Ill start with when I had my Stock injectors, FMU, and A32 MAF in the car, I was able to have the BOV open as much as I want without a problem. Idle was perfect, no surging problems, no compressor surge.

I then installed my:
Z32 MAF
JWT ECU
370cc injectors
and 3" charge pipe with the same Vortech BOV I was using before with no problem. With this setup I need to keep my Large Vortech BOV on the tightest possible setting to see a constant idle. (letting little to no Air out at idle) If I loosen it up AT ALL, more air vents from the BOV, and I then see a loopy up and down idle. I then took out the JWT-ECU and the car still acts the same. I know that the BOV is before the MAF so its NOT venting metered air, so it should affect the Idle at all, right?

Right now I have the BOV all the way tight, and i got a good amount of compressor surge (shift at say 2500-3000 RPM's and hear alot air going out the blower) and really need to winde it up to hear any type of Blow Off. The real function of the Vortech BOV is really to realease ALOT of air !!! and right now its not able to beacuse I cant keep the set screw loose at all.

Any type of fix for this ?? or any help ??

Heres a pic. The BOV is tightened down the absolute most it can.


-matt

 

I would flip that charge pipe around so that the BOV is closer to the blower-side. The Z32-MAF seems extra sensitive to air turbulence so the BOV releasing air so close to it might be affecting its readings. Who knows, give it a try

 

I was actually thinking that, but then the BOV will be exactly in the way of the dipstick and Oil cap <---Kind of a PITA.

I guess I could try that and Open up the BOV a bit to vent some air....When I was trying to figure out my idle issues when I did the install, I finally tightened the BOV and it fixed the problem..I just dont like the fact that it doesnt really open all the much.

-matt

 

did you rotate the MAF a few degrees? Remember when Ian had that problem?

 

Yea straight up and down is where is suppose to be after its rotated. First I had the connector pointing down and it was really loopy, stalling, Horrible.... I guess I could try that first but what way ???

 

Your blow off valve isn't working properly. At idle no air should leak at all even if you've loosened the screw a bit. None should leak until you reach a certain pressure, determined by the set screw. If yours is tightened down all the way and you can still get it to "blow off" I would think the BOV is broken, as you can't be running more than 8 or so psi max (pushing it) without a lower compression ratio. A BOV should be able to hold any amount of boost you are running with ease. HKS super sequential has a good reputation.

Check your injector connectors if they are the early style, they are very prone to corrosion.

Also, I don't know if your placement of the MAF would affect its working properly or not. It works by heating the screen inside it and measuring how much it is cooled. By putting it where you have, it is getting much hotter air from the SC than the ambient temp air it was designed for, as well as all of that engine heat. Just a thought, it might work just fine how it is.

 

The BOV is indeeed holding the Air with no problem. I dont think you understand the problem.

This is a brand NEW Vortech BOV. The Vacuum source that connects to the BOV pulls the Diaphram up. With it seeing vaccum at idle (about -20hg), and the set screw loose, the diaphram opens and leaks air out of the BOV. Its 100% working properly. If I tighten the Screw down a bit, and put more pushing down force on the diaphram, it opens LESS at idle, but still vents air at idle. At WOT shifts, I get a Good BOV sound, but any type of shift low, i get surge. I was told that the SSQV by HKS will work better because theres a Two Valve system in the BOV. One for slow moving shifts and one for high boost. The SSQV i know for a fact does not leak air at idle. All the other ones do...

Alot of the guys with the HKS unit, still see compressor surge though.

-matt

 

I get no surge with the TurboXS.

the difference between mine and yours is that I have a piston that moves up and down with the vacuum source. I have had no trouble with it. EVAR!

Last time I had it out, I cleaned and lubicated it and the way it opens and shuts is very smooth.

mine is the same one as seen here

 

No, I don't think it's broken. If he were turbo'd, then I would say the BOV should be closed at idle. In a turbo setup, the turbo isn't pushing much air at idle, so you want the BOV to be closed so theres no intake leaks.

In a supercharged setup, the blower is ALWAYS blowing air, even at idle. Infact, it pushes quite a bit of air at idle. This extra air needs to be vented out of the BOV so that the air in the charge pipe is unpressurized at idle. I have my Blitz set this way and I get no compressor surge and a perfect idle.

 

Z32 MAF or A32 MAF ??

-matt

 

A32 MAF, stock injectors, stock ECU, walbro pump, no afpr. I was just referring to how the BOV should be venting air at idle. My Blitz works the same way slimer's turboXS does. The "piston" moves up and down with vacumn.

More vacumn = piston stays up and is at minimal stiffness, allowing excess boost pressure to be released.
Less vacumn = piston increases downward force, some air goes out, some air stays in.
No vacumn (boost) = piston gets pushed down as hard as possible, no air is leaked out.

Theres also a spring inside to assist in the piston's up/down stiffness.

 

Yea the Vortech workes the EXACT same way as what you just explained. Same as my old greddy Type S.

If you read my orginal thread, I state I had it working perfectly, venting perfect alot of air at idle and alot after boost. Now with the Z32 MAF, it doesn't want to idle correctly unless the BOV tightenin screw is completly tight letting minimal air out at idle. It worked fine before the Z32 maf. Im close to just going back to the A32 maf.

-matt