L-98.
http://www.bbkperformance.com/produc...?car_motor_key[]=1502&car_motor_key[]=1513
Does any one know for what is the gold hose conection that appears hidden in the upper left of the picture? My car had connected one of the breathers from the valve covers, but i guess that doesnt make sense since there is preassure being sent in opposite directions through that hose..
Thanks!!
Le Mans Master
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[IMG]
[/IMG]
That is a throttle activated vacuum port, there is another, smaller port right below the one in question which is full time vacuum. If you don't need it just put a vacuum cap on it.
[/IMG]That is a throttle activated vacuum port, there is another, smaller port right below the one in question which is full time vacuum. If you don't need it just put a vacuum cap on it.
Last edited by Midnight 85; May 14, 2012 at 09:27 PM.
Le Mans Master
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comes from in front of the butterflies hence it has no vac on it
Filtered air goes from that port on the TB to the pass side rocker cover , through the engine then out the PCV valve on the drv side cover to the intake.
When you accelerate hard and there is no vacuum to suck fumes through the PCV valve, the engine fumes go in reverse;
from the pass side cover, back to the TB and into engine to get burnt
Last edited by rodj; May 15, 2012 at 04:46 AM.
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Thks for the replies. A couple of questions based on what you are telling me:
Midnight85, how do i know if i need it or not? In case i do not, what is a vacuum cap? A simple cap that prevents de air going out from it?
Rodj/midnight85, how would you connect the hoses? I have 2 holes in the pass side rocker cover, 1 hole in the driv, the bbk throttle body and a procharger supercharger with a conic filter with a hole in it, suggesting there was some kind of hose connected there...
Dont i penalise performance buy sending hot oil burnt gases through the car's intake?
Thank you very much and sorry for my little experience in the subject!
Midnight85, how do i know if i need it or not? In case i do not, what is a vacuum cap? A simple cap that prevents de air going out from it?
Rodj/midnight85, how would you connect the hoses? I have 2 holes in the pass side rocker cover, 1 hole in the driv, the bbk throttle body and a procharger supercharger with a conic filter with a hole in it, suggesting there was some kind of hose connected there...
Dont i penalise performance buy sending hot oil burnt gases through the car's intake?
Thank you very much and sorry for my little experience in the subject!
Le Mans Master
Joined: May 2004
Posts: 5,866
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From: Hellinois
Finalist 2020 C4 of the Year - Modified
[IMG]
[/IMG]Look at my first picture, you need the one that is hooked up in my picture. The one below it is constant vacuum and since I have no need for it it is capped with a rubber cap. Although it looks different than the new ones my throttle body is a BBK. I should add that my other side is exactly as rodj stated. I've added another picture of the driver side so you can see the vacuum hookup there. You have a port coming out of the intake between the runners, you can't see it that good but mine goes forward under the wire loom to a tee where the pcv taps in, the other side of the tee has a hose that runs up to the vacuum canister. I've done a lot of mods on mine but I believe yours should be exactly the same.
[/IMG]Look at my first picture, you need the one that is hooked up in my picture. The one below it is constant vacuum and since I have no need for it it is capped with a rubber cap. Although it looks different than the new ones my throttle body is a BBK. I should add that my other side is exactly as rodj stated. I've added another picture of the driver side so you can see the vacuum hookup there. You have a port coming out of the intake between the runners, you can't see it that good but mine goes forward under the wire loom to a tee where the pcv taps in, the other side of the tee has a hose that runs up to the vacuum canister. I've done a lot of mods on mine but I believe yours should be exactly the same.
Last edited by Midnight 85; May 15, 2012 at 09:28 PM.
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Thks for the replies. A couple of questions based on what you are telling me:
Midnight85, how do i know if i need it or not? In case i do not, what is a vacuum cap? A simple cap that prevents de air going out from it?
Rodj/midnight85, how would you connect the hoses? I have 2 holes in the pass side rocker cover, 1 hole in the driv, the bbk throttle body and a procharger supercharger with a conic filter with a hole in it, suggesting there was some kind of hose connected there...
