Th3_St33z

I bought a Turbo II swap and it didnt come with a stock Air Bypass Valve, so I wanted to know if this would work... Any suggestions will help.

Im removing this



from here...



and wanting to add this...



and connecting this BOV to the pipe



Is this going to work in place of the plastic? I was told yes by some local mechanics and I was told no by some others.

Thanks

RotaryRocket88

iTrader: (7)

Yes, however there are 2 things to consider:

1) There is no place for the BAC inlet on the new piece, so you'll either have to leave it open to the air, or remove the BAC entirely (bad idea).

2) That BOV will vent air to the atmosphere rather than recirculating it behind the AFM. The ECU will expect this air to still be present in the system, and the mixture will become extra rich between shifts.

Th3_St33z

So, is this a bad idea or a good idea with issues to work on?

Thanks for the feedback by the way.

arghx

iTrader: (3)

I would think that running the BAC open atmosphere on a stock computer (which directly meters intake air) would cause problems.

12AllWays

iTrader: (20)

If you don't need to worry about emmissions and don't mind a little roughness when cold put the bov on it and get rid of BAC and all the other emission components for that matter.

RotaryRocket88

iTrader: (7)

Yeah, forgot to mention that. Open to atmosphere is only ok if you're running a standalone.

The BAC is extra important on turbo engines, since the idle adjust screw is on it. If you remove it, not only will idle suffer, but overall idle speed will only be set by the throttle stop.

KhanArtisT

iTrader: (2)

Dumping the BOV to the atmosphere will cause no major issues whatsoever. You'll have a rich mixture on decel so the gas mileage will suffer slightly.

If you don't care about the sound you could sell that BOV, run no BOV and spend the money elsewhere.

EFF[[Buhrrito]]CEE

1)when you say leave the BAC inlet open your referring to it being unplugged right?

2) and with #2 so that means you cant run an aftermarket BOV at all?

RotaryRocket88

iTrader: (7)

By open I mean the nipple/hose would be open to the air, but that means big problems with a stock ECU.

You can use an aftermarket BOV with the stock ECU, but you'll just have the downside of rich mixtures between shifts. Lots of people do it anyway.

EFF[[Buhrrito]]CEE

oh ok. so there is no solution to fixing the open nipple? is there a site that i can get a stock air intake pipe?

12AllWays

iTrader: (20)

There is an idle adustment screw on the TB on that throttle stop. I have been running just like I told him to do for a year now. No regrets...

MMoore4545

iTrader: (7)

buy the recirculating adapter for the HKS SSQV. ($30ish)
then
run a hose to your TID.

for the bac.

Tap a hole into that hard pipe you buy/bought that has the bov adapter welded onto it, put the proper sized barb fitting and run a hose to the bac.

I'm currently running no bac/etc but then again I'm all stand alone. The Bac valve is an essential idle tool for the stock/aftermarket ecu. Especially if it's daily driven.

RotaryRocket88

iTrader: (7)

The throttle stop adjustment screw and the air bypass screw on the BAC (on TB on NAs) are two different things. You can use just the stop adjustment, but you lose the fine tuning ability of the other screw.

arghx

iTrader: (3)

it's a pain not having the air adjusting screw. I lost that capability when I switched to JDM s5 intake manifolds (hard to find USDM s5 turbo). And when you adjust idle with the throttle plate screw you can mess up your TPS calibration. It's workable but annoying.

there's two issues here. One is the richness between shifts with an aftermarket blowoff venting to atmosphere. I've had that before. It's not bad, it just backfires ridiculously and makes crazy flames when you may not want to attract attention.

The other issue is running the stock air bypass valve open to atmosphere without a check valve. That causes unmetered (and unfiltered) air to enter the system, because the stock style valves are always open when a certain amount of vacuum is applied. When you have a computer that does not use an airflow meter this doesn't matter so much. Aftermarket blowoff valves do not open at idle if they're working correctly, unless it's a synapse valve.