so lets see here.

if i am in an air tight room and someone puts a vacuum pump on the room you are saying my ears wont pop? if they pressurize the room my ears wont pop? your logic would say NO because im still at the same altitude?

thats crap

pressure is pressure. barometers don't look to see what is applying the pressure, they just measure it.

120mph in a vehicle most likely wont produce enough pressure to make your ears pop, but its very believable that the actual pressure differential can cause a whistling sound.

 

[QUOTE]Originally posted by ScottC
[B]Well, what you say is true (that your ears don't pop when riding a motorcycle but will when you scuba dive), but your conclusion (that air pressure differences caused by velocity are different than air pressure differences caused by depth or altitude) is incorrect.

There are a couple reasons that riding a motor cycle may not cause your ears to pop:
1. You're wearing a helmet - the helmet blocks the air from moving past your ears, so they experience fairly slow moving air and therefore don't see much of a pressure drop.
2. Your ears and face create turbulence that make the pressure around your ears closer to normal, therefore no popping.
3. The pressure change at 120 MPH is significantly less than you would see when scuba diving or flying or driving over mountains.
4. Fast moving air can cause pressure differences is different ways. If you place a pressure sensor at the end of a tube with an entrance facing the oncoming air, you will see an increase in pressure (like ram air). However, if you put a pressure sensor at the end of a tube that is perpendicular to the flow of air, you can actually see a reduction in air pressure (the venturi effect). You can vary the angle of the tube, and use the ram effect to cancel the venturi effect and end up with minimal pressure differential. So, if you consider your eardrum as the pressure sensor, and your ear canal as the tube, you can see that what you feel will depend on many factors.

To simply say that your ears don't pop because the pressure is caused by speed is not quite right. It's simply a matter of the magnitude of the pressure differential, and in this case it would be quite small.

It is possible that all along you were saying that the magnitude of the air pressure differential is too small at these speeds, and I maybe just missed that part of it.

-D'oh!

 

Yea, that is what I'm saying. It simply doesn't happen.

 

Anyone figure out the whistling noise yet? Maybe it's turbulence through the gas cap or across the door handle. Since the door handle is hollowed on the other side it might act as a whislte?

Ok, I admit that sounds crazy but that's where my girlfriend heard the noise at 120+mph. That was right before she freaked and made me slow down.....

 

In my old Eclipse, I took off my windshield wipers one day just because it looks better and it barely rains here, and it seemed to me that there was less noise just driving around at freeway speeds. But I don't know if it would cause a whistling... it's more of a whooshing.

 

FYI, actually you don't need to plug your nose.

 

I have been to 130+ many, many times now (found a great secret road) and I get the whistle above about 120 as well. I'm always concentrating too hard on what I'm doing to really think about it though.

 

There have been at least 3 instances now where i can hear the same frequency whistling sound, but at a much lower volume, even at speeds as low as 60 mph. The whistle is so slight that it is almost undetectable with the common background noise at highway speeds.

This sound doesnt sound mechanical in nature at all. And since the 350Z has an odd profile, im going to just assume its a result of crosswinds at certain speeds. A tradeoff in style vs better areodynamics if you will.

 

When you ride a motorcycle, your ears will feel a "loss of pressure" due to the fast moving air outside them. If they did pop on a motorcycle, you would actually have to hold your nose and suck IN. Get it? This is the difference, scuba diving is positive pressure on the eardrums, and motorcycle riding is negative air pressure.

 

Sorry to chime in so late, but i too have experienced the "whistling" sound..... but starting at around 100 mph. I only got to around 112 this last time with my brother in the car and i asked him what that sound was. He said he didnt know. So, i too hear that sound, but at lower speeds.

 

I also get the whistle sound. I experience it at speeds as low as 77 mph. But it seems dependant on the wind and direction...

Really gets annoying on a long roadtrip.. (Minneapolis to Winnipeg and back... ). Happened most of the way up and back when I was going over 85 mph. (All the way up to 142 MPH before I had to relieve my passenger)...

It definately seems like a wind issue, probably the windshield, maybe door handles or something else. I thoght it might be because I cracked my passenger front splash guard... I duct taped that up and it still continues... Hard to duplicate, of course for the dealer because the wind seems involved somehow...

 

Ive been at 130+ with with windows open / closed ac on / closed ac off... no odd noise at all.. and its SMOOOOOOOOTh...