Dont i penalise performance buy sending hot oil burnt gases through the car's intake?
Thank you very much and sorry for my little experience in the subject!
Midnight85, how do i know if i need it or not? In case i do not, what is a vacuum cap? A simple cap that prevents de air going out from it?
Rodj/midnight85, how would you connect the hoses? I have 2 holes in the pass side rocker cover, 1 hole in the driv, the bbk throttle body and a procharger supercharger with a conic filter with a hole in it, suggesting there was some kind of hose connected there...
Dont i penalise performance buy sending hot oil burnt gases through the car's intake?
Thank you very much and sorry for my little experience in the subject!
The penalty comes from NOT having the PCV system properly connected. The oil gets contaminated, sludge forms, moisture stays in the crank case, carbon accumulates, the engine becomes a toxic waste dump inside....so yeah, get it straightened out and help the engine live longer. PCV has absolutely nothing to do with anything except the life expectancy of your engine.
Le Mans Master
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From: Australia
You failed to mention that important little point 
Same as described above except the TB port will now be under pressure and need sealing up
With pressurized induction your PCV supply air has to come from before the SC ; hence the fitting on the air cleaner so supply air to pass side cover would originate there.
Same as described above except the TB port will now be under pressure and need sealing up
With pressurized induction your PCV supply air has to come from before the SC ; hence the fitting on the air cleaner so supply air to pass side cover would originate there.
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My PCV system is a real mess.
I will definetely seal the upper port of the TB given is is supercharged
The lower por of the TB receive a hose coming from the gas tank with a valve near the passenger valve cover. Is this ok or should i cancel this, and seal the other port also?
Thks!
I will definetely seal the upper port of the TB given is is supercharged
The lower por of the TB receive a hose coming from the gas tank with a valve near the passenger valve cover. Is this ok or should i cancel this, and seal the other port also?
Thks!
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This is that valve i am talking about..
http://www.youtube.com/watch?v=BqawDo7P8vQ
Also, does anybody know if i should bypass this valve? I guess it is only to circulate some intake gases to the exhaust. It suck air form befor the TB so i guess it may be lowering the boost?
Any problem with removing it?
http://www.youtube.com/watch?v=2pTnZBbtsr8
Thanks
http://www.youtube.com/watch?v=BqawDo7P8vQ
Also, does anybody know if i should bypass this valve? I guess it is only to circulate some intake gases to the exhaust. It suck air form befor the TB so i guess it may be lowering the boost?
Any problem with removing it?
http://www.youtube.com/watch?v=2pTnZBbtsr8
Thanks
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This is that valve i am talking about..
http://www.youtube.com/watch?v=BqawDo7P8vQ
Also, does anybody know if i should bypass this valve? I guess it is only to circulate some intake gases to the exhaust. It suck air form befor the TB so i guess it may be lowering the boost?
Any problem with removing it?
http://www.youtube.com/watch?v=2pTnZBbtsr8
Thanks
http://www.youtube.com/watch?v=BqawDo7P8vQ
Also, does anybody know if i should bypass this valve? I guess it is only to circulate some intake gases to the exhaust. It suck air form befor the TB so i guess it may be lowering the boost?
Any problem with removing it?
http://www.youtube.com/watch?v=2pTnZBbtsr8
Thanks
That's called the EGR which isn't open during WOT runs. The EGR helps prevent detonation but isn't as necessary when using a cam with sufficient overlap. Otherwise, it's a good idea to keep it.
Kinda hard to image it's hurting your boost. I doubt it's causing any problem.
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Thank you Gregg!
Would you also keep the valve on the second video? That is the one i suspect could be hurting the boost a little bit.
Would you also keep the valve on the second video? That is the one i suspect could be hurting the boost a little bit.
Last edited by CorvetteC4CABRIO; May 19, 2012 at 10:15 PM. Reason: Confused
Le Mans Master
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(like the tank purge port you mention ) may become pressurized when under boost.
Maybe a one way valve needed on the line to air does not go wrong way and pressurize something
The air injection goes into the exh manifold so it has no effect on engine or boost.Only there to clean up the emissions
