 |
|
|
|
MFL
Midwest
Senior Member
Joined: 11/28/2012
View Profile
Good Sam RV Club Member
 Offline
|
I've a forum friend on here with a 15 Ram 6.7 diesel DRW 4.10s towing a 40' MS FW, and double towing his cycle trailer behind that, about 33,000 combined wt, that gets similar mpg as Michelle's GM.
You know your truck though, and if it runs great, about the only real option is a bit slower. A deflector likely won't make it worse, and if you gain a little, at todays prices, may give a warm feeling! ![[emoticon]](http://www.rv.net/sharedcontent/cfb/images/smile.gif "smile")
Jerry
.jpg)
|
cj99
Tonopah,AZ
Full Member
Joined: 07/14/2006
View Profile
Offline
|
MFL wrote:I've a forum friend on here with a 15 Ram 6.7 diesel DRW 4.10s towing a 40' MS FW, and double towing his cycle trailer behind that, about 33,000 combined wt, that gets similar mpg as Michelle's GM.
You know your truck though, and if it runs great, about the only real option is a bit slower. A deflector likely won't make it worse, and if you gain a little, at todays prices, may give a warm feeling!
Jerry
Ya if nothing else , its a experiment I can post here. I may do a YouTube video as I could not find any current ones with 5th wheels , there are more TT videos that tired this . Also I got to tell ya if it doesn't cost me MPG and keeps the bugs off the front of the RV like most do claim it does .. then its not a fail to me . yes this truck has always had poor MPG ( compared to my 2003 F350 with a 6.0 it did much better ) , just the way it is. and I've owned it since 2015 and I bought it with 40k on it, now it has 140K .
Ill do my best to repeat driving conditions I.E. wait to I have no head wind , etc
* This post was
edited 07/31/22 07:57pm by cj99 *
|
cj99
Tonopah,AZ
Full Member
Joined: 07/14/2006
View Profile
Offline
|
I do know that at lower speeds like 55 to 65 trucks with 410 gears or even 430 have better MPG than mine with 373 gears, its when you break that 2000 RPM mark that the fuel efficiency really starts to drop on a diesel, I think even though mine feels like it has plenty of power its always under a load with the 373 gears
|
cj99
Tonopah,AZ
Full Member
Joined: 07/14/2006
View Profile
Offline
|
My dad had a 2008 Ford F350 with the 6.4 L he would get like 8-10 MPG empty truck all the time. the only upside was he got almost the same 8 to 10 with a trailer and he had 488 ( was tacked out at 65) rear gears ... he sold it after about a year as even at 2008 fuel prices it was bad on the wallet
|
fj12ryder
Platte City, MO
Senior Member
Joined: 08/19/2003
View Profile
|
My only comment is the semi's use them, but if you look closely, you'll see the trailing edge of the deflector is all but overlapping the beginning edge of the trailer. And very few use stand alone deflectors, they all have the whole top of the truck as part of the air foil. I don't think they'll be much difference with using just a regular wind deflector. But hey, I've been wrong before.
Howard and Peggy
"Don't Panic"
|
|
|
Cummins12V98
on the road
Senior Member
Joined: 06/03/2012
View Profile
Offline
|
Funny thing is those that have them run around BobTail with them up. Kinda like PIZZING into the wind. ![[emoticon]](http://www.rv.net/sharedcontent/cfb/images/wink.gif "wink")
2015 RAM LongHorn 3500 Dually CrewCab 4X4 CUMMINS/AISIN RearAir 385HP/865TQ 4:10's
37,800# GCVWR "Towing Beast"
"HeavyWeight" B&W RVK3600
2016 MobileSuites 39TKSB3 highly "Elited" In the stable
2007.5 Mobile Suites 36 SB3 29,000# Combined SOLD
|
cj99
Tonopah,AZ
Full Member
Joined: 07/14/2006
View Profile
Offline
|
The older ones yo see from the mid 2000 and older look like metal ones and are bolted into place , the one I bought is ABS and folds down flat when not in use. I think it will cause a decrease in MPG if you leave it up with no trailer
|
bucky
Raleigh metro
Senior Member
Joined: 05/07/2003
View Profile
Good Sam RV Club Member
Offline
|
With today's more modern transmissions that 3.73 rear gear is not hurting your mileage. It's helping it.
2005 Cummins 3500 2WD LB quad cab dually pulling a 2014 Blue Ridge 3025RL
|
JRscooby
Indepmo
Senior Member
Joined: 06/10/2019
View Profile
Offline
|
The trucking industry kinda dropped the cab mounted defector because unless the trailer was sucked up tight to the cab (just over a couple of feet) did no good. RVs have a hard time with that. Van trailers did better with the defector mounted on the nose, and now a lot of them are mounting things on the back to smooth flow there
|
cj99
Tonopah,AZ
Full Member
Joined: 07/14/2006
View Profile
Offline
|
bucky wrote:With today's more modern transmissions that 3.73 rear gear is not hurting your mileage. It's helping it.
I beg to differ , 3.73 , yes is helping when your truck is empty no load. 3.73 way better for highway speeds above 65, for sure. but a heavy load @ 55 to 65, 410 gears will keep the load off and you are still below 2k RPMs they will help you save fuel. With my 3.73 at speeds below 70 which is most of the time my truck is always under a load and burns more fuel.
plus my truck is a 2012 with a 5 speed auto, it doesn't have the 10 speed like modern trucks , heck even my wifes little ranger has a 10 speed LOL
|
|
|
|
|
|
|
|
