Turbo sound?

I got 335i and not sure if 328 makes the same sound or not. I think it's my turbo. It makes a pshhh type of sound at some point when I let go of my gas. Not complaining at all!! I love the sound. Just wondering if anyone know how to recreate it at will. I love hearing and tried to recreate but can't all the time. How or where is this sound coming from?
Also, is doing this bad for the car/turbo??


Sent from my SCH-I535 using Bimmer App

Its your bypass valve releasing the boost pressure.

Get on the gas, then back off of it.

The sound can be exaggerated if you like it by adding an aftermarket intake. Injen makes a nice one.

Originally Posted by Jamesonsviggen

Its your bypass valve releasing the boost pressure.

Get on the gas, then back off of it.

The sound can be exaggerated if you like it by adding an aftermarket intake. Injen makes a nice one.

Cool, thanks, will look into it. Will that kind of aftermarket void any of the warranty?

Sent from my SCH-I535 using Bimmer App

Originally Posted by Taeksoo

Cool, thanks, will look into it. Will that kind of aftermarket void any of the warranty?

Sent from my SCH-I535 using Bimmer App

Only if it's a proven failure relating to the part installed. If you blow a strut they can't deny the warranty due to your intake. If the intake has a screw shear off and go into the engine, well yes they could claim a causation with the intake.

It's not bad for the turbo at all. That's what it's designed to do. If you just floor it and then let off the gas it should make that sound.

Originally Posted by Jamesonsviggen

Its your bypass valve releasing the boost pressure.

Get on the gas, then back off of it.

The sound can be exaggerated if you like it by adding an aftermarket intake. Injen makes a nice one.

It's also called a blow-off valve. Greddy made the best for our Subaru (according to sources we researched) when we were doing some mods back in '04. I'm not sure what is best for a BMW.

You can adjust aftermarket blow-off valves for more back pressure and it sounds louder if you wish.

Originally Posted by beden1

It's also called a blow-off valve. Greddy made the best for our Subaru (according to sources we researched) when we were doing some mods back in '04. I'm not sure what is best for a BMW.

You can adjust aftermarket blow-off valves for more back pressure and it sounds louder if you wish.

Similar, but not the same.

A blow off valve releases pressure into the atmosphere, the bypass kind of recycles the air.

If you put a blow off valve on a car requiring a bypass valve you will get a check engine light as its similar to a vacuum leak.

Learned this with Saabs, as they moved from blow off to bypass. They both do the same thing, releasing boost...its just a matter of it being recycled or not. I am sure it's all about emissions.

I upgraded the one on my wifes Saab when I upped the boost using a Forge BPV. Very good quality.

A visual to explain above...

First is a BOV or blow off valve. The blue ring, is kind of a a horn where the boost is released to the atmospehere.
http://www.ebay.com/itm/Greddy-Type-...f94334&vxp=mtr

Next is a BPV or bypass valve. Note there is no horn. This is fed through vacuum lines and has no release to the atmosphere as it would cause a VAC leak and check engine light. Most cars from the past few years run BPVs.
http://www.ebay.com/itm/Forge-Motors...3df074&vxp=mtr

Upgrading the BPV will increase the sound very slightly. The intake dials up the BPV and induction sounds. My wifes Saab intake, its a bit overboard, but so far ones for the 335 are fairly subtle.

Originally Posted by Jamesonsviggen

A visual to explain above...

First is a BOV or blow off valve. The blue ring, is kind of a a horn where the boost is released to the atmospehere.
http://www.ebay.com/itm/Greddy-Type-...f94334&vxp=mtr

Next is a BPV or bypass valve. Note there is no horn. This is fed through vacuum lines and has no release to the atmosphere as it would cause a VAC leak and check engine light. Most cars from the past few years run BPVs.
http://www.ebay.com/itm/Forge-Motors...3df074&vxp=mtr

Upgrading the BPV will increase the sound very slightly. The intake dials up the BPV and induction sounds. My wifes Saab intake, its a bit overboard, but so far ones for the 335 are fairly subtle.

I learn something everyday. Thanks.

Originally Posted by beden1

It's also called a blow-off valve. Greddy made the best for our Subaru (according to sources we researched) when we were doing some mods back in '04. I'm not sure what is best for a BMW.

You can adjust aftermarket blow-off valves for more back pressure and it sounds louder if you wish.

Our 07 STi limited has this, the HPAI and catback. (all spt upgrades) the swooshing sound coming from the engine compartment is awesome during every shift.

