Aftermarket Exhaust Brakes

[JHumphries]

I've noticed that I can't find a manufacturer that sells a butterfly valve style exhaust brake for the 6. 7.

The owners manual also warns against installing an aftermarket brake.

Why?

Also, what is the difference in braking horsepower of the turbo vanes vs. a butterfly valve vs. a constant pressure valve like the Pacbrake?

 

[HBarlow]

Back pressure and braking horsepower is created when exhaust flow is blocked. Exhaust flow and the size of the exhaust outlet is equal and retarding force is going to be the same regardless of whether it is blocked by closed vanes of the turbo or a closed butterfly valve downstream.

Why would anyone want to install a downstream exhaust brake on an ISB6. 7 engine which already has an exhaust brake function in the turbo?

 

[JHumphries]

The part I don't know is how far the vanes actually move. Do they completely block flow or is it only partial.

It would seem to me that the vanes would not have enough movement to close completely.

If that is the case then a valve would be a better brake.

 

[Bill Stockard]

Go drive one! You will immediately notice that the built in exhaust brake works better than most aftermarket brakes.



Bill

 

[EricBu12]

my 6. 7 2009 using the brake on an Auto works well and I downshift it and it woks very well. . on off-ramps, by the time I shift down to 3rd, i just need a little foot brake to stop at the light... This works as well as my old 2001 with a jacobs E-brake and a 6 speed manual

 

[BrianJ]

When the 6. 7L came out it was published that the built in (turbo) exhaust brake held more than 30% better than an exhaust brake down stream from the turbo.

 

[HBarlow]

JHumphries,

You read the testimonials from other members who own or have driven one of the new trucks posted above. Driving one will make you a believer.

I can't answer your question as to how far the turbo vanes move or what percentage of exhaust flow is blocked. Obviously it is and cannot be 100% blocked and neither can a downstream add-on brake. Both are engineered for a balance between providing exhaust braking and allowing combustion gasses and pressure to escape.

I had Jacobs exhaust brakes on my two previous Dodges from date of purchase. The '01 was a manual six speed and the '06 was a 48RE automatic. Both worked great.

However, with the combination of the six speed automatic and tow-haul mode downshifting on ECM programmed command, 4. 10 gears, and variable vane turbo charge exhaust brake, all fully integrated by the ECM, the new ISB6. 7s provide awesome braking. The heavier the load the better it works.

 

[JHumphries]

Sorry, I should update my signature

I bought a 2010 2500 SLT Crew Cab Real Bed (8 ft) 4x4 Manual with 3. 73's

I have never driven a truck with a valve style exhaust brake.

I have noticed the brake seems to be getting stronger as the engine wears in.

I've only got 491 miles on it so far.

I was just curious.

I was wondering if the Pacbrake might be better. The theory is sound. Maintaining a constant back pressure true the rpm range.

 

[jelag]

OK... I've got several trucks, 04, 04. 5, 05, & 08 5500... . all my 5. 9's have the PRXB PacBrake we've installed and sold to a lot of TDR members... my 08 has the factory brake on the 6. 7... .

I think they perform almost at the same. . the difference is that the PacBrake's on the 5. 9's work to a lower RPM level than the 6. 7... . The ECM of the 6. 7 turns off the brake or decreases the vane angle to make it less effective than the Pac's at say below 1600 rpm...

That's my thought. . and OH BTW - the 6. 7 has to be in tow/haul for the most effective use... our 5500 with Asian transmission downshifts as needed... .

I don't think you'd gain enough advantage with an inline PacBrake to make it worth the expense...

 

[JHumphries]

OK... I've got several trucks, 04, 04. 5, 05, & 08 5500... . all my 5. 9's have the PRXB PacBrake we've installed and sold to a lot of TDR members... my 08 has the factory brake on the 6. 7... .

I think they perform almost at the same. . the difference is that the PacBrake's on the 5. 9's work to a lower RPM level than the 6. 7... . The ECM of the 6. 7 turns off the brake or decreases the vane angle to make it less effective than the Pac's at say below 1600 rpm...

That's my thought. . and OH BTW - the 6. 7 has to be in tow/haul for the most effective use... our 5500 with Asian transmission downshifts as needed... .

I don't think you'd gain enough advantage with an inline PacBrake to make it worth the expense...

That is exactly the comparison I was looking for.
Thanks
BTW I don't have a Tow/Haul ModeOo.