How does the Jacobs Extarder work?
My m/h is a 1994 Allegro Bus, 5.9B 230 hp (mechanical engine) Cummins DP. It is equipped with a Jacobs Extarder. From what I understand, to stop confusion in what it's called, it is now just called a Jacobs Exhaust brake.
I don't know how it's supposed to work. When I flip the dash switch, the lever arm on it flips 90 degrees so it seems to be working. In real life, I can't see that it does anything. I have been on some 6 percent downgrades and at the top, I will activate the Extarder but it does not slow me down going downhill. If I'm going 60 when I activate it and if I don't hit my brakes, I'll be going 75 by the time I get to the bottom. I recently was in very heavy stop and go traffic for about 40 miles of flat land. When i got about 10 miles from my destination, I lost about 90% of my braking power due to overheating the brakes. I talked to a diesel guy and he asked if I was using my exhaust brake and I told him I did not have it turned on and it does nothing to help me slow down.
My question is, what am I supposed to do to get some braking from it? Am I supposed to be in a lower gear before activating it, am I supposed to be at a certain speed before activation, is is supposed to change my gears for me to drop to a lower gear (remember, this is a mechanical engine).
From the looks of it, there doesn't seem to be much to it. It closes off the exhaust via a flapper in-line on the exhaust system. If it does that, why doesn't it slow me down?
I don't know how it's supposed to work. When I flip the dash switch, the lever arm on it flips 90 degrees so it seems to be working. In real life, I can't see that it does anything. I have been on some 6 percent downgrades and at the top, I will activate the Extarder but it does not slow me down going downhill. If I'm going 60 when I activate it and if I don't hit my brakes, I'll be going 75 by the time I get to the bottom. I recently was in very heavy stop and go traffic for about 40 miles of flat land. When i got about 10 miles from my destination, I lost about 90% of my braking power due to overheating the brakes. I talked to a diesel guy and he asked if I was using my exhaust brake and I told him I did not have it turned on and it does nothing to help me slow down.
My question is, what am I supposed to do to get some braking from it? Am I supposed to be in a lower gear before activating it, am I supposed to be at a certain speed before activation, is is supposed to change my gears for me to drop to a lower gear (remember, this is a mechanical engine).
From the looks of it, there doesn't seem to be much to it. It closes off the exhaust via a flapper in-line on the exhaust system. If it does that, why doesn't it slow me down?
