Lugging on hills?

[enfield]

I live in a pretty flat area and have never hit a hill requiring me to downshift, until today.
We took a little trip to the Frio River and it's extremely hilly in this region.
My question is when do I need to grab a lower gear?
I was downshifting below 1500 rpms, but was concerned that I should maybe keep my engine speeds higher on hill climbs. I know peak torque is 1800rpms, so I figured that was a good range to be in.

 

[Output Shaft]

1800 may be peak torque on the dyno but it's not a good RPM to be driving in for long under load. It is the bottom limit that only should be touched for a few moments before downshifting when pulling up a hill.

As a rule of thumb when driving up a hill and the RPMs start to drop, downshift at or slightly before 1800 RPMs. 1500 is way too late. 1700 is also too low. You are lugging the engine below 1800 RPM.

1800 IS a good RPM to be driving over rough dirt roads at slower speeds in lower gears. Under those circumstances, it is the sweet spot.


1500 should only be seen for a moment after upshifting (a little early) when poking around town on flat ground. You aren't doing the engine any favors spinning it that slow under load.

As a rule for the other thumb for the 2F, try to keep the cruising RPMs between 2000 and 2700 when under load. That is where this engine is happiest.

Since the 2F has such a narrow powerband compared to "normal" gasoline engines and not enough gears (it needs 6), hill driving often requires revving up to 3000 RPM or so before upshifting in order for the next higher gear to engage above 1900 RPMs.

But often it is found that one gear is too low, and the other is too high.
When that is the case... always choose the lower gear & higher RPM's & suffer the lower speeds. The cruiser will thank you for it.

 

[enfield]

Thanks, I'll go by that on my way home!

 

[gregnash]

1800 may be peak torque on the dyno but it's not a good RPM to be driving in for long under load. It is the bottom limit that only should be touched for a few moments before upshifting when pulling up a hill.

As a rule of thumb when driving up a hill and the RPMs start to drop, upshift at or slightly before 1800 RPMs. 1500 is way too late. 1700 is also too low. You are lugging the engine below 1800 RPM.

1800 IS a good RPM to be driving over rough dirt roads at slower speeds in lower gears. Under those circumstances, it is the sweet spot.


1500 should only be seen for a moment after upshifting (a little early) when poking around town on flat ground. You aren't doing the engine any favors spinning it that slow under load.

As a rule for the other thumb for the 2F, try to keep the cruising RPMs between 2000 and 2700 when under load. That is where this engine is happiest.

Since the 2F has such a narrow powerband compared to "normal" gasoline engines and not enough gears (it needs 6), hill driving often requires revving up to 3000 RPM or so before upshifting in order for the next higher gear to engage above 1900 RPMs.

But often it is found that one gear is too low, and the other is too high.
When that is the case... always choose the lower gear & higher RPM's & suffer the lower speeds. The cruiser will thank you for it.

Perfect advise! I live in a fairly hilly area with longer climbs and this is what I find I must do. I keep myself right until about 2k rpm and then I will downshift to keep the truck moving otherwise she starts to bog down and you see the speed drop dramatically. Remember this is a heavy tractor motor, so they are not meant for speed.

 

[dkyuss]

How does this compare to diesel 3b stock RPMs? I drove my rig home with no Tach and havent driven it since. Just curious for a baseline, although I have 33's and the 4 speed tranny.

 

[Heckraiser]

Depending on the hill (and power-robbing altitude), 3k rpm is good for climbing. Anything beyond 3500 and you're pretty much just making noise, but it is sometimes required when your pokey dinosaur is being a nuisance to fellow drivers.

 

[DanS HJ-45]

How does this compare to diesel 3b stock RPMs? I drove my rig home with no Tach and havent driven it since. Just curious for a baseline, although I have 33's and the 4 speed tranny.

Similar.

But really, why not just drive by feel? A motor will communicate to you where it is happiest, and what it doesn't like. Why not just listen instead of trying to follow strict rules about shifting?

