85-86 Intake whistle?
10-26-2011, 10:25 PM
#31
I've got a customer with the same issue and we can't seem to seal it up. Seems to be around the TB to T boot. All new stuff though.
10-26-2011, 10:33 PM
#32
Nordschleife Master
I wonder if it is the TB itself. I read somewhere there is an o-ring in the throttle body. Is that o-ring on the DS of the TB? I much fear my intake will be coming off again.
10-27-2011, 12:26 AM
#33
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If the 'T' is properly set into TB/'T' hose, and you can't find any other leaks, try turning up the idle a touch.
680 isn't the law, it's just a nice place to set the CO.
S3s will often idle better at 700+.
With my chipset, TQrings, and big gap plugs, the idle screw is usually turned almost all the way in for 680. This doesn't leave enough bypass air for good idle recovery, especially with manual trans. (The ICV can't do it all.) After setting the CO, back out the TB screw, a turn at a time, until the idle recovery is smooth. (The idle may be around 750 or higher.)
I spent a couple of weeks trying to program around 'the idle recovery problem', finally realizing I could just turn the TB screw.
680 isn't the law, it's just a nice place to set the CO.
S3s will often idle better at 700+.
With my chipset, TQrings, and big gap plugs, the idle screw is usually turned almost all the way in for 680. This doesn't leave enough bypass air for good idle recovery, especially with manual trans. (The ICV can't do it all.) After setting the CO, back out the TB screw, a turn at a time, until the idle recovery is smooth. (The idle may be around 750 or higher.)
I spent a couple of weeks trying to program around 'the idle recovery problem', finally realizing I could just turn the TB screw.
10-27-2011, 06:28 AM
#34
Craic Head
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I doubt that's where the whistle is coming from though.
Whistle usually means unmetered air but it doesn't have to be. In the case of the ISV, the valve will be open or closed based on where the idle set screw is (as Ken notes) and if it's just in the wrong spot it could be acting like a reed instrument with the air flowing over the valve at just the right resonance to whistle. Adjusting the screw will change the size and shape of that aperture so that can't be heard (if that is the source of the whistle). In fact thinking about it, even if it's not the ISV adjusting the idle will change that so no matter where it is, it might fix it anyway (or more accurately silence it).
10-27-2011, 11:15 AM
#35
Nordschleife Master
If the 'T' is properly set into TB/'T' hose, and you can't find any other leaks, try turning up the idle a touch.
680 isn't the law, it's just a nice place to set the CO.
S3s will often idle better at 700+.
With my chipset, TQrings, and big gap plugs, the idle screw is usually turned almost all the way in for 680. This doesn't leave enough bypass air for good idle recovery, especially with manual trans. (The ICV can't do it all.) After setting the CO, back out the TB screw, a turn at a time, until the idle recovery is smooth. (The idle may be around 750 or higher.)
I spent a couple of weeks trying to program around 'the idle recovery problem', finally realizing I could just turn the TB screw.
680 isn't the law, it's just a nice place to set the CO.
S3s will often idle better at 700+.
With my chipset, TQrings, and big gap plugs, the idle screw is usually turned almost all the way in for 680. This doesn't leave enough bypass air for good idle recovery, especially with manual trans. (The ICV can't do it all.) After setting the CO, back out the TB screw, a turn at a time, until the idle recovery is smooth. (The idle may be around 750 or higher.)
I spent a couple of weeks trying to program around 'the idle recovery problem', finally realizing I could just turn the TB screw.
There's an O-ring on each side of the TB where the butterfly rod goes through it (my terms).
I doubt that's where the whistle is coming from though.
Whistle usually means unmetered air but it doesn't have to be. In the case of the ISV, the valve will be open or closed based on where the idle set screw is (as Ken notes) and if it's just in the wrong spot it could be acting like a reed instrument with the air flowing over the valve at just the right resonance to whistle. Adjusting the screw will change the size and shape of that aperture so that can't be heard (if that is the source of the whistle). In fact thinking about it, even if it's not the ISV adjusting the idle will change that so no matter where it is, it might fix it anyway (or more accurately silence it).
I doubt that's where the whistle is coming from though.
