turbo auto

[dohc v6]

if i were to do a turbo on my z34 what kinda of sound would the blow off valve make.

[Robby1870]

The same sound as any other blow off valve makes

[dohc v6]

is that true for an auto. because in a five speed the trottle closes and then opens an auto doesn't

[gimp19]

Turbos actually work better with an auto trans.

[dohc v6]

can you please elaborate on that.

[99RegalGS]

I'm pretty sure this is why auto is better.

With an auto you never close the throttle so you don't waste any air via the blow off valve or air going through the wastegate. So the pressure won't drop and the turbo won't lose speed during shifts.

[dohc v6]

thats cool but no sound from the bov. is there any sound that comes out of it in an auto.

[99RegalGS]

The only time the BOV will make any noise is when the throttle closes.

[R Dubya]

I have a dsm BOV on my TGP and it sounds good, I like it better than the flutter sound it made when the wastegate released pressure. Not very loud but that's what I was hoping for.

[Guest TurboSedan]

I'm pretty sure this is why auto is better.

With an auto you never close the throttle so you don't waste any air via the blow off valve or air going through the wastegate. So the pressure won't drop and the turbo won't lose speed during shifts.

 

that is not why a turbo is better with an automatic car; that is why a BOV is more important on a car with a manual transmission. the BOV vents the pressure wave created when the throttle closes (during a shift), and thus the pressure wave will not slow the turbo down, which means you don't need to spool the turbo again. it also saves the turbo from un-needed wear that the pressure wave would create.

 

i really don't think a turbo is better on an automatic than a manual or vice-versa. it depends on how you drive it. if you have a turbo/manual car and really know how to work the clutch and shift, i think it might even be faster than the same car with an automatic (a STOCK automatic - not an auto built specifically for racing). the automatic limits you, the manual puts you in control of where the engine's RPM will be when shifting and where the RPM will be right after the shift.

 

the BOV on my GTS is also a 1g DSM BOV and it's VERY loud. i think they are louder on the lower IC pipe but i'm not really sure.

[Guest TurboSedan]

just wanted to add that a BOV should be louder on a speed-density (MAP) system since the air is released back to the atmosphere. on a car with MAF, the air needs to be re-routed back to the engine again and would probably mute the "psshhhttttt" sound.

[god910]

The BOV on Black Sunshine is a 1G DSM, and it's welded into the upper I/C pipe. It points right out the drivers side hood vent. Very LOUD! 8) Yes, the 1G DSM's were vented back into the intake tract. That is why they don't sound like my car.

[MaroonRegal]

So this BOV thing sounds really useful...is it a new development? Why isn't it even mentioned in Corky Bell's Maximum Boost?

[mfewtrail]

So this BOV thing sounds really useful...is it a new development? Why isn't it even mentioned in Corky Bell's Maximum Boost?

 

It's not really "new," earlier turbocharged cars usually utilized CBV's(compressor bypass valves..pretty much the same type concept going here, although most of the stock BOV's don't hold quite as much pressure as BOV's can withstand from what I've read..although there are ways to make a stock CBV perform better..I have a CBV on one of my volvos, it makes a slight noise when you let off the throttle, it's not really all that loud to me, I hear more of the turbocharger spooling than anything w/ the stock exhaust on the car). I have a spare CBV here if any of you guys want to experiment on a turbocharged car w/ it or something? I have no use for it since I plan on using a DSM bov on my Turbo GP.