matty

iTrader: (54)

Well all my idle problems and surging I think possibly have been solved...

I have a Vortech Race Blow off valve witch was venting at idle probably set half way tight...it was venting quite a bit of air at idle

I was on the phone with JWT talkin to Jim and he claimed there souldnt be ANY AIR AT ALL venting at idle...

My Blow Off even fully tight, vents air at idle but not really alot, but enought to feel it...I tightening it all the way down as tight as it goes and it seems to be idling alot better and not really surging AT ALL while driving...

I dont think this Vortech Unit has the option of NOT realeasing air at idle..but according to JWT, the BOV shouldnt be releasing ANY AIR while ideing ??

Any feedback guys ??

As of now I think the car the MAF issue is solved...I'm still kinda sceptical though

-matt

maxlinegtr

iTrader: (3)

It should not be venting air at idle at all. I think you might have to replace the diaphram if u wanna keep it. same thing with my Greddy type s.

matty

iTrader: (54)

Just got off the phone with Vortech and they said "Theres no way to replace the Diaphram" and "Thats the point of a BOV, to release air at idle" ??

The BOV is before the MAF so that, in my mind, would be fine to vent to atmosphere lets say on a shift...or dO I need to vent back to the filter

-matt

vortechpower

iTrader: (1)

Why not vent air at idle. If it doesn't need the air where is it going to go? I have the blitz and it usually releases air at idle depending on where I have it set. If you think about it , the blower creates alot more air at idle then the motor needs, plus with the original recirculating valve that comes with the v1 kit it was always recirculating air at idle. Having air released at idle also makes the drivability alot better. Thats where the wooshing sound came from when shifting at lower rpm with your old bov or my blitz. Even at cruising speeds on the highway depending on the bov tightness I can hear air going back out the blower, I cant stand it.

mingo

iTrader: (4)

i remember cheston and kev's car like that.. sounded like a tea kettle coming down a hill

Mximus

hmm, that sounds wierd, depending on the boost it should have no need to vent at normal idle as the engine would not be making harly any boost to matter to vent it. sounds like a bad bov to me, i know my bros doesnt do that and hes got a vr4.

Nealoc187

iTrader: (23)

Does an SC'd car have positive pressure even at idle? If not, there is no reason for a BOV to be venting at idle. The point of a BOV is to vent off charge air when there is more air in the intake tract than the engine can ingest. If your car is in vacuum at idle then there is no reason it should be venting at idle...

I30tMikeD

iTrader: (8)

That is what I am thinking, but I guess a SC is different

matty

iTrader: (54)

Do you think Air Going back out the Blower and making that deep Growl sound is bad for the blower ?? thats the only way for my car to run correct...the MAF is too sensative when the air is being thrown back and forth inside of the charge pipe

Well the S/C is always pushing a certain amount of air out at all times, even at idle, its ALOT....almost like a Leaf Blower on high ...since the BOV is vaccum sensative, all its doing is "sucking" the diaphram UP and letting air out of the charge pipe..correct..with the BOV set alittle lose it still lets air out....as tight as it goes, its still lets alittle air out..

Get it ??

The only way I can get the Z32 MAF to work is to have the BOV all the way tight so no air is being thrown back and forth on the MAF...

I could get a HKS SSQ BOV witch Vents NO air at idle supposidly


Its a Brand NEW Vortech BOV...

I30tMikeD

iTrader: (8)

The HKS SSQV indeed does not vent air at idle. At least with my turbo it certainly doesn't and that is the way they advertise it.

Nealoc187

iTrader: (23)

Take a vacuum gauge and measure the vacuum at idle after your throttle body and before your throttle body (but after the blower). If there is more pressure (less vacuum) before the throttle body than after, then you have your answer as to why the BOV is venting. That's how they work, they sense differential pressure between before and after TB, and they vent off air when there is more pressure before the TB than after.

