Chevrolet "de-modding" the Volt's aggressive front air dam on request

[Patrick]

The Mitsubishi 3000GT VR4 had an active front airdam. IIRC, it dropped down about 3". You can see it pop down and back up in this video:

http://www.youtube.com/watch?v=9c9dxEnYh3Y

[Frank Lee]

http://ecomodder.com/forum/showthrea...tml#post228044

I've been wondering if you still had that and how it's working.

[cfg83]

Frank -

Originally Posted by Frank Lee

http://ecomodder.com/forum/showthrea...tml#post228044

I've been wondering if you still had that and how it's working.

From a durability POV it's a spectacular success. It's been on for maybe a year(?) without problems. I don't have to de-install it when I take the car for service. If the zip tie fails the air dam just swings back out of the way and waits for me to re-zip it when I park. I think that's happened once.

From an MPG POV I don't know, so I don't talk about it much. I've given up aero MPG testing because I think it's El Mirage or nothing, especially in LA.

It's also not "finished" in the sense that I would like to do something about the sides. It could be a set of side pieces that fish-scale behind the first two. It could be a "connecting spongy" piece under the side of the bumper that closes the gap between the wheel and the bending side pieces when the air dam is fully deployed. The side pieces could also be cut off and reconnected in a "spring+hinge" configuration, but I am almost positive that would be unstable at transition speeds and would therefore be vulnerable to self-destruction.

Maybe I'll get my act together and film it in action.

CarloSW2

[Vekke]

I believe that purpose of that front lip is to generate "virtual" optimum nose shape. So that makes the nose virtually round if you add there a spline which goes over the highest points of the bumber. Most of air will go through that route. This is my scenario which worked pretty fine on one car actually cd were calculated by computer at valmet.

[aerohead]

Originally Posted by CigaR007

Any links to it ? All I could find is this patent for an active air dam.

http://octechinnovation.files.wordpr...8/07775582.pdf

All I have is a clipping from the late 1970s out of Popular Science or something like it with a small photo of the front clip of Volvo's car.Not really much to go by.

[winkosmosis]

Why don't they just used a flexible material? Being curved would keep it rigid at high speed I think,

[DrInnovation]

Reported differences in MPG (at gm-volt.com) are about 2-4 MPG in CS mode (i.e. using gas) and 3-4 miles of EV range. I'll keep my scrapers until they break off then decide.
Like the spring mounted idea of CarloSW2, but don't think that works well deep under the car (though maybe with a foward mounted dam and spring, so the air preasure pushes it down. When mine break I'm going to try that before going for $49 replacement shorter dams. Idea might be like this

BBumper--CCCCar
S\ /Dam
. \ /Dam
.. /Dam

GM has a patent on "flexible" (brush-like) dams. I've posted/wondered why they don't provide those an an option. With a stiff brush dam could get down to 2" clearance and still nor worry much a "scraping" -- heck it might clean off part of the driveway after a snow :-) I might try that too if the spring-dam does nto work well.


And FYI.. its not lawn edging, its recycled Gulf Oil Spill material. (Really!)

[jsatter]

Originally Posted by aerohead

I'm seeing a few shredded Cadillac CTS front airdams also.New Beetles ditto.

Nearly all the factory air dams I see on the cars at work (i work in remarketing for a large rental car company) are scrapped pretty badly. We have to replace them on a good number of he cars as well.

[COcyclist]

Originally Posted by jsatter

Nearly all the factory air dams I see on the cars at work are scrapped pretty badly. We have to replace them on a good number of he cars as well.

My mini tire-deflector/airdams scraped all summer so I scrapped the idea for the winter before snow and ice scrapes them off completely.

[Peter7307]

Talking to a hire car guy a few years ago about damage to air dams caused by parking in car parks with "positive stop" ahead of solid (ie brick or concrete )walls.

His comment was the dams flex up and slide over the concrete block and the drivers normally put the front wheels against the stop.

The damage is done when the driver then reverses back and , yep you guessed it , the air dam catches on the stop and is ripped off.

Not sure what the solution is apart from careful design and flexible materials.

Peter.