Exhaust Brake
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Try the same grade with the Tow/Haul disengaged and feel the difference.
The Exhaust Brake works best up around 2800 to 3400 rpm.
The Exhaust Brake works best up around 2800 to 3400 rpm.
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yup i use it on the exit that i get off for work.work's great, i just hit tow/haul ad tap the brake and it's like i stepped on brakes real hard when i didn't, keep's brake dust off front rims longer to lol.
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Keep in mind it's not an exhaust brake. It's braking assist... Only the Cummins has an exhaust brake.
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Might want to check your local GM dealer.
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It's all symantics. Whether you have a butterfly valve in your down stream exhaust pipe or a turbo that restricts the exhaust so it can't exit. The systems slow the exit of exhaust and cause back pressure on the pistons which causes braking to the drive line.
The difference in the terminalogy just reflects where the exhuast is restricted. The effect is basically the same, Back pressure on piston, creates a braking pressure as the piston compress the exhaust gas that was not expelled.
The difference in the terminalogy just reflects where the exhuast is restricted. The effect is basically the same, Back pressure on piston, creates a braking pressure as the piston compress the exhaust gas that was not expelled.
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The LML uses the same design as the Powerstroke. They adjust the turbo vanes to assist in braking. Not a true exhaust brake like the Cummins.
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Yes that's true but the turbo is designed to let air flow out the tailpipe only allowing a very small back pressure. Cummins almost blocks off the whole exhaust pipe causing way more back pressure.
I'm sorry I can't help the fact I wish I had a Cummins exhaust brake.
Just an FYI -- the 6.7 Cummins uses the turbo as well to generate the backpressure -- not a butterfly valve in the exhaust. It works better, too, generating more retarding HP than the previously employed Jacobs brake. :thumbsup:
5.9 and Dodge 6.7 Cummins (there are two 6.7's) did not use Jacobs engine brakes. Jake brakes go on the valve train under valve cover.
There may be an exhaust brake made by Jacobs for some applications but the term "Jake Brake" refers to their hardware on valve train.
There may be an exhaust brake made by Jacobs for some applications but the term "Jake Brake" refers to their hardware on valve train.
We know.
The New Jacobs Exhaust Brake for
http://cumminsengines.com/assets/pdf/4081477.pdf
The mechanism by which backpressure was to be generated changed with the implementation of the 6.7; it now uses the sliding nozzle in the VG turbo to restrict the area available for exhaust, thus creating the retarding HP desired.
GM uses a similar strategy, but they shut down the vanes rather than implementing a sliding nozzle. The net effect is similar, but I believe the nod goes to the Dodge for retarding HP with the current setups. There has been at least one interview with Ford engineers that confirmed the suspicion that they do not currently involve the turbo in their grade braking / "exhaust braking" strategy; this is quite likely why the complaints on the relative ineffectiveness of Ford's exhaust braking feature are nearly universal amongst reviewers... with only internet forum participants offering a counter to these observations. Now perhaps the engineer did not know what he was talking about. Perhaps the interviewer misunderstood. I doubt that these are the case, however, and my test drives fall more in line with that of the "professional" reviewers in that the retarding ability, in tow haul and on a hill, is significantly less with the Ford than it is with either the Dodge or the GM twins.
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Mine works fine. I do not tow much or heavy when I do. But when I do it works great.
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Good info guys! I never knew Cummins went to a sliding nozzle... Did the 08 Cummings have the sliding nozzle? I just drove my friends Cummins 1200 miles and had fun with his exhaust brake. Still like my Ford 10 fold.
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Part of the amount of Exhaust Braking that can be generated is based on how strong the valve springs are and how much back pressure they can tolerate before they float. The valve springs in the previous generation of Powerstroke engines (6.0L and 6.4L) were 40 lbs which was considerable less the 50 and 60 lbs springs that the Cummins and Duramax engines used. Hence the Powerstroke engines never had the potential of creating as much back pressure, and hence always had less exhaust braking than the other makes.
