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Discussion Starter · #1 ·
What RPM\'s Should I....

I will very shortly be taking a long trip, nonstop from FL to DE, in my Ram, listed below. Going north will be towing an empty flatbed trailer, about 2,000 pounds. Coming back south will be with a Jeep on that trailer. I have already ruled out Overdrive in either direction. MY only problem is, i have the factory 3.92s in my axles, and my 360 is turning 2000RPMs at only 55 mph. What RPM range should i be operating in? I have towed with this truck before, just not that much weight. It IS rated for 7,800 pounds. Please helpme before i break something!!! BTW, i've got almost 36,000 miles on it. Thanks in advance,

-Mike

98 Dodge Ram 1500 Quad Cab 4x4 Sport Plus, 5.9L 360, auto, Locked, 3.92s, BFG A/T KOs, tows my CJ-7.
 

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Re: What RPM\'s Should I....

rpms look good to me, I wouldn't pull it over 65 mph though.

/wwwthreads_images/icons/cool.gif Big Ed
'88 YJ, 4" susp,3" body,33's,283 Chevy V8,TH350,4.11's,D30,D35c
 
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Discussion Starter · #3 ·
Re: What RPM\'s Should I....

My dad has one of those 360 trucks & the rpm range seems very similar to my TBI 350. My truck is most comfortable when towing in Drive at 60-65 with 265/75R16's & 3.73 gears. You'll probably want to run around 55-60 with 3.92's in Drive if you have stock tires.

TEX

/wwwthreads_images/icons/wink.gif Got Mud?
G.U.M.B.O. Mud Racing
 
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Discussion Starter · #5 ·
Re: What RPM\'s Should I....

Thanks, a lot, guys, thats about the range i was thinking, which is going to make this a LONG trip! Thanks again!! BTW, they are not the stock POS tires, they are BFG A/T KOs, but they are the stock 265/75R16 size.

-Mike

98 Dodge Ram 1500 Quad Cab 4x4 Sport Plus, 5.9L 360, auto, Locked, 3.92s, BFG A/T KOs, tows my CJ-7.
 

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Re: What RPM\'s Should I....

I think what I've heard was 60 to 80 percent of the rpm at which the motor is rated for its horsepower is where the cruise rpm should be. Torque comes into play here. Now generally max torque comes in at a lower rpm. Thus the modern engines, on road and off road, are designed for low rpm torque. Torque is the amount of resistance to change in rpm. For cruise you are looking for the most amount of torque at the least rpm. You coming up I95? Many hills? Drive it by the seat of you pants. What rpm/speed does the truck want to travel? What speed/rpm do you need to give the least amount of throttle input to maintain that given speed/rpm? How about hills? If you are going up and down, do the same. At whatever speed/rpm you observe the least throttle input I just about guarentee that thats the best cruise therefore best gas mileage. Hey if it's 75 mph, let it be......hehehe. Good Luck. Jimmy Z.
 
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Discussion Starter · #7 ·
Re: What RPM\'s Should I....

Jimmy, that's a much better explanation than what I was trying to say about the truck "feeling comfortable" at certain speeds. The speed I picked requires little throttle input & at that speed, I lose the least amout of MPH on hills. Above or below that & I'm off my torque peak & will lose a lot more speed as I encounter hills. And optimum mileage for me is at 60-65 also (11 mpg towing the racer), while 70-75 yields only 8-9 mpg.

TEX

/wwwthreads_images/icons/wink.gif Got Mud?
G.U.M.B.O. Mud Racing
 
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Discussion Starter · #8 ·
Re: What RPM\'s Should I....

I don't know how flat it is in that part of the country that you will be traveling in, but I wouldn't hesitate using O/D on long flat stretches. The weight you are pulling empty isn't much and long flat stretches will save fuel and won't cause the transmission to overheat or the motor to lug. You can feel when the engine is lugging and you won't be able to increase your speed with increased throttle input. That's when you know to kick it back into Drive. Remember, you are driving a truck and it is built to handle a load. A 2000 pound trailer is nothing as long as you keep an eye on the tach and pay attention to what the engine is telling you.
 
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Discussion Starter · #9 ·
Re: What RPM\'s Should I....

I cannot help but put in my 2 cents.
If I was going to pull a trailer and jeep full time.
That would be what ?? 6000 to 7000 lbs I would
not worry if I was running up to 2800 RPM.
If you are new to towing or even a old hand
it is a great ,great, help to run a Vac gange.
On a long mileage pull you can start to pull the guts
out of a motor and not notice because it can happen so slow.
Like a long grade or change of wind dir. . A Vac, gange
will show you right away. Kind of like running a piszimitor[sp]=
exhaust temp gange in a diesel.

I think I'm right to say that O.D. going to be a weaker made
part of your trans. I'm sure you don't run a temp gange on your
trans. Even if you did just run that sucker in D for drive.
The pennys you save just is not worth the pain in the a$$
If you are wrong and damage that auto trans. Got to remember it
might not go out at the time but what about next year or the year after that
You know how that works just when you got places to go and things
to do is when it will go out .
 
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Discussion Starter · #10 ·
Re: What RPM\'s Should I....

And speaking of "D" for Drive, I'm assuming the newer Rams have that same stupid "O/D off" button instead of a separate "D" selection since that's what my dad's '94 has. If so, it defaults back to O/D on every time you shut off the engine. So, make sure to click it BACK off again when you restart. What a stupid piece of equipment that is BTW. Why don't they just give each forward gear its own selection on the shifter????

TEX

/wwwthreads_images/icons/wink.gif Got Mud?
G.U.M.B.O. Mud Racing
 

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Re: What RPM\'s Should I....

/wwwthreads_images/icons/tongue.gif I'm with gregg tanner on this one. Don't leave the yard without the two gauges that he mentioned: vacuum and auto tranny temp. Those will tell you when to long-stroke it in OD and save that fuel, and when to get the RPM up and save that crank. Gregg was referring to a PYROMETER when he mentioned the diesel boys. Thats PYRO....as in heat....and METER....as in telling secrets about what's going on./wwwthreads_images/icons/crazy.gif

CJDave
Quadra-Trac modified by the crack moonguy/wwwthreads_images/icons/wink.gif/wwwthreads_images/icons/smile.gif/wwwthreads_images/icons/tongue.gif transfer case team.
 
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