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Discussion Starter #1
I have a stage 1 BSR upgrade and when I accelerate hard I can hear the turbo generate a shrill/squeek/shrill/etc. anyone else have this. This is on my 2003 Vector 9-3 SS.

Will this damage something? Like the turbo?

The only thing I can think of that this is is that the turbo is suffocating and wanting more air -> sport filter.

Anyone know?
 

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rando67 said:
I have a stage 1 BSR upgrade and when I accelerate hard I can hear the turbo generate a shrill/squeek/shrill/etc. anyone else have this. This is on my 2003 Vector 9-3 SS.

Will this damage something? Like the turbo?

The only thing I can think of that this is is that the turbo is suffocating and wanting more air -> sport filter.

Anyone know?
The sound you are hearing is normal on stage1 and above. The sound is the turbo spinning. It spins up faster and to a higher ultimate RPM than non PPC'd cars. the turbos running on standard mapping are not worked particularly hard, as Saab have engineered in a big tolerence in the name of reliability and longevity. Stage 1 will make your standard turbo work harder, and ultimately could reduce the service life of the unit, but you would have to be pushing really hard, all the time for any significant reduction in longevity to occur. If your hearing this with the stock filter, if you fit a performance panel filter or a cone type filter, you will notice the sounds more so.
 

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PPC does ask that you install a sport filter insert with stage one, so I would do it. But the sound is normal. Some of it is blowoff also, I have found (aero), as I only note it at the high end of the boost gauge travel.

Do you note any turbo flutter under hard acceleration as well?
 

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That fluttering sound is indicative of a turbocharger that has reached its operating threshold. I experienced this alot with stg. 1 but less so with stg.3 b/c less boost is necessary. With stage 1 the power increase is accomplished with only software changes hence there is more stress on the engine than stgs 2-5. As an eg. my stg 1 ran a peak pressure of 22psi, stg 3 peaks at 17-18 psi with a much smoother power output.
 

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Discussion Starter #6
voodoochile said:
Do you note any turbo flutter under hard acceleration as well?
I am guessing by flutter is the needle on the gauge dancing around at the peak ... if so, I didn't notice. I don't remember observing anything abnormal there. I'll look for it but I don't press the car that hard to cause this noise that often. Maybe I am avoiding it. :confused:

So by reading the responses here that it is simply turbo RPMs that are high for the unit. Do the fins/fans of the turbo scrap the chamber in some type of bending within the unit or is it the shaft making that noise?
 

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rando67 said:
I am guessing by flutter is the needle on the gauge dancing around at the peak ... if so, I didn't notice. I don't remember observing anything abnormal there. I'll look for it but I don't press the car that hard to cause this noise that often. Maybe I am avoiding it. :confused:

So by reading the responses here that it is simply turbo RPMs that are high for the unit. Do the fins/fans of the turbo scrap the chamber in some type of bending within the unit or is it the shaft making that noise?
If the fins of the turbo where touching anything on the way round, believe me you would know the difference!
 

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No, the gauge is pretty well damped and won't jitter around. The flutter is more the stuttering, freewheeling effect of the impeller after the recirc valve opens. The sudden relief of force against the impeller allows it to freewheel, and it makes some funky noises, esp. if you have a flee-flowing insert in your airbox or open-air type intake. A recirculating bypass valve (9-3SS) helps to limit this noise versus an atmospheric blow-off vlave (NG9-3, etc).

Anyway, this flutter seems to occur much more easily and more often with PPC stage one, at least for me. I find I have to be very careful when I move the throttle so I don't dump the charge too early. I wish the mapping was just a whisker less aggressive, so I could hold it longer.

As for the whistling, the compressor wheel spins between 6,000 and 150,00 RPM in a turbo, so when it's really hauling some @$$, you will note it. The higher boost that PPC allows is definitely whipping the wheel at a much higher rate. No scraping, that would be the end of it all in a heartbeat.
 

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shift?

Hi What did you mean by this?? Do you shift faster to avoid this problem or
easy on the pedal when you shift? Thanks!

>>>>
Anyway, this flutter seems to occur much more easily and more often with PPC stage one, at least for me. I find I have to be very careful when I move the throttle so I don't dump the charge too early. I wish the mapping was just a whisker less aggressive, so I could hold it longer.

>>>>>>
 

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jcancio said:
Hi What did you mean by this?? Do you shift faster to avoid this problem or easy on the pedal when you shift? Thanks!
Easier on the throttle. A full stroke to get it spooling, then lift off just a bit to maintain a bit less than full pressure. It takes a bit of fiddling to get the feel for it, but once you do, it becomes second nature. Less of the chattering sound effects, and the maintains a heavy thrust as compared to a *heavier* initial thrust followed by some limp-wristed performance.
IME, this has been the case. I think that PPC varies a bit car-to-car, and certainly the cars seem inconsistent as well, both with hardware and software, somewhat all over the map. It's a bit disconcerting to read some of these posts in that regard.
 
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