tailgate spoiler question
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Joined: Nov 2007
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RE: tailgate spoiler question
i just hate the **** outta the black plastic deal on the back, but i cant just take it off cause theres holes...i really really want an srt-10 tonneau with wing, jus aint got that kinda money.i have a daytona wing...but i wouldnt be able to haul much in the back....the LUND spoiler looked kinda tight and relatively cheap and wouldnt be a big deal if i wanted to take it off....
Champion
Joined: Aug 2005
Posts: 3,313
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RE: tailgate spoiler question
It is strictly a guess
but I suspect it decreases lift at the rear wheels at high speed
but does not improve MPG at 55-75 mph typical highway cruise speed.
Coasting 5 times down a steep hill without the spoiler to see what maximum speed the truck gets to by gravity alone.
and then coasting 5 times down the same steep hill with spoiler installed
{keep about same air temperature and wind if possible}
would tell you whether it does anything
or is just for looks.
A 2nd Gen Ram of 5400 lbs weight will coast to about 70 mph down a 4% grade hill depending on air temperature. Many hills on the interstate that are going down to a river bridge are designed to 4% grade.
A 2nd Gen Ram of 5400 lbs weight will coast to about 80 mph down a 6% grade hill, which is about the steepest hill you will find on an interstate highway.
A Dakota has less 'frontal area' to push through the wind and at the same weight should be expected to coast to a higher mph.
You can use the ideas in this article to predict in advance how fast you will coast down a hill when your horsepower is zero:
http://www.etrucker.com/content/downloads/ccj0302.pdf
if you prefer to coast on a dead level flat highway this old archived web page will tell you your aero...which should improve with a good design rear spoiler:
http://web.archive.org/web/200408030...DownCalcs.html
but I suspect it decreases lift at the rear wheels at high speed
but does not improve MPG at 55-75 mph typical highway cruise speed.
Coasting 5 times down a steep hill without the spoiler to see what maximum speed the truck gets to by gravity alone.
and then coasting 5 times down the same steep hill with spoiler installed
{keep about same air temperature and wind if possible}
would tell you whether it does anything
or is just for looks.
A 2nd Gen Ram of 5400 lbs weight will coast to about 70 mph down a 4% grade hill depending on air temperature. Many hills on the interstate that are going down to a river bridge are designed to 4% grade.
A 2nd Gen Ram of 5400 lbs weight will coast to about 80 mph down a 6% grade hill, which is about the steepest hill you will find on an interstate highway.
A Dakota has less 'frontal area' to push through the wind and at the same weight should be expected to coast to a higher mph.
You can use the ideas in this article to predict in advance how fast you will coast down a hill when your horsepower is zero:
http://www.etrucker.com/content/downloads/ccj0302.pdf
if you prefer to coast on a dead level flat highway this old archived web page will tell you your aero...which should improve with a good design rear spoiler:
http://web.archive.org/web/200408030...DownCalcs.html