Whistle usually means unmetered air but it doesn't have to be. In the case of the ISV, the valve will be open or closed based on where the idle set screw is (as Ken notes) and if it's just in the wrong spot it could be acting like a reed instrument with the air flowing over the valve at just the right resonance to whistle. Adjusting the screw will change the size and shape of that aperture so that can't be heard (if that is the source of the whistle). In fact thinking about it, even if it's not the ISV adjusting the idle will change that so no matter where it is, it might fix it anyway (or more accurately silence it).
Definitely a must read before any intake refresh I will check out your suggestion. Thanks.
10-27-2011, 07:41 PM
#36
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I've been hunting leaks in my intake for a few months now. Installed a turbo last year. And the extra air has exposed all the leaks I have in my intake. When I pressurized my intake at the TB near the firewall, I would hear a loud whistle. The car also would buck under boost. So I assumed that the leak was causing a lean condition......thus the bucking. After replacing the center section of the Plenum with Purosil and using T-bolt clamps on the 3" plenum sections, and the vertical 3" section going into the center throttle body....... I have no whistling!!! Was going to fire it up and see how it idled and the battery was dead. I'll fire it up tomorrow and take it for a spin to see if the plenum leaks were the cause of my leaks/whistling.
Hopefully I'm getting closer or maybe fixed it!?!
Hopefully I'm getting closer or maybe fixed it!?!
10-27-2011, 07:45 PM
#37
Lemme know what you find Pele, are you going to bring it down to 3rd Coast?
10-27-2011, 09:23 PM
#38
Nordschleife Master
I've been hunting leaks in my intake for a few months now. Installed a turbo last year. And the extra air has exposed all the leaks I have in my intake. When I pressurized my intake at the TB near the firewall, I would hear a loud whistle. The car also would buck under boost. So I assumed that the leak was causing a lean condition......thus the bucking. After replacing the center section of the Plenum with Purosil and using T-bolt clamps on the 3" plenum sections, and the vertical 3" section going into the center throttle body....... I have no whistling!!! Was going to fire it up and see how it idled and the battery was dead. I'll fire it up tomorrow and take it for a spin to see if the plenum leaks were the cause of my leaks/whistling.
Hopefully I'm getting closer or maybe fixed it!?!
Hopefully I'm getting closer or maybe fixed it!?!
10-28-2011, 12:12 AM
#39
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10-28-2011, 12:14 AM
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10-28-2011, 01:22 PM
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10-28-2011, 04:19 PM
#43
Nordschleife Master
I need to find someone local with a smoke machine. They are pricey!
12-06-2011, 08:23 PM
#44
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Ken, can you adjust the idle screw at the TB with the plenums on? Seems pretty tight there. I'm having poor idle recovery too. I wouldn't mind having a slightly higher idle anyway.
BTW, your torque tubes worked out great! Everything seems so much more solid on the small runner couplers.
BTW, your torque tubes worked out great! Everything seems so much more solid on the small runner couplers.
If the 'T' is properly set into TB/'T' hose, and you can't find any other leaks, try turning up the idle a touch.
680 isn't the law, it's just a nice place to set the CO.
S3s will often idle better at 700+.
With my chipset, TQrings, and big gap plugs, the idle screw is usually turned almost all the way in for 680. This doesn't leave enough bypass air for good idle recovery, especially with manual trans. (The ICV can't do it all.) After setting the CO, back out the TB screw, a turn at a time, until the idle recovery is smooth. (The idle may be around 750 or higher.)
I spent a couple of weeks trying to program around 'the idle recovery problem', finally realizing I could just turn the TB screw.
680 isn't the law, it's just a nice place to set the CO.
S3s will often idle better at 700+.
With my chipset, TQrings, and big gap plugs, the idle screw is usually turned almost all the way in for 680. This doesn't leave enough bypass air for good idle recovery, especially with manual trans. (The ICV can't do it all.) After setting the CO, back out the TB screw, a turn at a time, until the idle recovery is smooth. (The idle may be around 750 or higher.)
I spent a couple of weeks trying to program around 'the idle recovery problem', finally realizing I could just turn the TB screw.
12-07-2011, 01:31 AM
#45
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Yes. You may have to move a small vacuum line out of the way (with a long screwdriver) while you connect the 7mm socket, but it's readily accessible.