I’ve been hearing a strange noise that seems to be coming from the BOV. I came to that conclusion because I only hear it after coming off of boost. It almost sounds like a muffled squeaking sound. It has also happened in more of an oscillating pattern under slight load at a steady speed (60mph, 10th gear, slight incline). I do have an aftermarket intercooler and I double checked to make sure I reinstalled the BOV harness in case that could’ve been causing the odd noises. Should I normally expect to hear anything from the stock BOV? If it is the BOV acting funny should I be concerned?
What does a stock blow off valve sound like?
- Thread starter MHay
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TheDoug
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The stock valve is pretty quiet but I can hear it. When you refer to the oscillating pattern, do you mean the turbo gauge is fluttering back and forth quickly?
If so i have had this happen occasionally as you described. I also have an aftermarket intercooler with a tune and other mods. I do not recall it doing this stock. I need to data log to see what's happening but have been lazy.
If so i have had this happen occasionally as you described. I also have an aftermarket intercooler with a tune and other mods. I do not recall it doing this stock. I need to data log to see what's happening but have been lazy.
Even stock, under low RPM with load on the engine the boost gauge will flutter. Mine does it at least twice per trip ( I live in mountainous terrain). It’s odd for sure and I can stop it by coming completely out of the throttle and then getting it to downshift.
Ouch! How many miles… I hope still under warranty. At the conditions you described (10th gear, slight incline) the engine should be under a steady boost condition.
A somehow popular issue with older gen ecoboost was exhaust leak due to warped exhaust manifold that makes a squeaking sound under boost. See 1:09-1:15 from this video by Aaron Hines for what I am talking about: https://youtu.be/3r9-UT_3kyY
I’m tuned and have a CAÍ I’ve gotten the turbo flutter just as you described both tuned and stock. Sounds like the turbo is over boosting and pressure is going backwards. That’s the conclusion I’ve come up with but it’s only a theory at this point since it makes the exact sound as when that happens.
That's a reasonable assumption. The turbo spools up but the throttle plate isn't opened up enough to accept the large quantity of air. The air then pulses back through the intake to the turbos. The stock BOV may be opening but even so, it routes the air back into the intake track in front of the turbos so it gets caught in a feedback loop... If one were to ditch the stock BOV or simply disconnect the intake return pipe and cap it, then the issue may go away. Possibly? On my previous ecoboost F150, I ran a Turbosmart BOV. While the noise was cool to hear winter road grime locked it up and I would have to take it off, disassemble, and clean it at minimum once a year...
TheDoug
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This is slightly off the op's topic, but how loud was your aftermarket blowoff valve? Can you make it quieter with some adjustment?
I run them on my F150 and have a tune. Under hard load and fast let off of the gas it puts a smile on my face. If the windows are down it is quite noticeable but otherwise not so much. However that is when operating VTA mode. If you reconnect the lines back to the air return it shouldn't be very noticeable. Also note that if you live in an emissions controlled state you must reconnect those lines.
The turbosmart had a very noticeable pshhhh under heavy load when you dropped off the throttle but was very quite under normal circumstances. An after market tuning company should be able to modify when the pcm tells the valve to open and for how long.
There is no way to reconnect the stock re-circulation tube to the turbosmart BOV so they provide a billet cap that locks inplace onto it to prevent road debris from entering the intake track.
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I need to look more closely at the turbo gauge to see if it’s fluttering. I hadn’t been paying attention to it much until recently, but I didn’t really notice the gauge bouncing back and forth when I happened to glance while the truck was making the sounds.
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