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Discussion Starter #1
Hi. Back in August I had my RS tuned - dyno tune, stage 1, by a well regarded local tuner. The car has no mechanical mods. Since then I've noticed a "chirp" when hitting the throttle to 100% and the engine is under load. Please have a listen to the linked clip. In making the clip I adjusted the audio and repeated one slice of audio 6 times to make it easy to hear the chirp sound. In reality the chirp is just audible.
Video clip with audio of the "chirp"
I suspect a boost leak, but where do I start? I have checked for obvious disconnected pipes and tightened the IC piping - at least those pipe I can reach without removing the front bar. The sound does not continue longer than one short chirp even when holding maximum boost (about 1.5 bar = 22 psi), and I'd expect a boost leak sound to continue for longer. Could this be the the 'bypass valve' (BOV) leaking? Perhaps the boost is spiking and causing some other problem? There is no CEL and no codes. Thanks for any experience with this.
 

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Are you able to do any data logging at all? A quick look at the log should show you if you are having a boost leak or not.

Judging from when the chirp comes in vs the rev range, it sounds like it has something to do with your recirc/bypass valve actuating. It's relatively easy to access and check (search youtube for DIYs). You can also upgrade it since there seems to be quite a few options out there ie Mountune, Boomba, etc.
 

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If it was a boost leak, it would be a sustained whistle or whine (I know I’ve had a few leaks). I’ve never heard a noise like that before
 

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I'm not in a place where I can listen ,but if it's a chirp right on innitial acceleration, it's pretty well documented on here and I don't think anyone ever solved it.

Sent from my SM-N960U using Tapatalk
 

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Dont forget the "chirp" problem from the front hubs. Plenty of history in search. Lubrication was the cure.

Ciao
 

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Discussion Starter #6
Are you able to do any data logging at all? A quick look at the log should show you if you are having a boost leak or not.

Judging from when the chirp comes in vs the rev range, it sounds like it has something to do with your recirc/bypass valve actuating. It's relatively easy to access and check (search youtube for DIYs). You can also upgrade it since there seems to be quite a few options out there ie Mountune, Boomba, etc.
Thanks BigFatFlip. I don't have data logging ability unfortunately. I agree with your thinking re the recirc valve. I could remove it to check for a split or whatever, but I may as well replace it while its out. But will I need to have the car tuned again if I change the recirc valve (not a venting type).?
 

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Discussion Starter #7
Dont forget the "chirp" problem from the front hubs. Plenty of history in search. Lubrication was the cure.

Ciao
Thanks Phil. I did not know about that so I looked at the threads on that topic - they all talk about low speed, low throttle applications, and that's not the scenario I'm facing. Also there's a recording of the hub 'chirp', and its quite different from the sound I'm hearing. So I think its a different problem.
 

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Thanks BigFatFlip. I don't have data logging ability unfortunately. I agree with your thinking re the recirc valve. I could remove it to check for a split or whatever, but I may as well replace it while its out. But will I need to have the car tuned again if I change the recirc valve (not a venting type).?
No need for a retune if simply replacing it with a recirc valve like the Mountune. A venting type (ie blow off valve) doesn't need a tune either but may need some tweaking (using a BRA/boost reference adapter, messing with the springs, etc.) to get the right noise and drivability.
 

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Thanks Phil. I did not know about that so I looked at the threads on that topic - they all talk about low speed, low throttle applications, and that's not the scenario I'm facing. Also there's a recording of the hub 'chirp', and its quite different from the sound I'm hearing. So I think its a different problem.
I thought it may be a long shot, but considered that it might only create the hub noise as the engine hit peak torque.

Ciao
 

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Discussion Starter #10
90% sure I've resolved this. The last intake clamp I checked was finger tight. See the circled clamp in the pic. I needed to get a 1/4" flexible drive because the starter solenoid is in the way, hence it took this much time to check & tighten (I was OS for 2 weeks also...). A quick repeat of a road test where the chirp was previously heard resulted in ... no chirp! I've never touched this part (as proven by my lack of a tool that could get to it!) so again I'll blame the anonymous tech who did the HG.