Originally Posted by jfox335i

Our 07 STi limited has this, the HPAI and catback. (all spt upgrades) the swooshing sound coming from the engine compartment is awesome during every shift.

Yeah, I drove my friends'05 Legacy GT with the works. Its quite fun.

Originally Posted by beden1

I learn something everyday. Thanks.

+1

Nice job, Jamesonsviggen

Occasionally when I am traveling and cruising at about 82 mph, I have a "necessity" to kick in the turbo in my E90. Usually hit well over 100 before backing off. But the sound, oh yeah, the sound! Takes about an hour to get the big SEG off my face.

I hope that doesn't change with my newly ordered F30!

Originally Posted by Frzdrdhppy

Occasionally when I am traveling and cruising at about 82 mph, I have a "necessity" to kick in the turbo in my E90. Usually hit well over 100 before backing off. But the sound, oh yeah, the sound! Takes about an hour to get the big SEG off my face.

I hope that doesn't change with my newly ordered F30!

And OF COURSE you don't do it on public roads Haha lol

They both do the same job, just different ways. One is atmospherically vented and the other is put back into the exhaust.

The actual job is to relieve pressure off of the turbo.

If we didn't have these, the reversion could bend and/or break the turbine vanes in the turbo. This is called compressor surge.

It's similar to water hammering in a pipe. That is the clunk that you sometimes hear when you quickly turn off a faucet and the water suddenly stops. It pretty much stops and then goes the other way and runs into itself.

Originally Posted by FreddyG

They both do the same job, just different ways. One is atmospherically vented and the other is put back into the exhaust.

The actual job is to relieve pressure off of the turbo.

I suppose, this is the reason my right side exhaust tip is black and sooty after driving for a week.




By the way isn't this BPV a "waste gate"?

Originally Posted by Dingers 335i

I suppose, this is the reason my right side exhaust tip is black and sooty after driving for a week.




By the way isn't this BPV a "waste gate"?

actually the reason for the dirtier exhaust pipe is that there's a valve in the left tip that closes at low rpm to reduce noise.

the bypass valve does not dump air into the exhaust, it dumps it back into the air intake system.

Originally Posted by Jamesonsviggen

Its your bypass valve releasing the boost pressure.

Get on the gas, then back off of it.

The sound can be exaggerated if you like it by adding an aftermarket intake. Injen makes a nice one.

Does the Injen intake also add extra HP? I love those subtle turbo sounds and of course the I6 sound in itself is a unique work of auditory art, so I wouldn't mind opening up mine a little bit on the engine side.

Originally Posted by Orient330iNYC

actually the reason for the dirtier exhaust pipe is that there's a valve in the left tip that closes at low rpm to reduce noise.

the bypass valve does not dump air into the exhaust, it dumps it back into the air intake system.

I'll second all that.

OP, I hear no noise w/stock valves. Issue?

Aftermarkeet valves'll give ya a rice rocket booosh....

Originally Posted by K-A

Does the Injen intake also add extra HP? I love those subtle turbo sounds and of course the I6 sound in itself is a unique work of auditory art, so I wouldn't mind opening up mine a little bit on the engine side.

The intake makers claim gains, but most tuners and reputable shops claim it's inflated and intakes are more for sound. They sometimes help revs and throttle response, but not so much increase hp.

Originally Posted by Taeksoo

I got 335i and not sure if 328 makes the same sound or not. I think it's my turbo...

Is it a noticeable sound on the 328i ?
I cannot recall that I have heard it from my 328i...

Originally Posted by LvdB

Is it a noticeable sound on the 328i ?
I cannot recall that I have heard it from my 328i...

Windows down, on and off the throttle quick you can hear it.

Originally Posted by Jamesonsviggen

Windows down, on and off the throttle quick you can hear it.

Aha, now I have another reason to "play" around tomorrow on my way to work. Come to think of it, I've never driven my F30 with an open window (apart from the sunroof), ever

BPV releasing extra boost. Drive an X5 and go past 3k rpm. Back off the throttle and you'll hear it as well. It's normal.

Originally Posted by Jamesonsviggen

Windows down, on and off the throttle quick you can hear it.

Windows were down, were on and off the throttle quick (more than once ), and I agree with Taeksoo, it's an addictive sound.

I cannot recall that I have noticed this sound from my turbo diesel vehicles (3.0 diesel X3 and 3.0 diesel C320cdi). I would have guessed that the turbo concept would be the same on both petrol and diesel variations, including the blow of system ...? Or maybe it's just not noticeable with the noisier diesel engines.