Anyone know of any problems with running the exhaust brake without a load or just during normal driving? Mine seems to be a little louder but thats it. Does it affect fuel mileage? Or does it wear out other components quicker? Don't really know to much about diesels.

 

I run mine all the time on my unloaded beltway bandit. There has been much discussion/recommendation that running the EB keeps the turbo vanes/shaft clean of soot. YMMV

 

I have heard the same. Running it helps keep it clean. We are all test dummies right now.

 

That's a good enough excuse for me. I keep mine on any time the truck is running.

 

I've only had my truck for a little more than a week, but I sure like using the brake all the time. The only goofy thing I've found is if I happen to let off the accelerator just when the trans is getting ready to shift and the exhaust brake engages, it will kind of "clunk" in the trans and then start slowing.

I'm not trying to steal a thread, but I think this is all related. Does anyone else smell diesel exhaust during or after they've used their engine brake? The only reason it's odd is because as you 6.7 owners with DPFs and Cats know, that smell has been all but eliminated.

Where do the exhaust gases go when the brake is being used? Is it possible that non-filtered diesel exhaust escapes during its use?

 

My dealer tech told me to use it all the time.... for the same reasons ^^^^^^^^^ they said!

 

I was told the same thing by several tech's. My "concern" with that is I should not have to run with the EB on to keep carbon build up off of the turbo vanes. This should be taken care of either with software or turbo design. All prior Cummings that I have owned did not have an EB, I never once had any concerns about carbon buildup. Hopefully these issues can get resolved soon.

 

I use it every day and I sit in traffic to and from work. I also use tow/haul. It keeps me from using my brakes in traffic-

BigD

 

Don't the vanes move during regular driving even if the exhaust brake isn't turned on? The sales booklet says...

"At low rpm the sliding nozzle is positioned to allow faster turbo spool up, reducing boost lag. When the engine speed increases, sliding nozzle opens, allowing more volume, matching the higher engine rpm."

Based on that info it looks like the turbo is more or less continuously adjusting with load and engine speed.

 

What about MPG's, does if effect mileage pos-neg if you run with it on all the time? Currently I run it to help warm the truck, tow and in stop and go traffic.

 

GOOD Question!! I had the e-brake engaged all the time on a couple 1,300 mile trips, both loaded & unloaded when the truck was brand new but felt at that time I was losing 1 m.p.g. over the whole trip. Of course that was back before they came out with all flashes. Unknown to me at the time, the truck was not regening and the problems didn't start showing up until 30k miles later. Now I only use it sporadically. Now that the truck is up to date with the flashes maybe I'll try using the e-brake full time on the next trip.

 

The vains don't move. The sliding nozzle does during normal driving. With EB on the sliding nozzle moves more to cut of exhaust when braking. Using it all the time keeps the shaft that it slides on free of soot. At least thats the way I understand it. I'm not sure how this could affect MPG's, but maybe it could.

 

The 6.7 turbo has fixed vanes, they don't move. It uses a sliding nozzle to change the variable geometry. Just that nozzle moves in and out and this is always moving even if the exhaust brake is off. Although the nozzle will go into a different position when the brake is actuated to block of the exhaust inlet. Check out the link below for a diagram.

Notice that when the exhaust inlet is blocked off (exhaust brake on) the shaft slides out to be exposed. If soot was a problem the nozzle (collar) could not come back for the inlet to be opened up when the turbo is required. When the turbo is opening up (full throttle) it slides back and covers up the shaft slide. So there is really not going to be a problem with this turbo if you leave the exhaust brake off for awhile as soot can't get to the shaft area with the brake off. When you get on it the shaft gets covered up.

In other words, all the exposed surfaces that could cause a problem (nozzle and sliding shaft) are not exposed when the brake is off. They get exposed to soot with the brake on.

http://www.holset.co.uk/files/2_5_1_5-VGT.php

The Fords use a variable vane setup if I'm not mistaken. The new Cummins 6.7 turbo is a entire different beast.

 

Thanks for the explanation and the link. I understand it better after watching the the cut-away drawing go through the motions. I'm a total noob, having owned a diesel for less than a week.

 

THX for the explanation & link. Still curious though, does it affect fuel mileage if left engaged all the time. Where does all that back pressure go??