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09-22-2015, 09:12 PM
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#1
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Senior Member
Join Date: May 2015
Location: Issaquah/Grand Coulee, WA
Posts: 1,073
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Towing with 5.7 hemi is miserable. Anyone made air splitter/spoiler to cut wind drag?
I am thinking...that hemi can EASILY tow that weight.
But the wind drag from the front flat face of the trailer is the major drag (literally).
Has anyone tried and made a wind splitter or spoiler that forces the wind over the bed of the truck and up and over or around the top or sides of the trailer, to reduce wind drag?
I tow a boat that is aerodynamic, and the truck doesn't even know it is there.
Then I tow this travel trailer, and anything over 55 mph and this thing is revving to 4000 rpms and hugging 3rd and 4th gear.
I figure if I can get the wind over the bed, and up and over the front of the trailer, it would free up tons of drag and make for a much nicer tow.
Anyone messed with any kind of wind splitter or spoiler?
__________________
2015 24' Rockwood UltraLite 2304DS w/Equal-I-Zer 4-Point 1000lb sway control.
2014 39' Montana 3402RL (full-time)
Towing with 2018 Ram 2500 and 2014 Ecodiesel Grand Cherokee
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09-22-2015, 09:20 PM
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#2
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Senior Member
Tiffin Owners Club Workhorse Chassis Owner
Join Date: Oct 2009
Location: Warner Robins, GA
Posts: 2,613
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__________________
Jon & Sue Francis (Retired U.S.A.F.)
Lil Girl-Rescued, Abby Rescued, Peaches Rescued
06 Allegro 35TSA Workhorse Chassis
2013 Chevy Spark Dinghy
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09-23-2015, 06:16 AM
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#3
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Senior Member
Join Date: May 2015
Location: Issaquah/Grand Coulee, WA
Posts: 1,073
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DUH! Didn't think of doing a google image search!
__________________
2015 24' Rockwood UltraLite 2304DS w/Equal-I-Zer 4-Point 1000lb sway control.
2014 39' Montana 3402RL (full-time)
Towing with 2018 Ram 2500 and 2014 Ecodiesel Grand Cherokee
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09-23-2015, 06:39 AM
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#4
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Senior Member
Join Date: Sep 2015
Posts: 106
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Which transmission do you have 4 or 5 speed? What's the rear gear ratio?
Those earlier Hemi's struggled with heavier loads. Rated for 345hp, but realistically threw down about 280hp to the rear wheels due to the low stall converters and Chrysler's wonderful torque management. And that's when it was new. Given that truck is 11-12 years old now, and depending on mileage, probably considerably less.
Best upgrades for pre-Eagle Hemi's is higher stall converter, tuning, exhaust and intake. Tuning being key. Moe's Performance offers the DiableSport Trinity tuner with free HemiFever custom tuning for life. You let HemiFever know your mods and needs and they'll send you a custom tune. I had them make me a towing tune for my '13 Ram 1500 5.7. It's like night and day.
That wing may help a little, but realistically it's going to transfer the drag from the TT to the TV in the form of down force.
Gearhead, I'm guilty of being one.
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09-23-2015, 06:49 AM
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#5
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Senior Member
Fleetwood Owners Club Ford Super Duty Owner
Join Date: Oct 2013
Location: northern IL
Posts: 2,557
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I have an 07 with a hemi and it has 214000 miles on it. Rear suspension beefed up and an exhaust. I pull a 24' race trailer with a big flat front and you know its there but I don't get the 4000 rpm deal. It runs pretty well at highway speeds. I think the 20 inch wheels might have a bit to do with it being a bit doggy when towing as well.
__________________
2014 Fleetwood Bounder 35k
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09-23-2015, 07:24 AM
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#6
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Senior Member
Join Date: Mar 2013
Posts: 515
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Quote:
Originally Posted by mojoracing
I have an 07 with a hemi and it has 214000 miles on it. Rear suspension beefed up and an exhaust. I pull a 24' race trailer with a big flat front and you know its there but I don't get the 4000 rpm deal. It runs pretty well at highway speeds. I think the 20 inch wheels might have a bit to do with it being a bit doggy when towing as well.
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Wheel diameter doesn't affect geariing, tire diameter does.
As for a way to help aerodynamics, a truck cap helps.
