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Discussion Starter · #1 ·
Eventually after many a conversation I decided to keep the Carly. I have modified it slightly:

Forge uprated wastegate actuator
Speedparts turbo gauge
Bilstein sprintline kit
cat bypass
brembo front discs
pagid fast road pads
poly wishbone
poly front arb
poly drop link
poly engine mount

Results:
Base boost is 0.5, peak boost 1.1. At 4k its still pulling 1.0 and gradually tails off to 0.75 by 5.5k revs.
This is without an MBC - it now pushes you back all the way through the range. I have noticed that the actuator has increased the noise at trailing throttle and idle - almost like a fluttering scraping rattle noise.
The suspension mods have made a massive difference, in fact the only thing that stops me cornering faster is the terrible tyres (only ones I could find. Long story). It corners very flat, and seems to respond a lot quicker. As with other peoples experience the back is quite a way lower than the front. The brakes are still bedding in, but seem to be better than standard. I haven't noticed any difference in vibration (top mount was shot so was terrible before).

Next upgrades:
new heater matrix!
upgraded software...when I find one suitable...
3" downpipe
Strutbrace
clear indicators!
refurb the wheels.

Im so glad I kept it....
 

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Glad to know that you are so pleased with the results Paul
!

   I have noticed that the actuator has increased the noise at trailing throttle and idle - almost like a fluttering scraping rattle noise.  [/b]
I am a bit confused about this . I recently upgraded mine to a 10PSI version but no such experiences as you. Perhaps someone else can advise?

Didn't see you mention any performance air filter . It seems to make a big difference in take-up performance, especially with the uprated actuator.
Looking forward to some pics from your reborn chariot very soon
!
 

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Glad you kept the car
Better in the hands of a Saab Nut than someone who wouldn't appreciate it. Sounds like you've got plenty extra
 

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Originally posted by StanleyB:
[qb]Didn't see you mention any performance air filter . It seems to make a big difference in take-up performance, especially with the uprated actuator.[/qb][/b]
I didn't notice the slightest bit of difference on my Aero with a performance filter. I'm running the standard one again for safety. I understand the standard 9000 air filter (at least the later cylindrical one) flows very well indeed. Perhaps it's a different story with the 9-3?
 

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You might well be right BillJ as far as the 9-3 goes. I wonder if that has anything to do with the way the airbox is positioned under the 9-3 hood,and any restrictive airflow that is the results of the layout.
But I wouldn't use your 9000 as a typical example . It ain't every day I see a video of a 9000 beating a Porsche and a Ferrari
.
 

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As far as the air filter goes, Hirsch stays with the OEM filters. They said that once filters are just a bit dirty, the OEM flows better than a performance type with the same amount of dirt.

As for the fluttering, scraping noise, I am not sure. As far as my 9-3 goes, I heard a pretty loud fluttering sound with the Optiflow intake, I could here the air going backwards through the turbo compressor when the throttle was shut. With my atmo Forge, once the intake pressure is low enough, the spring loaded part will close at idle leaving some pressure in the intake. That air needs somewhere to go, so it goes out the turbo's compressor and makes the fluttering sound. Maybe we need a little more info to figure out this sound.
 

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Eric

I have the same noise on my induction kit !!!!!!!!!!!!

So guys nothing to worry about, im told if I get a fully foam filter it will go away, yet to test that theory !!!!!
 

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Originally posted by BillJ:
[qb]I didn't notice the slightest bit of difference on my Aero with a performance filter.
[/qb][/b]
Difficult to tell because these things are so subjective, but I'm pretty sure the JR filter made a difference on mine ('97 CSE Auto 2.3 lpt with Abbott ECU). Seemed to pickup quicker and accelerate better from about 70mph - no noticeable difference at 30mph or so.
 

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The fluttering sound probably is air going the wrong way through the turbo. The technical term for it is "compressor surge".

