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Discussion Starter #1
I have noticed that there is a lot of noise when the windows are open and traveling at more than 40mph. It seems a lot more than any car I have owned previously. It is almost a throbbing and very powerful... so much so that I have to close the windows and can't drive the car with the windows open at that speed or faster. So far we haven't had much nice weather but if we do I will miss having the windows open.

Now, I know that open windows would reduce range but would they reduce the range more than using the A/C? My guess is probably not.

Any one else notice this?

I don't suppose there is anything we can do to reduce it... it must just be a product of the aerodynamics of the car.
 

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Hello Paul,

Chevrolet over here across the pond does make an outside mirror correction for the "wind buffeting" or thumping you get above 40 mph or at slower speeds in a cross wind situation.

I am having my mirrors corrected this week and can get back to you with the results.

With a little research I can come up with the GM part number and some of the threads on the Chevy Volt site.

My understanding is that they do a sort of "Art Deco" contouring of the upper part of the outside door mirrors.

Ross
 

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Hello again Paul,

These are two postings regarding the wind buffeting issue with the Chevy Volt. I don't have enough computer skill to forward the pictures but will try to forward the thread to you also.

Wind Buffeting Modification Photos
Just got back from the dealer where they did mods to the battery and side mirrors. There's been a number of posts on the battery enhancement so there isn't much to say except if you get it, the dealer tops off your gas tank, so you might want to keep that in mind.

The real mod I was interested in was the one to reduce wind buffeting. I live near the beach and like to drive the streets with the window down. My previous car was a roadster which I never drove with the top up, so driving around in a car with the windows up is a bit claustrophobic for me.

This modification consisted of two parts; a new "skull cap" over the mirrors and a different plastic piece at the A piller. Aero mods were made to both pieces to reduce the wind buffeting (see photos). There was no charge for this mod. Needless to say, these changes are made at the expense of aero efficiency, how much, I really won't know for some time. However, I'm happy to report that this modification greatly reduces the buffetting. I drove up to 55 mph with the driver's side window down without the buffeting noise. There was still, a tiny bit of pressure buffeting that was just barely noticable. I think this can be pretty much eliminated by cracking open other windows.

Both.jpgA Piller.jpgBoth2.jpg


GM has recently released a "kit" which modifies the side mirror housings and reduces this buffeting effect for those that like to drive with the driver's (or passengers ) window down. This buffeting is considered a normal artifact of the Volt's excellent aerodynamic signature, but it can be deemed objectionable by some. Due to a slight reduction in aerodynamic performance it MAY have a negative effect on electric range and/or fuel economy, (although I believe it to be minimal).

Included in the kit are replacement mirror bezels, door fascia, and "skull caps" (the common industry term for the outside mirror housing itself).The kit should require only an hour or so to install (both sides) however this does not include time for any painting of the skull caps if necessary.(which will obviously need to be completed prior to the actual installation of the kit)

So if this is something that you feel MUST be addressed, you can discuss it with your dealer. They will certainly find the necessary documentation if they search for the term "buffet" in their GM information systems.

HTH
WopOnTour
 

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One more piece of information. I have no idea as to how these numbers would cross reference to Vauxhall however.

"I believe the information on the mod is in Service bullitin B6804 9090. The new mirror kit part number is 22778043. The dealer has to paint the skull cap to match the car."

Ross
 

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Discussion Starter #7
Thanks for the REB. I did wonder if it was an "aero "feature".

Regarding the pics... I can't find them on gm-volt.com. Are they yours? If you don't want to add them to the thread yourself I will gladly do it if you email them to me?

I am going to have a think about this one. Even if there is a kit for the Ampera I am going to think hard before agreeing to have the mod done. I may decide just to put up with having the windows closed at higher speeds :)

Thanks for this info tho for the other members. This shows the power of the forum! ;)
 

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Good morning over here Paul.

The pictures aren't mind but I will try to take some when I am scheduled to get my Volt back later today with the modifications.

Ross
 

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At the Chevy Volt blog you can put in the phrase "wind buffeting modification photos" and this might work for you.
 

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There IS another solution.

According to the GM-Volt site, If you experiment with opening some of the other windows only an inch or two, (not sure which ones myself) you can cancel out almost all of the buffeting.
 

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Discussion Starter #12
SharkVolt said:
There IS another solution.

According to the GM-Volt site, If you experiment with opening some of the other windows only an inch or two, (not sure which ones myself) you can cancel out almost all of the buffeting.
I'll give that a try. Thx
 

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Today I found cracking the left hand rear window about 2 inches fixed the buffeting that was there with the drivers glass fully down.

This "feature" is common to a lot of cars I've driven including my first VW Beetle, too many years ago to confess!! It had a factory sun roof which caused a great deal of buffeting when fully open but again opening a side window eliminated it.

That's progress I guess!

Big Paul
 

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Discussion Starter #14
Cool! Many thanks everyone. Yes, that is much better.

I think I can live without the mod now.
 

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Hello Paul,,

Just to close the discussion for my part. I did get the modification of the mirrors and front door area that the pictures show from another blogger.

The comments above are mostly correct in that many modern cars can largely solve the problem by opening another window.

I note that with the modifications I can basically have back my youthful experience of the pre-airconditioning days of wind noise at speed but not the buffeting or air hammer effect of a modern 4 door sedan even with only one window open.

So I am happy with the modification but perhaps, it is not for everyone. I assume there is a penalty in fuel economy to be paid but I don't know how much it would be.

Ross
 

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I guess the optimum solution would be to design in mechanical flaps that deploy when you open the windows. then you get the best of both.
 

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I generally keep my windows closed when in an automatic car wash! ;)

(closed windows means aero flaps retracted, I've never had problems with filler cap.)
 
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