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Need Help Bad! Sort Of Boost Question W/pics!


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First what is this black and white line running from Vac tree to a small metal box in front of car? See pic below:

IMG_1235.jpg

Second what is this metal box it has two vac lines running to it one from Top of turbo (second picture) and the black and white line in question? Also has electronic hook up?

IMG_1236.jpg

IMG_1233.jpg

The black and white line is a little worn, can I replace with a straight silicone vacuum line?

The purple line is fine I replaced and elbow.

Reason I am asking seems I am not achieving the max boost I used to. I would normally get 15-15.5PSI now I am only getting 13.5. Car is 98 S70 T5 IPD chip, exhaust, with mechanical boost gauge (VDO) the car definitely does not pull as hard but still pulls decently.

And all I can find on here is an 850 Vac line diagram is there one for the S70?

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Without being so sure the second and the third pictures have to do with EGR.The first picture's black and white box is something like filter or it could be an one way valve.I'm telling from what I've seen to other cars not Volvos,but the EGR system is almost the same to all.

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Without being so sure the second and the third pictures have to do with EGR.The first picture's black and white box is something like filter or it could be an one way valve.I'm telling from what I've seen to other cars not Volvos,but the EGR system is almost the same to all.

I agree probably EGR, if I take the line off it functions as a vac line. I just want to know can I replace it with a straight silicone VAC line. ANYONE have the actual diagram for the S70 VAC lines?

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Of course and you can as long as you secure it at the side which is near the exhaust manifold.If it is near it can be burnt.

Right.. I really need a diagram for the S70.. I can only find 850 and I think that is off.

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"sas system" aka the air pump system.

The white/black vac line is a check valve inline with vac hose running to the air pump solonoid.

the metal thing is a valve for the same system. The valve opens (via control from said solonoid) to allow the airpump to pump air into the downpipe, pre-02 sensor.

The large hose on the valve runs to the air pump, found below the battery. The airpump's intake hose is the goofy hose attached to the airbox.

There should be no reason you cannot replace those with silicone, however make sure you clamp it all on tightly.

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"sas system" aka the air pump system.

The white/black vac line is a check valve inline with vac hose running to the air pump solonoid.

the metal thing is a valve for the same system. The valve opens (via control from said solonoid) to allow the airpump to pump air into the downpipe, pre-02 sensor.

I see very helpful. So can I replace the lines with silicone? Do you have a vac line diagram for s70? one found "under the hood"?

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x70 diagrams...

pcv.....

Picture1.png

air pump....

Picture3-1.png

turbo/CBV/BCS

Picture1-3.png

CBV diaphragm could be leaking externally; mine had a leak where the diaphragm mates to the turbo housing, I used scotchpad to remove the pitting, and that helped.

V70pressureTest0007.jpg

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for 1, replace all the clamps that are in the pictures wih screw type clamps. easy to lose boost there. Also the stylin motors vac line is thick enough to use for elbows, you should replcae anything that's suspect on the vac tree (which is everything). I relaced every soft vac line, every elbow with heavy silicone line, and every clamp without exception. Including the brake booster line. hope this helps

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