Stephen Max

iTrader: (59)

Yes, being belt-driven, a supercharger will always make boost pressure, even at idle. It may not be much at idle, but it will always be higher than atmospheric. The closed throttle plate results in a vacuum in the intake manifold even though the charge air pipe is pressurized.

Supercharger systems with the bov before the maf normally allow the boost pressure to escape through the bov. If the bov is after the maf, the air needs to be recirculated back to the blower inlet to prevent mixture richness due to loss of metered air.

If the excess air is not vented or recirculated at partial throttle cruising, then it will backflow through the blower. This can cause surging, and with it all kinds of strange and wonderful noises.

iansw

iTrader: (7)

I have had both a Blitz and HKS SSQ BOV on a V2 SC.

THe Blitz vented quite a bit air at idle, the HKS does not.
There is no difference in idle whatsoever - I surge slightly - but that was the same on the blitz. (With the A32 MAF).

Since the MAF is well behind the BOV - it really doesn't care. JWT is used to working on Z32 Setups more than anything (MAF on non-charged side, before BOV) and I find that they often try to apply Z32 theories like that to Maximas (Charged side MAF).

Now - interestingly, on my car - the Z32 MAF does not run well (car barely runs at all) on the Charged side with the Z32 JWT Chip and HKS SQ not bleeding at idle.

HOWEVER - once I remove the charge piping at the blower (so no SC air is going through) - it idles perfectly. There is some theory that it's because my HKS SSQ does not vent at idle, the air is being pushed back and forth in the charge piping, causing turbulence. I haven't had a chance to test this yet, but it is possible bleeding off at idle may help....I suppose - not sure I believe it's the problem - but it's a theory.

matty

iTrader: (54)

Well when I have my Vortech BOV venting air, lets say half way open, the car runs like c*ap...(idle is up and down, and I get a real bad surging when I come off boost)...at idle, if I cover the outlet to the BOV, the idle magically evens out...idles Perfectly if you cover the BOV, or if I tighten the BOV all the way down so very little air vents out, then take a ride, there is absolutely NO surging/shaking in the car, when I come off boost...but I do get that wooshing off air past the blower alot..

Having the BOV all the way tight, when I boost and let off I get that deep woosh of air going back OUT the blower and out the Filter...will this have a negative effect on the blower ????

-matt

vortechpower

iTrader: (1)

At idle my car is making half a pound (.5psi). This was measured with a OBDII . I don't think the air going back through the blower is as bad as a turbo but still. Sometimes my bov does not vent air at idle and seems to run fine. When the car is cold I get this up and down idle, if I pull the air temp sensor out it runs fine at idle. I must have leak somewhere when cold.

matty

iTrader: (54)

Im really not talking about idle...Im talking about boosting. Is it ok to have all that air rushing back out the blower, since I have my BOV so tight, it really only opens a tad bit ??

After boost I have a good amount of air rushing back out the blower

JWT said I should I should have a BOV that closes at idle and still is fully functional after boost when the throttle is closed...Like at -20 be closed, than -10 be open a good amount for air to release...

-matt

vortechpower

iTrader: (1)

Think of it this way , the blower is meant to suck in the air, not blow it back out. So, no it is not ideal to have air going back out the blower if you can find a setting that prevents this or keeps it at a minimum. I don't think it is a bad thing but it creates "conflict of interest" Air is being forced backwards through where its suposed to be forced inwards. I think the best solution is to contact Vortech and ask them what they think about the backwards flow of air. I am also concerned about this issue too Matty. I have mine set to the backward air flow at shifts between 2k and 3k are minimal. I am always messing with the damn thing!

matty

iTrader: (54)

Well the car wont really run right when the BOV is even open (loosened) the slightest bit..

Im gonna wait till monday to talk to Vortech about their BOV's and their Blowers recieveing back pressure air from the intake ducked.

I remember a few months ago a discussion on this and I believe its not bad, but can be over a long period of time...with a Turbo its VERY bad...

-matt