I understand that the best place to mount a BOV is as close to the throttle body as possible so the intercooler stays full of pressurized air. So why is it that every SR20DET I see has the BOV mounted on the hot pipe right after the turbo? Is there some advantage to this I don’t know or are people missinformed?
From what I’ve always heard it’s best to be as close to the throttle body as possible. Since I installed my intercooler though the car has been making fluttering sounds when I let off at very low boost. I figure this is because there isn’t enough pressure to open the BOV all the way, but I’m kinda freaked about it because I’m hearing a chuffing through the intake that sounds like the turbo is being kicked back.
Yeah, that sounds like the pressure coming back and hiting the turbine blades, slowing them down. A bad thing, can ruin the bearings. But you probably knew that. Sounds like the BOV isn’t opening at low boost, where do you get the vacuum source from? WHat kind of BOV is it?
Turbo chatter
Non-adjustable Forge Motorsports unfortunately. The BOV is opening, I can see it popping open and closed when the fluttering is happening. It just won’t stay open if it’s not a decent amount of boost.
Yeah, that’s common for cheaper BOV’s.
What if you narrowed the opening of the vacuum lines? Wouldn’t that make it open quicker and longer?
Vacuum only holds the little guard thing open. It’s the boost that has to push the valve itself open.
uhhh, that doesn’t sound right.
if the boost pushes the valve open, then it does the same thing as a waste gate, and a BOV would deside your maximum boost because it would open up when you hit a preset limit. And once you dropped below that limit it would close, so it would never vent pressure at lower boost.
I think the vacuum line connected to the BOV is supposed to be connected to the intake manifold, and when the throttle body closes from letting off the throttle, and the engine sucks in the air inside the manifold, the pressure created inside the intake manifold opens the BOV venting any pressure the tubo still makes after letting off of the gas. Then the extra pressure that would have build up between the throttle body and the turbo is vented so the pressure doesn’t hit the turbo blades slowing them down and causing them to vibrate (Chatter). So it allows the turbine to keep spinning freely causing less lag when you hit the gas after shifting.
Nopers. Try pushing the valve in your blow off valve open. You’ll need a shitload more than engine vacuum to pull that open.
then how can someone make different amounts of boost with the same BOV? If the BOV vents at 7psi, then when you cranked the boost up to 14psi the BOV would never close.
I don’t understand?
Then what’s the point of the vacuum line?
read this and you will understand
The BOV would most likely have a spring in the 20psi range. When you close the throttle plate all of that boost being compressed by the turbo increases the pressure in the inlet piping. While it may only be running 15psi into the engine, as soon as the throttle closes you have all of that air that’s no longer being consumed being compressed into a confined space. This raises the pressure and pushes the BOV open.
This is the same BOV I have. Inside those holes on the right is a guard that drops down when the car is under boost to help stop any boost leaks. When you back off the throttle, engine vacuum pulls this guard up and allows the excess air to escape.
Ahh, Okay, now that makes sense. The boost and the vacuum working together to open the BOV. Thanks for clearing that up for me!
Any ideas or opinions of the mitsubishi, first gen eclipse BOV? I have been told it is great for anything under 20PSI and is basicaly the same as the current HKS Re-circ valve. Anyone have any experiance or knowledge about it?
go buy an HKS SKQ! they work good
Well, I allready own a 1G eclipse BOV so I plan on trying it out B4 I buy anything new.
Just curious if anyone know anything about them? Good or Bad?
i’ve always known it’s better for the Turbo to have the BOV mounted on the hotside IC piping. i’d rather worry about blowing a turbo than losing pressure in my FMIC.
I thought the 1g dsm oem bov’s were plastic? If i’m wrong, correct me, but I’m sure I’ve heard that and that they aren’t great, but will do the job.
Considering that there are alot of decently priced bov’s on the market, it would be worth it to buy new.
It is actually better to have it as close to the trottle body as possible to allow the excess boost to be vented as far from the turbo as possible also it will blow off faster because it is closer to the closed throttle plate.
About the BOV:
The 1G was a metal one, alot like the HKS re-circ. That’s the one people often “crush” the top of to increase the spring load for higher boost. Making it sort of “adjustable” for higher boost. Anyway, it is supposed to make a great re-circ valve, but I have never heard anything from a nissan owner, only DSM owners. The 2G is the crappy plastic one.
About the BOV mounting location:
When the throttle plate closes, where is the first place the pressure will build up? At the throttle plate!! Also, the air flow coming out of the turbo will remain smooth and at a constant pressure. All the info I have found say, mount the BOV close to the throttle body.