So there you are... a boost leak may not make a continuous noise while on boost - it can be just a short burst of sound.

338061
 

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Discussion Starter #12
:cry:
I was wrong - the 10% chance that this was not resolved has occurred. Pushing the car hard enough brought the chirp sound 'back'. My earlier testing didn't get the car hot/boosted/sweaty enough. I was also wrong to describe the sound as brief - it does continue while on boost.

Here is another clip - this time a 'real time' (not looped) 30 seconds of pushing the car through some corners, up a hill to get sufficient load. You'll need to listen carefully to hear the 'chirp' or 'whistle' sound.
RS chirp sound v1

So is it:
  • A boost leak? From where?
  • Something the 'Sound Suppression Chamber' will fix?
  • Leaking bypass valve (BOV)? - see * below.
  • Leaking wastegate?
  • Noise from the throttle closing?
  • Small furry animals?
Thanks for your ideas.

I need to fix this, because I do not want to take this to a Ford dealer. Imagine: "Hi. Please beat the hell out of my car so you can prove that I'm not making this up".

* A comment on my first clip on youtube from an owner with the same issue said that he replaced the recirc valve, but it did not fix it.
 

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:cry:
I was wrong - the 10% chance that this was not resolved has occurred. Pushing the car hard enough brought the chirp sound 'back'. My earlier testing didn't get the car hot/boosted/sweaty enough. I was also wrong to describe the sound as brief - it does continue while on boost.

Here is another clip - this time a 'real time' (not looped) 30 seconds of pushing the car through some corners, up a hill to get sufficient load. You'll need to listen carefully to hear the 'chirp' or 'whistle' sound.
RS chirp sound v1

So is it:
  • A boost leak? From where?
  • Something the 'Sound Suppression Chamber' will fix?
  • Leaking bypass valve (BOV)? - see * below.
  • Leaking wastegate?
  • Noise from the throttle closing?
  • Small furry animals?
Thanks for your ideas.

I need to fix this, because I do not want to take this to a Ford dealer. Imagine: "Hi. Please beat the hell out of my car so you can prove that I'm not making this up".

* A comment on my first clip on youtube from an owner with the same issue said that he replaced the recirc valve, but it did not fix it.
How about you load the std tune back in and see if it still does it.

Ciao
 

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:cry:
I was wrong - the 10% chance that this was not resolved has occurred. Pushing the car hard enough brought the chirp sound 'back'. My earlier testing didn't get the car hot/boosted/sweaty enough. I was also wrong to describe the sound as brief - it does continue while on boost.
Bummer, finding that a fix you thought addressed the issue but turns out not to is the worst feeling lol. I know that feel bruh...

That said, with that bit of info (having to have the car "hot") does suggest that it has something to do with thermal expansion, which could mean something rubber or small metal item (since larger metal items don't typically expand to that extent at operating temps).

As I mentioned above, I would start with the easy stuff: check all the easily accessible hoses for cracks, tighten all the clamps (or check hoses with spring clamps for damage or partial install) and check the bypass valve (I know you had a comment on your video about replacing it not working, but still doesn't mean yours can't be faulty).

Good luck!
 

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Discussion Starter #15
Thanks kindly for your feedback and suggestions. I decided to replace the recirculation valve as it was 'suspect', and an easy target without any down-side except cost. Fitted a Ford Performance valve as discussed in another thread.
Unfortunately it has not resolved the issue i.e. the 'chirp' remains. The OEM valve I removed looked fine i.e. not damaged.

I think the next troubleshooting task is to remove and inspect the intake pipe work from filter to manifold. For me that's a large-ish task since it requires removing the cowl to get to the turbo clamp and the bumper to get to the intercooler.

Phil - the car was dyno tuned by UPG - only they can return it to stock i.e. I don't have the flashing device or map. I'd be fairly confident that returning it to stock would 'hide' the chirp, as the chirp occurs at full boost (1.5 bar) but below about 5000 rpm, a combination that did not occur on the stock tune. (The increase in torque at lower revs is of course the benefit of the tune.)

