What's that "hybrid" sound when braking?

CivicChina

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My manual 1.5t doesn't make any sound. Isn't it something related to cvt?
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kered424

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I don't believe its the turbo. I have an EX with a naturally aspirated engine, and I have that noise as well.
 

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My manual 1.5t doesn't make any sound. Isn't it something related to cvt?
Hate to reply to a third person here but I suspect that it's the CVT upshifting as you approach a stop. IIRC the CVT doesnt use a torque converter, instead uses a wet clutch (which is why it's a bit "jerky" in quick stop and go traffic) so I imagine the creeping-forward gear ratio is pretty low, so the sheaves probably need to move pretty far to get that gearing.
 


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Hate to reply to a third person here but I suspect that it's the CVT upshifting as you approach a stop. IIRC the CVT doesnt use a torque converter, instead uses a wet clutch (which is why it's a bit "jerky" in quick stop and go traffic) so I imagine the creeping-forward gear ratio is pretty low, so the sheaves probably need to move pretty far to get that gearing.
I am pretty sure it has a torque converter, I remember reading that in the launch technical bulletin
 

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It's not the CVT. If it downshifts to assist, you would see RPM changing too. I myself have never heard a "whirring" sound but it is most likely an electronic brake booster.
 

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It's not the CVT. If it downshifts to assist, you would see RPM changing too. I myself have never heard a "whirring" sound but it is most likely an electronic brake booster.
Not really... The sound only occurs when you're almost completely stopped like in the last second of a stop. The CVT isn't downshifting to assist in braking... It's downshifting so that when you accelerate you're not lugging the engine. It absolutely does downshift, and I can guarantee that. That isn't the question. The question is, if the downshifting that occurs when the transmission is only spinning a small amount makes an audible sound or if it's silent.
 


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I think it's a pump as mentioned. I heard a Honda Odyssey making a similar noise. Was wondering if it's a hydraulic pump for the CVT.

I think turbo spool is silent. Muffled completely by the intake resonators. I can only faintly hear the turbo on our V6 TDI Audi Q5 even, and it's gulping over 2.5x the air when rolling.
 

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Hate to reply to a third person here but I suspect that it's the CVT upshifting as you approach a stop. IIRC the CVT doesnt use a torque converter, instead uses a wet clutch (which is why it's a bit "jerky" in quick stop and go traffic) so I imagine the creeping-forward gear ratio is pretty low, so the sheaves probably need to move pretty far to get that gearing.
Honda Civic torque converter. Part number
26000-59C-305

It may be somewhat different internally from say, a regular AT 2009 CRV part, but it doesn’t seem to be much different looking. I’m quite sure it multiplies torque so it’s a torque converter.

I now hear this sound, it is there every time I stop. I also have impression it is the CVT.
The easiest way to disprove it is to find anyone with manual transmission who hears it.

It is much quieter than the quite obvious parking brake sound. I once took a refrigerator for recycling (yes, refrigerators fit in the hatch :D) and the curious lot attendant asked me what was that funky noise when I released the parking brake.
 

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Honda Civic torque converter. Part number
26000-59C-305

It may be somewhat different internally from say, a regular AT 2009 CRV part, but it doesn’t seem to be much different looking. I’m quite sure it multiplies torque so it’s a torque converter.

I now hear this sound, it is there every time I stop. I also have impression it is the CVT.
The easiest way to disprove it is to find anyone with manual transmission who hears it.

It is much quieter than the quite obvious parking brake sound. I once took a refrigerator for recycling (yes, refrigerators fit in the hatch :D) and the curious lot attendant asked me what was that funky noise when I released the parking brake.
Good to know lol, maybe the jerkiness is from the torque multiplication then -- it very much doesn't feel like your usual torque converter at least, nothing like the slushboxes of older autos, that's for sure
 

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It is not the CVT. I have the same sound on my Civic Si 6 speed manual. It is the power brake booster pump.

Sorry to shatter everyone's illusions. It is not something exotic like a warp speed generator. But, you can pretend it is.
 

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It is not the CVT. I have the same sound on my Civic Si 6 speed manual. It is the power brake booster pump.

Sorry to shatter everyone's illusions. It is not something exotic like a warp speed generator. But, you can pretend it is.
I don't know what equates a gear ratio change without engine noise to mask it, with something exotic like that lol. It's a valid theory, as is a brake booster pump. What id want to know is why you only hear it when 95 percent stopped, and not during the actual high load part of braking. The timing is right for a fast gearing change with the CVT sheaves though. I really don't think we can rule a gearing change out just cause some people say it isn't without providing an explanation as to why (are you sure your sound is the same one were hearing, when others who drive manual don't hear it, but everyone with the CVT does?)
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