Part of the problem with modern V8 gas motors (regardless of brand) is that they make peak torque and power at high rpms, so 4000 rpm is what the transmission gives you when you ask for speed. The only solution, other than a diesel truck, is to not use the cruise on hills and don't push the pedal down far enough for it to downshift.
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09-23-2015, 07:33 AM
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#7
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Senior Member
Join Date: Aug 2012
Posts: 1,580
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A bed cap does help a bit. You can come up with all kinds of contraptions to guide the air at the front, but much of the drag comes from the flat back of the trailer. Airplanes come to a point at the rear to reduce drag.
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09-23-2015, 10:25 AM
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#8
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Moderator Emeritus
Join Date: Jan 2000
Location: West Palm Beach, FL. USA
Posts: 27,519
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Those deflector devices have a lot of potential, but getting one that works with any particular tow vehicle and trailer is problematic. Just propping one up on the roof has almost zero chance of being effective - it takes a wind tunnel test to see how the air flows and how best to alter the flow to reduce resistance. Even then, you are still boring a 8x10+ ft hole through air and that isn't ever going to be easy on the engine.
Likewise, the real suction effect is another killer, but you need those big boxy wing things you see on the back of commercial trailers to make much difference.
Your premise is right - if you could eliminate the air resistance your towing mpg would go up dramatically. However, there is no genera purpose solution.
__________________
Gary Brinck
Former owner of 2004 American Tradition and several other RVs
Home is West Palm Beach, FL
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09-23-2015, 01:32 PM
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#9
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Senior Member
Join Date: May 2015
Location: Issaquah/Grand Coulee, WA
Posts: 1,073
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Well, I have 300,000 miles on this one, so I guess I just need to feel lucky that it still pulls a trailer AT ALL!!!
It pulls 8 mpg on level ground (highway with overpasses every mile or two) so that really isn't all that bad.
But it gets closer to 22 when not pulling a trailer. 14 pulling my 19' ski boat.
If I come across a camper cab, I might snag it, if for nothing else to keep a generator and other luggage dry during trips. It should help with wind drag a little, as well.
__________________
2015 24' Rockwood UltraLite 2304DS w/Equal-I-Zer 4-Point 1000lb sway control.
2014 39' Montana 3402RL (full-time)
Towing with 2018 Ram 2500 and 2014 Ecodiesel Grand Cherokee
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09-23-2015, 01:50 PM
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#10
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Senior Member
Join Date: May 2012
Posts: 976
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The "don't even know it's there" quote always makes me chuckle. I've owned lots of different full sized trucks and any time I've hooked up anything like a 19 foot boat I've most definitely noticed it was there, from the rougher ride to the loss of power. Guess some of you guys must have gotten the secret ones or don't really pay much attention to how your truck normally drives
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09-23-2015, 01:52 PM
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#11
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Senior Member
Join Date: Sep 2015
Posts: 106
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You, sir, have definitely gotten your moneys worth out of that Hemi!
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09-23-2015, 02:21 PM
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#12
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Senior Member
Join Date: May 2015
Location: Issaquah/Grand Coulee, WA
Posts: 1,073
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Not complaining...and gonna push it for another 100k if I can!
__________________
2015 24' Rockwood UltraLite 2304DS w/Equal-I-Zer 4-Point 1000lb sway control.
2014 39' Montana 3402RL (full-time)
Towing with 2018 Ram 2500 and 2014 Ecodiesel Grand Cherokee
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09-26-2015, 11:37 PM
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#13
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Senior Member
Fleetwood Owners Club Ford Super Duty Owner
Join Date: Oct 2013
Location: northern IL
Posts: 2,557
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Its the combination of the wheels and tires but yes your correct, the overall dimension of the tire is what effects gearing but the 20s dodge puts on with the stock tires definitely have a larger overall dimension than the standard rims and tires.
__________________
2014 Fleetwood Bounder 35k
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09-27-2015, 05:51 AM
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#14
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Senior Member
Join Date: Sep 2013
Posts: 1,781
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What's the rear end ratio?
A relatively cheap help/fix would be 4.10 ratio.
For aerodynamics, a cap on the bed helps, especially ones like the TW series from A.E.R.
__________________
Manny & Larissa
2013 Winnebago 2301BH-Red
2012 Ram 2500 Megacab HO CTD
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