Very High Engine Sound-VIDEO

I don't hear anything abnormal. You must realize that the sound volume varies with our speaker volume, so it's unlikely you will get a diagnosis of value.

 

The whole reason for using an Atkinson cycle engine is to minimize throttle losses. So as soon as you go into the red zone, the engine revs freely. That's all I'm hearing. It's not that I think my comment will help, but you seem unhappy that people watched the video without commenting

 

When I go into the red power meter the engine always sounds louder. Anything below the red power is lower volume.

I see in the video you jump into the red power area. That would cause the engine to go loud.

If you have a tach or scanguage let us know what RPM the sound starts to get loud.

I assume the volume of the engine is normal at a steady increase of speed (not going into the red range.)

my2cents.

 

The noise seems high to me. Yes, as rrg mention, we need to know what the RPMs are. Seems to be the engine is over-revving. What is the SOC (state of charge) read?

 

Also, would help the viewers by pointing out when (which second) in the video the noise accur.

If RPM range is normal, I would first look to see if the exhaust system is original or the previous owner changed it. Could also be an exhaust leak somewhere. A high-flow filter can also be the cause. Again, just posibilities.

 

Did I hear some warbling sound? The video is too short and too low sound and video quality to be of any value to help you. Compare to some other youtube recordings of engine noises.

 

There's no question that the 3rd generation Prius gets noisy any time the engine gets tasked. It does so rather abruptly as the engine gets asked to put out significant power.

If you're chugging along at 65 on the flat it shouldn't be particularly noisy. Uphill at the same speed (at least, uphill enough to put it into the red range) and it will be.

Overall, I find that my 2010 Prius's quieter than the 2002 manual Civic it replaced. But the audio amplitude difference between 65 on the flat and full throttle on that Civic wasn't as big and was definitely more gradual than how the Prius handles it.

As a previous poster noted this could be due to the Atkinson cycle engine, although I'm not the automotive engineer who could say that with any certainty. It could also be an artifact of the whole hybrid system. As a guess, when one goes over a certain power level, it could be that the demands on the engine rise dramatically and more abruptly than what would happen on a conventional power train. As others have noted, at high power levels the Prius engine is rather free-revving.

In order to separate out the Atkinson vs. Hybrid question on noise, it would be useful if a Chevy Volt owner could be induced to comment on what the power level vs. noise characteristics on that car look like: Does it have the same somewhat abrupt increase in noise as one move from medium to full throttle that the Prius does?

Finally, as mentioned previously, there's a question of sound levels in the recording. Given the variable gain on any recording device it's possible to make a Lincoln Continental sound like an Indy 500 car by turning the gain up enough. Not that I'm saying that you have the gain up in your recording, it's just hard to tell how bad it is, given that any 2010 Prius is somewhat noisier at high engine load. The only way to check would be to do a comparison between the absolute sound levels on your car and another, properly working Gen III Prius. There's gear that'll do that, but a nickel says you don't have it. You might take a test drive in a 2011/2012/2013 Prius and see if they're the same level or quieter; if they are quieter, well, mufflers do die, it's what keeps Midas busy.

KBeck