rsgstr

I could have sworn I read of an exhaust brake installation where one set the speed and the brake control did the rest, adjusting the brake to keep the speed to the setting. I've looked and looked, but could not find this again. Anyone seen this, or was I too close to the pump when I filled up last time.

I've got a 3500 2wdQC, with a 78gal AuxTank (great looking & easy to install, BTW), and tow a 35' 5ver 6-8kmiles/yr. Colorado was an adventure this summer, will go back this one, but not without an EB!!

Thanks from yet another newbie!

Mike

Ramflasher

I have not heard of this, but I can use my exhaust brake with the cruise control on...I try not to tho, cause it just seems like it would use more fuel. When it clicks on, the speed goes down too fast, and then the cruise wants to make up for it by trying to accelerate.

Dr. Evil

I havent towed very heavy with mine - but if you are unloaded it works great with cruise on.

But if you had a 15K+ trailer behind you, it would definitely slow down very quick and accelerate hard with the cruise on. The best solution is to have the switch attached to the shifter...then you can turn the brake on/off when needed. (rsgstr, you left out the most important part - what tranny do u have?)

P Kennedy

Basics of Engine brakes- when the brake control senses no throttle the brake will engage, when the cruise control senses a speed less than the one set it will apply enough power to increase the speed. So as Ramflasher said it can and will be counter productive for fuel milage and will create a surging effect even on flat ground. This effect will increase with wind or heavier loads, which is not what an engine brake was designed for and makes for uncomfortable long distance driving. The engine brake was designed to control a vehicle either slowing to stop or on grades easing the pressure and wear on the service brakes. Pacbrake says that their unit will produce up to 140 approx braking horsepower at 2700rpm so for the purpose of example assume the engine in your truck produces 140 hp at 2700 rpm. This would mean if you haul 10,000lbs gross up a 6% hill at 45 mph the truck can come down that hill at 45 mph with the brake on in the same gear at 2700 rpm without touching the service brake pedal. Advantage brakes will stay cool and wear non-existant for that part of the trip. Old truck driver rule was whatever gear you go up you can come down in, however when the truck generates 400hp and the brake generates 140 hp this theory won't work. For the purpose of argument a 2004 315 hp goes up that hill of 6% at 60 mph full throttle and is not accelerating or losing speed then on an exhaust brake of 140 braking hp should come down the same grade with the same weight at just under 30 mph with very little or no service brake application. Theoretically allowing a full cold brake emergency application if necessary giving maximum braking of the truck/trailer. The same vehicle with no brake will have heated the brake depending on the length of the grade or slowing distance and may have reduced stopping ability up to 70%. Engine brakes are referred to as having holding power not stopping power like service brakes, proper defensive driving techniques along with an engine brake increase abilty to control a panic situation. What does this have to do with your question- on flat ground where grade deviation is less than 2% grade the cruise control should along with wind drag and weight keep the vehicle close enough to the posted speed limit or speed set by the operator on cruise. PK

RAFTEN

You read about a Banks system.

KATOOM

Well that I must say was very well put! You dont get that kind of answer very often.
As for my exhaust brake and cruise control usage, I have yet to be in a situation that I felt at ease enough to leave the cruise on while I needed the exhaust brake. And for that matter if the cruise is on the truck hasn't yet slowed down at such a rate that the exhaust brake has engaged. I cant see the exhaust brake coming on and off on anything less than a very steep down hill grade since the engine is still capable of slowing the truck to a degree without totally letting off the throttle.

Dieseldude4x4

I think I posted and article a while back about driving down the Skyline Drive with the cruise set on 40 mph and the Jacobs on. I never touched the pedals for the whole 109 mile drive except for stopping at the overlooks and such. That was pretty cool.
I don't know about the rest of them but the Jacobs has a two second delay before it comes on. It will only come on automatically after the computer sees zero fuel for two seconds. It does not click off and on at will. I use it all the time and my front brake pads look like new at 140000 miles.

towpro

I had my last dodge hooked up with the E-brake wired to the Brake Pedel Switch. With the manual I found when the cruse control let off on a hill, the truck would just slow down way to much.

The way I had it wired, you had to hit the brake pedel for the e-brake to come on. You only had to hit it enough for the brake lights to come on.

Also before I wired it this way, I was driving through town and had someone almost rear end me when I slowed down with the ebrake.

rsgstr

Thanks for the quick replies - I wouldn't want to have the normal cruise control on when I'm applying the EB - Seems counter-productive, I would think.

