Going down mountains.

[blw2]

Originally Posted by JamieGeek

Coming back from our recent trip I noticed something you can do while on those long rolling hills.

When going uphill the cruise control tends to wait until the speed drops too much before downshifting thus causing it to downshift too far in an effort to catch back up to the set point. (I note that most discussions here involve turning off the cruise in hilly areas because of this.) What I found was that just as the coach is entering the hill and speed begins to drop if you give it enough gas at that point to downshift a little("a little" = a gear) and then take your foot off the gas the cruise will tend to hold the speed in the new gear without all the drama of a further downshift (unless the hill is either too long or too steep). You do have to wait until the speed starts to decrease a little otherwise it will simply upshift again when you remove your foot from the gas.

I found using this method makes for a relatively stress free way to maintain speed on those long hills and still be able to carry on a conversation (and to continue to use cruise control).

I have been known to do this sort of thing sometimes

I'll also sometimes allow speed to build a bit higher that the cruise set point on the downhill by feathering in a bit more gas pedal (just a little, not too fast)....and then kill the cruise control on the uphill just before that big downshift and just let the speed bleed off.

I don't know....kind of depends on road condition and mood.
on the big downhills though, I just let tow/haul do its thing.

[penguin]

PATIENCE----Good Tip

[bigben]

Your gonna be fine following the advise you've gotten. Relax and let it happen Captain. We've got 35K miles on our Challenger to include two round trips coast to coast with lots of steep grades in the Rockies and Sierra Nevadas including drives through Yellowstone NP. No problems - the V10 is a beast.

[croused]

Originally Posted by rick kirby

Going to darlington SC Tuesday and it'll be my first time driving my 37' Challenger through there.
I know it's going to add the Pucker factor, and I'm going to be xtra careful, any tips from you veterans who've drove the mountains ?

Yup, the tow/haul mode brake sequence is the best for downhills....very impressive!

[Budman]

Originally Posted by Joe-FL

A couple years ago I would have been in the "never use your flashers" camp also. When pulling fivers with diesels I generally went up the grades at 60 and came down the same with exhaust braking taking over. With these V-10's it is a different animal.

We encountered a bunch of grades during our 4 months on the road this summer. There are many distracted drivers out there running up and down those grades at 80mph plus. Now here I come along with my struggling V-10 going up one at 40mph and without flashers on you could have some close calls. This is the only time I EVER use my flashers. As a retired Trooper I can assure you a large vehicle moving under 45mph on the interstate will never be ticketed for this.

I agree completely especially going up the hill at 40-45. I have encountered 8-9%% grades in KY, NC, and WV and someone will run over u going uphill. Now downhill, I normally turn off flashers and can control down hill a little faster. The trick is never let it start going too fast but I don't think there is a hard and fast rule. BUT, never go down faster than you're comfortable with, use lower gears, and never ride the brakes. Just my 2 cents. Thx, Dennis.

[TurnerFam]

Originally Posted by croused

Yup, the tow/haul mode brake sequence is the best for downhills....very impressive!

as I deliver brand new units from the factories to dealers, both gas and diesel, I can attest that the 'tow/haul' mode only serves to shift 'later', allowing the engine and transmission to stay in a lower gear longer, giving you slightly more lower gear time both uphill and downhill - though, touching the brakes when downhill allows the transmission to downshift earlier providing more 'braking' and not having to use the service brakes(brake pedal) as often.
Even when towing a vehicle, which is most of the time, I've not seen the 'need' to use tow/haul mode as I'm not necessarily concerned about the speed up hills, but more with fuel economy.
The engine/transmission works very nicely down the hills, just touch the brake pedal when you are at the speed you want to try to 'hold' while starting to descend(crest of the hill)...

Diesels work similarly, though they have either Exhaust Brakes or Jake Brakes, causing the engine to automatically 'slow' while descending, while the transmission follows in a lower gear. Cummins engines typically have a 'Mode' button, though it is to provide the opposite of the 'tow/haul' mode on gas coaches - it provide the ability for the transmission to shift earlier, providing better fuel economy. My Palazzo has probably only been out of MODE for a handful of times in over 75,000 miles... unless you want to pass everyone on the way up a long hard grade, it's not really needed to come out of MODE.

[rick kirby]

Well, I survived going down the West Virginia mountains.
I must say, it sure keep a person focused on what they're doing !

[Laco]

One of the times I miss my former DP. Though it weighed over 40,000 pounds, it also had a full two stage jake brake, which would really hold downhill speed from getting away from me. I rarely had to use service brakes on downhill's.

[BSexton]

I just went up and over the Rockies on I70 west bound yesterday. I was very pleased at how well the cruise control and to/haul mode handled everything. I set the cruise control for about 55 and it down shifted and held that speed. I think it got down to 3rd and was running at about 3500 RPMs going down the 6-7% grade.

[Blackjeepjk]

Originally Posted by rick kirby

Well, I survived going down the West Virginia mountains.
I must say, it sure keep a person focused on what they're doing !