Problem - Wind Noise With Full Length Flooring on an SD Rack

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RKurk

Member
Apr 20, 2004
18
0
Aptos, California
I have a Safety Devices ?Highlander high? rack on my 2002 Discovery. I have a floor for it made out of MDO plywood with a coating of fiberglass resin. I first made and installed a section for the rear ?upper? area of the rack. I then made a second section for the front ?lower? area (the tapered section in the middle is left open). When I installed the front section the noise from the rack increased substantially. Without the front floor section in place there is a moderate general level of wind noise at 45 mph +, but it is quite tolerable. However with the front floor section in place there is a very loud, low-to-medium pitched howling, most noticeably from the center of the vehicle just slightly back from the windshield. There is an oval cutout 10? back and centered in the floor section to gain access to the tubing for tie downs. As an experiment I taped over this hole but there was basically no change. A guess is that the air coming up over the windshield is being ?squeezed? between the roof and flooring (and over the SD rack tubes) causing the howl, as there is no easy exit for it. Final note, there are no lights mounted on the rack at this time to block or disperse the air.

Those of you who have the full floors of aluminum or other material like the plastic RhinoPro flooring have you experienced the same problem? If so, how did you fix it or do you just live with noise? One solution might be an air dam/deflector but I would really not like to do that. I noticed on the Rhino floor website (offroadtuff.com) that they state the floor reduces noise due to better airflow over the roof/rack. This seems to make sense, so I am wondering why is my set up so loud?

Comments, suggestions, real-life-experiences, and solutions are welcome.

Thanks.
 
S

syoung

Guest
Would it be possible to cover the centre part that is open between the two floors?
 
D

discoal

Guest
Turn the radio up

I have aluminium flooring and notice an increase in noise when I added the floor decking.
I notice when I install lights up there it brought the noise sound to a lower pitch. I thought about installing a shield to push the air above the the underside of the rack. Mostly I just turn up the radio and tune out the wind noise. You'll find out with anything you mount up there your noise pitch shall change. The shield would probably help out but I would not want to mess with the finely tune aerodynamics of a Disco 1. This could effect my gas mileage.
 
utahdog2003

utahdog2003

Well-known member
Apr 20, 2004
1,842
0
North Florida
you could buy some Lexan and create a fairing that fills the void between the floor and the roof of the truck...ala those Yakima and Thule type things you see all over. They aint just for stickers you know. :D Try out a chunk of cardboard and some zipties to hold it on and I bet you find it quiets it down significantly. all you need to do is keep the air from being forced into and tumbling in that space between the floor and the roof.
 
M

mike falconer

Well-known member
Dec 11, 2004
94
0
Oregon
www.oregonmediaservices.com
RKurk said:
I have a Safety Devices ?Highlander high? rack on my 2002 Discovery. I have a floor for it made out of MDO plywood with a coating of fiberglass resin.
Click to expand...

I'm waiting for delivery of a full length rack from NWP and while noise is one issue to deal with I'm wondering how your gas mileage has been doing since you've had the rack.

Have you kept track of it?

Thanks,

Mike
 
R

RKurk

Member
Apr 20, 2004
18
0
Aptos, California
Mike, the SD rack was installed the first week I owned the Disco so I do not have a point of reference regarding the racks impact on mileage. Currently (with only the rear floor section in place, no rack lights) I get 12-13 mpg around town and 14-15 on the freeway. My guess is that the rack has no noticeable impact on the mileage. Even with camping gear piled on top, the back loaded with camera equipment, and a couple of passengers the mileage varies little. In a negative view ... it can't get a lot worse ! However, my earlier Suburban (454 cu in.) got 10-11 mph around town and tops of 13 mph (once) on the freeway !

Question for you ... the flooring you are getting is from NWP ? Help .. the acronym stands for ? Also, what is the flooring made of ?

Thanks,

Rich K.
 
R

RKurk

Member
Apr 20, 2004
18
0
Aptos, California
To all those who have replied so far, thank you. I think I will try a couple more experiments based on the suggestions. I will check out a simple/quick air dam over the very front-middle of the rack (where the source of the noise seems to be). I will also try the same approach over the open area between the lower and upper rack sections. I saw the 'bib' awhile back on SD's web site and tried a quickie homemade version. It definitely cuts down on the 'general' wind noise (when the front floor section is not installed) but does not seem to have any impact on my current problem with the front floor section installed.

I posted this issue on Expedition Exhange's BB at the same time and got two replies that basically said that the full rack floor creates noise but it can be cut down a lot with lights installed, in the case of the responders, Hella 4000's (large !). Rack lights aren't at the top of my purchase list but maybe they need to be.

If I find a great solution I will post it.

Thanks.
 
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