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Black 2008 Saturn Sky Redline (manual)
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Discussion Starter · #1 ·
Last fall the GF bought a 07 redline with many aftermarket bolt ons. There is definitely a tune along withCAI, charge pipes, bigger intercooler, catless DP, and opel injectors (or so I was told on that one), and bosch MAP sensors. I just replaced stock ducting that was previously removed under the car to make the bumper more secure and ensure proper airflow to the radiator as they had not been replaced after the mods.

That brings me to the issue that I'm having with the car now. I've been doing some hard acceleration road testing and found that it no longer gets the 24psi boost that it had previously. I'll see 15 psi on the dash readout maybe 16 psi at WOT and once it peaks there I hear a high pitch whistle that is definitely not not a normal turbo whine/whistle. There are no CEL's (yet) and I've searched the forum as well as a general google search and haven't found anything conclusive. Partly because I'm not sure what part is failing, if any. I'm comfortable wrenching, but I am fairly inexperienced and am constantly learning here. With my limited knowledge and experience I want to say that it may be a blow off valve issue, but I am uncertain. Any help in diagnosing this would be grateful.
 

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The stock intercooler hose clamps are known to be a problem at high boost, and there are aftermarket replacements available that are significantly stronger. Are yours stock, or were they replaced with the intercooler?
 
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Black 2008 Saturn Sky Redline (manual)
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Discussion Starter · #3 ·
There's a mix of t-bolt and standard worm drive clamps. I've gone through those hoses and they are as tight as I can reasonably get them. May end up getting some quality t-bolt clamps if there's not an obvious reason for this.
 

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The only other thing that I can think of would be the MAP sensor o-rings.

Clearly I don't have any real answers for you.
 
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There's a mix of t-bolt and standard worm drive clamps. I've gone through those hoses and they are as tight as I can reasonably get them. May end up getting some quality t-bolt clamps if there's not an obvious reason for this.
This is the standard set-up from the factory, but - as JR said - the worm clamps on the driver side have been known to 'let go' under pressure (and yet still look fine). HOWEVER, if you get a boost leak, you should also get codes and have the car go into 'limp mode', shutting down any boost. I've never heard of a leak just reducing pressure.

In case it is just a leak though, you can:
a) undo those worm clamps and make sure the grip slots are not worn (see pic here: Stock charge pipe hose coming loose question... pics...)
b) check under your car for a cracked/damaged or ballooned intercooler.

Lastly, another similar post here (though it doesn't explain the sounds): CEL. P2178
 

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This is going to sound odd but it could be totally fine. (Though the whistling sound would be a clue it isn't.)

Trifecta is a company that offers tunes for these cars and their tunes have an on/off feature. You can turn the tune off and, if you do, you'd see boost levels like you mention. Normally it was set to the cruise control master switch (master cruise on = tune off...because why would you need the extra power if you are planning on using cruise control is I guess their logic????) but it could be configured to other switches/conditions. Not sure how to tell if you have a Trifecta tune or not...and like I said the whistle is odd...but may be worth a shot.
 

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Black 2008 Saturn Sky Redline (manual)
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Discussion Starter · #7 ·
Well, as of right now I managed to get it back to normal operation. After John said to check the clamps, I decided to go back through them. Of course I end up with egg on my face. The passenger side intercooler hose wasn't engaged all the way and the clamp was tightened down above the pipe. 🤦 Not sure about the whistle sound.

Now there's a check engine light, but that's an adventure for another time.

Thanks again for the advice.
 

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Find out what the new engine light code is? Replacing the worm style clamps
with T-clamps is the ticket. I have one worm clamp left on mine. Seems the original
owner replaced most of them before I bought the car.
The whistling sound is an odd one though- during boost, or when letting off the gas?
Turbo related- diaphragm, vac hose, blow off valve? Can it be reproduced while sitting
still in the driveway or garage? Is this happening only under your hard test runs?

LAC
 

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Black 2008 Saturn Sky Redline (manual)
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Discussion Starter · #9 · (Edited)
The whistling sounded like the blow off valve when letting off the throttle but constant at peak 15 psi boost. Wondered if it was that the boost loss was causing BOV to react that way. I could be not understanding the system correctly though.

Haven't checked the code yet, but we've had one before for running rich. The tune was originally done in Louisiana and we have it in Kansas now. Wonder if we'll need to get it retuned because of that. The guy we bought it from said it had been done with HP tuners. So shouldn't be too much trouble. Just the cost of ownership.

Makes me hesitant to do similar mods to mine. I'm enjoying the stock setup with the trifecta. Not too noisy, more manageable to drive casually, and less troubleshooting.
 

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I was thinking that the whistle was the air escaping through the loose hose.

The closer to the edge you push something to get the ultimate performance, the more likely you are to fall off of that edge.
 
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I had that whistle as well, and I think I asked on here a few years back. I had a bad injector replaced and it hasn't happened since.
 

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If the whistle sounds half way between a squealing fan belt and the air escaping out of an inflated balloon stretched taught at the opening (that would be the shrieking version, not the flatulent version), that is the sound of air escaping past a loose hose clamp. Check all your clamps and/or replace the worm-drive clamps with t-bolt clamps.

Also, nobody has mentioned checking your intercooler for bulges or cracks -- not sure if that would produce a whistle or not.

Finally, you mentioned you now have a code, you should read that code. There are a few codes that can be thrown when metered air escapes the system. If you recently tightened clamps and the codes could be about lost metered air, you should reset the codes and see if they come back (because you might have already fixed them by tightening the clamps).
 
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Black 2008 Saturn Sky Redline (manual)
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Discussion Starter · #13 ·
Boost issue fixed. Was a hose clamp that I missed when checking previously. The code has to do with the catless downpipe and downstream O2 sensor. Getting that sorted next week. Thanks for the help though!
 
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