best rpm/mph when towing??

[Jim Smith]

What is the best rpm/mph when towing? My vehicle is 2004 quad cab, long bed,4X2 auto, 4:10 axle. My 5th wheel is a heavy ( 13k) Kountry Star, triple slides and a lot of options. Some time ago somebody mentioned keep it above 1700 rpm but I don't know if it was this new engine or the old version. Thanks.

 

[DCaswell]

I have found that staying under 2000 rpm provides the best fuel economy with the 6 sp. Should hold true for the auto

 

[GaryCarter]

Best for what? Economy? Holding top gear in the hills? Noise? There is no single answer.

For economy, the 48RE will hold OD down to some really low revs, probably slower than you really want to drive.

Slightly north of 2,000 revs will give about the best power to hold OD on grades. Unfortunately some drone shows up about this speed too, which bothers some people.



Find the speed that feels right for you and let 'er eat. For me some days it's 45-50, other times its 75. Might even be a tad more when there's a PSD around.



Gary

 

[Mundgyver]

Have your truck dyno'ed and then look at where your peak TQ is developed. What is the rpm and speed that this peak TQ is developed. If you know the rpm or max TQ developed, then that will be your most efficient speed for power and mpg overall.

 

[LEnglish]

For my turck I have to keep it over 1700rpm to keep EGT's in check. I think for noise and power around 2k is the best. The OD spilt is quite huge on our trucks so 55-60mph up hills in Drive and 65-70 in OD. This is what works best for my truck with a 12V.

 

[Bertram65]

With the auto and 4. 10s you will find best power to be above 2000rpm, I like to run about 67-68mph, this puts me at about 2100rpm, I have plenty of power for climbing hills and passing and the trans stays cool. With my truck anything less than 2000rpm and it is gutless. I get about 12mpg towing my 10klb 5th wheel.

 

[jeepit]

For me staying at 65mph is the best. Higher, and mileage starts to decrease. I watch my guages when towing and try and stay 8lbs boost and under 700 degrees egt while cruising; that seems to work for me too.

 

[Jim Smith]

Thanks

Thanks for the help on my rpm/mph question. I usually try to be around 62 mph and near 2000 rpm when I'm towing. This is my comfort zone. I still don't know where this stay above 1700rpm came from maybe the factory.

 

[DBF]

Thanks for the help on my rpm/mph question. I usually try to be around 62 mph and near 2000 rpm when I'm towing. This is my comfort zone. I still don't know where this stay above 1700rpm came from maybe the factory.

Probably you read it in one of the forums here. One I read said: Never Lug A Diesel! In other words, don't pull loads at rpm much below the torque peak. Tis said it's better to run at 2500 or above all day than to lug 'em down.



DBF

 

[Buffalo]

At May Madness, this year, we were given a seminar by the man in charge of the development & building of the third gen. engines. The Buck stops at his desk.



He said that this engine was designed to be most effecient at 1800/1900 rpm's.



My personal experience with an '03,HO, 6-sp. , 3:73 rearend gearing, towing a 25' bumper pull trailer, approximately 7500lbs. , is that the best mileage, towing on flat land (Texas panhandle & OK. ) was 15 mpg. driving about 55-57 mph. Did that on two different tankfuls of diesel. About 62 mph, I'm at the 14 mph. level. 67-70 mph. I'm getting into the 13 mpg. range.



On a recent trip from Phoenix to Palmdale, CA. , I averaged 13. 86 mpg. driving about 67 mph. in AZ. & around 60 mph. in CA. (55mph. speed limit, towing in CA. ).



Hope this helps.



Joe F. (Buffalo)

 

[jwduke]

I seem to get my best milage, staying under 2000 rpms with my 5er.

