[Markk9]

Originally Posted by ironeagle2006

Millis transfer to this day still sets them up that way so does Henderson Trucking.

ironeagle, I think your giving some false info about Millis. I drive for Millis and my fan doesn't come on when I use the jake set a full. I've driven 3 different trucks for Millis and none did this.

Mark

[silvan]

Originally Posted by Doghouse

So it seems like then if I'm going down a grade at gross then setting 3 would be used, and the other 2 settings are for lesser grades or weights?

When I used to haul bedroom furniture, I was so light that #3 on the Jake was in real danger of killing my engine. (That was a mechanical engine. Modern ones will cut the Jake off below 1200 RPM (or whatever is appropriate for your particular engine.)) With that setup, I used to flip the switch up and down to vary the braking when going down a steep hill, and of course I didn't really need it, and I was just playing with it because it was there, and it made a nice obnoxious noise.

With the new job and new truck, I find I leave it on #3 all the time. I never have less than 19,890 pounds in the box, and the Jake doesn't seem to do anything at #2 or #1 except make useless noise.

I don't really *need* a Jake where I'm running now, for that matter, but it reduces the number of times I have to break the cruise.

[Doghouse]

Thanks for the info,....I was scared out of my seat when that thing came on inside the garage the first time. I was trying all the switches and buttons, and walla,....that obnoxious noise!!

[ToxicWaste]

Originally Posted by silvan

When I used to haul bedroom furniture, I was so light that #3 on the Jake was in real danger of killing my engine. (That was a mechanical engine. Modern ones will cut the Jake off below 1200 RPM (or whatever is appropriate for your particular engine.)) With that setup, I used to flip the switch up and down to vary the braking when going down a steep hill, and of course I didn't really need it, and I was just playing with it because it was there, and it made a nice obnoxious noise.

With the new job and new truck, I find I leave it on #3 all the time. I never have less than 19,890 pounds in the box, and the Jake doesn't seem to do anything at #2 or #1 except make useless noise.

I don't really *need* a Jake where I'm running now, for that matter, but it reduces the number of times I have to break the cruise.

If the jake was going to kill the engine you were obviously in too high of a gear to be going down that type of grade. If you downshift and go too slow, than you didn't need the jake in the first place

[Fredog]

Originally Posted by ToxicWaste

If the jake was going to kill the engine you were obviously in too high of a gear to be going down that type of grade. If you downshift and go too slow, than you didn't need the jake in the first place

not true on the older trucks. the jake never quit. if you stopped the truck and put the parking brake on and then let out the clutch without turning the jake off, the truck would stall. it was real embarrassing when the boss was standing there

[slacker]

I've been doing the same thing Steve has.......

On my Cummins ISX 450, the engine fan does increase the braking, and as far as using it or not, you might as well turn it on, because the engine temp can creep up 25 degrees on the hills anyway.

I prefer going down 6% grades with my feet on the floor as well, that way I can use my brakes if I need them, to keep from crashing into the wrecked trucks at the bottom that operated otherwise.

IMHO, use the technology you have.

jonboy

[mudpuddle]

Yep Rev is just wrong on this one. Most of the engine fans on Superior Carriers trucks are programmed to come on after ten seconds of continuous jake brake use. I looked on Cummins website and it turns out Iron Eagle was almost dead on, an ISX fan uses about 60 HP at 2100 RPM. It is in the Every Mile section of their website about fuel mileage and efficiency. The fan can really be useful in getting the last little bit of slowing power on steep grades.

[Part Time Dweller]

Originally Posted by mudpuddle

The fan can really be useful in getting the last little bit of slowing power on steep grades.

If you need the extra slowing power from the fan, then you started the downgrade in the wrong gear and too fast.

All the Cat powered trucks I had the fan w/jake option deselected, I never saw the need for wearing out the fan clutch prematurely nor did I like the noise.

[Rev.Vassago]

Originally Posted by mudpuddle

an ISX fan uses about 60 HP at 2100 RPM.

If you are running an ISX at 2100 rpm, then you have even more issues than wearing the fan clutch out.

[mudpuddle]

My CAT was made maximum rated horsepower at 2100 rpm and was governed at 2300. I haven't driven a ISX but the N14 was similar to the CAT. Any heavy diesel is designed to be able to run at 95% of rated power for long periods of time without doing any damage. I have never been able to get any truck to hold on steep (7% or more) grades on gear and jake alone in any gear when loaded to eighty thousand pounds. The fan is just a little added help and has been programmed to come on with full jakes on every computer controlled truck I have ever driven.