no bov sound

[foxracing2216]

so i just put my car back together and drving around. before i could hear my stock 1g bov. now it doesnt make a sound. i dont hear a single thing, when before i could hear it loud and clear. its recirculated, but i could hear it fine before.. how bad is driving it without a bov letting pressure loose? also, if turbo seals are bad, could that wreck the diaphram in bov from oil getting in there?

 

[Dsmkauai]

Did you check the vac line for bov by chance to see if it's hooked back up?

 

[foxracing2216]

yes sir. even put a new vac line on it as well. im lost. i guess im going to buy a new bov, but do you think its bad to drive with it not working?! what could happen?

 

[Dsmkauai]

Yes very bad for your turbo if its not working bro if it wasnt you wouldn't need the valve. If your making a lot of boost and let off the gas all that are will travel backwards toward the turbo and cause compressor surge. Basically makes the turbo spin the wrong way and that's bad. If you stay out of boost you should be fine though. What you should do is take the vac line off the bov and recirc tube hook a mighty vac up to the vac nipple. Now pump the mighty vac and see if the valve moves at all. So ? for ya you say you just put the car back together right. What all did you do and are you even able to make boost?

 

[gusu]

The compressor surge myth needs to die.

The reason for the blow off valve is simply because it is much quieter than the flutter from the throttle plate being closed.

In serious endurance races where reliability is a trillion times more important than performance they don't run them. For example the 12 and 24 hour races at Le Man's or the 45 lap race at the ring (156 turns).

Lots of factory cars do not come them stock.

They were never used in F1 before the forced induction ban either.

True comprosser surge is a different beast all together.

Your compressor will never fully stall or spin backwards. The reason you hear a flutter is the air waves slamming together. Believe it or not, even at boost levels of 80 psi the pressure is typically around 3 PSI roughly.

If you don't believe me do yourself a favor and look it up.

Also don't trust BS sources of information like turbo or BOV manufacturers who are looking to move the most profit. If they can find a reason to void a warrenty they will.

 

[Dsmkauai]

Interesting thanks for the info, but I still wouldn't risk running without it working properly.

 

[Calan]

The compressor surge myth needs to die.

The reason for the blow off valve

<snip>

Can you tell us which of the people on this list are not running BOV's?

I'd like to get their take on it.

 

[Dsmkauai]

Also you maybe right that a track car runs that way. Because they can afford to . But on a daily drivin turbo car If you had surge all the time from high boost your thrust plate/bearing wouldn't last to long I'd imagine. Also explain why guys running big turbo setups run duel bov setups.

 

[ofgofg]

In the old days there was no such thing as a blow off valve. We just lost boost between shifts. No worries. Just get it fixed asap so you can spool quicker between shifts.

 

[WES_393]

OP- Is the car actually boosting? Do you have an aftermarket boost gauge? Any changes done to the intake such as adding the stock filter cover? It's strange to me that you don't hear anything at all. Even if the valve was completely seized up you should hear compressor surge even at low boost. One option would be disconnecting the recirculation tube temporarily (and plugging it), then take the car for a drive and see if you can hear it. That would verify that the BOV is actually working, just quieter than before for some reason.

As for the BOV discussion: Toyota rarely (if ever) used a BOV on the 3SGTE found in the MR2, Celica, etc. Instead a device called a "harmonic intake" uses a valve after the air filter to control unwanted noise such as compressor surge. So apparently the engineers at Toyota didn't find a BOV very important. However, one of the first mods done to them is a BOV.

 

[maddogxx]

My wife's Audi A4 doesnt have a bov, also my buddies FORD F150 Truck with the ecoboost twin turbo V6 does not have a bov either

 

[honda_burner]

So when the throttle closes and the turbo is still spinning where is all that pressure and air flow going? Kinda seems like to me that it would have no where else to go other than backwards through the turbo causing compressor surge/stalling.

 

[Diamond Star Werks]

alot of turbo deisel I see don't have bovs either. actually never seen one with one.

 

[GRAVEDIGGER]

I know the Audi uses the recirculated air to help spool the turbo. Other vehicles with automatic transmissions like the F-150 don't use one because of the free-wheeling nature of automatics and no direct engagement with the engine like through a manual transmission.

 

[T is for TURBO]

The compressor surge myth needs to die.

The reason for the blow off valve is simply because it is much quieter than the flutter from the throttle plate being closed.

In serious endurance races where reliability is a trillion times more important than performance they don't run them. For example the 12 and 24 hour races at Le Man's or the 45 lap race at the ring (156 turns).

Lots of factory cars do not come them stock.

They were never used in F1 before the forced induction ban either.

True comprosser surge is a different beast all together.

Your compressor will never fully stall or spin backwards. The reason you hear a flutter is the air waves slamming together. Believe it or not, even at boost levels of 80 psi the pressure is typically around 3 PSI roughly.

If you don't believe me do yourself a favor and look it up.

Also don't trust BS sources of information like turbo or BOV manufacturers who are looking to move the most profit. If they can find a reason to void a warrenty they will.

Straight from the horse's mouth.

Turbos By Garrett

The reason some cars don't have bypass valves is because they don't see that second type of surge due to certain circumstances. Low boost, auto, amount of time in boost...

OP, what kind of vacuum are you pulling?

 

[cammons]

its possible its working but you just dont hear it cause there isnt enough boost

 

[bradselph]

alot of turbo deisel I see don't have bovs either. actually never seen one with one.

You will never see a diesel with a bov because they dont have throttle plates.

 

[Diamond Star Werks]

You will never see a diesel with a bov because they dont have throttle plates.

thats news. then what does the gas pedal do?

 

[Fejery4491]

Changes the amount of fuel injected

 

[4g63t]

thats news. then what does the gas pedal do?

control the injector pump.

 

[Notstock]

thats news. then what does the gas pedal do?

There is no need to control air volume in a diesel. The "gas pedal" simply controls how much fuel gets delivered to the cylinder.

 

[flaatr]

thats news. then what does the gas pedal do?

There is no need to control air volume in a diesel. The "gas pedal" simply controls how much fuel gets delivered to the cylinder.

^ What he said...

Most turbo diesels don't have throttle plates so it's pointless to have a recirculation or BOV. And they don't have a 'gas' pedal either

Engine speed is controlled by the injection pump system.

-Raffi <--- TDI owner

BTW, we laugh at guys who install BOV on their diesels just to be 'cool' like their gasser buddies

 

[Diamond Star Werks]

^ What he said...

Most turbo diesels don't have throttle plates so it's pointless to have a recirculation or BOV. And they don't have a 'gas' pedal either

Engine speed is controlled by the injection pump system.

-Raffi <--- TDI owner

BTW, we laugh at guys who install BOV on their diesels just to be 'cool' like their gasser buddies

haha thats funny. I understand it though. Explains why moving the injector plate on a cummings increases hp.

 

[Theturdburgler]

If it wasn't working you would here it surge unless it's stuck open. Check it for debris holding it open and make sure your turbo is
Good

 

[AK Maniak]

My wife's Audi A4 doesnt have a bov, also my buddies FORD F150 Truck with the ecoboost twin turbo V6 does not have a bov either

My 2008 A4 has a diverter valve, and from my understanding it is pretty much the same thing as a BOV.