 

[RDelissen]

above 1750 rpms otherwise it lugs the engine and the EGTs shoot up through the roof :-laf

Now mph is another one, depending on whether or not I can handle the 'drone' around 65

 

[SSage]

I prefer staying over 65 mph with a 2003 3500 with 4. 10s. Rpm while pulling say 14K plus is 2100 to 2300 with the auto trans. With 14 to 15K I get 11. 1 mpg in the south east. I pulled my travel trailer (10,000 pounds plus) at 60 and got 13. 33 mpg. Then I got guages and now I don't do that in OD. Buy the EGT guage, lug the engine below 1900 rpm and watch the EGT's climb in OD, go back to direct drive and see what it does. My truck drops 300 to 400 degress with rpms over 2000. I stay in 3rd while running under 60 mph pulling heavy with the auto.

 

[Mundgyver]

The interesting thing about an EGT gage, is that it is your quickest way to determine fuel mileage. The lower the temp at cruise speed or when pulling, means less fuel used. I know that when pulling hills, if I down shift to 5th, my EGT's will drop and my overhead mpg gage and the one on my Roadrelay 4 show an increase in mileage.



If you know where your peak TQ is developed, it is interesting to watch the EGT's at peak TQ RPM while driving. These two bits of knowledge about ones own rig, pay rewards in fuel economy when paid attention to, with an eye for saving money.



I drive a 6 speed, and with a 7,000 lb load hooked up and a truck weight of 7,400 for a combined weight of 14,400 on flat level ground I can average 18. 5 at 65 mph. That is the sweet spot for my particular rig with the mods that I have installed.



I pay very close attention to my EGT and RPM knowing where my truck develops it's peak TQ. This coincides with a 65 mph and 1700 to 1900 rpm.

 

[DiTrani]

Yeah, unless you have an EGT guage it's better to err on the side of more rpm. If you do have a guage and you have the power to pull your load at 18-19K and the temps don't skyrocket, then great. My truck gets hot fast when I do that.

 

[GLASMITHS]

Some time ago DTT said that you should not pull below 1700 rpm if the boost is at or above 12#. Thats if you have an auto.

 

[Bug Out]

pulling 15K 5th wheel

I found the best "overall" RPM was 2000-2200. That seemed to be where I got decent power with the 6 sp/4:10 and no lugging and would hold its speed on small hills when cruise on.



I like to stay MAX speed 65, but comfy at 62-63..... I get approx11-13MPH no A/C towing... ... . 8-10 with A/C on towing.

 

[SnoKing]

Some time ago DTT said that you should not pull below 1700 rpm if the boost is at or above 12#. Thats if you have an auto.

Bill and I talk about this again the other day when I was there, regarding the Catcher and it's power down low. He said they had to re-engineer to that. I never roll into mine hard below 1700-1800 when towning. 4:10 mild upgrades, 2000RPM at 63MPH. Tows 5er really well, and I stay in OD on all but the BIG hills.



I have never driven or rode in a Catcher truck, but from what I read, it would keep my wife out of the nurserys, as she would not want to drive it.



SNOKING

 

[Cummins4WD]

When I was pulling my 10K enclosed 5er back from Chicago to Denver at 70mph with a pretty serious headwind through Iowa I was always around 2000 to 2200 rpms but my Boost was peged at 22 to 26lbs basically the whole time... Is this bad in any way other than chewing through the Diesel. I was easily maintaining speed and my EZ was on setting 4 which kept me in OD and still allowed me to accelerate.



My EGTs never went through the roof at all and it was always between 900 and 1200 degrees.



I'm just assuming that due to the head wind the turbo was basically locked into full boost but is this bad in any way for the turbo or the engine? As I said EGTs were always good but my god I've never stopped for Diesel so many times in my life. I must have only been getting 10 or 11 mpg but I needed to get back to Denver and 70 to 75 in the right lane was what I was doing.



Hell a couple of times I had to use one of my two 6 gallon reserve tanks in the trailer as I was totally on Empty and trying to find a fuel station I could pull into with my 44' trailer. Time for a Transfer-flow in bed tank.

 

[GLASMITHS]

This is about what I do. But if I cannot accelerate at 1800 it gets down shifted. My truck runs best between 2100 and 2500rpm.