I no longer run a bov on my car. Nearly 1800 miles on my new engine with 1300 miles of abuse. No issues :)

:icon_tup: :nod: :egrin:

I'm running no BOV on my car. I always get great responses when asked what BOV i have.

How bad does your engine make that "purging" sound/vibration?

Interesting read. Never considered this. But it does make some sense.

You can hear it about 6:55 in this video; both after the burnout, and the race. And then at the very end when I was having fun with the 2step. :)

I wonder if any throttle body mods add or decrease the purging sound/ vibration, the sound is from the pressure on the plates right?

you get surge even with a blowoff valve, mine has been disconnected for at least 3 years and the turbo and engine are just fine.

what about 3 BOV's ?

What is specifically happening when the sound occurs?

when the throttle is closed the air backs up in the intake stream, causing the compressor wheel to stall, it can't continue to push air into the engine so the noise is the air pushing against the air in the intake causing the wheel to surge as it can feed the little bit it can in.

diesels for example have no throttle plate, so no surging. they make power solely based on how much fuel is pushed into the engine.

But if you let out of a diesel it will make the same sound as a car with throttle plates but it has no throttle plates... hmm. Don't listen to the kid in the video,he's a tard but around a 1 min listen to the truck.

Another, this tard call's it a waste gate.

duramax sled pul loud ass turbo fart - YouTube

Here's is Dallas Penn's truck. His Pop is part owner of Suncoast. No turbo flutter but a fast ass truck. I used to R@R tranys there. Seen some pretty cool trucks.

Is there an advantage to keeping the intake stream completely full constantly? Will you spool faster or slower?

In my opinion, it feels faster when you grab the next gear after you shift. I have a HKS SSQ so I can just unplug the vac line and the valve stays shut.

Some of the Aussie guy's claim that the wheel speed stays higher nonBOV. They have mesured it with turbo tach's.

I have been goin for a while with out it now. Been back n forth a few times. I like no BOV

That makes sense, and makes engine bay look cleaner without one for those of us without a tig welder at home. Now i cant drive around blowing off everywhere on purpose like all the subarus that put down 178hp to the wheels though, darn. I guess twice the power and half the weight will have to do for now....

No +1 for that?

In my opinon it has nothing to do with the throttle plates as both Diesel(no plates) and cars(plates) make the noise. So what is actuall going on is the Turbine has lost all of the energy driving it, so there is nothing(NO EXHAUST ENERGY) to keeping the compressor compressing., so the air blows back through the compressor inlet. You can also here the turbine making noise out the exhaust but I havn't got that one figured out yet.

lets ask.... a SCIENTIST!!!

Bill Bye?

Nye?

thewird

I asked a "scientist" and this is what he told me causes the sound.

if you want a BOV, turbo a civic or some riced out pos

1983-1989 Mitsubishi Starions/Chrysler Conquests did not have BOV or BPV. Vehicles driven hard experienced turbo failures in under 50k miles. Very seldom does one get over 100k out of a stock turbo with no BOV on those cars. This was in the early age of turbos on street cars. It was an experimental stage and much was learned from mistakes.

And that being said, I installed one on my completely stock car and noticed a significant difference. Without a BOV, that car had horrible compressor surge. I'd lay back into after every gear and it would need to spool back up every time.


After installing the BOV, it hit full boost almost instantly once I layed back into it.



Turbos spin well in excess of 15k rpms...some much much higher. When there's no BOV/BPV, air finds the path with the least resistance, and thats back the way it came, or popping a hose off. When it goes back over the blades, depending on boost levels and compressor speeds, I've seen cases of compressor blades actually bending. You're taking something from spinning at 15k rpms to a halt almost instantly.

With a BOV you're giving that compressed air somewhere to go, therefore its not forcing the turbine to a stop allowing it to more or less free wheel until the next gear gets it back to its full rpm or until it gets down to its idle speed as you shut down after a run.

Yes it evacuates all the air out of the system, but the turbo remains spooled, therefore will make boost as soon as the throttle plate allows air through the engine and out the exhaust. Without a BOV your also taking all the air out of the system, but now your stopping the turbine so it has to rebuild its RPM damn near completely.

Plus, lets not forget the back pressure in the exhaust playing a part. In the exhaust manifold before the turbine, there's usually double, sometimes more, pressure than the boost level your running at (thats why backpressure isn't a problem in turbo cars, and large exhaust is best). Now thats trying to continue on its journey outward while the air on the compressor side is also trying the same. Therefore the compressor stall, or surge since they're forcing it in opposite directions...also causing severe heat.


And BOV/BPV serve no real emissions purpose. Car companies don't put them on for nothing.
They install BPV/BOV from the factory because they don't want to have to replace turbos under warranty. A penny spent now is a dollar saved later.


Running without a BOV is no different than shutting your car off everytime after a run without letting it cool down. There's no instant effect (usually), but overtime the effects are obvious. But just like this topic, many swear with modern turbos you don't have to let it cool down.


Kinda like double clutching versus shoving it in reverse and dumping the clutch between every gear.
They make setups for some cars now that cut timing so you can stay full throttle between shifts and it limits your revs to keep the turbo spooled fully.

Thats the best way to go.

Most ignorant post I've read all day.