I read that the 'LBZ' has a variable-geometry turbocharger that is capable of providing exhaust braking. What I read indicated that function as being available on some medium-duty truck models and replaces add-on exhaust brake hardware. The new exhaust brake system is controlled by a signal from the engine controller and can be activated by the driver.

I have an '06 'LBZ' on order and was wondering if anyone has experience with making an alteration that replicates the signal from the engine controller, henceforth activating the exhaust brake that's already incorporated in the turbo on the 'LBZ' engine?

I'm curious about that too. I have not read the manual yet though so maybe it's in there.

I posted the same question a few weeks back and go nothing useful. I'm not sure that the exhaust brake on the 4500 uses the variable geometry feature. Rather, I believe it is the same old damper valve as used in the past. I think there are a whole bunch of us waiting for a develpment in this area.

I believe it is the same old damper valve as used in the past.

There was an article in GM-Trucks (http://gm-trucks.com/home/content/view/227/1/) back in August that I was quoting from. It mentioned that the brake was designed into the Turbo and controlled by a signal from the controller.

Maybe it was just hype or BS put out without any factual basis. :rolleyes:

Richard

According to my manuals that came with mine the exhaust brake is only active while in tow/haul mode. I towed my 18' and my John Deere tractor the other day for the first time and figured I would see what it would do. You can definitely feel the braking! I think my load was around 8K but man was it nice not having to use the service brakes a lot. Nice feature!

According to my manuals that came with mine the exhaust brake is only active while in tow/haul mode.

Clay,

Are you referring to an exhaust brake or is it the grade retarding feature of the Allison tranny you're activating? If it is indeed an exhaust brake, did you install it as an aftermarket product or is it incorporated into the factory turbo?

Richard

Now, I am confused (not necessarily surprising). The 4500 comes with an optional exhaust brake with switch in the cabin. Bushwhacker says his has an exhaust brake available when ever in the tow/haul mode. Is this more than the braking we have had in the previous models in Tow/Haul Mode? If so, why is there an option for something in the 4500. I understand both the new LLY (installed in the 4500) and LBZ use the same turbo. As the used to say on Laugh-in, "Very, very interesting!"

Sorry for the confusion. I mis read the brochure! DOH! It is the allison feature and not with the turbo, the grade braking/cruise grade braking feature. (just pulled out all the literature in the glove box) Sorry guys!

After looking at the VVT turbochargers, I'm sure they could be used as an "exhaust brake". If the vanes are commanded fully closed, it would create an "exhaust brake" type situtation. Instead of using a flapper valve like a typical setup it could just close the exhaust system with the vanes.

If the vanes are commanded fully closed, it would create an "exhaust brake" type situation.

How could someone trick them into closing using a switch located on the dash board?

Richard

anybody find out about this? is it programing or a pin on the ecu that must be grounded during braking while in tow/haul?

The exhaust brake function is enabled on the 2006 C4500/C5500 models only as an option. It requires special PCM programming to acheive this. Although not as efficient as a butterfly style exhaust brake it still does make a difference.

Christian Roth,

Thanks for the reply. Maybe some of the aftermarket tuners will be able to reprogram the PCM for this brake feature.

The 4500 and 5500 have a flapper type e-brake. Mine stuck closed a number of times and I had to climb under the truck to give it a wack. I did not think that the med duty had the LBZ so how would the var. geo. turbo work on those if its not there? Hated my 4500. Traded it and took a bath!

Banks has been working on this since the LBZ was announced. So far, no product has been released, I have been asking every month and the best I can get from them is maybe in February they will have it ready. We will see.

You could do it with the new DSP option from EFILive.

On edit: not for the 06LLY or LBZ but for early LLY's.

You could do it with the new DSP option from EFILive.

Really? Can you do this on mine clyde? I would love to have an exhaust brake when towing big, i could really use it! BTW doesnt the LLY still come in the 45/5500 and NOT the LBZ.

Anyone ever figure out an exhaust break for the LBZ???

I think soon enough there will be a programer
that is capable of re prgraming the pcm to rotate the turbo
vanes when youlet off the gas.
I have an Sct w/ tow tune on my powerstroke that does this.

I did not think that the med duty had the LBZ so how would the var. geo. turbo work on those if its not there?
Unless the 4500 still has the LB7, it's got the VVT.

We have one for the LBZ, give us call.

1.800.887.5030

We have one for the LBZ, give us call.

1.800.887.5030

$1300, huh?

When I was young and growing up, my dad would always tease me/pretend that his pickup was a "big truck" and would personally make the jake break sounds. If/When I have a diesel pickup it would be worth the $1300 to have him ride along and have it start going pa-pa-pa-pa for real...and the look on his face. Especially if i made the sound on my own first as he use to and hten flip it on...