Intake for turbo noise?

[Cursed Bronco]

Hello! Has anyone replaced their intake, particularly on the 1.5, with a CAI and had it result in more audible turbo noise?

I know the 1.5 isn't really a performance engine, but there have been numerous times where I hear the obvious compressor surge "stutututu" sound. I would like to explore if any intakes increase the intake sound substantially and amplify any turbo noise?

I understand the intake is tuned pretty well from stock, so this would just be for vanity.

Thanks!

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[gatornek]

Sir, if you're hearing "compressor surge", then there may be a problem with your blow off valve. You should never be hearing the "shtututututu" sound in a stock setup.

On my Mustang, I run an oversized intercooler, about twice the size of stock. I kept the OEM blow off valve, and its a fairly small diameter tube. So with full-on WOTS, as soon as I release the throttle, you can her the whoosh of a fully charged intercooler trying to dump its contents back into a small tube, and then, at the very, very end, you hear the smallest whisper of a 'shtutu". That, in my opinion, is a good sound on my tuned 2.3 full bolt-on Mustang. Not sure about "shtututututututu" on a 1.5 stock Bronco Sport.

 

[Cursed Bronco]

Sir, if you're hearing "compressor surge", then there may be a problem with your blow off valve. You should never be hearing the "shtututututu" sound in a stock setup.

On my Mustang, I run an oversized intercooler, about twice the size of stock. I kept the OEM blow off valve, and its a fairly small diameter tube. So with full-on WOTS, as soon as I release the throttle, you can her the whoosh of a fully charged intercooler trying to dump its contents back into a small tube, and then, at the very, very end, you hear the smallest whisper of a 'shtutu". That, in my opinion, is a good sound on my tuned 2.3 full bolt-on Mustang. Not sure about "shtututututututu" on a 1.5 stock Bronco Sport.

I'm not sure I agree with you about a problem with the BOV, but I have nothing to back that up so maybe you are correct. It does happen only in a precise gear band and, like you said, when releasing after WOT. I do not believe it is audible outside the vehicle as you can barely hear it internally as well. It's very hard to actually make it make noise, though.

Also, I was doing research before on upgrading a BOV for that precise sound, but found a lot of conflicting information suggesting it wouldn't work on the 1.5 anyway because of engine design.

 

[gatornek]

I'm not sure I agree with you about a problem with the BOV, but I have nothing to back that up so maybe you are correct. It does happen only in a precise gear band and, like you said, when releasing after WOT. I do not believe it is audible outside the vehicle as you can barely hear it internally as well. It's very hard to actually make it make noise, though.

Also, I was doing research before on upgrading a BOV for that precise sound, but found a lot of conflicting information suggesting it wouldn't work on the 1.5 anyway because of engine design.

I would defer to other 1.5 owners here. I don't hear the slightest hint of a compressor surge on my BS; and that would be mostly due to the closed element air intake and a fully functioning BOV. But Im also RARELY wot'ing my Bronco Sport ... and that's really the only time you're going to build up enough pressure to hear anthing. Again, if its loud enough to be fully discernable ... it would be eyebrow raising to me, at this point, based on my experience in the 2.0

Its possible you may be focusing on such a quiet sound, no one else in a 1.5 has really noticed due to things like road noise, radio, air conditioning, etc.

 

[davidg4781]

I've noticed that sound and not going WOT. This is my first turbo car so I thought it's a normal thing. It's very quiet. I want to say I usually hear it on my way to work. Maybe it's something with a colder engine? I'll try to keep an ear on it today.

 

[gatornek]

This is my first turbo car

I think we're getting to the bottom of what's happening here. ?

I think you guys are overstating the sound.

This is what compressor surge sounds like:


That was off a faulty BOV. If its not that, then it ISN'T compressor surge

 

[Mark S.]

Compressor surge occurs when the turbo is producing high boost at low RPM. If you are only hearing the noise when you close the throttle then you are not hearing compressor surge. These engine incorporate an electronically controlled recirculation valve, which opens when you close the the throttle to allow high-pressure air between the compressor and throttle body to flow back into the intake tract ahead of the turbocharger. (Note: this is different from a blow-off valve, which vebts to atmosphere, making the hissing sound desired by some.)

Because the recirc valve is electronically operated, the PCM may open it even at partial throttle, not just a full throttle. My guess is the noise you are hearing is the recirc valve operating after you let off full throttle without fully closing the throttle. The PCM may open and close the recirc valve under whatever the parameters Ford programmed it for. As it opens and closes you may hear pressurized air moving around in the intake system.

EDIT: My fingers got a bit ahead of my brain. Compressor surge generally only occurs on engines that do not have a way to release pressurized air between the turbine compressor and the throttle.

 

[Cursed Bronco]

I think we're getting to the bottom of what's happening here. ?

