It's so easy to over generalize our answers, when the specifics of the combination of many different factors will dictate the best approach to hill climbing, and decent. (Weight of coach. Specific engine, say like the 8.3 like the OP's, with Exhaust Brake Assist vs say a CAT15 with 2 Stage Jake Compression. Gearing of coach. Drums vs Disc brakes. Etc., etc.) What is good input for one specific coach, could be dangerous to someone driving a coach with totally different parameters.
Getting the engine serial number, and calling to get that specific engine's operating parameters, is a good move for any owner. Max HP/Torque. Max RPM. Max RPM with Exhaust or Jake Compression.
A few general observations, from many of you and others over the years, has helped me over the years:
-On hill climbs. The ECM's of engine and transmission 'react' to grade changes. Us who are driving, have our eye's to see the change of grade ahead. So we can pro actively downshift to maintain the optimum RPM for our specific engine. Which us usually relatively close to Max HP RPM. While climbing a hill, if our coach will not say hold the speed in say 5th gear at the Max HP RPM, once it's dropped about 100-150, maybe even 200 RPM's below this Max HP RPM, manually downshift. (Experiment, as this will vary based upon tire sizes, and rear end gear ratios.)
-Learn to reach over and on your specific coach, feel the transmission keypad, and memorize it's layout. So that you can reach over and Down/Up shift, without removing your eyes from the road.
-On down hills. I do understand the rule of thumb mentioned about going down as you came up. But way too many times, the decent is totally different then the grade, and or number of curves compared to what you may have just climbed
! So, sure keep it in mind. But again use your eyes, and judge what is ahead of you. (We like the Mountain Directory (East or West) for Trucks and RV'er's. It gives you a good feel for what to expect on both climbing, and descending.)
-As much as possible, use the combination of you're engines compression and transmission gearing to try to hold your speed. Limit your braking, if at all possible. That being said, a big difference in what a BIG BLOCK 2 or 3 Stage Jake Compression combo of Braking Horsepower is, compared to a Small or Medium sized block engine, and Exhaust Assist braking's Braking Horsepower will provide. (CAT C7/C9 and Cummins ISB, ISC and ISL are Small to Mid Block sized engines. I consider anything above 10 liters, to be the entry into Large Blocks (Many will say it's 12 Liters and above, and that's OK
!). But take say a BIG BLOCK ISX engine, 12 or 15 liters, but in this example, the 15 liter - lots of Braking Horse Power via Jake Compression!)
-Since their are so many variables in our coaches engine sizes, and again Jake Compression vs Exhaust braking, along with Drum vs Disc brakes - learning how your coaches combination of Braking Assist, and actual braking, work with each other - is an important step of learning your coach.
-I personally, when to able to maintain a desired down hill speed while using my Mid Size ISL with 2 Stage Jake Compression. Like to firmly apply my brakes, and slow down to about 5MPH's below my desired speed. Example If I'm truing to 45MPH in 4th gear, and in High Compression Braking position. Once my speed gets up to a max of 50MPH, I firmly brake until my MPH is dropped down to 40 MPH. (I use common sense on picking the speed I allow my coach to go up to above my desired speed. Based upon is it a straight downhill say vs curves with slower speeds dictated. I also watch the grade changes. If I see it's getting to a steeper decline, I might brake at say 48 or even 47MPH.). But the key, is to slow your coach down as relatively as fast as you can, to a speed somewhat below what you feel is what you want to hold (And not always the posted MPH's, as they are for cars, unless specifically calling out Truck MPH too, and do follow the Truck posted MPH limits.). Then get off that brake pedal, so the drums/pads or disc's can cool down.
And practice. Go learn your coach. Always drive within your comfort zone. Don't worry about people behind you. SET YOUR FLASHERS ON, if going up a hill to slow, and or down a hill too.
This is not a race. And with 30 up to 55K pounds of coaches under our seats - driving for safety and for your rig, is a skill to master.
$.02
!
Be safe, have fun, and learn the specific's of your coach
!
Smitty
Linear Mode
