# Prius C Drivers Enter



## Null (Oct 6, 2015)

Google didn't come up with this, but with my Prius C at freeway speeds, rolling down either or both of the rear window(s) at freeway speeds causes the headliner to pulsate causing rapid fluctuations in cabin pressure that just DRILLS into my ears. Opening either of the front windows equalizes the pressure.

It's done this since I drove it off the lot and it's just now starting to bug me (for a while, it was a feature to stop pax alcohol hot drunk pax from making my cabin 55 degree air).

Service department says it's normal but he'll have the tech test drive it.... when his ears bleed he'll know.

But just checking with other drivers who have/had this with their Prius C. If so, what you/dealer did to fix it. Mine's with Toyota now so want to stock up on ammo if they give me an answer I don't like.


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## Beur (Apr 14, 2015)

I haven't noticed an issue, I'll have to give it a test today when I'm out. I have a 2015, what year is yours.


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## Null (Oct 6, 2015)

Beur said:


> I haven't noticed an issue, I'll have to give it a test today when I'm out. I have a 2015, what year is yours.


Same. 2015.

Hit a bumpy section of road at 45+ and roll the rear right window down half way. If you have the issue you'll instantly know what I mean.


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## Dontmakemepullauonyou (Oct 13, 2015)

All cars do that don't they?


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## Null (Oct 6, 2015)

Dontmakemepullauonyou said:


> All cars do that don't they?


Wind noise yes, but this is like someone stuck an air tight rubber film over your ear and started pushing and pulling from the center a few hundred times a minute.

It's too painful to drive with only the rear windows down. I window lock pax that don't get the hint.


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## Fauxknight (Aug 12, 2014)

I drive a C, it's technical name is 'the helicopter effect' (or Helmholtz resonance), and the C isn't the only vehicle effected by it (though it's probably enhanced by the C's peculiar aerodynamics). It's an air pressure issue, which is why it seems loud and can hurt/annoy your ears. You need to roll a front window down far enough to allow proper air flow (in the front and out the back), otherwise the cabin continuously fluctuates up and down in air pressure, creating that whop whop whop effect. If the rear window is just cracked open then you only need a front window cracked, if the rear window is wide open you need the front window around 1/3 open.

I prefer windows up on the freeway, but I automatically counter any rear window action with my own window.

Most cars do this, but again, the C is particularly annoying with it. Toyota isn't going to be able to do anything to fix it, I don't know why you would ask them to do so.

A good explanation:

http://jalopnik.com/why-do-slightly-opened-car-windows-make-that-awful-soun-1447498738


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## Null (Oct 6, 2015)

Cool, never had it this bad in a car. Dealer basically said the same thing. I knew the solution but it seemed like it shouldn't be necessary.


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## observer (Dec 11, 2014)

Happens on my 97 Toyota Fourrunner too. You have to get the windows just right.


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## B-kool (Feb 28, 2016)

Noticed the other night. Unknown if pax is able to hear the pulse when window is let down, but I had to open my window to offset the effect.


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## Fauxknight (Aug 12, 2014)

B-kool said:


> Noticed the other night. Unknown if pax is able to hear the pulse when window is let down, but I had to open my window to offset the effect.


Yes, pax notice the hell out of it, the pressure of the entire cabin fluctuates. If it's minor they may not say anything, but it can get pretty bad at high speeds.

The C isn't as much about getting the windows just right as it is simply opening a front window to counter. Because of the aerodynamics of the C, only rear windows cause this effect (not sure about moonroof) and it is directly countered by the front windows. Other cars with different aero signatures can have the front windows cause the effect and are a little trickier on the window balance.


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## KnightRyder (Feb 13, 2016)

I thought I was the only one that noticed. That stuff is murder on your ears and it took me all but 2 min to realize it was a air pressure issue. That's when I subsequently put the front windows down to equalize the pressure.. Never felt that in a car before ever...


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## B-kool (Feb 28, 2016)

KnightRyder said:


> I thought I was the only one that noticed. That stuff is murder on your ears and it took me all but 2 min to realize it was a air pressure issue. That's when I subsequently put the front windows down to equalize the pressure.. Never felt that in a car before ever...


So if we C customers get a tricky shotgunner, we crack back window for passive aggressive assault


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## rtaatl (Jul 3, 2014)

My Chrysler 300 does the same thing if one of the passengers opens up the window. The resonance is deafening. I have to crack my window to offset it.


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## PHXTE (Jun 23, 2015)

Dontmakemepullauonyou said:


> All cars do that don't they?


I don't know about all, but many of them do, yes. My VW Jetta used to do the same thing if one of the windows was open with the sunroof.


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## tohunt4me (Nov 23, 2015)

Fauxknight is correct.
Helicopter effect.
The more aerodynamic the vehicle, the worse it seems to be.
Just put a gap in a other window to counter the effects.


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## MulletMan (Mar 2, 2016)

Null said:


> But just checking with other drivers who have/had this with their Prius C. If so, what you/dealer did to fix it.


Same Issue on my 2012 C. Dealer fixed it by supergluing rear windows in closed position. Then he grabbed a tire iron and hit my poodie (in pic). Dealer scolded poodie for having such a stupid owner.


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## MulletMan (Mar 2, 2016)

Fauxknight said:


> Most cars do this, but again, the C is particularly annoying with it. Toyota isn't going to be able to do anything to fix it, I don't know why you would ask them to do so.


I came up with my own fix... works perfectly. After i chipped off the superglue from the dealer, I went to my sheet metal shop and, after some aero engineering equations i remember from AE at Tech, I came up with this, although slightly modified for my Prius C. Works like a charm. Plus i chain poodie to the top spoiler whens she peepees my car.


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## MulletMan (Mar 2, 2016)

Null said:


> But just checking with other drivers who have/had this with their Prius C. If so, what you/dealer did to fix it. Mine's with Toyota now so want to stock up on ammo if they give me an answer I don't like.


As far as ammo goes, Stock up on 357 magnum hollow point.. But please, use this gun so we don't have to see any more frivilous posts. jk man, but cmon...


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## Null (Oct 6, 2015)

MulletMan said:


> As far as ammo goes, Stock up on 357 magnum hollow point.. But please, use this gun so we don't have to see any more frivilous posts. jk man, but cmon...
> 
> View attachment 33827


S&W 500 or bust.


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## elelegido (Sep 24, 2014)

I use earplugs during the drunk shift. They make me immune to noise from screeching women / shouting bros, stupid drunken conversations, car door slams and also booming open rear windows.


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