V10 Redline going downhill

[Roll]

Originally Posted by Tony Lee

the other half have their engine or exhaust brake doing most of the work and when that is working, the brake lights will be on even though the drivers foot isn't on the brake pedal 95% of the time.

Can you elaborate please. Are you saying my brakes lights might be on when I am using T/H and engine compression to hold my speed down on grades.

Roll

[96 Wideglide]

I spend a lot of time driving in the mountains, 8-9% grades.
I'll let the tach climb to 4000 brake hard till it's back to 3000, then repeat....

[justimagination]

Originally Posted by Arch Hoagland

I travel in mountains a lot. When at the very top and starting to descend I manually move my transmission to third and watch the RPMs. At 4000 RPM I will mash on the brakes hard for no more than five seconds.

That will usually drop me to about 3,000 RPM. If need be I'll drop to 2nd gear.

I go slow down mountains, 95% of the time it's 4 lane and people can go around me, however I will never speed up going downhill for the benefit of anybody behind me.

Rv's pass me all the time and I see them riding the brakes all the way down the mountain. I'm always curious how their brakes are after that. Can't be good.

I climb mountains based on the max torque for my engine which is around 3,500 to 3,800 RPM. I could care less how fast I'm going, getting over a mountain at breakneck speeds is not important to me.

Just take it easy and don't get caught up in the need for speed. If you want speed drive a sports car.......

..So well put, I just had to second this, it's exactly what I do.
david g.

[George Schweikle]

Tony's right. Engine braking from downshifting won't always provide sufficient braking on a steep enough grade. You will need to brake aggressively, then let off, brake again when the speed builds up, then repeat as necessary. Do NOT just ride the brakes.

We have a trip to Oregon and California planned, and will buy a newer version of this: Mountain Driving Guide for Truckers, RV and Motorhome Drivers It's really informative and allows one to review the grades in advance.

Originally Posted by Tony Lee

At this point, if you don't recognise the situation you are in, you are seconds away from big trouble.

Look up "snub braking" on the internet and use it to keep things under control. Big diesels don't have the same degree of inbuilt engine braking as do gas engines so their techniques are different and unless they have some form of engine braking or retarder, they can have more trouble keeping speed under control.

BTW, re those big RVs going fast down the hills - probably half haven't a clue and are riding the brakes all the way down saying their prayers, but the other half have their engine or exhaust brake doing most of the work and when that is working, the brake lights will be on even though the drivers foot isn't on the brake pedal 95% of the time.

[CLIFFTALL]

Originally Posted by George Schweikle

Tony's right. Engine braking from downshifting won't always provide sufficient braking on a steep enough grade. You will need to brake aggressively, then let off, brake again when the speed builds up, then repeat as necessary. Do NOT just ride the brakes.

We have a trip to Oregon and California planned, and will buy a newer version of this: Mountain Driving Guide for Truckers, RV and Motorhome Drivers It's really informative and allows one to review the grades in advance.

X2 to all of the above especially the mountain directories. I have both the East and West editions and they were invaluable to me.




Cliff

[Tony Lee]

Re brake lights on when engine brake is working. Have got off topic a bit and into the realm of braking and braking techniques generally and that leads to use of engine brakes.
I can't vouch that all systems are the same, but since you are technically braking, wouldn't it make sense for the brake lights to be on as a warning to following traffic if the Jake brakes were operating..
Of course if you are just using gas engine compression to hold speed and don't have the sort of engine/exhaust brakes fitted to many large diesels, then there is no mechanism to switch on the brake lights. Not sure what T/H means, but if you were using manual override on trailer brakes, that should bring on the brake lights.

Pretty sure that mine are on - based on the fact that if I have the cruise control on and have forgotten to switch off the exhaust brake, when the rig goes over a bit of a hill and the cruise control backs off the throttle to the point where the engine brake comes on, the cruise control drops right out - and I assume that is because the brake light comes on.
Your rig may differ but if you Google "brake lights on when engine brake engages" you will get lots of hits which without reading all the details, seem to confirm my experience - including comments on interaction with cruise control and discussions about the legality of the toad brakes or brakes lights not operating under these conditions.