Because of the centrifugal nature of the turbo compressor any time it is spinning there is a pressure jump from inlet to outlet. When there is no where for the air to go the pressure increases until it ballances the maximum pressure drop for that speed then the air inside the turbo just stops.

Because the movement of the air is what creates the pressure increase from inlet to outlet, once the movement of the air stops there is nothing maintaining that increase, and because there is already more pressure on the oulet than on the inlet side the air goes backwards until the pressure has been released a little. Then the cycle repeats.

Not 100% sure that's what it is since I've not heard this particular example, but if one wanted to be daring (and perhaps debatably daft) one could plug their BOV or BPV and drive just long enough to get one good shift under boost. If the sound you hear through your intake is the same, only louder, then that is what the fluttering was. (BTW, doing so is generally NOT harmfull as long as you don't leave the valve plugged and continue to drive it that way on a daily basis. It's not a one time failure sort of thing even at full boost.)

Compressor surge generally makes sort of a "WHEW WHew whew whew" sound ... with intensity proportional to the boost pressure and a pitch proportional to the speed of the compressor blades.

Dubbya~
 

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Adrian is correct. I have found other names like: blow-back, compressor-surge, etc. It's an indicator that the BPV is not recirculating all of the surge. Not a horrible thing, but it does hinder compressor RPM.

I know this after several attempts to install the BOV correctly on my T16S.
Here are records of my trials...

1. Remove Bosch BPV, plug with solid object (end of broomstick) and tighten.
2. Cut throttlebody-to-BPV pipe closer to throttlebody.
3. Instert base of BOV into this pipe.
4. Connect vacuum line to BOV, and make adjustments to spring rate.

I drove around, and it fluttered. a LOT.

5. Talked fried who works at BOEING to WELD the BOV onto the induction elbow, so as to increase the passage way to the BOV. The OEM hose that leads to the BPV is TOO small.
6. Remove OEM hose (for temporary measure, cut the hose near the base, and a AA battery will work as a good plug) and plug with cap & tighten.
7. Install BOV and connect vacuum line.

No fluttering at ALL.
Just a great big FSSSSHHHHHH! into the atmosphere. Pretty good Compressor RPM retnetion.

What i am getting at, is... If you hear excessive flutter (blow-back) the OEM path from the throttle-body to the BPV (Bosch, GFB, Forge, etc) is too small in ID, I think. The Forge dump-valve is designed VERY well, but the rubber hose just deosn't cut it.

Consider matching the blow-off point to the BPV (relocate, if need be)inlet ID, and attach it with corresponding ID pipe.

I you look at the OEM pipe/hose, you 'll see that it is FLUTED.
 

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Which word are you referring to? Fluttering?

I'll try to post some pics.
In the meantime, you can see the install of the BOV as per the fllowing link.
http://www.pbase.com/image/24388541

If you follow the induction route to the throttle-body, there is a red "boot" that connects the throttle-body and the elbow. Right after that, sprouts out (towards centre of engine bay) a hose. See that hose get fatter as you follow it towards the compressor (turbo)? That hose is what connects the throttle-body and the Bosch BPV (not BOV). It's simply too narrow & inefficient - me thinks.

Since the picture was taken, I removed the hose, and capped it off with a rubber sock(?) and cinched it down.

So, now instead of the 1/4" or so ID hose, I have a BOV that has an inlet of about an inch, and the inlet is MUCH closer to the actual discharge point. The bound-up pressure escapes much more efficiently than having to travel miles and miles of narrow hose, only to be dumped back in front of the compressor.

The caveat is, the AMM thinks there is, say, 100 parts of air in the induction system, where, in actuality, 20 has escaped into the atmosphere via the BOV. The remaining 80 parts of compressed induction will meet the appropriate fuel that is injected for the aforementioned 100 parts of induction. ...this results in a RICH mixture, but the difference has been so small, the most I see is a puff of smoke in the mirror, once in a while. Plugs seem fine, but the inner side of the tail-pipe is fairly sooty.

