Blow-off valve connection

[fabio420]

Hey there! I finally got my car boosting up to 6 lbs. However, today was just the first day of test drive. I am having a bit of an issue trying to find a good vacuum source for my blow off valve. Does any one have ay idea? I'm using thye line of the charcoal canister, but I need another one.P.S. I have an external wastegate from xs, and it has 2 thread holes int it. one is obviously for a boost line, but what is the other? and which one is which?Thakx

[Ligouri Rd]

I am currently using the brake booster line teed off before the check valve. Its convenient for me since my BOV is on the hot side of the intercooler and the brake booster is already on that side of the car. Anyone, feel free to critique that if they feel that won't work well. On an external wastegate (tial for example) one port is for the boost line to actuate the wastegate the other is to bias wastegate to make it open at a higher pressure. Basically your boost controller (if you have one) intercepts the second line and feeds pressure to keep the wastegate closed until the desired pressure is reached. I have "heard" that if you cap off the second line you will gain an extra pound or so of boost pressure due to having to compress the wastegate spring and pressurise the bias side of the wastegate.

[rn240sx]

Hey there! I finally got my car boosting up to 6 lbs. However, today was just the first day of test drive. I am having a bit of an issue trying to find a good vacuum source for my blow off valve. Does any one have ay idea? I'm using thye line of the charcoal canister, but I need another one.P.S. I have an external wastegate from xs, and it has 2 thread holes int it. one is obviously for a boost line, but what is the other? and which one is which?Thakx

The MOST common vacuum source for the bov is to tee in with the Fuel pressure regulator line..The best place is DIRECT to the manifold with nothing else.... But thats another story..!!

[DRIFTEADOR]

unless you have an electronic boost controller, leave the top port on the wg vented, but not plugged. you don't want the boost pressure to be working against pressure trapped inside the top half of the wg.

[rn240sx]

unless you have an electronic boost controller, leave the top port on the wg vented, but not plugged. you don't want the boost pressure to be working against pressure trapped inside the top half of the wg.

I have the Tial 35mm and the top port has NEVER been hooked up to anything. Its always been vented. Even with my EBC, its still vented..

My ebc is hooked up IN-LINE between the compressor and the wastegate side port...

No problems so far

[Import_Ant]

I have the Tial 35mm and the top port has NEVER been hooked up to anything. Its always been vented. Even with my EBC, its still vented..

My ebc is hooked up IN-LINE between the compressor and the wastegate side port...

No problems so far

exactly. the purpose of the top nipple on the Tial wastegates is to ADD pressure as a form of raising boost instead of bleeding the pressure off like most people do. you can still choose that option (I'm using a Hallman MBC inline with the boost ID line) works fine for me

but in regard to the topic of this thread: try to tee off from a source on the intake plenum itself. I redid all my vacuum lines when I installed my kit and I chose to run one of the unused nipples off the upper intake plenum to the upper nipple on my Greddy type S, then I T'd off from my boost ID signal (directly ON my compressor housing on the turbo that goes to the wastegate) to the lower nipple on my BOV. You dont have to run the second line, its purpose is to maintain positive pressure in the lower portion of the BOV's chamber, making the action more crisp. the BOV will still work just fine without it. Think of it as pushing a block. when your throttle plate is open (on the gas) there is positive pressure on both sides of the chamber so you would be pushing on both sides of the block equally, thus keeping it in one place (closed) with the throttle plate closed (off of gas) there is a vaccum in the top chamber of the BOV. so you now have positive pressure in the bottom chamber pushing up on the BOV and negative pressure pulling on it.

hope that makes sense.

[DRIFTEADOR]

what kind of ebc are you using? what I described is the way they're supposed to be plumbed. check the directions. using the top port gives it more precise control over boost.

[Import_Ant]

what kind of ebc are you using? what I described is the way they're supposed to be plumbed. check the directions. using the top port gives it more precise control over boost.

im using a Hallman MBC

I'm too cheap for an EBC