I actually don't like the feature because I figure anyone following me down a steep hill will think I'm one of those ignorants who ride the brakes all the way down praying as I go - when in fact I go down hills very conservatively and rarely touch the brakes. That comes of owning an 1978 MC8 MH conversion back home - 17 tonnes, four speed crash box that forces you to get in the right gear long before the engine speeds get so high that it is impossible to downshift, NO ENGINE BRAKING of any sort, and drum brakes that fade pretty fast if you start abusing them. With that vehicle, you can't afford to let things get out of hand because there is no way to recover. In comparison the Airstream is a doddle to drive,

[CD]

I don't own a MH (never have) but don't be afraid to use the lowest gear you have if you are not sure what to use. If you get on the steep part and don't need that low of gear you can shift up a gear at a time to where the engine can barely hold it and save the brakes. Better than too high of gear and too much speed. With practice you can look at the % sign and pretty well know what gear to start down in.
My exhaust brake is not hooked into the brake lights. Maybe it should but I had it installed by the dealer that sold it. Sure works good on people that ride your bumper going by your brake lights.

[hanko]

Originally Posted by ga traveler

We went out west in 2007 08 and 2009. In the rockies we encountered several 12% grades. We had no problems pulling them in 2nd gear. I kept the rpm's at 4000. We never had a temp. problem. Downhill, I braked at 50 down to 35. Let off the brakes at 35 and let it build back to 50. You MUST let off the brakes and let them cool. If you stay on the brakes, they will overheat and fail. This is with a 35 ft. towing a Honda civic. Remember to keep the rpm's up going uphill. The water pump has to turn fast enough to keep the water going thru the radiator fast enough to keep it cool.

12% grade, i doubt it. I dont believe there is any. Ive seen %10 in Virgina off the beaten path.

[jamesrxx951]

with the 4R100 transmission if you were to hit the OD cancel button that will release the overdrive clutch and give you 3rd gear. The coast clutch is turned on at this point. The coast clutch is used to increase your engine braking power. As most of the others stated try to decend slow and as your speed increases to high apply the brakes to bring it down. I would not however keep the engine rpms close to the engine fuel cut off. Personally i would keep it under 4K and more like 3K if i can help it. The reason for this is i would be worried about to much high rpm cylinder vacuum due to the closed throttle blades. When the newly released 5.0 mustang was released there were engine failures due to lack of oil. This was on engines that were not even due for there first oil change. They were all 6sp manuals also. After the investigations it was found out that the owners were using them as the design intent but when slowing down they would keep it in the low gear and slow down from 7K down in gear. This was causing the rings to pull in slightly and pull engine oil into the combustion chamber. New ring design fixed it but i have no idea how the V10 will handle contant high rpm under high cylinder vacuum. Checking your engine oil after a trip may not be a bad idea just to make sure.

[ga traveler]

Originally Posted by hanko

12% grade, i doubt it. I dont believe there is any. Ive seen %10 in Virgina off the beaten path.

Why would you call someone a liar without a shred of proof? We took back roads through parts of Wyoming and Montana. The road was marked 12% with a state sign. That is the only time I have ever had to go to first gear in the motorhome. It just would not pull the grade in second.

[LI-Camper]

Here is some info I found online:From the Pennsylvania East section of the Mountain Directory East: Pennsylvania highway 125 (between Shamokin and Good Spring, PA.) Large vehicles may want to avoid this 18 mile section of road. It crosses four mountains and includes numerous 15 mph hairpin turns and many more 20 and 25 mph curves. Regardless of your direction of travel you will have to climb and descend some very steep hills. Much of the grade is 7 to 9% but there are numerous sections that must be 12% or more, some lasting almost a mile. Brake shoes don't have enough time to cool much between descents.

[ga traveler]

From motoringconbrio.com/great-driving-roads I quote:yellowstone to red lodge Montana. There are quite a few steep grades. Up to 12% along the route.

[bigcritter]

I have a few questions concerning motorhomes decending steep mountain grades. First, just how effective is the tow/haul feature on a gas chassis? I have a 2011 Winnebago Vista 30W, Triton V-10 engine, F53 chassis, with tow/haul. I've used it on some shallow grades, but I've never been on anything really steep yet. Second, does anyone have any experience with the electronic/magnetic transmission/driveshaft retarders? Do they still make those? I remember reading about them a number of years ago, and they sounded like they would be really effective on steep grades. Third, everyone talks about changing the brake fluid every year/every two years. I remember reading somewhere that an easy way to do this is to take a turkey baster and suck out a large portion of the fluid in your reservoir, making sure never to go so low that it allows air to enter the intake at the bottom of the tank. Then replace that fluid with fresh fluid. The old dirty fluid in the lines will rise back up to the resevoir after it's been driven for a bit, and you repeat the process. After a few times, you would have replaced most of the old fluid with new. Would this process actually be effective?? Don't know if this would actually work or not, but it sounds easier than draining, replacing, bleeding, etc. :>O Thoughts and comments???

[stuhly]

Always use the same gear going down the hill you would climb it in. Will save a lot on brakes. Just remember, if you smoke your brakes you are screwed big time.