The various methods of improving your truck bed's aerodynamics were
wind-tunnel tested on a Ram a couple years ago. A Ram isn't a Dak but
it's still valuable & relevant data.
http://mars.wnec.edu/~ehaffner/did.htm
Short version:
3. Baseline condition Cd = 0.432 (without mirrors)
4. Square Cap Cd = 0.480 11.11% Increase in drag
5. Replace tailgate with a cargo net Cd = 0.461 6.71 % Increase
in drag
6. Removed Tailgate Cd = 0.447 3.47% Increase in drag
7. Lowered Tailgate Cd = 0.414 4.17% Decrease in drag
8. Tonneau Cover Cd = 0.381 11.81% Decrease in drag
9. New Cap Design Cd = 0.302 30% Decrease in drag
They don't specify whether it's a hard or soft tonneau; I imagine a hard
tonneau will give slightly better results than a soft one.
Ronald Wong wrote:
> Actually studies have proven that a hard cover will reduce drag. The debate
> is driving with the tailgate down which creates turbulence thereby
> increasing drag and decreasing gas mileage. Yet, a lot of folks just don't
> believe that as they drive around town with the gate down or none at all.
>
> Ron
> 00 PB SLT QC 4X2 5.9 46RE 3.92 LSD
> For modifications see my DML Profile (URL follows)
> http://www.twistedbits.net/WWWProfile/dakota/Kw9pV1EkFeOYY
>
>
> -----Original Message-----
> From: owner-dakota-truck@dakota-truck.net
> [mailto:owner-dakota-truck@dakota-truck.net]On Behalf Of Sevrence, Sean
> (S.J.)
> Sent: Thursday, July 18, 2002 6:18 AM
> To: 'dakota-truck@dakota-truck.net'
> Subject: DML: RE: Highway cruiser how-to???
>
>
>
> Hey Punch!
>
> First I would suggest a tonneau cover. Very light weight but keeps the wind
> from gathering at the tailgate. I have gained 1.5mpg after installing mine.
> I have re-verified those numbers often by simply rolling up the tonneau and
> driving with the tailgate up. It never fails. I think the people that wrote
> the study about this issue must have been funded by the oil companies ;) My
> checkbook knows the difference!
>
> As for the gearing, I would not go above the 3.92 gear set. 4.10's will turn
> higher rpm's at the same speed, using more fuel. I am only pulling around
> 2200lbs with our pop-up camper, but the 3.92's are perfect. My '92 has the
> standard 3.55's (which I'm guessing yours does) and I have pulled this
> camper with it. Going into a head wind, it felt like I was driving a Yugo ;)
> The 3.92's will help dramatically.
>
> I have no experience with lowering the vehicle, other than that defeats the
> purpose of a truck. The sway bars should not impact highway travel, only
> cornering.
>
> HTH!
> Sean
> '92 RC Sport 3.9L 5spd - 256,000mi!
> '01 CC SLT+ 4.7L 5spd 3.92 LSD Mobil-1 - 48,700mi!
> http://www.twistedbits.net/WWWProfile/dakota/DnuuSncssJujU
>
>
> -----Original Message-----
> From: Punch [mailto:2punch.crash2000@AHM.com]
> Sent: Thursday, July 18, 2002 12:53 AM
> To: dakota-truck-moderator@bent.twistedbits.net
> Subject: DML: Highway cruiser how-to???
>
>
>
> Due to my new job (same company), and future re-location, I will be spending
> sometime driving on the highways.
>
> what is the best way to turn my 98 V6 sport into a nice highway cruiser?
>
> change gearing to 4.10's
> change to a less aggressive tread pattern during summer?
> lower vehicle?
> add better sway bars?
>
>
> also my hill climbing speeds suck any ideas?
>
> p.s. please keep in mind, I will be towing with this vehicle in the near
> future, and need to drive during winter.
>
> Punch
>
-- -andy andylevy@yahoo.com Maintainer, DML FAQ - http://www.dakota-truck.net/faq/ http://home.twcny.rr.com/andylevy/dakota/ '99 CC 4x4 318 auto
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