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New BOV for me speed?

M

mazdamn02

Guest
I'm getting a little compressor surge at WOT in sixth gear, me thinks a new BOV may help? Or not? Any ideas? I'm such a turbo noob.
 
dmention7

dmention7

Hater
Josh, I assume you're talking about boost spiking? As in the boost momentarily rises above the normal pressure (15-16 psi for the spped3, IIRC), then settles back down again... If so, how high are you spiking? A little bit is pretty normal.

Otherwise, compressor surge happens when you suddenly let off the gas while you're in boost. If your BOV (or BPV in the case of the stocker) doesn't open up fast enough or flow a large enough volume of air, the pressure wave caused by the sudden obstruction of the intake tract by the closed throttle plate will travel back hit the blades of the compressor.

Either way, if you're honestly concerned, it should be a warranty issue. You might have trouble getting them to do anything about boost spike/creep if you've opened up the exhaust with anything but a cat-back, but just a CAI (and a mazdaspeed one, at that) should have no impact on spiking or compressor surge.
 
N

niterydr

Legendary Status!
As mentioned above, the factory system shouldn't have those issues.

Maybe your factory CBV is failing.

If mazda can't help you out, we can certainly come up with an appropiate upgrade for you.
 
M

mazdamn02

Guest
The issue is boost will go from 15/16 psi to 18/19 and back and forth until I let off the throttle at WOT in typically sixth gear, but it has happened in other gears. Its pretty intermittant so I don't think warranty would help at this point. I'll have to wait and see. Any ideas on what would cause this?
 
dmention7

dmention7

Hater
Does the boost fluctuate relatively slowly, or does the needle bounce wildly around?

I've heard at least a few reports on mazda3forums of boost fluctuating in 6th gear. Kind of a rolling, surging feel to the power delivery. I don't think any of them had boost gauges, but the speculation was that boost was fluctuating slightly.
 
M

mazdamn02

Guest
dmention7 said:
Does the boost fluctuate relatively slowly, or does the needle bounce wildly around?

I've heard at least a few reports on mazda3forums of boost fluctuating in 6th gear. Kind of a rolling, surging feel to the power delivery. I don't think any of them had boost gauges, but the speculation was that boost was fluctuating slightly.
Click to expand...
That's exactly what I'm talking about. If you're sitting in your work go back and forth in your chair a bit, that's how it feels when it happens.
 
dmention7

dmention7

Hater
Might want to search for that thread at m3f. I don't know if it ever came to a conclusion or not, but at least a few people mentioned experiencing it.
 
J

JustROLLIN

Guest
If you are not lifting off the throttle and still feeling the surge, its likely not a BOV issues. Sounds more like boost regulation issue - IE wastegate or whatever mazda uses to electronically control boost.

Maybe Josh or another LSE guy can elaborate.
 
dmention7

dmention7

Hater
The running theory in that thread, is that the ECU is relearning the boost/fuel/throttle maps after installation of a CAI. This would fit you've scenario... but you've had that intake for a while.
 
N

niterydr

Legendary Status!
Doesn't sound like a bov issue, possibly a messed up wastegate signal/filter/control.

For some reason your boost control solonoid is pulling duty cycle. Weather it is on the fritz or something is "Up" with your engine, not sure.

Best bet would be to put the stock intake on it and bring it in to the dealer to have them check it out. The boost should NOT oscillate like that.
It spikes then bleeds off on the MS6 and MS3's.
 
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