Good Freeway RPMs for OHV 4.0L?

[RangerX]

My usual freeway rpms tend to run between 2100 and 2500. This is for daily cruising, to work, etc. With my 37's and 4.56 gears, this translates to roughly 55-72 mph.

A few weeks ago, I did the ORR board's Death Valley run. To get there took hours of empty freeway driving, and to keep up with the flow of traffic, I drove maybe 85mph for 'extended periods of time'. Generally, the tach was on 3000 rpm for a couple hours.

My question is, in that type of situation/conditions, what is okay, and what is too high? Or what is the OHV 4.0 'comfortable' spinning at on a long road trip?

Please disregard your and my tire size, gear ratio, and driving speed. My bottom line interest is only RPMs.

Thanks!

 

[Alec]

I find 2300-2500 is good for economy. However, mine also hovers around 2800-2900 during "spirited" highway driving with my 4.30 gears and 33"s. My motor gets a little warmer and gets a little worse mileage, but that's about it.

 

[jssong]

from what i understand, the OHV is a very solid motor. I dont think you will have any problems running for hours at that RPM. i guess just making sure your fluid levels are fine, and your engine isnt overheating, i dont see anything wrong

 

[Metallic2001]

I ran my 94' around 80-85 for about 4 hours going into the mountains and it ran around 3000rpm...as long as ur fluid levels are good it doesnt hurt the motor

 

[FAKRWEE]

I've been doing between 2800-3200 RPM's for the last couple of years and I havn't noticed any negative effects or problems. The 4.0 is pretty sturdy and reliable. As long as you keep everything in working conditions you should be OK.

 

[RiverRat]

RangerX

Three years of thousands of miles towing 4600 pounds in the summer and no problems except for the clutch. Most of this was done in third or fourth at 2800 - 3800 rpm.

I thought the 4.0 felt best around 3000 rpm +/- 200 rpm. You got a cool truck. The DV trip rocked!

 

[RangerX]

I guess I'm alright going that high, thanks guys.

A couple years ago, I read in a mag "this engine could run all day at 3000 RPM without complaints", about the Jeep inline-6, and I always wondered about our V-6.

 

[VairKing]

My 91 EB didnt have OD when I got it, as it would only shift to third and that was it. I drove it for 2 years like this without anyproblems (other than the 15mpg on the highway, it got better milage in the city ) It would run from 3000-3500rpms while running 70-75mph, and the only time it would get hot was when running the A/C...It shouldnt hurt your engine at all

 

[hvac man]

stock 4.0 with 3.73 gears and 5 speed running 235/75/15's traveling down the road at 75 will be at 2700-2800 RPM's. Ford can't be wrong on how many of these trucks.

 

[Texplorer]

Crusing at 70 Im at 2500. Anything above that and Im at 3000. The only bad effect I have had at 3000 is bad gas mileage. But maybe that is because of the safari rack and tire

 

[Maniak]

Our '92 with 4.10's and 32" tires spins at 2750 rpms @ 80 (sounds very close to what you have).. and I drive 60 miles of freeway every day that way.. no problems.

I used to cruise at 2900 rpms (almost 85) but I got tired o watching for cops, so I just slowed down.


BTW. when I tow I drive right at 3000 rpms (67mph) and I do that for hundreds of miles at a time (I just love cruise control)...

No problems so far.. and I actually get better mileage towing at 3000 rpms with the trailer than I do in OD with the trailer at 2500 rpms...

3000 isn't a problem..

Btw.. we have been doing this for the last 140k miles (we are now @ 283k) and no ill effects on the motor.

~Mark

 

[RangerX]

Okay, new question! tonite I drove my wife's 92 Ex, and at 65mph, it was just a hair over 2000rpm. This is with auto tranny in OD. Anybody think that's too low, i.e. bad for the engine? I do plan to regear it eventually, but MY truck has needs!(locker, etc)

 

[Maniak]

I don't think that is hard on the motor at all unless your doing that in a hilly/mountainous(sp?) area.

If the tranny has to hunt all over when your trying to drive at that speed (becuase of hills etc) then it is bad. Since the motor doesn't make that much power at 2k, if you go up a hill you may drop out of lockup or od. If it does that often, it will wear out the tranny.

Otherwise it doesn't hurt anything other than performance. It will problably even help your mileage if you aren't towing or going up hills.

~Mark

 

[iroczddp]

i just drove to lousiana and was crusing about... 85ish the whole way down there... tach read 2800-3k i have 3.73's with 31's so i dont know what it would change the mph's to but it drove great and when i wanted to pass some one it did it with ease, and got about 240 miles per tank....

 

[hvac man]

Sorry I can't answer that question RangerX I have never driven 65mph...lol

 

[Maniak]

hvac,

Is that becuase you can't go that fast?

I know what you mean.. I only drop to 65 in town.. speed limit in town where I normally drive is 55 or 50 (until I really get into town when its 35).. but the freeway for me is 75mph and even my 2 lane road is 50 (but I drive 70 there)..

~Mark