I have no idea what the current 6.7L has for valve springs. Just remember it has more to do with the total system, than just where the back pressure is created. If Ford has continued using lighter valve springs, Then the limiting factor is what the springs will tolerate and not whether the turbo can produce higher back pressure than a butterfly valve located downstream in the exhaust pipe.
I have no idea what the current 6.7L has for valve springs. Just remember it has more to do with the total system, than just where the back pressure is created. If Ford has continued using lighter valve springs, Then the limiting factor is what the springs will tolerate and not whether the turbo can produce higher back pressure than a butterfly valve located downstream in the exhaust pipe.
Just to add my .02 worth -- I traded a 6.7L Dodge DRW for my 2011 F350 DRW and the Dodge's exhaust brake was head and shoulder's stronger than my new Ford's. With the Dodge coming down a local hill (not a mountain, simply a hill which begins with a speed limit of 50 and ends in a 4-way stop), I could take my food off the accelerator and the truck would slow to 20 mph by itself well short of the stop signs; the Ford actually increases speed even though I tap the brakes and feel it downshift and engage the exhaust brake (have even hit the brakes 3, 4, and more times to down-shift / increase RPMs to a much higher level) and it never gets below 40 mph. Hauling my Cedar Creek RV (approx 13000 pounds), the Dodge would do the same as before, albeit I would have to brake near the end to ensure I didn't run the stop signs; the Ford never gets below 50 with the 5er attached on that hill. I don't imagine it will be different on a Mountain downgrade but that is just supposition since I have yet to get that opportunity with the Ford.
I'm with one of the drivers who posted above, there are times when I wonder if it is even on. I do hope it is a programming issue and Ford takes a good hard look at it and tightens it down some.
That said, I love my Ford -- I see this as one small minus to a whole lot of pluses over the Dodge in my opinion.
I'm with one of the drivers who posted above, there are times when I wonder if it is even on. I do hope it is a programming issue and Ford takes a good hard look at it and tightens it down some.
That said, I love my Ford -- I see this as one small minus to a whole lot of pluses over the Dodge in my opinion.
I must ask a simple question to begin with; are you using tow/haul mode when you are descending the hill? If not, that is the first problem.
I have had my 2011 6.7 truck for over a year and have put 31000 miles on it. 10000 of those miles have been pulling a 13000# Heartland Big Horn fifth wheel. I have weighed my rig more than once. The gross combined weight is 22200 #. I have towed it up and down the hills on US 30 between Hershey, Pa and Pittsburgh, Pa. There are several 8% and 9% descents in that stretch of highway. I can top any of these hills easily at the speed limit of 65 mph. I have found that if I begin my descent at 50 mph, in tow/haul mode, a tap on the brake pedal turns on the EB and I hold 50 mph all the way down these 3 mile long grades. If I desire less speed, another tap on the brake pedal provides a 10 mph drop in speed. The total integration of the EB with the transmission and tow/haul mode and the lack of an obvious on/off switch has certainly caused some confusion, especially with those owners that had OB's with an on/off switch.
Your results, unfortunately, mimic the results published in the infamous "Rumble" advertisement paid for by GM. I would not argue that the Dodge or GM EB may be stronger, but the Ford EB works well for my application, which is similar to yours. Many others who have figured out the nuances of it's operation would agree.
Regards
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Yesterday I took my horses up to a trailhead that I frequently use. As I was leaving I pulled out with the truck in tow/haul and just let the truck do it's thing. It's a very steep hill for several block and then a 90 degree left turn and then another block to the traffic light. There are a couple of house along the street so the posted speed is 25mph.
Once I got pulled out of the parking lot, I took my foot off the pedal and just let the truck roll. the engine held me at 20 mph all the way down the grade. No need for braking at the hard left corner. I never touched the brake to initiate the EB. 1st gear @ 20 mph is 2800 rpm.
My 2006 truck with a B&D Exhaust brake would never do that. The B&D after market product disables it's self at speeds below 25 mph. So my rig would roll down that same hill at 30-35 mph or I would have to use the pedal to slow.