I think you guys are overstating the sound.

This is what compressor surge sounds like:


That was off a faulty BOV. If its not that, then it ISN'T compressor surge

Yes, this is the sound but it is not every time. It is when coming off the throttle, sometimes, under a hard pull. I think it's more likely there's a very small band where boost is sufficient when releasing the throttle. Unless I have a faulty BOV that is only randomly messing up.

 

[Cursed Bronco]

Compressor surge occurs when the turbo is producing high boost at low RPM. If you are only hearing the noise when you close the throttle then you are not hearing compressor surge. These engine incorporate an electronically controlled recirculation valve, which opens when you close the the throttle to allow high-pressure air between the compressor and throttle body to flow back into the intake tract ahead of the turbocharger. (Note: this is different from a blow-off valve, which vebts to atmosphere, making the hissing sound desired by some.)

Because the recirc valve is electronically operated, the PCM may open it even at partial throttle, not just a full throttle. My guess is the noise you are hearing is the recirc valve operating after you let off full throttle without fully closing the throttle. The PCM may open and close the recirc valve under whatever the parameters Ford programmed it for. As it opens and closes you may hear pressurized air moving around in the intake system.

I don't disagree that this may be causing a sound, but I do in fact hear the stututu from the video gatornek just posted. Does the re circulation valve act like a BOV? From my research, the 1.5 doesn't have a traditional BOV but I do hear the stututu and not as much of PSHHH like a BOV sound.

 

[Bucko]

Save the money spent on a CAI. Invest it in other useful stuff.

 

[V8 Yankee]

I have a aFe CAI on my 1.5. The turbo noise doesn't become noticeable till around 3000 rpm and really sings at 5000. The turbo sounds even better IMO with the CAI. I also have a custom exhaust to add to the sound salad the little dragon makes when wound up. I might be biased but my 1.5 sounds better than most 4 cylinder cars with similar mods. The video posted sounds nothing like mine, I would look at the few things others have mentioned. If its under warranty get it into the shop in case its something more serious, ( and expensive ).

 

[V8 Yankee]

Good post

 

[gatornek]

I don't disagree that this may be causing a sound, but I do in fact hear the stututu from the video gatornek just posted. Does the re circulation valve act like a BOV? From my research, the 1.5 doesn't have a traditional BOV but I do hear the stututu and not as much of PSHHH like a BOV sound.

The recirculation acts exactly the same as a blow off valve, except there's a tube attached from the valve back to the CAI in the 'recirclation' setup, wheras in the 'blow off' setup, that pressure is simply released to atmosphere.....the "psssssshhhttttt" sound a lot of turbo owners purposefully love for some reason.

To be clear, the video I posted above was off a BAD valve by Turbosmart. I had to return it. Your car should not be doing that. That is compressor surge. So its strange to me that you are describing it as what is happening to you, and also that a CEL has not come up.

 

[Mark S.]

I don't disagree that this may be causing a sound, but I do in fact hear the stututu from the video gatornek just posted. Does the re circulation valve act like a BOV? From my research, the 1.5 doesn't have a traditional BOV but I do hear the stututu and not as much of PSHHH like a BOV sound.

I made an edit to my previous post; my fingers sometimes get ahead of my brain...

A recirc valve serves the same purpose as a BOV: it prevents pressurized air between the compressor and the throttle from slowing the compressor turbine when you close the throttle. If the turbine slows down, it must get back up to speed before producing boost, which contributes to turbo lag. Turbocharged engines that lack a means to release the pressurized air between the compressor and the throttle will make that typical "chuffing" or "chattering" sound many call "compressor surge" when you close the throttle:



Mechanical recirc or blow-off valves simply close when the throttle closes--these are connected with a vacuum line to the intake between the throttle and the intake manifold. When you close the throttle you create a vacuum in the intake manifold which opens the BOV. When a BOV operates you'll hear a whooshing or hissing sound as the pressurized air escapes.

I haven't found any data online regarding type/location/operation of the recirculation valve on the 1.5L engine, but I'm almost certain Ford included a means to release pressurized air to prevent slowing the turbine and subsequent turbo lag. If it's a recirc valve then it likely functions the same as Ford's other EcoBoost engines. That is, it's electronically controlled by the PCM. Electronic control allows designers more flexibility in when and how much the valve opens. As such, they do not require the throttle to be fully closed before they open, and they may be partially open during partial throttle application. You may be hearing the movement of pressurized air around your intake system as that valve opens and closes. I don't think what you're hearing is compressor surge.

 

[Bucko]

.... that pressure is simply released to atmosphere.....the "psssssshhhttttt" sound a lot of turbo owners purposefully love for some reason.
...

So how come when I create that noise while sitting in the passenger seat after a bowl of pinto beans, my wife gets mad?

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