Another consideration is that the car is running fine. The 'chirp' has been with me since August and the car has travelled nearly 10,000 km, much it driven hard on a back road run Melbourne-Brisbane. No problems, no DTCs <touch wood>.

Other suggestions very welcome.
 

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Thanks kindly for your feedback and suggestions. I decided to replace the recirculation valve as it was 'suspect', and an easy target without any down-side except cost. Fitted a Ford Performance valve as discussed in another thread.
Unfortunately it has not resolved the issue i.e. the 'chirp' remains. The OEM valve I removed looked fine i.e. not damaged.

I think the next troubleshooting task is to remove and inspect the intake pipe work from filter to manifold. For me that's a large-ish task since it requires removing the cowl to get to the turbo clamp and the bumper to get to the intercooler.

Phil - the car was dyno tuned by UPG - only they can return it to stock i.e. I don't have the flashing device or map. I'd be fairly confident that returning it to stock would 'hide' the chirp, as the chirp occurs at full boost (1.5 bar) but below about 5000 rpm, a combination that did not occur on the stock tune. (The increase in torque at lower revs is of course the benefit of the tune.)

Another consideration is that the car is running fine. The 'chirp' has been with me since August and the car has travelled nearly 10,000 km, much it driven hard on a back road run Melbourne-Brisbane. No problems, no DTCs .

Other suggestions very welcome.
You don't have to actually remove the cowel to get to the turbo.

Sent from my SM-N960U using Tapatalk
 

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...I decided to replace the recirculation valve as it was 'suspect', and an easy target without any down-side except cost. Fitted a Ford Performance valve as discussed in another thread.
Unfortunately it has not resolved the issue i.e. the 'chirp' remains.

Damn! I was really hoping that was the solution. I had convinced myself the little stock recirc diaphragm wasn't holding up. Subscribed to hope we get an answer some day.
 

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Thanks kindly for your feedback and suggestions. I decided to replace the recirculation valve as it was 'suspect', and an easy target without any down-side except cost. Fitted a Ford Performance valve as discussed in another thread.
Unfortunately it has not resolved the issue i.e. the 'chirp' remains. The OEM valve I removed looked fine i.e. not damaged.

I think the next troubleshooting task is to remove and inspect the intake pipe work from filter to manifold. For me that's a large-ish task since it requires removing the cowl to get to the turbo clamp and the bumper to get to the intercooler.

Phil - the car was dyno tuned by UPG - only they can return it to stock i.e. I don't have the flashing device or map. I'd be fairly confident that returning it to stock would 'hide' the chirp, as the chirp occurs at full boost (1.5 bar) but below about 5000 rpm, a combination that did not occur on the stock tune. (The increase in torque at lower revs is of course the benefit of the tune.)

Another consideration is that the car is running fine. The 'chirp' has been with me since August and the car has travelled nearly 10,000 km, much it driven hard on a back road run Melbourne-Brisbane. No problems, no DTCs <touch wood>.

Other suggestions very welcome.
Maybe try upgrading the sound suppressor. It seems the intake system is right on the limit of the std one which cant even deal with a simple change of air filter. They are pretty cheap. Maybe the tune changes the schedule or rate of opening of the throttle valve which creates an effect in the intake syatem.

Ciao
 

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Maybe try upgrading the sound suppressor. It seems the intake system is right on the limit of the std one which cant even deal with a simple change of air filter. They are pretty cheap. Maybe the tune changes the schedule or rate of opening of the throttle valve which creates an effect in the intake syatem.

Ciao
Huh, interesting idea. I did change the filter... Maybe that really is it. I'll order one tonight, see if that does the trick.

I figured the suppressor was just for the big sucking sound when cold starting the car with a new filter. Worth a shot though.
 

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The suppressor is for the annoying and very noticeable, whistle, almost like a kettle, that happens on cold start, which is VERY noticeable, it does nothing for the big sucking noise, which is normal.
 
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