Koreandude

Hey Yuri, i was told that one couldn't use a blow off valve on a turbocharged engine that still uses a MAF...it would have to be an air bypass or recirculatory valve. I mean it makes sense that a BOV that vents the charged air into the atmosphere would drop the air flow in the intake track to nothing and confuse the MAF right?

Well, i saw that you're using a greddy type-s BOV while browsing through your pics on imagestation.com (lots-o-pics, nice!!) and you're still using the MAF (btw, where is it??? Between the compressor housing and air filter??) So how'd you do it Yuri???

Bat Lord

Well the thing is that YES as of now you can say it's not "correct" what I'm doing still allowing the air to vent into the atmosphere... but I'm waiting till I relocate the battery to the rear to make the tube longer, than I will go ahead and add a tube from the BOV to the tube by the MAF... although I've been told time and time again here that this in no way affects it... but I'm willing to try both styles, I just don't know if me losing that sweet "TURBO SOUND" is worth it... hehehe

Shadohh

That is correct. To have good "Performance" To want a recirculating valve.

Not just blowing it to the atmosphere.

What happens is, the ecu adds all that fuel for that air you just blew out to the atmosphere. And so your engine bogs down from running super rich.

The SAFC has features to compensating when slowing down thou.


Also you can get certian blow off valves, that have valving in to vent 10% to the air, for that sound, and recirculate. So you keep your performance up.

Thats what I will be using.

Viper966

if u put the BOV before the MAF than why would it matter as much? i mean when the throttle plate closes the maf has only metered the flow in the air that has passed by it... does the BOV vent enough air to clear out the area between teh MAF and the throttle plate?

i mean it shouldt make that much of a differance.... as it should only cause the car 2 run rich for .4 seconds and when the car does go rich ur off the throttle anyways... so u arent loosing performance... when u get back on throttle the BOV is closed and no air is being lost

or am i missing something

MadElantra

I'm with viper. Far as I know, the performance gain from the recirclulating valve is that you will have increased throttle response due to the air never leaving the system.

sharkey9883

i may be stupid, but wouldn't the opposite happen? when the throttle plate closes, wouldnt' the air back up and reverse the flow through the maf and confuse it? don't you want the maf before the BOV?

Viper966

that depends on ur location of ur BOV and how fast it vents... i mean its only detecting flow... so when the t plate closes more doesnt flow past it just backs up really and flows against the turbo... but since the intake piping is so long and the maf is so high i dont see that as being an issue especially since u would haev some sort of BOV

Curtas

Unless you have an aftermarket MAFS (don't even know how to get/calibrate one for the Beta engines), you will want the MAFS before the compressor. The higher velocity, pressure, and temperature air flow will destroy our stock MAFS quickly. The stock one can handle about 6 to 7 psi's worth of more flow to the engine (so it's okay to use it with a lower boost setup), but be sure to keep it ahead of the compressor.

with this setup, you need a recirculating BOV and route the piping back in front of the compressor.

Here's how mine will layout:
Filter (where the batter was) --> MAFS --> elbow pipe --> piping --> compressor inlet.

I'm going to use the stock elbow pipe to connect the MAFS and the compressor inlet. Off of that, I'm going to use one tube for the recirculating BOV and the other (after I widen it) will go to the IAC (Idle Air Controller).

I wish I had a diagram to show this.

hope this helps,
ac

Koreandude

So how is your car "running"? Does it "bog down" everytime you get off the accel. pedal? This can't be good for the engine..

I'm not sure if i follow you here...

Anyhow, that venting/recirc. BOV that Shaddoh mentioned sounds like the thing we need function w/ sound!

VALKYRIE YB70

Just to make it clear to Viper & others: the MAF is in the downpipe to the turbocharger & the BOV is in the up-pipe taking compressed air to the throttle body.
The hybrid BOV`s mentioned re-circulate 90% of the expelled air, but blow the top 10% of boost-pressure to atmosphere...(presumably because a richening of mixture at high boost could be advantageous!).