Can you be more specific, as to what you'd like to see in pics? Install? Before & After? Smoke?

The T16 i in the shop today (A/C work), so I'll try to get some pics after I get her back.

BTW, the annual US SAAB Convention is starting today, only a couple hours away from where I live. I'll try to visit tomorrow (no guarantees, as family comes first) and take some pics. I'll post it somewhere, if I get the chance.

Cheers!
 

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One more thing, Rob.

If you have a non-OEM air filter setup, you'll hear more flutter. The trash-can type of filter housing that is OEM is a great sound-deadener...

Again, flutter won't kill your turbo. It doesn, however, put a load on it, and lowers the RPM of the wheel - thereby causing lag. The BOV is designed to lessen that lag, by taking the surge OUT of the induction process/system and into the atmosphere.

The negative aspect is a slight richness in A/F mixture.

Cheers!
 

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Discussion Starter · #15 ·
I'm actually thinking possibly an exhaust leak sonewhere - although I have a major increase in lag - 50-70 in 5th is twice the time as before, it takes the turbo so much longer to build up boost (but when it does....
)also I still have no overboost,,
 

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Originally posted by paulmanchester(now cockermouth):
[qb]I'm actually thinking possibly an exhaust leak sonewhere - although I have a major increase in lag - 50-70 in 5th is twice the time as before, it takes the turbo so much longer to build up boost (but when it does....  
  )also I still have no overboost,, [/qb][/b]
Sounds like a leak in your induction system or a faulty wastegate. In which case, the exhaust leak will flow by the turbine until the amount of exhaust flow overcomes the loss. Then...


Check the induction piping boots for leaks, all vacuum lines, and the operation of the wastegate actuator (along with wastegate itself - should have minimal play in it). Modify the length of the WG actuator rod, if necessary...?

Cheers!
 

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To add on ...

Compressor Surge (fluttering) will not instantly destroy the turbo. However ...

Fluttering and surging can be very hard on the bearings of the turbo. It's a very jerky motion. If severe enough it can actually bend the blades of the compressor, though that is an extremely rare occurance.

Something tangental to the subject which should be considered:

I often hear people with broken turbos blaming "excessive boost". Boost pressure will almost never destroy a turbo in itself. Higher turbo duty cycles can increase the heat a little, and if the boost does not taper before redline increasing it too much may spin the compressor outside the boost map. But very rarely is the peak boost to blame for turbine failure. Most turbochargers are more than adequately designed for pressure ratios approaching and exceeding 3:1. At sea level that's roughly 29 psi of boost pressure. A small turbo on a large engine running at 29 psi will quickly move outside the compressor map towards redline. A small engine with a large turbo will not. Anywhere between those two extremes is a grey area, and excessive boost should not be immediately blamed for the destruction of a turbo.

The reason this is related to the current subject is that often when the boost is raised the factory BOV/BPV is no longer adequate and you get mild compressor surge/stall. This, over the course of time, causes bearing failure. Combined with spinning the turbo to the far right of the compressor map (whether at high or low boost) is generally what causes turbo bearings to fail pre-maturely even when well maintained.

Sorry for the slight off-topic, but I thought it should be considered. Also remember that an aftermarket BOV/BPV can cause exactly the same problem if not setup correctly. Most "one size fits all" BOV's will cause mild compressor surge. Not all do, but some. You should always check for surge if you've installed a new BOV/BPV to ensure a long and happy turbo life.

Dubbya~
 

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Can't agree more - Not all aftermarket BOV/BPVs (or any other contraption that will allow pressure relief - not to be confused with Pop-of valves, however) are made to serve a forced induction motor adequately.

As Adrian mentioned, the bearing takes a lot of the stress, and IIRC, the factory thrust bearing is a 300* unit. Aftermarket ones are outfitted with 360* ones, which give greater endurance and ability to take higher limits.

This, of course, doesn't have much to do with the issue at hand, but a good thing to keep in mind, nonetheless.

Cheers!
 
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