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Discussion Starter · #1 ·
hey guys,
recently upgraded my stock exhaust to an injen ses 3" exhaust. I'm currently tuned and finalized it before this upgrade.
but after the upgrade, i get a pulsating exhaust note between gears around 3-4k rpm with the pedal about 35%. easy reproducible. my tuner is working on it, but it seems he has to tune it down a bit. i was hoping to go up in power. you think there's an underlying (mechanical)issue going on here? just looking for a good starting point. thank in advance!
 

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Do you have your sound symposer hooked up still? Some users have reported the two notes "interfering" and creating a sound similar to this.
 

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Discussion Starter · #3 ·
Do you have your sound symposer hooked up still? Some users have reported the two notes "interfering" and creating a sound similar to this.
actually its deleted. sounds horrible with a loud exhaust. i have another flash tune that sounds fine. but its a flash tune, not much for power. my custom tune has power, but my tuner is having to bring it down to get the note to settle. just wondering if i need to start looking into a mechanical issue.
thanks for the heads up btw!
 

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I have a custom Freektune and it does the same thing. I sent Justin logs of the WGDC and he said everything looks fine. Same thing - with the flash tune I have it does not pulse. I've just gotten used to it, and now I hardly even notice it.
 

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Discussion Starter · #5 ·
I have a custom Freektune and it does the same thing. I sent Justin logs of the WGDC and he said everything looks fine. Same thing - with the flash tune I have it does not pulse. I've just gotten used to it, and now I hardly even notice it.
well, i'll let you know on my side. let me see what we end up with after all the tuning. on rev7 now...
 

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I have a stratified tune and MBRP exhaust and sometimes on startup when the car is warming up I will get the pulsating exhaust note where I can actually see my RPM needle jumping up and down a bit...and then after it warms up it is gone. This is different than your scenario, but perhaps it can help.
 
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I have a stratified tune and MBRP exhaust and sometimes on startup when the car is warming up I will get the pulsating exhaust note where I can actually see my RPM needle jumping up and down a bit...and then after it warms up it is gone. This is different than your scenario, but perhaps it can help.
Not to remain off topic, but this happens with my car as well. I am also Stratified tuned w/ COBB exhaust. First time it happened I was worried, but now I just ignore the weird looks I get when people think I'm doing it on purpose lol!
 

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Not to remain off topic, but this happens with my car as well. I am also Stratified tuned w/ COBB exhaust. First time it happened I was worried, but now I just ignore the weird looks I get when people think I'm doing it on purpose lol!
Yeah I just ignore it too. It happens once in a while and others on here have said the same.
 

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Log your two tunes and compare them.
Specifically, I'd look at VCT Timing.
Changing when and how the pulses hit the exhaust (which VCT timing does affect) changes the sound.

Unless you're flat out misfiring, my guess is it's just related to that.
 

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Discussion Starter · #11 ·
Log your two tunes and compare them.
Specifically, I'd look at VCT Timing.
Changing when and how the pulses hit the exhaust (which VCT timing does affect) changes the sound.

Unless you're flat out misfiring, my guess is it's just related to that.
thank you for your response! i'll do that(compare logs)! you know, honestly its the stratified 93flash tune that i have that sounds near perfect.
 

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Discussion Starter · #12 ·
Could just be drone too and I wouldn't chase tuning the car around the drone. Best would be to physically change the exhaust to fix it (change/add muffler or res, Helmholtz res, etc.).
well the exhaust has drone too. i CLEARLY understand what that is now:) so i don't think were chasing drone here. i can live with the drone.
this is a pulsing sound from the exhaust, and my only reference at this point is the note, when shifting from 3rd and 4th at the 3 and 4k rpm marks. then will go away around 3.4 and 4.4k respectively as i continue to press the pedal.
weird. i know.
 

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Tuned by Unleashed and I get a pulsating sound on partial acceleration. I'm not sure if it's drone (true resonance can pulse) and if outside the car it sounds completely normal. I've kind of gotten used to it.
 

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I believe the pulsing sounds are the ECU trying to minimize compressor surge. Monitor the BPV PID and you can see it opening and closing in step with the rise of the pulse. It also actuates the wastegate.

I used to run the BPV directly of the manifold and it pulsed really bad so I switched back to solinoid control. Tamed it down but it's still there.
 

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So I posted about this over the last few weeks in the Unleashed page. 16 st3 about 9.5k miles 93 octane tune cpe intake and ford racing exhaust.

Here's a video of you listen close you can hear it.
 

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Discussion Starter · #17 ·
I believe the pulsing sounds are the ECU trying to minimize compressor surge. Monitor the BPV PID and you can see it opening and closing in step with the rise of the pulse. It also actuates the wastegate.

I used to run the BPV directly of the manifold and it pulsed really bad so I switched back to solinoid control. Tamed it down but it's still there.
thanks for the info! i'll look into this
 

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Discussion Starter · #18 ·
So I posted about this over the last few weeks in the Unleashed page. 16 st3 about 9.5k miles 93 octane tune cpe intake and ford racing exhaust.

Here's a video of you listen close you can hear it.
i'll post a vid of mine pulsating when i get back to the states. looks like sometime next week.
thanks for sharing!
 

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I had the MBRP CBE with no tune and it would pulse sometimes. I wish I had paid attention to when exactly it did it, I don't have the car or exhaust anymore to test it. I never though much of it and performance never seemed to be affected. I did two track days and multiple autocrosses with the exhaust on the car and felt no ill effects.
 

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Discussion Starter · #20 ·
I had the MBRP CBE with no tune and it would pulse sometimes. I wish I had paid attention to when exactly it did it, I don't have the car or exhaust anymore to test it. I never though much of it and performance never seemed to be affected. I did two track days and multiple autocrosses with the exhaust on the car and felt no ill effects.
i hear ya! and yeah, i can push through it and it goes away. just annoying sounding though. especially with a loud exhaust.
 
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