need BOV???

6owed

6owed

gettin' faster
Joined
Aug 31, 2006
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203
when i'm driving at work I notice that if I just tap the gas or let off suddenly my turbo lets out a wierd sound (turbo fart?) I think that it needs some kinda blow off valve or something would fix it
I'm completely guessing at this so don't laugh too hard.
what do ya think
 
Nope, it closes the vanes instead to "regulate" the pressure instead of having to blow it off.
 
so then that sound like SOUNDS like a sequential blow-off valve is what y'all refer to as "turbo-fart" then correct?
 
ok, this topic always gets mixed up, especially in the diesel world for some reason.
there is a big defference between a blow off valve, and a wastegate! i wastgate is what (usually) controls the speed of the turbine to regulate boost. ofcourse in our situation that is non relavent, due to VGT's we have.
a blow off valve, is a spring and pressure laoded valve on the compressor side of the turbo, usually somewhere between the turbo and the (throttle body) on the CAC. ofcourse this is for a normal gas motor that utilizes throttle plates. the blow off valve blows off the compressed air in the CAC when the throttle plates close. this was so on manual tranny vehicles to make the turbos spool quicker after a shift. the turbo wouldnt slow down as much cause it wasnt blowing into a wall(throttle plates closed) that would back up the turbo, and put majore stress on it.
now on diesels, a blow off valve would not work cause there is no thottle plates in diesels. they always injest the VE(volumetric efficiency) of themselves, no butterfly to limit that. so, in theory the diesel doesnt need one, but the (farting) issue still arizes. and to say, it would be vary hard to get one to work on a diesel cause there is no positive pressure and vaccum sorce on a diesel to operate the blow off valve.
 
Well said! And by the way. My non-vgt turbo has a wastegate and still makes the same noise if you let off too fast.
 
Retorical said:
Well said! And by the way. My non-vgt turbo has a wastegate and still makes the same noise if you let off too fast.
Click to expand...

yeah, that's what I was tryin to get at. I realize that there is no BOV on diesels, but I was tryin to relate the sound I hear from the turbo when I do the same action as retorical said as sounding like a sequential blow off valve that some put on their hondas (not sure if you've heard a sequential BOV blow off before, but its def. different sounding. haha)

--Ryan
 
ok thanks

I hate that sound it sounds like something is messed up
I guess I should get used to it
thanks for the great info guys
 
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Just for info, I run one on a Dmax with a very large turbo. It is controled through a Jaycar voltage switch (p/n KC5377) that is hooked to the throttle position sensor wire (drive by wire) which sends a signal (voltage) to a spool valve (available through BD Power), which in turns is hooked to the manifold pressure and sends pressure to the blowoff (Tial 50mm) (or relieses it when voltage is sent to it through the voltage sensor) which in turn lets the I/C pressure blow off through it when I let out of the throttle. No turbo bark. BD Power has these kits available. I am not affiliated with them in any way. I put my own together. I run over 50psi, so it needed it. It stops the turbo from reversing at throttle let off under higher boost pressures (the WOOOSHH, WOOOSSHH,WOOOSSHH you hear). It isn't very good on the turbo center bearing. Just info to share.
 
that sounds like the setup to have, nice work! i was always wondering how it would be possible to put one on a diesel, but couldnt get around the whole "pressure to keep it closed, and vacuum to open it" thing. but it looks like that is the ticket!
 
that sound is called stacking basically the air gets stacked back into the inlet of the turbo making that fart sound
 
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