BOV Mounting Location Help

[Maxx Mazda]

Just bought the MAM FMIC kit for my Spool setup. I'll be blocking off the BPV hose nipples, but I want to know a good place to mount my HKS SSQV. Sorry for the crude drawing, but let me know. I searched, and found that the BOV after the MAF might cause stalling. Is that true or only on the MSP's?

 

[khaosman]

You are teh Photoshop mastar!!!

 

[Maxx Mazda]

I Am Teh W1n!!!

 

[igdrasil]

With the HKS SSQ you may not have bad stalling issues...not as bad as the HKS Standard which stays open longer.

 

[Maxx Mazda]

locations fine.
mspaint skillz need work.
the goal is to get it as close to the tb as possible.
hopefully you wont stall. Does the ssqv have an adjustment screw?

Yes it does, but it's also a "sequential" BOV i nthe sense that it has 2 "levels" of opening. The first section opens alone if you are releiving a little bit of pressure, and just kind of "wooshes" it to the atmosphere. The second "level" (don't know how else to describe it) comes into play if you let off alot of pressure (hard driving) and it lets it all out at once, very siddenly, but then when the pressure drops below a certain point the second stage closes and the 1st stage closes slower, so that's why not many people have stalling issues with it.

 

[NetGuy]

I'm not sure if it's supposed to be really close to the throttle body, but that's where mine is. Interesting about the 2 stages of bypass...I didn't know that (I guess that's why it's called sequential, duh).

 

[Maxx Mazda]

I'm not sure if it's supposed to be really close to the throttle body, but that's where mine is. Interesting about the 2 stages of bypass...I didn't know that (I guess that's why it's called sequential, duh).

Yup!

 

[igdrasil]

i think is better if closer to the turbo...

 

[Maxx Mazda]

I thought closer to TB is better?

 

[igdrasil]

Well, I think closer to the TB will send shock waves to the compressor shaft,...

while having it closer to the compressor, it will release pressure and aleviate the shockwave.

 

[Maxx Mazda]

But the TB controls when the air is let out, essentially, and having it closer to the TB would mean that it doesn't have to rush back through alot of pipe to relieve pressure.

 

[NetGuy]

I agree fully with Maxx...closer to the TB seems like it would create less turbulence in the charge tubes. I suppose at the end of the day it's probably not a big deal either way.

 

[Bigg Tim]

Closer to the turbo is better. That is what I have been told by many turbo guru's. It has to do with what igdrasil said.

 

[Maxx Mazda]

No, I disagree. So the air is rushing in, toward the TB, and suddenly the TB closes. Now, if the BOV is closer tothe turbo, you get all that air from the TB back to the BOV, having to suddenly stop and change direction so to speak to ext the BOV. If the BOV is closer to the TB, the rushing air will just be diverted out of the BOV.

 

[Bigg Tim]

No, I disagree. So the air is rushing in, toward the TB, and suddenly the TB closes. Now, if the BOV is closer tothe turbo, you get all that air from the TB back to the BOV, having to suddenly stop and change direction so to speak to ext the BOV. If the BOV is closer to the TB, the rushing air will just be diverted out of the BOV.

So you ask a question and already have your opinion.....then why ask the question. MOST turbo guru's will tell you it should be closer to the turbo. Why release all the pressurized air from the pipes when you don't need to? The whole point of a BOV or BPV is to help prevent compressor surge, not to give the "cool" sound. So having it closer to the turbo means that the BOV only releases the air needed to prevent surge. With it close to the TB, it releases more air then needed.

 

[NetGuy]

Where's the bypass valve in the MSP6? the MSP? I know in my car it's right next to the throttle body. I guess the final answer is "it doesn't really matter, just put it where it fits". The place you chose seems to be where just about everybody else puts it.

 

[Bigg Tim]

Stock units are BPV's, so it doesn't matter where they are because they recirculate the air back into the intake system. A BOV releases air so it is said to put it closer the the turbo so it will only release what is needed, instead of "all" of the pressurized air. A BPV IMO is more efficient because it doesn't release metered and pressurized air, it puts it back into the system, but I do like the sound of BOV's and IIRC they can hold higher boost levels too.

 

[igdrasil]

No, I disagree. So the air is rushing in, toward the TB, and suddenly the TB closes...

Yeah but part of that wave will hit the compressor blades, the bypass/blowoff will just let air out, the wheels keep running, but that first big shock will be felt on the turbo.
Remember, the actual pressure inside the plenum will be lower than before the intercooler.

Having the BOV in the hotside of the intercooler, or in the compressor itself should be more efficient.

Try it once...but keep your hand very far from the compressor inlet, you could have a bad accident:

Rev up the engine, and step off the gas, the BOV will release air, but you will notice that for a fraction of a second or even longer, air will blow thru the inlet of the compressor, out!

 

[Maxx Mazda]

Rev up the engine, and step off the gas, the BOV will release air, but you will notice that for a fraction of a second or even longer, air will blow thru the inlet of the compressor, out!

Are you serious? That's crazy! But the compressor won't fully stall obviously... Will it?

 

[igdrasil]

Are you serious? That's crazy! But the compressor won't fully stall obviously... Will it?

yeah, I got a friend who got a finger chewed by the turbo because of this...so if you are going to try it, put a screen on the inlet.