The highlights of this E-brake upgrade are as follows. I have photos of the installation but Photobucket is down for maintenance so couldn't download them to this post.

1. The exhaust brake components supplied by BD Performance are fine from a quality standpoint.

2. The installation and testing documentation as it applies to a C8.3L Cummins installation leaves a lot to be desired. In the end I relied more on PAC-brakes installation instructions than on the BD Performances instructions.

3. When I ordered the exhaust brake kit it was for a 300 hp C8.3L Cummings, Holset Turbo and Allison MD 3060 transmission. What I got was a generic exhaust brake for a 4" exhaust system which required 2 custom adapters to be fabricated. This wasn't a big deal but it wasn't planned for so therefore took extra time.

4. The control switch supplied was a generic lighted bat handle SPST switch with no mounting plate or name plate. I ended up buying a lighted DPST rocker switch on Ebay that said EXHAUST BRAKE on it.

5. Specific information for interfacing the E-brake with the Allison MD3060 was for the most part left out of the instructions. Here again I relied on PAC-brakes instructions.

The jury is still out on this one but if I had to buy another E-brake I would go with a PAC-Brake. Their instructions are quite good and their tech support is excellent.


The following letter was sent to BD Performance.

Sir

I bought a BD exhaust brake kit and Cummins heavy exhaust valve springs this past August. The valve springs, exhaust brake, pressure regulator and control switch have been installed and tested by me. The MD 3060 Allison transmission has been programmed to operate the exhaust brake when it senses throttle at ZERO position and the control switch is on.

The brake operates as indicated but it's performance is mediocre at best.

I have two 100 psig pressure gauges installed, one to monitor back pressure and one to monitor pressure to the actuating cylinder. When the brake is activated at 60 MPH the cylinder shows 80 psi and the back pressure fluctuates rapidly between 50 and 57 psi. If the back pressure reaches 58 psi it appears that the supervising pressure switch opens and disables the E-brake as the back pressure will temporarily drop to about 40 psig, then recover, then drop again as the back pressure approaches 58 psig. I have tried several different pressure (60psi, 70psi, 80psi, 90psi) settings for the actuating cylinder but nothing increases the brakes performance. Do you have any idea why the E-brake performances is so poor?

Attached are photos of the BD Performance exhaust brake I installed. I had the transmission shift program cleared so it could learn to shift with the e-brake installed. I must say it does work better but still nothing to write home about. The test gauges for back pressure and actuating cylinder pressure have made it much easier to fine tune. I'll probably have to make a few adjustments when I'm loaded and towing a vehicle but for now the e-brake works OK.

What an excellent installation sir! I agree with you that BD's instructions are mediocre at best, but it is the superior brake. As I told you on the phone, Pac uses a hole in the butterfly to limit (control) pressure which is static while BD uses the air pressure regulator which offers dynamic control. Once I had the Allison folks reprogram the ECU, it was a daylight & dark difference in brake performance. Good luck with it, you have a fine product.

Billyt,

Thanks for the compliment.

Since my original post on the subject I had the Allison shifting memory cleared and did some fine tuning on the brake controls which has improved it's performance.

For reference: at idle (720 rpm) and E-brake forced closed with 76 psi on the cylinder, my exhaust back pressure fluctuates rapidly but evenly between 20 psi and 40 psi so I'm calling it 30 psi at idle. If I had put a snubber in the line it would have dampened the pressure pulsations condsiderably but I didn't have one.

With a lightly loaded coach and not towing a vehicle the back pressure was relatively constant at 52 psi down a 4% grade in 4th gear. If memory serves me correctly I was going about 45 mph. I'm certain additional tuning will be necessary when loaded and towing a rig.

In order to monitor the performance and back pressure I'm going to install two 0 to 100 psi gauges. One in the instrument panel and one down stream of the brake control solenoid valve. The major problem now is trying to fit the back pressure gauge , the boost gauge and the EGT gauge in the instrument panel.

Thanks again for your advice.

Roman