Dan

 

[dkyuss]

Similar.

But really, why not just drive by feel? A motor will communicate to you where it is happiest, and what it doesn't like. Why not just listen instead of trying to follow strict rules about shifting?

Dan

I agree, that how she drove home, handles the hills fine. But when am I pushing her too much? 3500 rpm up a long hill?
PS Ive never owned a diesel, and this is my first cruiser

 

[DanS HJ-45]

I can't imagine getting a 3B up to 3500 rpm without feeling like the world will end.

I'm guessing 3000 RPM is about the top end of where the 3B is happy--and even that is probably too high. Our 3B doesn't have a tach, so I'm guessing at RPM.

But 3500 RPM would be scary in the 12HT.

Dan

 

[CruisinWithDogs]

I just floor it until it starts slowing down, then I downshift and floor it even more ! That's how my 2h gets me over the hills.

 

[Speediet44]

Run my 3b up to 2200-2300 before shifting. it will be happy pulling a hill at 2100rpm, though im normally in 4th as my bj60 is a 5 speed. maintaining 70mph calls for 2600rpm, and it doesnt sound happy. About 2800 the noise changes....as the valves start floating.

 

[Elbert]

only two rules to really apply. (1) don't lug the engine...and (2) don't over-rev the engine. After a few runs with the truck to get a feel of the setup (gears,tires,drivetrain...etc). Under load you don't let the rpms fall to far without downshifting (situation dependent)...and on the other end of the spectrum you don't let the rpms exceed the operational range of the engine on the high side.

If your rpms are two high...the choice is easy....(1) slow down or (2) shift to next higher gear. If you are lugging the engine (where rpms are low and you have less power and non-responsive engine...you shift down to the next lowest gear or gears without exceeding the operational rpm range, which will get you back into a rpm vs road speed relationship where you have some power.

You don't have to stay glued to the tach or follow some regime of RPM vs gear selection. The situation is dynamic and depends on speed, weight, grade, load...etc.

Most of the above can easily be accomplished by simply paying attention to the "feel" of the truck and good judgement of the dynamics you are dealing with. Of course don't really expect to power your way out of things on hill climbs...you basically are going to have to find a gear in which your rpm range is acceptable and most likely with the 2f that's going to mean some very slow hill climbs...just a fact of life.

 

[enfield]

only two rules to really apply. (1) don't lug the engine...and (2) don't over-rev the engine. After a few runs with the truck to get a feel of the setup (gears,tires,drivetrain...etc). Under load you don't let the rpms fall to far without downshifting (situation dependent)...and on the other end of the spectrum you don't let the rpms exceed the operational range of the engine on the high side.

If your rpms are two high...the choice is easy....(1) slow down or (2) shift to next higher gear. If you are lugging the engine (where rpms are low and you have less power and non-responsive engine...you shift down to the next lowest gear or gears without exceeding the operational rpm range, which will get you back into a rpm vs road speed relationship where you have some power.

You don't have to stay glued to the tach or follow some regime of RPM vs gear selection. The situation is dynamic and depends on speed, weight, grade, load...etc.

Most of the above can easily be accomplished by simply paying attention to the "feel" of the truck and good judgement of the dynamics you are dealing with. Of course don't really expect to power your way out of things on hill climbs...you basically are going to have to find a gear in which your rpm range is acceptable and most likely with the 2f that's going to mean some very slow hill climbs...just a fact of life.

That is basically what I felt I was doing. It was maintaining speed up the hills at 17-800 rpms and didn't seem to be rattling too bad. Just wanted an expert opinion, since I have zero experience driving a manual in hills. I typically cruise down flat city streets at 12-500 rpms, because there is no real load on the engine.

 

[Elbert]

if its "rattling" or pinging....you probably are lugging the engine (shift down to the next lowest gear)... if not then you are good. A little hard to express over the internet.... as some of this has to be learned in the old school way. Biggest thing on the 60 with stock enigne is to get a tune up and go from there....and get the carb rebuilt after 20+years...