I find the same high level of integration at higher speeds. Trappers Loop in Utah has a 6-7 mile 7% and 8% grade. It is a 55 mph road with 40 mph corners. If I top the summit at 55 mph with the cruise on the rig will creep up to 60-65 mph and I will have to brake hard at the sharp curves. If I crest the summit at 48 mph cruise set. The powertrain will pretty much hold me at that speed down the descent, with me never touching the brake pedal. Between the Cruise control, Tow/haul, the truck is smart enough to engage the EB and downshift as needed to get the RPMs up into the 2800-3000 range where there is enough back pressure to provide some engine braking. It is all in selecting the right speed where the engine is effective. 5-7 mph faster and I'm in the wrong gear and don't see the braking.
I agree with Rickic, It's all about learning the nuances of the system. It's probably not the strongest EB out there, but it's not a worthless implimentation either.
Once I got pulled out of the parking lot, I took my foot off the pedal and just let the truck roll. the engine held me at 20 mph all the way down the grade. No need for braking at the hard left corner. I never touched the brake to initiate the EB. 1st gear @ 20 mph is 2800 rpm.
My 2006 truck with a B&D Exhaust brake would never do that. The B&D after market product disables it's self at speeds below 25 mph. So my rig would roll down that same hill at 30-35 mph or I would have to use the pedal to slow.
I find the same high level of integration at higher speeds. Trappers Loop in Utah has a 6-7 mile 7% and 8% grade. It is a 55 mph road with 40 mph corners. If I top the summit at 55 mph with the cruise on the rig will creep up to 60-65 mph and I will have to brake hard at the sharp curves. If I crest the summit at 48 mph cruise set. The powertrain will pretty much hold me at that speed down the descent, with me never touching the brake pedal. Between the Cruise control, Tow/haul, the truck is smart enough to engage the EB and downshift as needed to get the RPMs up into the 2800-3000 range where there is enough back pressure to provide some engine braking. It is all in selecting the right speed where the engine is effective. 5-7 mph faster and I'm in the wrong gear and don't see the braking.
I agree with Rickic, It's all about learning the nuances of the system. It's probably not the strongest EB out there, but it's not a worthless implimentation either.
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I think this exhaust brake sucks. I was onboard with it when I had my smaller 5er, but out here in the mountains the thing is a joke. Last time I came down Eisenhower pass, my brakes were on fire at the base. Smoke pouring out of the fronts and the truck was going 70 in 3rd gear at about 3700 RPM. Rabbit ears pass coming into Steamboat Springs? 8% grade, was going 45 mph in 2nd gear! It seems to do absolutely nothing to slow the truck down. I had to pump the brakes all the way down both passes to dump speed. I love this truck, but my experience has been the same as the tow test in the rockies that was posted about 6 months ago.
In answer to Ricatic's question -- I do have tow/haul mode on -- given the experience and guidance I learned on the Dodge, it is the first thing I turn on when after I start the truck -- albeit, I have now started turning it off some to allow the truck to upshift at lower speads in city driving. As I mentioned, in my Dodge all I had to do was take my food off the accelerator and the truck would start slowing down; I have learned over the past few months of owning the Ford to press the brake pedal to begin the slowing down. That said, I have a Cedar Creek that GWR is 13800 but both times I have weighed it, it came in at or just shy of 13000 pounds. The hill I'm talking about is rated at 5% and is only 1.5 miles long, really not much of a test however it is enough that both my wife and I have noticed the difference in exhaust braking (or whatever you want to call it).
Another item, solo with the E/B on, we get thrown up against the seat belts at about 20 mph as the truck hits its last downshift. That one does retard us before it disengages at about 16 or 17 mph as indicated on the speedometer.
As mentioned, we love the truck but it is one thing that we do think Ford should look into and make better. Hopefully in a manner that can be retrofitted / modified on trucks already in service at their expense :lol:. Thanks for letting me put in my .02 worth.
Another item, solo with the E/B on, we get thrown up against the seat belts at about 20 mph as the truck hits its last downshift. That one does retard us before it disengages at about 16 or 17 mph as indicated on the speedometer.
As mentioned, we love the truck but it is one thing that we do think Ford should look into and make better. Hopefully in a manner that can be retrofitted / modified on trucks already in service at their expense :lol:. Thanks for letting me put in my .02 worth.
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