I'll have to look at the Banks stuff to see if that's where I read it. I'm looking for a brake control, I guess, that will adjust the EB on/off to restrict the speed to a given value, if that's possible. That's what I thought I saw, but it may have been some Marketing Wonk's careful wording trying to imply something that's not really possible.

Do the brake's have a "partially on" capability? When they come on, and the truck is empty, is it going to snap my neck forward? It seems that there's a lot of braking power available, so how is it managed to avoid "face plants into the dash"?

Thanks to the good Dr. Evil for pointing out the omission - I have the 5 spd manual. I updated 2+ years ago from a 96 3/4T, and when researching this one, I found what everyone else seemed to know - the Auto couldn't stand the weight that the rest of the truck could - rated tow capacity was 4K lbs less!! Sure wish I'd spent the extra for the 6 spd, tho. It's a long reach from 3rd to 4th some times.

Mike

Dr. Evil

[quote author=rsgstr link=board=4;threadid=23378;start=0#msg220618 date=1070951027]

Do the brake's have a "partially on" capability? When they come on, and the truck is empty, is it going to snap my neck forward? It seems that there's a lot of braking power available, so how is it managed to avoid "face plants into the dash"?

Thanks to the good Dr. Evil for pointing out the omission - I have the 5 spd manual. I updated 2+ years ago from a 96 3/4T, and when researching this one, I found what everyone else seemed to know - the Auto couldn't stand the weight that the rest of the truck could - rated tow capacity was 4K lbs less!! Sure wish I'd spent the extra for the 6 spd, tho. It's a long reach from 3rd to 4th some times.

Mike

[/quote]

Mike, I use my brake unloaded all the time.....and no they dont face plant you into the dash. The braking is more pronounced when you are at higher RPMs....so over time you get a feel of what gear you need/should be in. Don't be worried, you will still be able to use your exhaust brake unloaded - works just fine. Like I said before, its a good idea to get the stick mounted on/off switch so you can turn it on and off when need be. (I have to get one of those switches myself).

As for the auto, I think its a combination of not being able to handle the weight of the load AND the incredible torque made by the Cummins.

As well, the 6 speed isnt all its cracked up to be.....yes it excells at towing but sure can be a bear to drive at times....u definitely dont want one for everyday rush hour traffic.....In my opinion, they are a LOT less fun to drive than the 5 speeds...

Dieseldude4x4

One word of caution I will share and that is be carefull with a dually towing an empty trailer on a wet road especially in a sharp curve. If those back wheels slow enough to break traction, the thing will jack knife and it gets ugly after that. Speaking from experience here, it is not a good feeling.
The thing is not that strong that it will sling you forward when running empty but if the revs are high enough, you can definately feel it. I use mine all the time empty or loaded. It is a very worth while investment in my opinion and should be standard equipment on these trucks or an option anyway for those that know they are going to pull some serious weight.
Just my two copper coated aluminum discs.

Edward

I use my E brake all the time loaded or empty no difference. Using the E brake and the cruse is wonderful. As long as the engine needs the slightest amount of accelerator pedal the E-brake never engages. But when going down a hill and you want to maintain a set speed the combination works great. When the speed increases above what the cruse is set for the accelerator pedal goes to zero and you get E brake. If you are in OD the holding power of the is not has strong as high gear so it is smooth. In fact if I had to describe how it works I would have to say it’s seamless. Just set the speed and drive. 8)

Edward

Dieseldude4x4

[quote author=Edward link=board=4;threadid=23378;start=0#msg221852 date=1071122162]
Just set the speed and drive. 8)

Edward

[/quote]

Yep, what he said. 8)

P Kennedy

As per DD4x4's reply about ice and slippery roads combined with my previous explanation applying 100+ reverse HP to the wheels loaded or empty will cause traction problems. This would be the number one cause of "jack-knifing" besides sudden brake applications on slippery surfaces for trucks hauling trailing equipment. On another forum area the question of travelling on slippery surfaces is discussed aka bridges etc. In any case torque values causing traction loss whether speeding up or slowing down can cause an out of control situation therefore an exhaust brake may increase the chance of the drive tires losing what little road adhesion you had. Experience using these goodies on dry roads will make bad roads easier to deal with and you should be able to feel the right and wrong time to apply. PK

rattle_rattle

I almost "bought it" on an icy bridge last week. Forgot the EB was on and went sideways when it engaged. Woke me up!