Blow off Valves on F8x

[YMB-M3-J2]

Is this possible? I dont hear much about that kind of stuff on the BMW's but i always liked the sound in my street racing ricers days!

[A418t81]

Originally Posted by bmw328jc

Is this possible? I dont hear much about that kind of stuff on the BMW's but i always liked the sound in my street racing ricers days!

The diverter valves on the S55 are built directly into the compressor covers and are entirely electronically controlled (not pneumatic like most others). I suppose it may be physically possible to add one, but you'd certainly piss off the ECU and it would be redundant as the ones on the turbos would be providing the vast majority of the bypass. Don't do it.

[Boss330]

Originally Posted by A418t81

The diverter valves on the S55 are built directly into the compressor covers and are entirely electronically controlled (not pneumatic like most others). I suppose it may be physically possible to add one, but you'd certainly piss off the ECU and it would be redundant as the ones on the turbos would be providing the vast majority of the bypass. Don't do it.

I suppose he isn't talking about wastegates but the blow off valves that release boosted air (not exhaust, but air in the intake after the turbo). These valves are blowing off air when the throttle is closed to avoid the pressure wave bouncing off the closed throttle valve and thereby slowing down the turbo.

On a DCT car adding one make less sense since the throttle is open during shifts... And in Sport mode the S55 is dethrottled, meaning that the Valvetronic (which is used instead of a traditional throttle valve) never fully closes. A blow off valve would probably not have any effect in that setting (and by effect here I mean the sound the OP is looking for...)

And a blow off valve could possibly confuse the DME as well with boost pressure disappearing when it shouldnt etc...

[Dawko]

If you want more woossh on your car, get some drop in filters.
Blow off valves etc remind me of JDM Honda's.. or this:

[RickMonet]

Originally Posted by Boss330

I suppose he isn't talking about wastegates but the blow off valves that release boosted air (not exhaust, but air in the intake after the turbo). These valves are blowing off air when the throttle is closed to avoid the pressure wave bouncing off the closed throttle valve and thereby slowing down the turbo.

Are the blow off valves releasing boosted air responsible for the characteristic "Brraaaaap" sound of the S55 motor in the F80/F82?

[Boss330]

Originally Posted by RickMonet

Are the blow off valves releasing boosted air responsible for the characteristic "Brraaaaap" sound of the S55 motor in the F80/F82?

The braaap sound comes from the exhaust, so not blow off valves.

Blow off valves sounds like this:

[consolidated]

Here you go, second best option. $9 on ebay, but we'll four of them for a full symphony. I'm joking, but on second thought it would hugely entertaining for a day, just to upset people.

[YMB-M3-J2]

Originally Posted by GregD

If you want more woossh on your car, get some drop in filters.
Blow off valves etc remind me of JDM Honda's.. or this:

LMAO! Yeah its completely the JDM days.

[YMB-M3-J2]

Originally Posted by Boss330

I suppose he isn't talking about wastegates but the blow off valves that release boosted air (not exhaust, but air in the intake after the turbo). These valves are blowing off air when the throttle is closed to avoid the pressure wave bouncing off the closed throttle valve and thereby slowing down the turbo.

On a DCT car adding one make less sense since the throttle is open during shifts... And in Sport mode the S55 is dethrottled, meaning that the Valvetronic (which is used instead of a traditional throttle valve) never fully closes. A blow off valve would probably not have any effect in that setting (and by effect here I mean the sound the OP is looking for...)

And a blow off valve could possibly confuse the DME as well with boost pressure disappearing when it shouldnt etc...

Yeah you are right. i did mean the actual blow off valve. I here the one in my F30 now because its a 6MT and my M3 will be as well so a friend(that was a ricer as well) asked me if anybody ever put them on Beemers and i did like the sound but figured it would piss off the ECU and made bad things happen. i think i will just leave it alone! no pppssssttt sound for me.

[karbonphiber]

Originally Posted by GregD

If you want more woossh on your car, get some drop in filters.
Blow off valves etc remind me of JDM Honda's.. or this:

[jc05e46m3]

Dats only in da mornin, you posed to be up cookin breakfast or somethin, so, its like an alarm clock- WHOO WHOOO

[Ging]

S55 has no Blow off valves only waste gates for the exhaust side of the turbos. BMW is using a different way of releasing the boost pressure on throttle closure. I have a theory but have proof yet.

[YMB-M3-J2]

whats your theory?

[RickMonet]

Originally Posted by Ging

S55 has no Blow off valves only waste gates for the exhaust side of the turbos. BMW is using a different way of releasing the boost pressure on throttle closure. I have a theory but have proof yet.

Anyone have a theory what causes the Braap! exhaust sound?

See video in my previous inquiry:

http://f80.bimmerpost.com/forums/sho....php?t=1019364

Cannot find a good explanation yet...

thanks

[Ging]

Originally Posted by bmw328jc

whats your theory?

The oem tuning might play with the valve timing(vanos) and valve lift(valvetronic) as you lift off the throttle and allow the manifold psi to blow through the cylinders straight to the exhaust/turbos pretty much giving the car huge overlap cam timing. The BRAAB noise caused by each cylinder opening to the exhaust. A bonus to this is its like a kinda anti-lag giving a big burst of hot gases to the turbos every time you lift.

[YMB-M3-J2]

that makes sense and could be totally possible. I guess we will have to wait until some of the companies that do the major engine upgrades to tear one apart.

I noticed a company selling BOV for the 135i and some of the other models so they must be doing something to not pissed the ECU off so it tells me i think it can be done but will require more research and maybe some R&D.

[///M ARMY]

Originally Posted by jc05e46m3

Dats only in da mornin, you posed to be up cookin breakfast or somethin, so, its like an alarm clock- WHOO WHOOO

Hahah just for decorations Mann

[jc05e46m3]

Originally Posted by ///M ARMY

Hahah just for decorations Mann

Dats it and dats all man.